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Hermit crab biocoenoses: A worldwide review of the diversity and natural history of hermit crab associates
Abstract
The symbiotic associates of hermit crabs (excluding parasites and flora) are reviewed worldwide. The review includes species found on the shells occupied by hermit crabs (epibiotic species), species boring into these shells (endolithic species), species living within the lumen of the shell (either free-living or attached to the shell), species attached to the hermit crabs themselves, and hypersymbionts. In total over 550 invertebrates, from 16 phyla are found associated with over 180 species of hermit crabs. Among these associates, 114 appear to be obligate commensals of hermit crabs, 215 are facultative commensals, and 232 are incidental associates. The taxa exhibiting the highest number of associates are arthropods (126), polychaetes (105), and cnidarians (100). The communities of species associated with Dardanus arrosor, Paguristes eremita, Pagurus bernhardus, Pagurus cuanensis, and Pagurus longicarpus are the best studied and harbor the most diverse assemblages of species. While trends in biodiversity of hermit crab assemblages do not follow predicted patterns (e.g., hermit crabs within the Indo-West Pacific do not harbor more species than those from temperate regions), this is suggested to reflect a lack of sampling rather than a true representation of the number of associates. Hermit crabs date to at least the Cretaceous and provided a niche for a number of groups (e.g., hydractinians, bryozoans, polydorids), which were already associates of living gastropods. Apparently hermit crab shells initially supplied a substrate for settlement and then these symbiotic relationships were reinforced by enhanced feeding of symbionts through the activity of the hosts. Through their use and recycling of gastropods shells, hermit crabs are important allogenic ecosystem engineers in marine habitats from the intertidal to the deep sea. Hermit crabs benefit from some symbionts, particularly cnidarians and bryozoans, through extension of shell apertures (alleviating need to switch into new shells) and by providing protection from predators. However, hermit crabs are also negatively impacted (e.g., decreased reproductive success, increased predation) by some symbionts and a review of egg predators is provided. Thus, the symbiotic relationships between hermit crabs and many associates are difficult to characterize and often exhibit temporal changes depending on environmental and biological factors. Research on the biology of these symbionts and the costs/benefits of their associations with hermit crabs are analyzed. While some associates (e.g., Hydractinia spp.) have been studied in considerable detail, for most associations little is known in terms of the impacts of symbionts on hosts, and future experimental studies on the multitude of relationships are suggested.
... Any external pressure, such as artificial sound pollution, can compromise these fundamental tasks for the food webs integrating the marine ecosystem. In soft-bottom benthic communities, the empty shells are likely to be buried in the substrate unless they are used by hermit crabs as protection (Creed, 2000); thus, hermit crabs influence the abundance and distribution of other invertebrates by using these gastropod shells (Gutiérrez et al., 2003;Williams and McDermott, 2004). The gastropod shells inhabited by Fig 8. Box plots showing the setae density in the hermit crab medial group The boxes are delimited by the 25 th and 75 th percentiles, the median is the red line; whiskers extend to at most 1.5 times the interquartile range, the distance between the bounding percentiles (or to the furthest sample within that distance) with red + markers showing outliers beyond that range. ...
... B: Total hair cell count per test group (Kruskal-Wallis, P = 0.40).C: Percentage of extruded/missing hair cells. hermit crabs are colonized by a wide variety of other epibiont and endolithic organisms, forming marine micro-communities (Caruso et al., 2003;Turra, 2003;Williams and McDermott, 2004). Hermit crabs help prolong the presence of empty gastropod shells on the seabed, allowing them to be colonized by these small organisms (Williams and McDermott, 2004). ...
... hermit crabs are colonized by a wide variety of other epibiont and endolithic organisms, forming marine micro-communities (Caruso et al., 2003;Turra, 2003;Williams and McDermott, 2004). Hermit crabs help prolong the presence of empty gastropod shells on the seabed, allowing them to be colonized by these small organisms (Williams and McDermott, 2004). Therefore, the distribution and abundance of hermit crabs and their selection of gastropod shells influences the presence of shell microinhabitants (Jones and Gutiérrez, 2007). ...
The sea anemone Calliactis parasitica, which is found in the East Atlantic (Portugal to Senegal) and the Mediterranean Sea, forms a symbiotic relationship with the red hermit crab, Dardanus calidus, in which the anemone provides protection from predators such as the octopus while it gains mobility, and possibly food scraps, from the hermit crab. Acoustic pollution is recognised by the scientific community as a growing threat to ocean inhabitants. Recent findings on marine invertebrates showed that exposure to artificial sound had direct behavioural, physiological and ultrastructural consequences. In this study we assess the impact of artificial sound (received level 157 ± 5 dB re 1 μPa2 with peak levels up to 175 dB re 1 μPa2) on the red hermit crab and its symbiotic sea anemone. Scanning electron microscopy analyses revealed lesions in the statocyst of the red hermit crab and in the tentacle sensory epithelia of its anemone when exposed to low-intensity, low-frequency sounds. These ultrastructural changes under situations of acoustic stress in symbiotic partners belonging to different phyla is a new issue that may limit their survival capacity, and a new challenge in assessing the effects of acoustic disturbance in the oceanic ecosystem. Despite the lesions found in the red hermit crab, its righting reflex time was not as strongly affected showing only an increase in the range of righting times. Given that low-frequency sound levels in the ocean are increasing and that reliable bioacoustic data on invertebrates is very scarce, in light of the results of the present study, we argue that anthropogenic sound effects on invertebrates species may have direct consequences in the entire ecosystem.
... Cnidarians are one of the most frequent epibionts on crustaceans (Fernandez-Leborans, 2013). The symbiotic relationships of anemones with their hosts is dynamic and can exhibit temporal change, going from commensalistic or mutualistic to parasitic depending on environmental and biological factors (Williams and McDermott, 2004;Fernandez-Leborans, 2013). The anemones on the hermit crab's pleon are sessile animals on a mobile platform which are essentially hitching a ride. ...
... In his case, Probeebei mirabilis are thought to actively grasp anemones (Lemaitre, 1998). As a consequence, the anemones gain mobility and increase their distribution, but do not choose the area frequented by the hermit crab, though advantages of their interaction are presumed for both (Williams and McDermott, 2004). ...
... The closely related deep-sea hermit crab Tylaspis anomala from the same family, also no longer living in shells, was known to hold anemones for protection (Wolff, 1961;Lemaitre, 1998;Anker and Paulay, 2013). In this scenario, anemones would thus protect their mobile host from predators using their nematocysts for their defence or offering camouflage and in return benefit from leftover food or particles dropped by their hosts (Williams and McDermott, 2004). Contrastingly, the presence of an anemone epibiont could restrict growth and moulting of the organism providing attachment surface (the basibiont), in this case the hermit crab (Fernandez-Leborans, 2013). ...
The deep Peru Basin is characterised by a unique abyssal scavenging community featuring large numbers of hermit crabs (Probeebei mirabilis, Decapoda, Crustacea). These are atypical hermit crabs, not carrying a shell, but on some occasions carrying an anemone (Actiniaria). The reason why some hermit crabs carry or not carry anemones is thought to be indicative of a changed environment, outweighing the cost/benefit of their relationship. Here we present the temporal variation of abundances of P. mirabilis with and without anemones, spanning more than two decades, following a benthic impact experiment. An overall decrease in hermit crab densities was observed, most noticeable and significant after 26 years and characterised by a loss of Actiniaria on the Probeebei mirabilis' pleon. Whether this is a delayed response to the benthic impact experiment carried out 26 years’ prior or a natural variation in the population remains to be corroborated by an extension of the time-series. Attention is drawn to the limitations of our knowledge over time and space of the abyssal community dynamics and the urgent necessity to fill in these gaps prior to any type of deep-sea exploitation.
... This feature is also clear in the Recent hermitted muricid ( Figure 3E,F) as well as in the Pliocene hydractiniid-encrusted shells ( Figure 4J-L). The close relationship between cnidarians (both solitary and colonial forms) and the secondary inhabitants of the gastropod shells (essentially hermit crabs and sipunculid worms) is well-known from the extant seas and includes several cases of obligate or nearly obligate symbiosis [61] (Table 1). Among the latter, those with hydractiniids (e.g., Hydractinia echinata and Stylactaria inabai) and the ahermatypic coral Epizoanthus are the most well-known and ecologically relevant [61]. ...
... The close relationship between cnidarians (both solitary and colonial forms) and the secondary inhabitants of the gastropod shells (essentially hermit crabs and sipunculid worms) is well-known from the extant seas and includes several cases of obligate or nearly obligate symbiosis [61] (Table 1). Among the latter, those with hydractiniids (e.g., Hydractinia echinata and Stylactaria inabai) and the ahermatypic coral Epizoanthus are the most well-known and ecologically relevant [61]. ...
... The symbiosis between colonial corals and gastropods/secondary shell inhabitants is an example of facultative mutualism. The coral colony gains the capability to move on different substrates and avoid burial, plus a constant flow of seawater (and consequently of nutrients) provided by the shell movements [18,20,[30][31][32][33]61]. These benefits are especially remarkable for symbiont-bearing corals as keeping them clean from sediment particles improves the photosynthetic activity of their algal symbionts. ...
In order to investigate the serendipitous find of a gastropod encrusted by the symbiont-bearing colonial coral Oculina patagonica, we examined several specimens of cnidarian-encrusted gastropods, ranging in age from the Pliocene to the Recent, and characterized in detail their sclerobiont cover. The results of our analysis suggest that gastropod shells can be encrusted by symbiont-bearing colonial corals at various times: (1) when the gastropod is alive; (2) when the shell is being used by a secondary inhabitant (e.g., hermit crabs or sipunculid worms); (3) when the shell is discarded but yet to be buried. The relationship between the symbiont-bearing coral and the inhabitant(s) of the encrusted shell is an example of facultative mutualism, i.e., it is non-obligate yet beneficial for both ends as the former obtains the capability to move, and the latter improves the resistance and resilience of its armor, thus obtaining extra protection from predators. Being able to move could prove particularly useful for a symbiont-bearing coral because, in addition to removing the risk of being smothered by sediment, it would also favor the photosynthetic activity of its algal endosymbionts by allowing the coral to be always clean of sedimentary particles. Although the resulting epibiotic association would be limited in size by the ability of either the gastropod or the secondary inhabitant of the shell to move at the seafloor, these small and easy-to-miss benthic islands might become the seeds that allow sessile carbonate producers such as hermatypic colonial corals to colonize unconsolidated substrates.
... 492). In contrast, encrusters and borers on hermit crab-occupied shells were considered epi-and endobionts by some (e.g., Williams & McDermott, 2004;Fernandez-Leborans & Gabilondo, 2006). In Wahl's sense, epibionts and endobionts, and by extension epibiosis and endobiosis, must refer to organisms specifically located only on and in, respectively, the body of hermit crabs and not colonizing dead hardparts (i.e., the hermit crab-occupied shells). ...
... Motile fauna (e.g., grazers such as sea stars and urchins, and chitons) visiting hard substrates are considered as a case of sclerobiosis. (Williams & McDermott, 2004;Vermeij, 2020), which means they are unambiguously now part of the living biocenosis of the hermit crab. There are also colonizations of the shell prior to the occupation of the crab, including active selection of shells already colonized (crabs choosing epibiont covered shells) or that have occurred during the intermolt stage of hermit crabs (Bell, 2009;Stanski et al., 2018;Vermeij, 2020). ...
... organisms, encrusters, and borers mentioned as species associated with different substrates colonized (e.g.,Reiss et al., 2003;Williams & McDermott, 2004) or encrusting/ epibionts, nestlers, drillholes, and other bioerosional traces (e.g.,Vinn, 2017;Romero et al., 2018;Gordillo et al., 2019).Most modern studies of hard substrate colonization consider only fouling and epibiosis. Consideration of "sclerobiosis" would extend the knowledge of the associations between organisms and host and the specific richness of a study area. ...
Ancient and modern marine environments are usually characterized by colonizers associated with living and dead organisms, as well as inorganic substrates. There are different terminologies to characterize these colonizations, i.e., if the roots of the terms refer to the colonizer or the colonized substrate. The terminology stated by Paul D. Taylor and Mark A. Wilson is considered here as background to characterize marine ancient and modern assemblages on hard substrates. These authors define the term “sclerobiont”, but not “sclerobiosis”. We focus on the term “sclerobiont” and the need for a formal term, “sclerobiosis”. There is no definition of the latter, which is beginning to be used as a synonym for “epibiosis”. Here we define “sclerobiosis” as the spatial association between any kind of hard substrate and a diversity of life forms, which can occupy different spatial location of the hard substrate. With regard to colonization of marine hard substrates, “epibiosis” is included within “sclerobiosis”. The goal is to clarify in which cases the use of each term is more appropriate, according to the criteria considered in the cited definitions of the terms. When studying different aspects of the colonization of living, dead and inorganic hard substrates, and even when we want to establish comparisons of colonizations over time and space, it is useful to have a term that encompasses all these associations between substrates and colonizers. “Sclerobiosis” is proposed to aid a uniform language among deep-time and modern ecology researchers, especially those working on both settings.
La colonización de organismos vivos y muertos, así como también de sustratos inorgánicos, es un proceso común en ambientes marinos fósiles y actuales. Existen diferentes terminologías para caracterizar estas colonizaciones, esto es, si las raíces de los términos se refieren al colonizador o al sustrato colonizado. En este trabajo se considera la terminología de Paul D. Taylor y Mark A. Wilson para caracterizar los ensambles marinos fósiles y actuales sobre sustratos duros. Estos autores definen el término “esclerobionte”, pero no “esclerobiosis”. Por ello, nos centramos en el término “esclerobionte” y en la necesidad de un término formal, “esclerobiosis”. No existe una definición original para este último, el cual se está comenzando a utilizar como sinónimo de “epibiosis”. “Esclerobiosis” es la asociación espacial entre cualquier tipo de sustrato duro y una diversidad de formas de vida que puede ocupar diferentes ubicaciones espaciales del sustrato. Considerando la colonización de sustratos duros marinos, “epibiosis” queda incluida dentro de “esclerobiosis”. El objetivo es aclarar en qué casos el uso de cada término es más apropiado de acuerdo con los criterios considerados en las definiciones citadas. A la hora de estudiar diferentes aspectos de la colonización de sustratos duros vivos, muertos e inorgánicos, e incluso cuando queremos establecer comparaciones de colonizaciones en el tiempo y el espacio, es útil contar con un término que englobe todas estas asociaciones entre sustratos y colonizadores. Se propone el uso de “esclerobiosis” para promover un lenguaje uniforme entre los investigadores de la ecología moderna y de la paleoecología, especialmente aquellos que trabajan en ambas disciplinas.
... Although there have been several outstanding reviews of specific taxa and comprehensive reviews of the parasites within specific host taxa, until now there have been no systematic reviews attempting to cover the diverse range of parasites in the entire host subphylum. Notable reviews include systematic treatment of the parasites of cladocerans (Green 1974), copepods (Ho and Perkins 1985), euphausiids (Gómez-Gutiérrez and Morales-Ávila 2016), amphipods (Bojko and Ovcharenko 2019), and specific decapods, such as freshwater crayfish (Edgerton et al. 2002;Longshaw 2016), brachyuran crabs (Shields and Overstreet 2007;Shields et al. 2015), anomuran hermit crabs (Williams and McDermott 2004;McDermott et al. 2010) and lobsters (Shields et al. 2006;Shields 2012). Several earlier reviews coalesced the literature and offered seminal insights into many of the parasites and pathogens of crustaceans (Couch 1983;Johnson 1983, Overstreet 1983. ...
... Turbellarian worms include free-living, symbiotic, and parasitic taxa. The best-known examples from crustaceans are symbionts of hermit crabs (Williams and McDermott 2004;McDermott et al. 2010) and freshwater crayfish (Edgerton et al. 2002). For example, Temnocephalidae is a family of highly modified symbionts with a specialised relationship with crayfish. ...
... Annelida is a large clade (ca. 22,000 species) of mainly free-living, segmented, coelomate worms They are not common symbionts on crustaceans, albeit there are several well-known symbiotic relationships, particularly with polychaetes commensal on hermit crabs (see Williams and McDermott 2004) and branchiobdellids on crayfishes (Gelder 2010). The paucity of relationships may be a result of predation pressure as many decapods can preen themselves, thus feeding on potential symbionts (Shields et al. 2015). ...
As with all animals, crustaceans serve as hosts to a very diverse taxa of parasites. These parasites range from unusual dinoflagellates that parasitise the hemocoels or eggs of their hosts, to classical helminths that use crustaceans as intermediate hosts, and to the bizarrely adapted tantulocarid and rhizocephalan crustaceans with their highly derived life styles. Here, I review the major parasitic taxa that use Crustacea as hosts. The parasites of decapods, particularly those in shrimps, crabs, and lobsters are the best known, primarily because of their impact on populations of their commercially important hosts. Several of these parasites are outright pathogens that cause widespread mortality, feminisation, and stunting in their host populations. Other parasites, particularly those in copepods, cladocerans, and amphipods have also received attention because of the ecological importance of these hosts in food webs. They have received notable studies on vertical transmission, the influence of cryptic species complexes (both host and parasite), as well as the emergence of new pathogens in these hosts. A few parasites are also known from brine shrimp (Anostraca) and barnacles (Cirripedia) which have served as laboratory or ecological models, respectively, but few of these parasites have received much study other than their initial taxonomic descriptions and systematic placement. Although molecular tools have revealed the systematics of many of the parasitic taxa, their biology and ecology remain poorly known.
... The symbiotic association between hermit crabs and sea anemones is an example of mutualism. At least 35 symbiotic sea anemone species belonging to 14 genera have been found on the chelipeds of hermit crabs or the shells they inhabit (Williams and McDermott, 2004;Antoniadou et al., 2013). Carcinoecium-forming mutualism is a remarkable relationship between the sea anemones (i.e., genera Calliactis Verrill, 1869, Paracalliactis Carlgren, 1928, andStylobates Dall, 1903) and hermit crabs living on the deep-sea floor (Daly et al., 2004;Gusmão, 2010;Crowther et al., 2011;Gusmão et al., 2020). ...
... Hermit crabs are critical physical ecosystem engineers in various marine habitats. At least 550 invertebrate species from 16 phyla, from the intertidal/littoral zone to the deep sea, are associated with the shells inhabited by hermit crabs (Jones et al., 1994(Jones et al., , 1997Williams and McDermott, 2004). Of these, some communal associations of Polynoidae are thought to affect the host's survival because the species inside the shell are known to steal food from the hermit crab's mouth and feed on crab eggs soon after extrusion (Brightwell, 1951;Williams and McDermott, 2004). ...
... At least 550 invertebrate species from 16 phyla, from the intertidal/littoral zone to the deep sea, are associated with the shells inhabited by hermit crabs (Jones et al., 1994(Jones et al., , 1997Williams and McDermott, 2004). Of these, some communal associations of Polynoidae are thought to affect the host's survival because the species inside the shell are known to steal food from the hermit crab's mouth and feed on crab eggs soon after extrusion (Brightwell, 1951;Williams and McDermott, 2004). A communalistic scale-worm species, Eunoe issunboushi Jimi, Hookabe, Moritaki, Kimura & Imura, 2021, was recently reported from inside the carcinoecium of S. calcifer sp. ...
Here we describe Stylobates calcifer sp. nov. (Cnidaria, Actiniaria, Actiniidae), a new carcinoecium-forming sea anemone from the deep-sea floor of Japan. Stylobates produces a carcinoecium that thinly covers the snail shells inhabited by host hermit crabs Pagurodofleinia doederleini. The new species is distinct from other species by the shape of the marginal sphincter muscle, the distribution of cnidae, the direction of the oral disk, and host association. The species’ novelty is supported by the data of its mitochondrial genes 12S, 16S, and COIII and nuclear genes 18S and 28S. Also, we conducted behavioral observation of this new species, focusing on the feeding behavior and interaction with the specific host hermit crab. Our observations suggest that this sea anemone potentially feeds on the suspended particulate organic matter from the water column or the food residuals of hermit crabs. When the host’s shell changed, intensive manipulation for transference of S. calcifer sp. nov. was recorded. However, although the hermit crab detached and transferred the sea anemone to the new shell after shell change, the sea anemone did not exhibit active or cooperative participation. Our data suggest that the sea anemone may not produce a carcinoecium synchronously to its host’s growth, contrary to the anecdotal assumption about carcinoecium-forming sea anemones. Conversely, the host hermit crab’s growth may not depend entirely on the carcinoecium produced by the sea anemone. This study is perhaps the first observation of the behavioral interaction of the rarely studied carcinoecium-forming mutualism in the deep sea.
... Epibiosis is a common phenomenon in aquatic systems, especially in marine environments where wave turbulence has caused many mobile and sessile organisms to evolve a system of settlement and attachment to hard, relatively stable surfaces provided by other organisms [8][9][10]. The calcified body surface of decapod crustaceans is known to be a suitable substrate for many species of marine animals and plants [8,[11][12][13]. Investigations have focused on studying the nature of epibiosis. ...
... This is important because they can contribute to basic knowledge on important aspects of the hosts' biology including molting and growth patterns, behavior, and migration activity [14]. In many cases, studies on the flora and fauna associated with living marine invertebrates can provide new information on the biology of epibionts and symbionts, and can clarify biodiversity data in the region [11]. Long-term studies of the advantages and disadvantages for hosts and epibionts, together with examinations of the hosts' health, can help to evaluate or re-evaluate the nature of the relationships between the epibionts and their hosts [15][16][17][18]. ...
... Most likely, this pattern reflects the size differences observed among the crab species: the smallest CW is registered for great spider crabs and the largest size for red king crabs [52]. Smaller hosts have less surface area for settling, and a positive association between body size and infestation indices was reported for many decapodcrustacean-epibiotic associations across the world's oceans [8,11,[53][54][55][56]. ...
Crabs are important ecosystem engineers in marine habitats worldwide. Based on long-term data, we analyzed the species composition and infestation indices of epibionts and symbionts colonizing the great spider crab, Hyas araneus, and two lithodid crabs—the northern stone crab, Lithodes maja, and the red king crab, Paralithodes camtschaticus—in the coastal zone of the Barents Sea. The epibiotic communities found on great spider crabs were closer to northern stone crabs (33%) compared to red king crabs (25%). The prevalence of mobile symbionts (amphipods, Ischyrocerus, and polychaetes, Harmothoe) and common epibionts, such as barnacles and hydrozoans, was low on great spider crabs and high on the body and in the gills of lithodid crabs. Epiphytes were abundant on great spider crabs but not present on both species of lithodid crabs. Egg symbionts found on H. araneus and P. camtschaticus do not affect their local populations. Differences in the fouling communities found on the three crab species are associated with host size range, surface properties of their carapaces, and behavior patterns.
... For marine symbiotic fish and invertebrates, hosts are vital resources providing protection from predators, competition and environmental stress, food, and mating and larvae hatching spaces. Therefore, the necessity of preserving such a resource predicts widespread territoriality among symbionts in the marine environment [16][17][18][19][20] . ...
... In symbiotic marine invertebrates, host bodies or structures associated with them (e.g., shells, tubes, burrows) are often the territory being defended 16,18,21 . Defending small, simple and sparsely distributed hosts requires less investment of time and energy 5,22 , while the energetics of defending complex and densely distributed hosts becomes too high, forcing symbionts to share hosts with conspecifics 23,24 . ...
... Characteristics of the association. We collected 84 hosts (22 in Mun Island,23 in Mot Island, 19 in Point Nam and 20 Dam Bay) and 53 symbionts (10 in Mun Island, 16 in Mot Island, 12 in Point Nam and 15 Dam Bay). The overall prevalence was 63.1% and the intensity of one symbiont per host. ...
Among marine invertebrates, polychaete worms form symbiotic associations showing a wide variety of host use patterns. Most commonly, they live solitary on hosts, likely resulting from territorial behavior, yet little is known of the precise nature of the involved interactions. Based on field and laboratory observations, we described the symbiotic association between Ophthalmonoe pettibonae and Chaetopterus cf. appendiculatus from Nhatrang Bay (Vietnam). Then, by experimentally manipulating the competitor-to-resource ratio, we analyzed symbiont behavior and we assessed whether the 1:1 uniform distribution observed in nature could be driven by agonistic territorial behavior. Hosts and symbiont populations had low densities, lacked size relationships and showed higher prevalence when denser. Symbiont behavior included territoriality, expressed through conspecific recognition and intraspecific aggressive interactions (pursuit and escaping, hiding, choosing position, aggressive fighting, and targeting a specific bite zone). Our experiments proved that territoriality led to host monopolization by a single symbiont, provided the first empirical evidence that symbiont body injuries were caused during territorial contests, and allowed us to first suggest that a marine symbiotic invertebrate may control a territory extending beyond its host, even including neighboring hosts. Overall, this is the first report of such a complex symbiotic behavior for an annelid polychaete.
... Ectosymbiosis is commonly observed in extant marine ecosystems, as well as documented in past ecosystems (Williams and McDermott, 2004). Among biotic substrates a clade of echinoids, the Cidaroida, appears to be especially suitable for ectosymbiosis. ...
... Unlike to the cidaroids, rocks can sink into and become covered with mud, while cidaroid spines offer a permanent position in the water column. Similar prevention from burial has been shown to be one of the major benefits of symbionts of hermit crabs (Williams & McDermott 2004). ...
Access and competition for hard substrate is a critical factor in the distribution and diversity of organisms, especially in deep-water benthic environments. In this context, we present a unique association of grypheid oysters Neopycnodonte navicularis Brocchi 1814 settling on the spines of echinoid Stylocidaris polyacantha (Reuss, 1860), from Middle Miocene (Badenian) mudstones of Šentilj in northeastern Slovenia. The sediments are interpreted as having been deposited in a rather calm environment of a muddy deep lagoon (> 30 m) behind a protecting coral reef.
... The latter, which seldom have a free-living life stage and are challenging to collect using conventional methods, can benefit greatly from epibiosis research [9,10]. Moreover, analyzing fouling communities can yield valuable insights into the impact of epibionts on host populations [11][12][13][14]. Symbiotic and epibiotic interactions of the red king crab in its new habitat were studied at deep sites [15][16][17] and shallow-water locations [9,10,18,19]. ...
... In the Barents Sea, the species has also been found on spider crabs (Oregonidae [27]) and northern stone crabs (Lithodes maja [19]). In other regions, barnacles in the genus Balanus are registered in fouling communities of hermit crabs (Paguroidea [12]), cancrid crabs (Cancer spp., [28]), snow crabs (Chionoecetes opilio; [29]), and shrimps (Caridea [30]). The amphipod I. commensalis is a well-known symbiont of P. camtschaticus both in the Barents Sea [16,19,23] and in its native areas, e.g., in Alaska and near Sakhalin Island [31,32]. ...
Simple Summary
Information on epibionts and symbionts of the introduced Barents Sea red king crab during the winter period is currently lacking. To address this gap, we examined the species composition and infestation indices of epibionts on this host in the northern part of Kola Bay in November. Our findings indicate a higher infestation rate of barnacles and amphipods during the winter season compared to the summer. In contrast, infestation rates of other species remained low during winter, reflecting seasonal fluctuations in both the size distribution of red king crabs and prevailing temperature conditions. Our research provides novel data on the growth patterns of commonly associated organisms, which could prove invaluable in determining the age of red king crabs in the Barents Sea.
Abstract
The species composition of epibiotic communities on red king crab was investigated in Sayda Bay, Russia, during November of 2015 and 2016. The community consisted of 12 species in total. Among epibionts, the barnacle Balanus crenatus was most prevalent (67.0%), while the amphipod Ischyrocerus commensalis was the most frequent symbiont (77.3%). Infestation levels in May–June 2005 and September 2004 were higher, as a larger proportion of small crabs without fouling species were present during those seasons. The lower infestation intensities recorded for other common associated organisms during winter can be attributed to their increased mortality due to unfavorable temperature conditions. The localization of epibionts and symbionts were related to larval settlement patterns of attached species and feeding behavior of mobile species. Monthly growth increments for I. commensalis and B. crenatus were estimated at 2 mm in body length and 1.35 mm in basal diameter, respectively. Size-at-age data for epibionts can aid in the age determination of large male crabs that may skip an annual molt.
... Differences in the taxonomical composition and abundance of taxa (i.e., infidelity between living assemblages (LA) and their counterpart death assemblages (DA)) can be related to the changes in environmental conditions (Kidwell, 2007;Kowalewski et al., 1994;Tomašových and Kidwell, 2017), or as the result of biological influence such as the classical case of transport out to habitat and biological-induced concentrations of gastropod shells used by hermit crabs (Walker, 1989). Moreover, gastropod shells occupied by hermit crabs are usually inhabited by particular groups of epibionts and endobiont organisms (Williams and McDermott, 2004), which have been described in the fossil record (Buttler et al., 2022;Buttler and Taylor, 2019;Casadio et al., 2007;Klicpera et al., 2013;Taylor, 1994;Taylor et al., 1989;Walker, 1992). ...
... Pennatichnus, such as their preferential occurrence on shells of Olivanciallaria urceus, could also be a hermit crab's influence. Studies demonstrating a close relationship between hermit crabs and epibionts, highlighting their association with bryozoans, are not news (Buttler and Taylor, 2019;Casadio et al., 2007;Taylor, 1994;Walker, 1992;Williams and McDermott, 2004). Moreover, researchers working directly with hermit Table 2 List of taxa encrusted by epibionts and the abundance of epibionts for each shell zone (see Fig. 2). ...
... Among the diversity of reef mesograzers, hermit crabs have received little attention. It is thought that some species may contribute to ecosystem functioning through grazing (Pearson et al., 2018) or through the use of mollusc shells that would otherwise have been buried by sediments, promoting shell turnover (Gutiérrez et al., 2003), which in turn can sustain a new community of epibiotic and endolithic species (Williams & McDermott, 2004). ...
... Many brachyuran crabs have generally been recognised as ecosystem engineers due to their capacity to modify habitats (Bertness, 1985;Stachowicz & Hay, 1999;Munday et al., 2004;Cannicci et al., 2008;Glynn & Enochs, 2011). Historically the role of hermit crabs (Anomura) in ecosystem engineering has been mostly attributed to their ability to recycle gastropod shells (Williams & McDermott, 2004), but there are studies that highlight the potential of hermit crabs to actively graze on epilithic algae (Benvenuto et al., 2003;Tran, 2014), which can aid in the regulation of particular algal communities (Ruesink, 2000;Altman-Kurosaki et al. 2018) or even in maintaining coral reef health (Pearson et al., 2018). Reef-dwelling hermit crabs can reduce the amount of algae growing on corals (Coen, 1988) and are able to feed on them when many other herbivorous species are not due to the toxic compounds that some algal species possess that affect most fauna (Hay & Fenical, 1988), but not some species of brachyuran crab (Stachowicz & Hay, 1999). ...
Following an incidental observation of captive Clibanarius corallinus (H. Milne Edwards, 1848) supposedly removing algae from each other's shells, we conducted a feeding experiment over 72 hours to understand its potential role as a mesograzer in coral reef ecosystems. Epiphyte-covered, coral rubble fragments of Acropora spp. were exposed to hermit crab (N = 41) activity for 72 h in a flow-through seawater aquarium system at Heron Island, southern Great Barrier Reef, Australia to understand whether hermit crabs could remove epilithic algae and if so, to what extent. Coral fragments exposed to the hermit crabs had 9.1% less chlorophyll at the end of the experiment. The detritus generated in the experimental setup had 2.4 times more chlorophyll and 33.4% less organic biomass than the detritus generated in the control environment. The crabs did on average lose 0.11 g of their initial weight, which could have been a consequence of the experimental setup. These results suggest that C. corallinus has the potential to contribute to the control of epilithic algae in coral reefs, with such effect having hitherto been overlooked as a result of the cryptic behaviour of this hermit crab species.
... Differences in the taxonomical composition and abundance of taxa (i.e., infidelity between living assemblages (LA) and their counterpart death assemblages (DA)) can be related to the changes in environmental conditions (Kidwell, 2007;Kowalewski et al., 1994;Tomašových and Kidwell, 2017), or as the result of biological influence such as the classical case of transport out to habitat and biological-induced concentrations of gastropod shells used by hermit crabs (Walker, 1989). Moreover, gastropod shells occupied by hermit crabs are usually inhabited by particular groups of epibionts and endobiont organisms (Williams and McDermott, 2004), which have been described in the fossil record (Buttler et al., 2022;Buttler and Taylor, 2019;Casadio et al., 2007;Klicpera et al., 2013;Taylor, 1994;Taylor et al., 1989;Walker, 1992). ...
... Pennatichnus, such as their preferential occurrence on shells of Olivanciallaria urceus, could also be a hermit crab's influence. Studies demonstrating a close relationship between hermit crabs and epibionts, highlighting their association with bryozoans, are not news (Buttler and Taylor, 2019;Casadio et al., 2007;Taylor, 1994;Walker, 1992;Williams and McDermott, 2004). Moreover, researchers working directly with hermit Table 2 List of taxa encrusted by epibionts and the abundance of epibionts for each shell zone (see Fig. 2). ...
... Symbiosis is generally defined as a close biological association between at least two different taxa for long periods (Dimijian, 2000). Symbiotic associations between animals are commonly found in all marine environments from shallow coral reefs to the deep-sea (Morton, 1988;Martin & Britayev, 1998;Buhl-Mortensen & Mortensen, 2004;Williams & McDermott, 2004;Anker et al., 2005;Stella et al., 2011) and play important roles in the structure and dynamics of marine communities (Williams & McDermott, 2004, Stella et al., 2011. Symbiosis can be found both in terrestrial and marine environments, and understanding the extent to which this relationship can be maintained and how it relates to the diversification of associated organisms is one of the key issues in ecology and evolutionary biology. ...
... Symbiosis is generally defined as a close biological association between at least two different taxa for long periods (Dimijian, 2000). Symbiotic associations between animals are commonly found in all marine environments from shallow coral reefs to the deep-sea (Morton, 1988;Martin & Britayev, 1998;Buhl-Mortensen & Mortensen, 2004;Williams & McDermott, 2004;Anker et al., 2005;Stella et al., 2011) and play important roles in the structure and dynamics of marine communities (Williams & McDermott, 2004, Stella et al., 2011. Symbiosis can be found both in terrestrial and marine environments, and understanding the extent to which this relationship can be maintained and how it relates to the diversification of associated organisms is one of the key issues in ecology and evolutionary biology. ...
Symbioses play important roles in forming the structural and distributional patterns of marine diversity. Understanding how interspecies interactions through symbioses contribute to biodiversity is an essential topic. Host switching has been considered as one of the main drivers of diversification in symbiotic systems. However, its process and patterns remain poorly investigated in the marine realms. Hexacoral species of the order Zoantharia (=zoantharians) are often epizoic on other marine invertebrates and generally use specific taxa as hosts. The present study investigates the patterns of host switching and the diversification history of zoantharians based on the most comprehensive molecular phylogenetic analyses to date, using sequences from three mitochondrial and three nuclear markers from representatives of 27 of 29 genera. Our results indicate that symbiotic zoantharians, in particular those within suborder Macrocnemina, diversified through repeated host switching. In addition, colonization of new host taxa appears to have driven morphological and ecological specialization in zoantharians. These findings have important implications for understanding the role of symbioses in the morphological and ecological evolution of marine invertebrates.
... The coexistence of marine animals with hard shells and their epibionts including both plants and animals and both sessile and mobile organisms is a very common phenomenon in the World Ocean [2][3][4]. Although the presence of symbiotic flora and fauna on crustaceans has long been known [5], it is only recently that a new perspective has been brought to their research [1,6] because epibiotic relationships can provide new insights into the biodiversity and conservation of marine provinces and eco-regions [7,8] as well as into biological aspects of species which form close symbiotic associations with their hosts and cannot be sampled by standard methods [5,[9][10][11][12][13][14][15][16][17]. ...
... The coexistence of marine animals with hard shells and their epibionts including both plants and animals and both sessile and mobile organisms is a very common phenomenon in the World Ocean [2][3][4]. Although the presence of symbiotic flora and fauna on crustaceans has long been known [5], it is only recently that a new perspective has been brought to their research [1,6] because epibiotic relationships can provide new insights into the biodiversity and conservation of marine provinces and eco-regions [7,8] as well as into biological aspects of species which form close symbiotic associations with their hosts and cannot be sampled by standard methods [5,[9][10][11][12][13][14][15][16][17]. ...
Coryne hincksi Bonnevie, 1898 (Cnidaria, Hydrozoa) is a rare corynid hydrozoan that was first found in the coastal Barents Sea on the surface of other hydrozoan species and on the body of spider crabs in 1913. After the introduction of red king crabs into the Barents Sea in the 1960s and their range expansion and population growth, colonies of C. hincksi were registered on this host as well. In this paper, we update a list of C. hincksi records on red king crabs and present a detailed description. Also, for the first time, we provide quality photographs of a living colony of this species. Despite relatively low prevalence rates (1.4–3.2% in certain years), currently in the Barents Sea, C. hincksi occurs on crustaceans thus exhibiting a predominantly symbiotic lifestyle.
... The diverse symbiotic, competitive, and predator-prey interactions of sea anemones certainly rely on venoms [11], although precise correspondence between venoms, ecology, and physiology has yet to be demonstrated (but see [12]). Among the most compelling of the interactions in which venoms play a key role are mutualisms: sea anemones partner with photosynthetic and chemosynthetic microbes (e.g., [13,14]), other marine invertebrates (crustaceans, sponges, gastropods: [15][16][17][18][19]) as well as vertebrates, including clownfish [20]. ...
... Hemorrhagic toxins similar to zinc metalloproteinase/disintegrins were recovered in all species. Peptide isomerase heavy chain transcripts were recovered across all species and heavily expressed in C. adhaesivum (17) and E. quadricolor (15). ...
Sea anemones are predatory marine invertebrates and have diverse venom arsenals. Venom is integral to their biology, and is used in competition, defense, and feeding. Three lineages of sea anemones are known to have independently evolved symbiotic relationships with clownfish, however the evolutionary impact of this relationship on the venom composition of the host is still unknown. Here, we investigate the potential of this symbiotic relationship to shape the venom profiles of the sea anemones that host clownfish. We use transcriptomic data to identify differences and similarities in venom profiles of six sea anemone species, representing the three known clades of clownfish-hosting sea anemones. We recovered 1121 transcripts matching verified toxins across all species, and show that hemolytic and hemorrhagic toxins are consistently the most dominant and diverse toxins across all species examined. These results are consistent with the known biology of sea anemones, provide foundational data on venom diversity of these species, and allow for a review of existing hierarchical structures in venomic studies.
... The spiral zooids may also prey on the zoeae released through the aperture from the females. Williams and McDermott (2004) believed that Hydractinia might deter some predators (e.g., Octopus and other crabs), and can also influence the outcome of the competition between other hermit crabs for shells. ...
... Hermit crabs are decapod crustaceans, most of which have a noncalcified soft weak abdomen that requires protection from predation (Dollfus, 1906;Williams and McDermott, 2004). The fossil record of hermit crabs extends back to the Jurassic; however, finding of hermit crabs preserved in situ within their shelters is not common. ...
The Upper Eocene rocks (Qasr El-Sagha Formation) at northwestern Qarun Lake, in Fayum depression, revealed numerous abraded and bio-eroded Kerunia cornuta specimens, with calcified hydractinian encrustation. The symbiotic relationship between the encrusted genus Hydractinia and the host gastropod shell is discussed through thin section examination. A report of in situ hermit crab in the host gastropod shell in Kerunia cornuta is documented here for the first time from the Eocene rocks of Egypt. The studied bioerosion structures in Kerunia are attributed to three ichnospecies: Gastrochaenolites lapidicus Kelly and Bromley1984; Gastrochaenolites torpedo Kelly and Bromley1984 and Gastrochaenolites isp. These ichnospecies are related to Trypanites ichnofacies in an offshore environment under storm wave base. The taphonomic processes that affected the Kerunia cornuta specimens are also discussed in this work. The present study indicates that the paleoenvironment prevailed during the deposition of the Kerunia cornuta specimens reflects shallow agitated and bioturbated environments.
... Among them, many members belonging to the Polydora complex have symbiotic associations with other marine benthic invertebrates (Martin & Britayev 1998. The species of the genus Polydora have a broad range of hosts including mollusks, barnacles, shells of hermit crabs, corals, sponges, bryozoans, brachiopods, echinoderms (only fossil record), and coralline algae (Martin & Britayev 1998Williams & McDermott 2004;Wisshak & Neumann 2006;Rodrigues et al. 2008;Abe et al. 2019). One remarkable feature is their ability to bore into various hard calcareous substrates (Blake & Evans 1973). ...
... Shell borers in mollusk aquaculture are often harmful because a heavy Polydora infestation can negatively affect the host mollusk (Sato-Okoshi 1999;Simon & Sato-Okoshi 2015). Although most borers are opportunistically associated with various host species (facultative associates), others are specialists or even obligate symbionts of a particular host or a group of similar host species (e.g., Williams & McDermott 2004;Radashevsky 2012;Martin & Britayev 2018). Recently, a new obligate symbiotic association between a nonboring Polydora species and a lingulid brachiopod was discovered (Abe & Sato-Okoshi 2020). ...
Polydora tunicola Abe, Hoshino & Yamada, sp. nov., a new spionid species currently considered an obligate symbiont of styelid ascidians, is described based on materials collected from Polycarpa cf. cryptocarpa kroboja (Oka, 1906) and Cnemidocarpa sp. in Izu-Oshima Island and Polycarpa sp. in Wakayama Prefecture, Japan. Polychaete–ascidian symbiotic relationships are known only in two syllid species: Myrianida pinnigera (Montagu, 1808) and Proceraea exoryxae Martin, Nygren & Cruz-Rivera, 2017. The latter has been the only polychaete known to bore into the tunic of an ascidian. Polydora tunicola sp. nov. is the second known example of a tunic-boring polychaete, which constructs U-shaped burrows in the tunic of the host ascidians. Worms were often concentrated near the host siphons and assumed to use water currents created by the filter-feeding host for suspension feeding. Although the boring mechanism into ascidian tunica is unknown, the plate assay and zymography results consistently detected cellulase activities, suggesting that cellulose digestion may enable the worms to bore into the cellulose-rich ascidian tunics. Polydora tunicola sp. nov. is morphologically similar to P. aura Sato-Okoshi, 1998, P. cornuta Bosc, 1802, P. fusca Radashevsky & Hsieh, 2000, P. glycymerica Radashevsky, 1993, P. latispinosa Blake & Kudenov, 1978, P. lingulicola Abe & Sato-Okoshi, 2020, P. nanomon Orensky & Williams, 2009, P. robi Williams, 2000, and P. vulgaris Mohammad, 1972 in having a single median antenna on the caruncle and chaetiger 5 without dorsal superior capillaries but with ventral capillaries. The new species is unique in having a black-rimmed pygidium, distinguishing it from these species. The phylogenetic analyses of the concatenated 18S, 28S, and 16S sequences recovered P. tunicola sp. nov. as the sister species to P. aura within a well-supported clade also including P. lingulicola and P. cf. glycymerica. The bright yellow body color of P. tunicola sp. nov. in life is similar to that of P. aura, however, these two species are distinguished by the former not having modified posterior notochaetae. The symbiotic nature of the association between P. tunicola sp. nov. and styelid ascidians is discussed.
... Hermit crabs occupy an important position in the food web of coastal ecosystems, not only as food for other animals such as fish, but also as scavengers that feed on the carcasses of animals and plants [7]. In addition, hermit crabs function as ecosystem engineers, providing a habitat for other organisms by re-using gastropod shells, which are usually buried on the sea floor [8]. Therefore, a decrease in the diversity and biomass of hermit crabs could have a significant impact on coastal ecosystems. up in June 2014; tyres were partially buried into the seabed (mainly pebbles, sand and mud, with small stones and shells) to a depth approximately one-quarter of their width. ...
... The negative impact of tyres on hermit crabs was unexpected, and the effects of ghost fishing on their populations, and cascading effects these may have on coastal communities and ecosystems, are unknown. Because hermit crabs are important as both prey and scavengers [7,19] and ecosystem engineers [8], the extent of the ghost fishing effect that tyres may have on them and other benthos warrants further study. royalsocietypublishing.org/journal/rsos R. Soc. ...
Poorly managed waste tyres pose serious environmental and health risks, ranging from air pollution caused by fire, leaching of heavy metals and outbreaks of mosquitos, to destruction of vegetation and coral reefs. We report a previously unrecognized ecological risk to marine organisms from waste tyres. Over 1 year, we made monthly counts of hermit crabs ( n = 1278) invading and/or being trapped within six tyres anchored to the seabed at 8 m depth in Mutsu Bay, Japan. A complementary aquarium experiment in which hermit crabs were released into a tyre confirmed that they could not escape. We report marine-dumped waste tyres to ghost fish in a manner analogous to discarded fishing gear. Because hermit crabs play important roles in coastal food webs as both prey and scavengers, declines in their numbers as a consequence of this ghost fishing might affect coastal ecosystems.
... While consequences of colonization by S. droebachiensis, O. sarsii and C. frondosa for P. camtschaticus are unknown, it seems unlikely to provide disadvantages due to the small sizes of these epibionts and their localization on the abdomen and carapace. Usually, small epibiotic species may pose a threat to their crustacean hosts if they live in the gills or on hosts' broods causing a decrease of hosts' gill efficiency and an increase in egg mortality and a further decrease of population density of the hosts [12,[48][49][50]. ...
... On the other hand, it may be expected that the presence of A. rubens could have negative effects for P. camtschaticus owing to the increased weight, reduced mobility, and restriction of the functions of several organs such as eyes and appendages. For example, the barnacle Amphibalanus amphitrite (Darwin, 1854) adds weight to gastropod shells and causes their rejection by hermit crabs in Tampa Bay, Florida [50]. Other epibionts such as bryozoans and tunicates add significant weight to hermit crabs from Australia and the USA [51,52]. ...
During diving surveys for a Russian research project that monitored introduced species, red king crabs (Paralithodes camtschaticus) were collected at a coastal site of the Barents Sea to study the structure and dynamics of this species. Sampling of the organisms colonizing the crabs was part of this research project. For the first time, the presence of relatively large specimens of the common starfish Asterias rubens as epibionts of P. camtschaticus was observed in July 2010, 2018, and 2019. In 2010 and 2019, we also found three other echinoderm species (the Atlantic sea cucumber Cucumaria frondosa, the green sea urchin Strongylocentrotus droebachiensis, and the brittle star Ophiura sarsii). These findings add to the current list of associated species on king crabs not only in the Barents Sea but also in native areas of this host. Red king crabs have been documented as predators for these echinoderm species, and our records show additional possible interactions between king crabs and echinoderms in this region. More likely, the epibiotic lifestyle allows these echinoderms to avoid predation from red king crabs. There are no potential disadvantages derived by red king crabs through their relationships with the echinoderm epibionts due to low occurrences of these associations. We suggest no negative effects for the local red king crab population and populations of other commercial species in the Barents Sea.
... Hermit crabs are decapod crustaceans (Superfamily Paguroidea) most of which have noncalcified abdomen and for their protection typically use gastropod shells (Williams and McDermott 2004). This behaviour allows the hermit crabs to occupy a range of different marine environments and is one of the principal factors determining the evolutionary success of the paguroids (McLaughlin 1983;Williams and McDermott 2004). ...
... Hermit crabs are decapod crustaceans (Superfamily Paguroidea) most of which have noncalcified abdomen and for their protection typically use gastropod shells (Williams and McDermott 2004). This behaviour allows the hermit crabs to occupy a range of different marine environments and is one of the principal factors determining the evolutionary success of the paguroids (McLaughlin 1983;Williams and McDermott 2004). Hermit crabs play an extremely important ecological role, as both scavenging omnivores that contribute to the decomposition of organic matter, and a source of prey for many marine species, including seabirds and commercially-important fishes (Fransozo et al. 2008;Laidre and Greggor 2015). ...
The present study investigated the structure of the crab Clibanarius symmetricus (Randall, 1840) population found in a biogenic reef formed by the polychaete Sabellaria wilsoni Lana & Gruet, 1989 on the Amazonian coast. The population was sampled over a one-year cycle on a reef located in the mesolittoral zone of a sandy beach. The mean and maximum size of the crabs collected on the reef were smaller than those recorded in other tropical and subtropical coastal habitats, given that most of the specimens collected were immature (undetermined sex juveniles and sexually immature adults). Thaisella coronata (Lamarck, 1816) was the gastropod species whose shells were most occupied by the hermit crabs (70% of the specimens), although the smallest juveniles have used more the shells of other species. The results of the study suggest that C. symmetricus uses the reef as a nursery habitat, with bimonthly peaks in density that reflect recruitment periods. The sexually mature adults appear to use the reef only as a foraging area and, occasionally, as a refuge. The results demonstrated the importance these reefs on the population biology of this species and supports the need for more detailed monitoring studies and conservation actions for these habitats.
... Hermit crabs are decapod crustaceans with a soft, noncalcified abdomen. Thus, they usually protect themselves from predators by occupying empty gastropod shells (Williams and McDermott 2004). Although most species of hermit crabs are opportunistic with regard to the gastropod shells they inhabit, crabs in the field usually occupy a distinct subset of the available species of shells, suggesting that this selection is nonrandom (Hazlett 1981;Rodrigues et al. 2020). ...
... In the latter case, they enhance the shell cavity as the crab grows (López- , thus minimizing the number of, or avoiding shell exchanges (Taylor et al. 1989). The best known examples of obligate symbiosis between bryozoans and pagurids are found in the bryozoan genus Hippoporidra, whose encrusting species develop thick, mamillated colonies on gastropod shells (Ryland 2001;Williams and McDermott 2004). Cook (1968Cook ( , 1985 showed experimentally that larvae of H. senegambiensis were more attracted to shells inhabited by hermit crabs than to live gastropods. ...
Bryozoans are common on gastropod shells inhabited by the hermit crab Pagurus comptus in the southern southwest Atlantic. The aim of this study was to test whether bryozoan biodiversity was higher on larger and more complexly sculptured gastropod shells, as well as to analyze spatial and bathymetric changes in bryozoan assemblages. Forty-four bryozoan species were recorded on 59 gastropod (morpho) species. Larger shells tended to host a higher number of bryozoan species than smaller ones. Bryozoan species richness differed significantly among gastropods with different shell ornamentation, but richness did not increase along a predicted qualitative scale of increasing ornamentation complexity. Almost smooth but large shells had a much higher bryozoan richness than expected, and small shells with prominent ornamentation had unexpectedly the lowest richness, suggesting that shell size may be more important than ornamentation in determining bryozoan richness. Most of the shells hosted two bryozoan species, although up to 11 species per shell were observed. Maximum bryozoan richness occurred between 99 and 137 m. Bryozoan species richness on gastropod shells occupied by P. comptus was higher in the Burdwood Bank than around Tierra del Fuego and Isla de los Estados. Epibiont assemblage composition and species richness differed among the six most abundant gastropods (Trophon ohlini, Pareuthria atrata, Cerithiopsis caelatum, Fuegotrophon pallidus, P. fuscata, Argeneuthria cerealis). The two most abundant bryozoans, Burdwoodipora paguricola and Odontoporella adpressa, do not overlap in their occupation of shell surfaces. This is the first study analyzing the relationships among bryozoans, gastropod shells, and hermit crabs in subantarctic waters.
... Symbiotic relationships between animals are ubiquitous and diverse in marine environments and play an important role in shaping the spatial pattern and structure of marine biodiversity (Williams & McDermott 2004;Anker et al. 2005;Macdonald et al. 2006). Many of the polychaetous annelids that belong to the genus Polydora (family Spionidae) have symbiotic associations with other marine benthic invertebrates (Martin & Britayev 1998 and are capable of boring into hard calcareous substrates, such as mollusk shells (Blake & Evans 1973). ...
... Evidence of boring by Polydora and related genera (i.e., polydorids) is ubiquitous in fossil and recent substrates, and the host spectrum of these boring taxa is broad, including members of various phyla: Arthropoda, Brachiopoda, Bryozoa, Cnidaria, Echinodermata (fossil record only: Wisshak & Neumann 2006), Mollusca, and Porifera (Martin & Britayev 1998Rodrigues et al. 2008). Boring worms can also bore into non-biogenic hard substrata, such as limestone, mudstone, and sandstone, and even though most borers are opportunists that are associated with a range of host species, some borers are specialists or commensals that are associated with a specific host species or with a group of similar host species (Martin & Britayev 1998Williams & McDermott 2004;Radashevsky 2012). Records of trace fossils attributed to the boring activities of spionid polychaetes (known as some ichnogenera including Caulostrepsis) reach back to the Paleozoic (Cameron 1969) and are much better documented for the Holocene and fossil mollusk shells (Taylor & Wilson 2003). ...
A new spionid species Polydora lingulicola sp. nov., a novel symbiont of Lingula anatina Lamarck, 1801 is described here based on materials collected from the Yatsushiro Sea and Ariake Sea, southern Japan. Polydora lingulicola sp. nov., morphologically closest to P. glycymerica Radashevsky, 1993 and P. vulgaris Mohammad, 1972, is distinct from latter two shell-boring species by its smaller size, long maximum caruncle length, non-boring lifestyle, presence of subspherical yellow chromatophores on chaetiger 5 (visible in living specimens), and larval morphology. The new species was observed to construct mud tubes on the surfaces of L. anatina shells, with the tube apertures located near the lateral inhalant pseudosiphon of the hosts, and utilizes the water currents created by the filter-feeding host for feeding suspended food particles. Polydora lingulicola sp. nov. represents the first polychaetous annelid reported to exhibit an obligate symbiotic relationship with a lingulid brachiopod. Epibiotic polychaetes previously reported as P. cornuta Bosc, 1802 to occur on L. anatina shells from Japan in 1902 may belong to P. lingulicola sp. nov. The possibility that the wild populations of P. lingulicola sp. nov. may be vulnerable to extinction because they only associate with L. anatina, wild populations of which are near threatened by habitat loss, coastal pollution, and fishing pressure.
... Paguroidea species usually reside in empty gastropod shells to protect the abdomen. Representatives of some species occupy bivalve and scaphopod shells; some species are known to inhabit attached shells of vermetid gastropods or polychaete calcareous tubes [104]. Hermit crabs are edificators: utilizing gastropod shells, they modify the environment and influence the abundance and distribution of other invertebrates. ...
... Hermit crabs are edificators: utilizing gastropod shells, they modify the environment and influence the abundance and distribution of other invertebrates. More than 550 species of symbionts are known to be associated with approximately 180 species of hermit crabs [104]. ...
... The sponge-hermit crab relationship can be regarded as being mutualistic. For nearly a century, sponges with mutualistic hermit crab interactions have been recorded worldwide (Sandford, 1995, McLaughlin, 2015, with the great majority associated with sponges in the family Suberitidae (Davenport et al., 2017;Sandford & Kelly-Borges, 1997;Sol e-Cava & Thorpe, 1986;Van Soest, 2002;Williams & McDermott, 2004). ...
... The difference in diversity between true and false crabs stands in line with some observations from literature 12,13,29 . False crabs represent some of the more charismatic ingroups of Decapoda, with some adult hermit crabs having specialized morphologies adapted to hiding in shells 30 , or the adult robber crab adapted to climb trees 31 . True crabs seemingly lack such extreme forms, which might be one reason for the smaller morphological diversity of their adults. ...
Brachyura and Anomala (or Anomura), also referred to as true and false crabs, form the species-rich and globally abundant group of Meiura, an ingroup of Decapoda. The evolutionary success of both groups is sometimes attributed to the process of carcinization (evolving a crab-like body), but might also be connected to the megalopa, a specific transitional larval phase. We investigate these questions, using outline analysis of the shields (carapaces) of more than 1500 meiuran crabs. We compare the morphological diversity of different developmental phases of major ingroups of true and false crabs. We find that morphological diversity of adults is larger in false crabs than in true crabs, indicating that taxonomic diversity and morphological diversity are not necessarily linked. The increasing morphological disparity of adults of true and false crabs with increasing phylogenetic distance furthermore indicates diverging evolution of the shield morphology of adult representatives of Meiura. Larvae of true crabs also show larger diversity than their adult counterparts, highlighting the importance of larvae for biodiversity studies. The megalopa phase of Meiura appears to be plesiomorphic, as it overlaps between true and false crabs and shows little diversity. Causes may be common evolutionary constraints on a developmental phase specialized for transitioning.
... This type of symbiotic relationship provides an excellent model for investigating patterns of biodiversity across different geographical landscapes at multiple scales. Investigating epibiotic relationships can enhance the understanding of the critical biological characteristics of basibionts [1,2]. ...
Sarsia tubulosa (M. Sars, 1835), a colonial hydrozoan of the family Corynidae, is common in the Barents Sea. This study provides new evidence that the species acts as an epibiont of the red king crab Paralithodes camtschaticus, a non-indigenous but remarkably abundant decapod crustacean of immense commercial value in the coastal regions of the sea. This finding adds to the current collection of identified epibionts on the red king crab and highlights the prospect of ongoing symbiotic relationships between the crab and the regional fauna. We also provide photographic evidence of S. tubulosa colonies and a comparative morphological evaluation with another closely related corynid, Coryne hincksi Bonnevie, 1898, previously found on the red king crab. The main differences between these two species are the location of the gonophores (reproductive organs) on the hydranths and the final stage of their development: in the form of free-floating medusae (S. tubulosa) or remaining sessile as sporosacs (C. hincksi). Other distinguishing features include variations in hydranth morphology, number and arrangement of tentacles, and structural development of gonophores.
... Hermit crabs, with their unique non-calcified abdomen, rely on external structures for cover and shelter (Williams and McDermott, 2004), with empty gastropod shells being the most commonly used resource (Vance, 1972;Kellogg, 1976;Bertness, 1981). Within the Parapaguridae, Sympagurus dimorphus (Studer, 1883) is a widely distributed species in the southern hemisphere, inhabiting depths ranging from around 90 to 1995 meters (Lemaitre, 2004;Landschoff and Lemaitre, 2017), and frequently associated with zoanthid cnidarians that build a pseudo-shell, rather than inhabiting empty gastropod shells (Schejter and Mantelatto, 2011). ...
The Parapaguridae comprises hermit crabs that inhabit deep-water environments. In these environments, shell availability can be limited, mostly consisting of small and fragile-shelled gastropods. Thus, different strategies have evolved to mitigate this limited shell supply. Sympagurus dimorphus (Studer, 1883) lives in association with a zoanthid cnidarian that creates a pseudo-shell that grows with the hermit crab. In contrast, Oncopagurus gracilis (Henderson, 1888) inhabits small, calcified gastropod shells. Therefore, we selected these two species as models to test sexual dimorphism and shape patterns of their chelipeds and cephalothoracic shield, due to their different shelter acquisition methods. We photographed the animals and digitized the images to employ comparative geometric morphometric techniques. We tested the differences in shape between the sexes within each species, and also tested sexual size dimorphism based on centroid size. For O. gracilis, we found shape differences for the chelipeds and cephalothoracic shield, however, we only observed sexual size dimorphism for the chelipeds. For S. dimorphus, an inverse pattern was found, in which females presented more robust chelipeds, and sexual size dimorphism was present in which males were larger. These differences can be reasonably explained by their shelter acquisition methods, in which O. gracilis depends on small shells that limit growth, while S. dimorphus grows with its cnidarian pseudo-shell. The robustness found in the shape patterns may also be related to their behaviors, e.g., in addition to competition for shells, they also fight during mating. However, we emphasize that future studies with other populations of these species are needed for comparative purposes.
... Feeding experiments have shown that D. commensalis can engage in a predatory feeding on relatively large, motile zooplankton (Williams and McDermott 1997) and swimming nauplii (Dauer 1991). Also, this species is reported to be a predator on eggs of host hermit crabs (Williams and McDermott 2004). Another commensal of hermit crab, Polydora robi, is known to prey on fertilized eggs and developing embryos attached to the pleopods of host hermit crabs (Williams 2006). ...
The fatty acid (FA) composition of spionids co-occurring in shallow water and occupying various habitats was analyzed to characterize spectrum and diversity of their food sources and elucidate their feeding habits and trophic relationships. These included free-living and tube-dwelling species, and also opportunistic and specialized shell-borers and their hosts. A plot of principal component analysis (PCA) scores based on the FA compositions of nine spionid species recognized five distinct groups with different feeding strategies and revealed differences not only between the species, but also within the same species from various habitats. The predominance of 20:5n-3, C16 polyunsaturated FAs, and 16:1n-7 in suspension feeders indicated that they feed on diatoms. Benthic dinoflagellates and diatoms, as well as bacteria, constituted a major part in the diet of deposit feeders. On the basis of high 22:6n-3 and 18:1n-9 contents, Dipolydora commensalis was attributed to omnivorous with a predominance of animal dietary input. The selective detritivore Polydora glycymerica relies on a microbial food web. FAs of Laonice aff. cirrata indicated the importance of foraminifera in the diet of this subsurface feeder. Polychaetes were found to have a capability of changing their feeding habits depending on habitat. Specialized shell-borers adapt their feeding habits to the host’s diet. The results obtained provide evidence that these species actually represent several non-overlapping groups characterized by different feeding strategies, which leads to weakening of their competitive relationships. Partitioning of food sources is regarded as one of the main mechanisms explaining the successful coexistence of spionid species.
... mutuki. Hermit crabs are known to have symbiotic associations with many cnidarians, such as hydrozoans, sea anemones, and corals (Williams & McDermott, 2004;Jung & Kim, 2017). ...
Calcinus is the colorful hermit crab genus belonging to the family Diogenidae and is often found in coral reefs of the tropical Indo-West Pacific region, including southern Honshu, Japan, which is the northern limit of their occurrence. In the present study, we found C. vachoni for the first time in the intertidal zone of Jeju Island—the southernmost island of South Korea. We examined their morphology and provided a diagnosis of their morphological details with illustrations. In addition, the Korean Calcinus population was genetically characterized using mtDNA cox1 sequences and by placing them into three previously reported regional haplogroups. The phylogenetic tree from maximum likelihood analysis revealed that Korean C. vachoni is assigned to the C. vachoni haplogroups exclusively, one of the three well-supported mitochondrial haplogroups with distinct geographic ranges ( i.e ., C . vachoni , C . aff. vachoni Cooks, and C . aff. vachoni Mascarenes). This result provides new information on the species distribution of C.vachoni , extending their geographic range further north into the southern coast of Korea. In this study, we also first report the potential association of C. vachoni with their co-occurring colonial anemone species Palythoa aff. mutuki and dead coral head of Pocillopora species based on our on-site observation and a public coral collection database of Calcinus species. However, their ecological association with co-occurring coral species is putatively assumed for now and therefore has to be validated by compelling evidence from further field observation and experimental studies ( i.e ., whether the presence/absence of colonial anemones affects the behavior and survival of the hermit crabs).
... The loss of eggs in decapod crustaceans can be due to several factors: the increase in egg volume during embryonic development can cause a physical restriction of space, resulting in a reduction in the number of eggs that can be significant (Corey and Reid 1991;Lardies and Wehrtmann 1997); the occurrence of diseases (Kuris 1991), of invertebrate predators of eggs, such as the polychaete worm of the genus Polydora Bosc, 1802, which pierces the shell and feeds on the eggs (Williams and Mcdermott 2004); abrasion caused during burrowing behaviour (Mantelatto and Fransozo 1997); and parasitism by isopods of the family Bopyridae (Mcdermott et al. 2010;Ribeiro et al. 2019). ...
We performed a comparative analysis of fecundity and reproductive effort of two hermit crab species, Clibanarius antillensis and Calcinus tibicen, distributed along the two marine provinces in Brazilian coast. Samples of both species were manually collected during spring low tides on a two-month basis, from February 2011 to January 2012 at locations separated by ~ 3000 km: North-eastern (NE) region – Pedra Rachada Beach (Ceará); South-eastern (SE) region – Araçá Beach and Grande Beach (São Paulo). The size of ovigerous females, as well as the fecundity values, egg volume, internal volume of occupied shells, and reproductive effort were analysed, and the results evidenced significantly higher values for females of both species collected in SE localities. In females collected NE, there was also the presence of aberrant eggs, which influenced the reproductive parameters analysed for these species, resulting in lower reproductive effort. Biomass invested in egg production varied between populations, but ovigerous females of SE invested a higher percentage of their weight in the production of its egg mass, showing significant
differences in the reproductive effort. Variation in reproductive performance detected for both species may be related to latitudinal location and associated to the habitat’s characteristics.
... commensalis can engage in a predatory feeding on relatively large, motile zooplankton (Williams and McDermott 1997) 379 and swimming nauplii (Dauer 1991). Also, this species is reported to be a predator on eggs of host hermit crabs 380 (Williams and McDermott 2004). Another commensal of hermit crab, Polydora robi, is known to prey on fertilized 381 eggs and developing embryos attached to the pleopods of host hermit crabs (Williams 2006 14 20:1n-11, and 18:1n-7 (Table 1) ...
The fatty acid (FA) composition of spionids co-occurring in shallow-water and occupying various habitats was analyzed to characterize the spectrum and diversity of their food sources and elucidate their feeding habits and trophic relationships. These included free-living and tube-dwelling species, and also opportunistic and specialized shell-borers and their hosts. A plot of principal component analysis (PCA) scores based on the FA compositions of nine spionid species recognized five distinct groups with different feeding strategies and revealed differences not only between the species, but also within the same species from various habitats. The predominance of 20:5n-3, C16 polyunsaturated FAs, and 16:1n-7 in suspension feeders indicated that they feed on diatoms. Benthic dinoflagellates and diatoms, as well as bacteria, constituted a major part in the diet of deposit feeders. On the basis of high 22:6n-3 and 18:1n-9 contents, Dipolydora commensalis was attributed to omnivorous with a predominance of animal dietary input. The selective detritivore Polydora glycymerica relies on a microbial food web. FAs of Laonice aff. cirrata indicated the importance of foraminifera in the diet of this subsurface feeder. Polychaetes were found to have a capability of changing their feeding habits depending on habitat. Specialized shell-borers adapt their feeding habits to the host’s diet. The results obtained provide evidence that these species actually represent several non-overlapping groups characterized by different feeding strategies, which leads to weakening of their competitive relationships. Partitioning of food sources is regarded as one of the main mechanisms explaining the successful coexistence of spionid species.
... Empty gastropod shells play a vital role for most hermit crab species' life history (Kellogg 1976). As these animals lack a calcified abdomen, they require external structures for protection (Vance 1972b;Kellogg 1976;Williams and McDermott 2004). The quality of the shell can have an important influence on different aspects of the hermit crab biology such as: population structure, size, reproduction, mortality, growth, among others (Vance 1972a;Abrams 1980;Buckley and Ebersole 1994;Carlon and Ebersole 1995;Angel Aquat Ecol 2000;Gorman et al. 2015;da Silva et al. 2018;Stanski et al. 2018;Rodrigues et al. 2020). ...
Gastropod shells play an important role in the life story of hermit crabs, influencing biological characteristics directly. The adequacy of shells for hermit crabs can be evaluated through the Shell Adequacy Index, which calculates the shell's ideal size/weight compared to the actual dimensions of the occupied shells. To avoid competition for shells, animals can display a variety of strategies including alterations in their circadian rhythms. This study aimed to evaluate if two sympatric species of hermit crabs—Pagurus brevidactylus and Pagurus criniticornis—are competing for the best fitting shells and if they present differences in their circadian rhythms. Their shells were identified and measured regarding the aperture length and width. The shell adequacy was calculated using linear models of the Shell Aperture Length and Width, and the period of activity of the animals was filmed for 24 h and later analyzed. The period between 10 am and 2 pm represented daytime, while 10 pm to 2 am represented nighttime. Pagurus brevidactylus occupied mainly Cerithium atratum and Claremontiella nodulosa shells, while P. criniticornis occupied mainly C. atratum shells. Our results showed that the two species are inhabiting shells with similar traits, which may indicate competition. The species do not present distinct activity periods; however, the shell occupation pattern suggests a competition at the functional level.
... The superfamily Paguroidea contains more than 800 described species of hermit crabs, nearly all of which are marine (McLaughlin 2003). They are best known from intertidal areas where they can be scavengers or predators being important ecologically as allogenic engineers, i.e., those engineers that transform living or non-living material from one physical state to another (Williams & McDermott 2004). Hermit crabs, with a non-calcified abdomen, obtain protection from predation by inhabiting empty gastropod shells, promoting the association with a wide variety of symbionts, including strict parasites, of which bopyrid isopods make up a substantial proportion (McDermott et al. 2010;Williams et al. 2019). ...
Six species of bopyrids were detected from the examination of hermit crabs collected along the Atlantic coasts of Mexico and deposited in the Colección Nacional de Crustáceos housed at the Universidad Nacional Autónoma de México. Asymmetrione tuxtlaensis sp. nov., the third species of the genus from the west Atlantic, is described. The occurrence of Asymmetrione desultor, Pseudostegias atlantica and Stegias clibanarii are recorded for the first time from the Mexican Atlantic coasts and the distribution range of the last two species is extended. Both a new host and three new localities for Mexico are reported for Anathelges hyptius and Bopyrissa wolffi, respectively. Distribution and reproductive data are provided for all six species examined. A key to genera and species of bopyrid isopods that parasitize hermit crabs in the Mexican Atlantic is provided.
... The results of statistical analyses showed that host size is the most important factor affecting the indices of infestation (Table 2). Greater prevalence levels for associated species on larger crabs seem to be a common pattern in crustaceans and other hosts [70][71][72][73]. Large adult crabs provide a larger area for settling organisms. ...
The biodiversity, infestation patterns, and spatial distribution of organisms living in association with the introduced red king crab Paralithodes camtschaticus were studied in Dalnezelenetskaya Bay, southern Barents Sea, in 2009–20013 to update a list of species, reveal long-term changes in this epibiotic community, and identify key factors affecting the prevalence and intensity of infestation. A total of 90 associated species were found throughout the study period, or twice as many as in 2004–2008, reflecting relatively low similarity between these periods. Half of the species were found on one to three crabs only. Copepods had the maximum diversity (23 species). For the first time, macroalgae were found as epibionts of red king crabs. Overall, the highest prevalences were found for the amphipod Ischyrocerus commensalis (74.2%), the copepods Tisbe furcata (57.7%) and Harpacticus uniremis (29.4%), the amphipod Ischyrocerus anguipes (27.3%), and the fish leech Johanssonia arctica (16.2%). Redundancy analysis showed that host size was the most important driver of species abundance, followed by shell condition, water temperatures in the coastal Barents Sea in May and June, and sex. These factors, coupled with the range expansion of red king crabs and climate changes in the Barents Sea, provide good explanations for the differences between the 2004–2008 and 2009–2013 fouling communities. Distribution patterns for common taxa on the host reflect larval settlement patterns and/or relationships between the host and associated species. These results expand our knowledge of infestation patterns for the invasive red king crab and provide a reference point for further monitoring.
... For aquatic arthropods, bryozoans are the most common epibionts (Ross, 1983;Wahl, 2009). Basibionts are represented by sea spiders (Wyer and King, 1973;Barnes and Clarke, 1995;Key et al., 2013), king crabs (Rao and Rao, 1972;Key et al., 1996bKey et al., , 2000, barnacles (Gostilovskaya, 1984;Mayer-Pinto et al., 2000;Yakovis, 2007;Yakovis et al., 2008;Cáceres-Chamizo et al., 2017), isopods (Campbell, 1992;Barnes and Clarke, 1995;Key and Barnes, 1999), and decapods (Eggleston, 1971;Abello et al., 1990;Key et al., 1999Key et al., , 2017Steksova, 2003;Savoie et al., 2007), as well as gastropod shells, occupied by hermit crabs (Cook, 1985;Taylor, 1991;Taylor et al., 1989;Williams and McDermott, 2004). It should be emphasized that bryozoans form their colonies both on living basibionts as well as their skeletons and fragments left after their death (e.g., McKinney, 1996;Ostrovsky, 1998b;Ostrovsky and Grischenko et al., 2006;Harmelin et al., 2011Harmelin et al., , 2012Souto et al., 2016;Cáceres-Chamizo et al., 2017). ...
The life of sedentary organisms faces strong competition for space against neighboring epibionts, and the impact of predators. The emergence of various adaptations to cope these problems includes establishing various interactions with other members of benthic communities. Various symbiotic (commensal, mutualistic, and even parasitic) relationships presented in multiple variations allow not only to succeed in the competition for free space, but also provide other equally important advantages for survival. Being one of the most abundant groups of colonial invertebrates in marine benthic ecosystems, bryozoans are not an exception. This group demonstrates both common and unique symbiotic associations. This article provides an overview of all known forms of symbiosis in Bryozoa, fossil and modern, and discusses the consequences of such relationships.
... The empty gastropod shells are likely to be buried in the substrate unless they are used by hermit crabs as protection (Creed 2000;Stachowitsch 1977). Therefore, Hermit crabs serve as ecosystem engineers by using gastropod shells which affect the abundance and distribution of other invertebrates (Gutiérrez et al. 2003;Jones 1994; Williams and McDermott, 2004). ...
The current work presents hermit crab species inhabiting the intertidal and shallow subtidal region on the coast of south Andaman Islands, along with an updated checklist of hermit crabs from Andaman and Nicobar Islands (ANI) and an identification key for surveyed hermit crabs. Five species of hermit crabs representing two families (Coenobitidae and Diogenidae) under the superfamily Paguroidea were recorded in the intertidal and shallow subtidal regions of the south Andaman Islands. Among the five species, one species of the genus Coenobita , one species of the genus Calcinus , two species of the genus Clibanarius and one species of the genus Dardanus are reported for the first time from the intertidal habitats of the Andaman Islands. Live coloration and description of several species are described for the first time from this region.
... Ectosymbiosis is a type of symbiosis in which a symbiont lives on the body surface of the host (Williams and McDermott, 2004). This relationship portrays a greater level of host specificity than in the case of epibiosis (Douglas, 2009). ...
Chemoautotroph bacteria have evolved symbiosis with different organisms, invertebrates in particular, allowing them, among other, to colonize new habitats that are extreme for most animals. In this work we aim to detect if a symbiosis occurs between sulfur-oxidizing bacteria of the genus Thiothrix and microcrustaceans especially groundwater cyclopoids and ostracods that live in sulfidic subterranean waters from the mesothermal aquifer of Mangalia, Romania and compare them with the already known associations between sulfidic groundwater amphipods and Thiothrix.
... The vacant shells of molluscs (mainly gastropods) are often used as shelters by diverse animal taxa, including hermit crabs (Reese, 1969), tanaids (Kakui, 2019), polychaetes (Hylleberg, 1975), sipunculans (Cutler, 1994) and fishes (Bose et al., 2020). In addition, the shells used by hermit crabs and sipunculans are known to be inhabited by a variety of symbiotic animals (Gage, 1968(Gage, , 1979Kristensen, 1970;Williams & McDermott, 2004;Goto et al., 2007;Igawa et al., 2017;Yoshikawa et al., 2018;Jimi et al., 2021;Herrán et al., 2022). The vacant shells are thus considered to play an important role in engineering the ecosystem and maintaining the biodiversity in the sea bottoms, as suggested in Gutiérrez et al. (2003). ...
Sipunculans are non-segmented marine worms with an anterior retractable introvert, which are commonly included in Annelida based on molecular phylogenetic and phylogenomic analyses. They generally burrow in the soft sediments or live inside the crevices of hard substrata (e.g. calcareous/coralline rocks). However, members of some sipunculan genera (mainly Phascolion and Aspidosiphon ) are known to have a peculiar habit of dwelling in vacant shells of gastropods or scaphopods. In this study, we investigated the shell utilization and preference pattern of the species of Phascolion and Aspidosiphon in Japan. We collected 302 sipunculans, comprising 273 and 29 individuals in Phascolion and Aspidosiphon , respectively, from 57–800 m depth of three study sites in the Pacific coast of Honshu Island, Japan. The species of Phascolion were found in vacant shells of 38 genera of 27 families of gastropods and six genera of four families of scaphopods, whereas the species of Aspidosiphon were found in 11 genera of 11 families of gastropods and one genus of scaphopod. These results suggest that members of each genus use a wide range of gastropod and scaphopod shells. The body size of the sipunculans was positively correlated with the shell size, suggesting that they change the shells as they grow. Furthermore, we investigated the shell preference of Phascolion species by comparing morphological characteristics of shells occupied and unoccupied by sipunculans. Generalized linear mixed model (GLMM) analyses suggest that the species of Phascolion tend to use long and narrow shells. Such shells likely fit well the elongated trunk of sipunculans.
... This was particularly evident in species known to show a high degree of swimming activity, such as the shrimp P. longirostris and the portunid swimming crabs L. depurator and M. tuberculatus. The large, well-protected hermit crabs D. arrosor showed no significant size differences, because the gastropod shells they use may provide them with protection and allow them, to a certain degree, to inhabit the trawled area (Williams and McDermott 2004). ...
The establishment of fisheries no-take areas is considered an effective method for the recovery of populations of exploited species and their habitats. Here we study the faunistic composition of decapod crustaceans after the implementation of a no-take area in the Gulf of Roses (NW Mediterranean) in 2014. We studied the occurrence (presence/absence) and density of all decapod crustaceans sampled by trawling inside and outside a no-take area from March 2015 to July 2018. Sizes were assessed for all common species. A total of 33 species of decapod crustaceans were recorded. Four species showed significantly higher occurrences in the no-take area and three in the open area, while significantly higher densities were found for four species in the no-take area and three in the open area. Multivariate analysis showed marked differences between the no-take area and the open area, while also showing that the two areas were undergoing a divergence. The comparison of sizes between the two zones showed species-specific patterns that in many cases showed that both the smallest and the largest individuals were present in the no-take area, suggesting that the closing of this area would be important for recruitment and juvenile development, as well as for protection of large-sized individuals. All evidence indicates that the establishment of the no-take area has led to an improvement in biodiversity and species population descriptors.
... However, there have been few detailed studies of the associations between cnidarians and live gastropod mollusks with an external shell, particularly in comparison to cnidarian association with gastropod shells occupied by hermit crabs (e.g., Brooks & Gwaltney, 1993;Gusmão et al., 2020;Williams & McDermott, 2004). Several hypotheses have been suggested to explain symbioses between cnidarians and live gastropod mollusks. ...
There have been few detailed studies on the associations between cnidarians and gastropod mollusks. Several hypotheses have been suggested to explain the origins of these symbioses. However, respective benefits for gastropod mollusks and cnidarians have generally not been well examined, as there are many understudied cnidarian taxa associated with gastropod mollusks, and in particular, species of the order Zoantharia in the family Epizoanthidae remain poorly studied. In this study, we examined family Epizoanthidae specimens associated with Granulifusus gastropods via morphological observations combined with molecular phylogenetic analyses. Based on our results, we formally describe a new Epizoanthus species from the northwest Pacific Ocean. Our phylogenetic analyses recovered at least two independent origins for associations with gastropod in Epizoanthidae. Furthermore, during the course of this work, we reconfirm the existence of the enigmatic species Paleozoanthus reticulatus, the only species of the genus Paleozoanthus, for the first time since its original description, and we add information on this species’ morphological characteristics. This study provides a basis for evolutionary and behavioral studies of symbiotic associations between zoantharians and gastropods. Continued investigations examining the diversity of gastropod-associated zoantharians have the potential to greatly expand our overall comprehension of anthozoan-gastropod symbioses.
... Shelters offer places for animals to mate, breed, and rest, as well as provide protection from predators and harsh climatic conditions (Sato, 1994;Shervette et al., 2004;Almany, 2010;Mautz et al., 2011;Kerry and Bellwood, 2017). Some aquatic crustaceans seek existing shelters and show preferences for specific ones (Boudreau et al., 1990;Mariappan and Balasundaram, 2003;Williams and McDermott, 2004), which is manifested by their longer or more frequent occupancy of a particular shelter type (Matthiopoulos, 2003). ...
Crustaceans select shelters non-randomly, and their preferences may be mediated by the structural properties of shelters. Providing shelters is an effective approach to improving the survival of pond-raised crabs, but the structural properties of shelters that would significantly benefit the survival rate remain unclear. Here, a laboratory experiment was conducted to examine the preference of swimming crabs (Portunus trituberculatus) for three types of shelter with different depths, heights, and widths using an animal behavioral observation system. The residence time of crabs in each shelter was calculated, the changes in their preference were described by the program PFunc, and the correlations between the carapace width and preference function traits were analyzed. The results showed that juvenile swimming crabs (carapace width = 5.08 ± 0.34 cm) preferred shallow, high, and wide shelters, and the strongest preferences observed were for depth and height. There was a correlation between crab carapace width and preference function traits, which suggests that preferences became stronger as the carapace width increased. Height and width are the two major dimensions that need to be controlled when designing a shelter, and their value should be determined by the carapace width of the crabs. Providing the crabs with shelter at their preferred dimensions in the pond can prolong the residence time, which may help to reduce the frequency of agonistic encounters and improve the survival of the crabs.
... HERMiT cRABs usually protect themselves from predators by inhabiting empty gastropod shells (Williams & McDermott, 2004). Bryozoans are one of the most frequent invertebrates encrusting the surface of pagurized shells, sometimes even enlarging the size of the chamber occupied by the crab (Taylor, 1994). ...
... A model of metabiosis interactions is the association between hermit crabs and gastropod shells (Abrams, 1980;Bertness, 1981;Kellogg, 1976;Vance, 1972a). Despite being crustaceans, hermit crabs have a soft pleon due their unique evolutionary history (Tsang et al., 2011) and, therefore, rely on empty structures for shelter and protection (Williams & McDermott, 2004). The hermit crabs do not remove living gastropods from their shells (Laidre, 2011); thus, they spend their lives constantly looking and/or fighting for empty shells in order to grow and thrive (Angel, 2000;Asakura, 1995;Burciaga et al., 2021;Carlon & Ebersole, 1995;Imazu & Asakura, 1994;Kido & Wada, 2020). ...
The relationship between hermit crabs (Paguroidea) and gastropod shells has attracted the attention of researchers toward a network approach. These networks seem to present recurrent patterns that are often modular, i.e., a pattern in which the network can be divided into compartments that represent species interacting more with species belonging to its own compartment than with species composing another compartment. A modular interaction network occurs when species tend to interact more intensively within subsets of species (modules) than with species outside of it. Since modularity is a characteristic in which different hermit crabs interact with different sub‐sets of shells, we proposed that these patterns should be a reflection of different morphometric traits, as well as that species specialization (measure which indicates if a given species is specialist or generalist in resource use) could be related to such traits. Three different hermit crab–shell networks in which the modularity and species specialization have already been determined were chosen. The animals were sampled in three different regions with the same sampling effort in the same type of substrate. After sampling, the animals were taken to the laboratory where they were identified and measured. A PERMANOVA was used for the hermit crab morphometric traits from each region using each compartment as grouping variable. In order to test if morphometric traits influence species specialization (d′), linear mixed models were created and selected through Akaike's Information Criterion. Our data show that hermit crabs presented different morphometric traits in each module they occupied. Also, d′ was influenced by morphometric traits; thus, hermit crabs with different sizes need different types of shells, which reflect in different specialization levels.
... Therefore, our data strongly suggest that, based on the ecological and behavioral features mentioned above, the development of male dwarfism in E. issunboushi is more likely to be relate with their symbiotic lifestyle inside gastropod shells occupied by a hermit crab. However, there are other symbiotic polychaete species (e.g., Neanthes fuscata[Savigny, 1822]) living in the same habitat that have not evolved to have dwarf males(Marin & Britayev, 1998;Williams & McDermott, 2004). The unique environmental and ecological traits of E. issunboushi sp. ...
Extreme sexual size dimorphism is one of the most striking phenomena in evolutionary biology. While the origin has been well discussed and some causes have been suggested, the evolutionary history remains unclear. We found a new species of deep‐sea scale worm (Annelida: Polynoidae) inside gastropod shells, either empty or occupied by hermit crabs collected at 140–306 m in depth, Mie Prefecture, Japan. This highly specialized habitat, together with the fact that it has never been found free‐living, led us to consider the scale worm to be an obligate symbiont. The species is characterized by males being dwarf, with their minute bodies (ca. one‐fourth the length of females) always riding on the dorsal side of females, being thus the first case of extreme sexual size dimorphism in scale worms. Based on a detailed morphological, histological, and molecular phylogenetic approach we are here describing a new species, Eunoe issunboushi sp. nov.
The hermit crab-sea anemone (HCA) partnership is a common facultative mutualism. The anemone protects its host from predators such as cephalopods and shell crushing crabs by its stinging cells. The crab provides the anemone with a hard substrate and increased access to oxygenated water and food and in some cases with protection from predators. These partnerships are extremely diverse and complex. This overview addresses issues related to formation of the associations, the early history of these partnerships, placement of anemones on the hermit crab shell, intra and interspecific competition amongst hermit crabs over sea anemones, costs and benefits for crab and anemone from being associated and the evolution of these partnerships based on molecular phylogenies using nuclear and mitochondrial markers.
Hermit crabs (Diogenes edwardsii) are adapted to a variety of marine environments, inhabiting not only shallow ranges but also deep waters, inter-tidal zones, sandy beaches, and other land areas. They have the characteristic trait of using empty mollusks' shells as their habitat. They sometimes establish symbiotic relationships with various organisms via shells. Symbiotic organisms not only receive a more efficient food supply from hermit crabs, but also benefit in various ways, such as gaining mobility, reducing contact with predators, and increasing reproductive opportunities. For the hermit crab, it has been found that the symbiosis with sea anemones may provide protection from predators such as octopuses. In this study, we collected hermit crabs provided by a fisherman in Sosogi, Wajima, in Ishikawa Prefecture, Japan. A notable feature of Diogenes edwardsii is its symbiosis with sea anemones via the left cheliped, although its ecological significance remains unknown. Here, about 200 individual crabs were analyzed for the presence or absence of a symbiosis with sea anemone via the left cheliped. The presence or absence of symbiosis with anemones on the shell being utilized was also analyzed. Additionally, we successfully demonstrated that the symbiosis between anemones and Diogenes edwardsii protect the latter from predators, especially the common octopus.
This study investigates epibiont communities, including both protozoan and metazoan species, associated with Astacus leptodactylus in the Shiyan Dam reservoir situated in the Kermanshah province of western Iran. A total of 220 crayfish were collected for comprehensive parasitological surveys, targeting various body parts, including the gills, exoskeleton, mouth cavity, and internal organs. Protozoan species identified included Cothurnia sieboldii, Chilodonella sp., Vorticella similis, Zoothamnium sp., and Pyxicola annulata. In the metazoan category, notable species consisted of Branchiobdella kozarovi (Annelida), Philodina acuticornis (Rotatoria), Rabdochona sp. (Nematoda), and Mesocyclops strennus (Copepoda). P. acuticornis exhibited the highest prevalence among gill epibionts at 18.2%, while Chilodonella sp. showed the lowest prevalence at 0.9%. The study also revealed seasonal variations, with the highest infestation occurring in the spring (82%), and the lowest in the winter (24%). This research presents the first documented evidence of epibionts on A. leptodactylus in western Iran.
This is the first record of an epibiotic association between an acontiate sea anemone and a fish. We collected unidentified epibiotic sea anemones living on the necto-benthic fish Inimicus japonicus (Cuvier 1829) from the Seto Inland Sea, Japan. Molecular analyses revealed that the anemones were most closely related to Verrillactis paguri (Stimpson in Verrill 1869) sensu England (1971), which has a mutualistic relationship with hermit crabs. Therefore, we tentatively assigned the collected species as Verrillactis sp. (Actiniaria: Sagartiidae). This finding of sea anemones using fish as substrate is unprecedented. Future research into this relationship to determine if this is an incidental occurrence or facultative symbiosis is warranted. Our findings contribute to a wider understanding of symbiosis in sea anemones.
Paguridea in the Indo-Pacific have 10 harpacticoid copepod associates: 3 Sunaristes, 3 Brianola, 1 Porcellidium, and 3 Paraidya. Four of these copepods are reported from hermit crabs in the Moluccas: Sunaristes tranteri Hamond, 1973, from Dardanus guttatus, Dardanus lagopodes, Calcinus latens, Calcinus minutus, Calcinus gaimardi, Calcinus sp., and Trizopagurus strigatus; Porcellidium brevicaudatum Thompson and A. Scott, 1903, from Dardanus guttatus, Dardanus lagopodes, Dardanus megistos, Calcinus latens, Calcinus minutus and Trizopagurus strigatus; Paraidya minor Sewell, 1940, and Paraidya major Sewell, 1940, from Dardanus guttatus, Dardanus lagopodes, and Dardanus megistos.
Sixteen species of porcelain crabs are described from the Gulf of Urabá and Santa Marta including Neopisosoma curacaoense which presents a new record from Colombia. With the tatter species the total number of porcelain crabs reported from the Caribbean Coast of Colombia reaches 31. The distributions of the species of the upper intertidal is described and discussed in some detail.
A soft bottom benthic community at a depth of 23 m in the North Adriatic Sea (Gulf of Triest) was found to contain a high density of hermit crabs (1.88 individuals/m2). This population is composed mainly of the species Paguristes oculatus which inhabits the shells of the gastropod species Aporrhais pes-pelecani, Murex brandaris and M.trunculus. Over 50 species of epifaunal as well as boring invertebrates were found to be associated with the hermit crab occupied shells. Both species of Murex as well as Aporrhais pes-pelecani were frequently found at the base of established multi-species clumps which are characteristic for this bottom and account for the large epifaunal biomass (370 g/m2). The hermit crab microcosm is compared to these clumps in an attempt to determine whether the gastropod shell of the hermit crab forms the basis of the observed sedentary associations. In situ experiments as well as diver taken samples show that as opposed to living gastropods, empty shells and artificial substrates, hermit crab occupancy affords a unique opportunity for the development of a fauna and flora which is capable of survival and further growth once deposited by the hermit crab.
This study on recent and fossil acrothoracic cirripeds describes burrows of the recent species Trypetesa lampas in the same way as fossil burrows. Subsequently, fossil and recent burrows are compared. Recent burrows of T. lampas were found in whelk shells (Buccinum undatum) inhabited by pagurids; fossil burrows resembling Brachyzapfes elliptica in belemnites (Oxyteuthis sp.) from the Barremian of Alstatte, West Germany. The burrows of T. lampas are smaller but relatively deeper and wider than the Alstatte material. This is probably due to the reduction of the abdomen and appendages in T. lampas. The brood pouch and ovaria of T. lampas are probably larger than those of the fossil borer. In the present material, burrows of T. lampas were mainly produced by young barnacles. This may be explained by a frequent change of shells by hermit crabs which causes an early death of the acrothoracics. -Authors
The majority of tropical marine families demonstrate their greatest concentration of species within the relatively small East Indies Triangle. In every direction, the species diversity decreases with distance from the East Indies. Other patterns suggest that the East Indies is where the average generic age is youngest, where some historical routes of dispersal originate, where the most apomorphic species occur, where genetic diversity is the greatest, and where extinctions are likely to originate. These coincident patterns provide support for the hypothesis that the East Indies has been operating as a center of evolutionary radiation. The driving force for this dynamic system is apparently the predominance of successful speciation involving relatively large populations with higher genetic diversity. This mechanism fits the centrifugal speciation model that was proposed more than 50 years ago.
The paleobiogeographic histories of three North Atlantic hermit crab lineages were compared with a single-copy DNA-DNA hybridization phylogeny of their symbiotic hydroid genus Hydractinia to test hypotheses of shared history between these host and symbiont lineages. A survey of the geologic literature suggests that two vicariance events in the Quaternary are responsible for existing range disjunctions of the host hermit crab lineages. The Hydractinia phylogeny revealed two distinct clades, one with a primarily northern and the other with a primarily southern distribution. In two of three cases, hydroids associated with closely related hermits on both sides of the range disjunction appear as sister taxa in the phylogeny. A linear scaling between a measure of hydroid sequence divergence and independent geologic estimates of the timing of the vicariant events believed to have established the hermit crab range disjunctions is consistent with the claim of temporal coincidence of cladogenic and vicariance events. These findings provide evidence for shared history of symbiotic associations in two of the three cases.
Gilchrist, S.L. 2003. Hermit crab population ecology on a shallow coral reef (Bailey’s Cay, Roatan, Honduras): octopus predation and hermit crab shell use. In: Lemaitre, R., and Tudge, C.C. (eds), Biology of the Anomura. Proceedings of a symposium at the Fifth International Crustacean Congress, Melbourne, Australia, 9‐13 July 2001. Memoirs of Museum Victoria 60(1): 35‐44. Shells can be a limiting factor in allowing hermit crab populations to increase. Predators of gastropod molluscs and of hermit crabs release shells into reef environments where hermit crabs find and cycle them within their populations. Predators also play a role in distributing shells among hermit crab species. To highlight how octopuses influence shell availability to hermit crabs, observations were made on members of Octopus vulgaris Cuvier, 1797 and O. briareus Robson, 1929 at Bailey’s Cay Reef (Roatan, Honduras) during July and August each of three years, 1999‐2001. In addition to feeding while foraging, Octopus vulgaris and O. briareus individuals create shell and debris middens outside of their temporary dens. These middens concentrate shells and food for hermit crabs in the reef environment where locating an empty shell could be difficult. However, because hermit crabs are prey items for octopuses, hermit crabs using the middens risk predation from the den occupant. Relatively small hermit crab species such as Pagurus brevidactylus (Stimpson, 1858) and P. criniticornis (Dana, 1852) were found commonly in dens and among middens, opening the possibility that the den functions as a refugium for some species as well.
[Aporobopyrus curtatus (Richardson, 1904) wird wiederbeschrieben. Diese Art ist ein Schmarotzer von Petrolisthes galathinus (Bosc) in Sudflorida und St. john, Westindien, P. armatus (Gibbes) in Florida, P. marginatus Stimpson auf Barbados und Porcellana sayana (Leach) in Nordcarolina und St. John. Aporobopyrus johannis Nierstrasz & Brender a Brandis, 1929, wird als Synonym von A. rurtatus eingestuft. Es wird ferner eine neue, zu einer neuen Gattung gehorende Art, Astalione cruciaria, beschrieben; diese Art parasitiert Clastotoechus vanderhorsti (Schmitt) auf der Insel St. Croix., Aporobopyrus curtatus (Richardson, 1904) wird wiederbeschrieben. Diese Art ist ein Schmarotzer von Petrolisthes galathinus (Bosc) in Sudflorida und St. john, Westindien, P. armatus (Gibbes) in Florida, P. marginatus Stimpson auf Barbados und Porcellana sayana (Leach) in Nordcarolina und St. John. Aporobopyrus johannis Nierstrasz & Brender a Brandis, 1929, wird als Synonym von A. rurtatus eingestuft. Es wird ferner eine neue, zu einer neuen Gattung gehorende Art, Astalione cruciaria, beschrieben; diese Art parasitiert Clastotoechus vanderhorsti (Schmitt) auf der Insel St. Croix.]
Five species of Porcellanidae from the Caribbean Sea have been found to establish commensal relationships with other animals. In four of the described cases, comparable relationships were found to exist also in the Eastern Pacific. Therefore the origins of the discussed commensalisms are assumed to date prior to the final formation of the Central American land-bridge. In all cases the host provides protection to the commensal crab. In the species Minyocerus angustus (Dana), Polyonyx gibbesi Haig, and Porcellana sayana (Leach) the host serves as an auxiliary substrate which enables the porcellanid crab to colonize soft bottom habitats, normally not suitable for porcellanids. This interpretation is supported by P. sayana whose different hosts are not characterized by systematic relationship but by having the same habitat and by the requirements of the commensal as to the external structure and the habits of the host. The present observations show, that species which are found to live as obligate commensals in a definite geographical region, may be free-living elsewhere under different ecological conditions. As regulating factors, competition and predation are considered.
Observations and experiments have been made with the encysted phoronts of Gymnodinioides inkystans on the gills of the hermit crab (Pagurus longicarpus) and of Gymnodinioides sp. on the gills of the fiddler crab (Uca pugnax). The phoronts of both species would excyst in vitro, in a mixture of crab blood with sea water and antibiotics, and give rise to engorged trophonts, only if the cysts were taken from gills of a crab which was near molting. This excystation occurred somewhat more readily in the presence of blood from the same crab, near the molt, than in the presence of blood from a crab not close to molting. It is concluded that the encysted phoronts probably require a series of stimuli from the host in order to prepare them for the final stimulus which produces excystation just before the actual molt.
The association of the Galápagos Islands with the birth of Darwinian evolutionary theory has inspired many detailed studies of their fauna and flora. Yet the cirripeds, the only invertebrates to receive Darwin’s personal attention as a systematist, are virtually unknown for the region. His monographs on the Cirripedia (Darwin, 1851,1854) contain references to three species collected during the voyage of the Beagle: Balanus tintinnabulum (Linnaeus) and Tetraclita porosa (Gmelin) from rocky intertidal areas, and Platylepas decorata Darwin from marine turtles.
The taxonomic position of Kerunia cornuta is a matter of controversy. It has been classified as a cephalopod, a species of the hydrozoan genus Hyractinia and as a stromatoporoid. Oriented thin sections, serial sectioning and SEM studies reveal a basically hydrozoan microstructure. The characteristic shape of Kerunia is the net result of a complicated symbiotic relationship between a hydrozoan, a hermit crab, and its original home inherited from a gastropod. Functional morphology, associated epibionts, and field observations suggest that Kerunia cornuta lived on shallow marine bottoms. © 2003 E. Schweizerbart'sche Verlagsbuchhandlung, D-70176 Stuttgart.
McLaughlin, P.A. 2003. Illustrated keys to families and genera of the superfamily Paguroidea (Crustacea: Decapoda: Anomura), with diagnoses of genera of Paguridae. In: Lemaitre, R., and Tudge, C.C. (eds), Biology of the Anomura. Proceedings of a symposium at the Fifth International Crustacean Congress, Melbourne, Australia, 9‐13 July 2001. Memoirs of Museum Victoria 60(1): 111‐144. Keys, with illustrations of selected diagnostic characters, are provided for the seven families and 122 genera of the anomuran Superfamily Paguroidea, commonly known as hermit crabs and king crabs. In addition, abbreviated diagnoses are presented for the 69 genera presently assigned to the family Paguridae.
