No full-text available
To read the full-text of this research,
you can request a copy directly from the author.
Eggs and egg-laying
Abstract
This new book offers a full-scale treatment of British butterfly ecology. We have not had a comparable source-book for many years, and now it comes at a time when many butterfly populations worldwide, including about half the British species, are in decline. The authors bring together new ideas, facts, and figures from recent studies to discuss individual butterfly behaviour and adaptations; population dynamics, community structure, distributions, and habitats; and the underlying genetics and evolutionary pathways. The last chapter focuses on conservation. Information is presented in considerable detail, and the volume includes an extensive glossary, full bibliography, many tables, appendices on hostplants and habitats, and more than ninety figures. Students of butterflies, ecology, and natural history will find it an invaluable reference tool as well as a benchmark in ecological studies. The authors are well known for their work in research, conservation, and education. They are: Roger Dennis, Tim Shreeve, Keith Shreeve, Keith Porter, Martin Warren, Paul Brakefield, Jeremy Thomas, and Caroline Steel. Derek Whiteley prepared the figures.
... Therefore, the visibility of plants is crucial in selecting oviposition sites and depends on local features of the soil morphology, the vegetation structure, and the physical size of the host plant present within a habitat patch. This topic has been studied by several authors and recognized as related to the presence of eggs (Porter, 1981;1992;Anthes et al., 2003;Konvicka et al., 2003;Fowles & Smith, 2006;Liu et al., 2006;Stefanescu et al., 2006;Betzholtz et al., 2007;Botham et al., 2011;Pennekamp et al., 2013). our observations on E. a. provincialis have led us to the same conclusion and show that there was no preference in the choice of the host plant in this species and the egg deposition was determined only by host plants visibility and accessibility to females. ...
... The observed pattern of host plant use is of great relevance to the conservation of the species E. a. provincialis, with the data showing selection of the same G. cruciata plants year after year. Accordingly to observations on E. a. aurinia (Porter, 1992;Anthes et al., 2003;Sardet & Betremieux, 2006;Singer, 2003In: Stefanescu et al., 2006 females of E. a. provincialis also lay their eggs on the same plant where other females have previously laid. The multiple batch placements seem unrelated to host plant availability. ...
... Female prefer to lay their eggs on the plants where other females have previously oviposited as in E. aurinia aurinia (Porter, 1992;Anthes et al., 2003;Sardet & Betremieux, 2006;Singer, 2003In: Stefanescu et al., 2006. In E aurinia, living in larval groups seems to be evolutionary selected through laying egg batches. ...
In this paper, we show the results of research that can inform conservation measures elsewhere in Europe for the endangered butterfly Euphydryas aurinia. A five year field study was undertaken to identify the host plant preference of larvae of Euphydryas aurinia provincialis in the Mediterranean and which signals are used by females to lay their eggs. The females oviposit on Gentiana cruciata, Scabiosa columbaria and Cephalaria leucantha; the larvae feed on all these plants and additionally on Lonicera caprifoliumin the wild and on Gentiana lutea in the laboratory. The females do not show any preference for a specific host plant and the larvae move from one species of plant to another without any difficulty. The most important factors in determining the female oviposition are the visibility, accessibility and sun-exposure of the host plants. The vegetative state of host plants is the key factor in larval use of plants during the pre- and post-diapause period. The large-sized host plants, G. cruciata and C. leucantha, are optimal for the growth and survival of the pre-diapause I-III larval instar, while they are unavailable to the larvae in Spring because of their delayed vegetative growth. The post-diapause larvae preferentially feed on plants of S. columbaria, and to lesser degree L. caprifolium, as they provide and abundant food source compared with G. cruciata and C. leucantha. The results also suggest that, there is an evolutionary advantage in large numbers of caterpillars feeding together, with the females of E. aurinia provincialis preferring to lay their eggs nearby or above egg batches
laid previously by another female, and selecting large plants for oviposition. Despite the competition for food among caterpillars, the oviposition behaviour of females is advantageous and increases the larval survival rate on large plants. The gregarious larval behaviour provides several benefits during both pre-diapause period (avoiding starvation) and post-diapause period (efficiency in thermoregulation).
... Lysandra bellargus males live for 4±10 days, females for 10±12 days (Davies et al., 1958). Females lay up to 60 eggs singly on the foliage of H. comosa (Thomas, 1983; Porter, 1992). After the ®rst instar, larvae are tended by ants, mainly by Myrmica sabuleti and Lasius alienus (Thomas, 1983). ...
... A rather speculative explanation would include seasonal differences in nutritional requirements. The needs of females for amino acids in their adult diet may be related to the status of egg maturation when females emerge from their chrysalides, and may also be governed by food reserves accumulated during the larval stages (Porter, 1992). Poor larval growing conditions late in the season and energy costs for larval overwintering may particularly reduce the nutritional state of females at emergence in spring. ...
1. Field observations in the Swiss Jura mountains showed that males and females of the bivoltine Adonis Blue butterfly Lysandra bellargus Rott. differed significantly in their flower visitation patterns.
2. In both generations, females visited a broader range of available nectar plants than did males. The specific flower visitation patterns of males and females were not affected by the general availability and abundance of potential nectar plant species during both flight periods, indicating high selectivity for nectar plants by both males and females.
3. In addition, the sexes differed in their nectar foraging behaviours: distances between successively visited flowers were significantly longer in males than in females, indicating that male and female butterflies have different foraging strategies.
4. Investigations of nectar characteristics showed that the sexes preferred flowers with different nectar compositions. Males of both generations preferred flowers with high proportions of sucrose and high amounts of total sugar, whereas females preferred flowers with high portions of glucose in their nectar, and, in the spring generation, flowers rich in amino acids.
5. Flowers visited exclusively by males or females in spring differed significantly in their amino acid composition.
6. This clear-cut pattern did not hold for the autumn generation, most probably due to the limited availability of flowers.
7. The observed nectar foraging patterns underline the importance of adult feeding for longevity and reproduction in butterflies. The findings are particularly relevant for conservation, because L. bellargus is an increasingly threatened species in many European countries.
... Pieris napi laid most of their eggs in semi-open and semi-closed microhabitats, and P. rapae, in open ones (Table 1 and Figure 2). These results indicate that habitat choice preceded host-plant selection, as has long been proposed (Courtney 1986, Porter 1992, Dennis 2010) and as has been found for this pair of species (Ohsaki 1982, Ohsaki and Sato 1999, Friberg and Wiklund 2019. ...
Ecotones linking open and forested habitats contain multiple microhabitats with varying vegetal structures and microclimatic regimes. Ecotones host many insect species whose development is intimately linked to the microclimatic conditions where they grow (e.g., the leaves of their host plants and the surrounding air). Yet microclimatic heterogeneity at these fine scales and its effects on insects remain poorly quantified for most species. Here we studied how interspecific differences in the use of microhabitats across ecotones lead to contrasting thermal exposure and survival costs between two closely‐related butterflies (Pieris napi and P. rapae). We first assessed whether butterflies selected different microhabitats to oviposit and quantified the thermal conditions at the microhabitat and foliar scales. We also assessed concurrent changes in the quality and availability of host plants. Finally, we quantified larval time of death under different experimental temperatures (thermal death time [TDT] curves) to predict their thermal mortality considering both the intensity and the duration of the microclimatic heat challenges in the field. We identified six processes determining larval thermal exposure at fine scales associated with butterfly oviposition behavior, canopy shading, and heat and water fluxes at the soil and foliar levels. Leaves in open microhabitats could reach temperatures 3–10°C warmer than the surrounding air while more closed microhabitats presented more buffered and homogeneous temperatures. Interspecific differences in microhabitat use matched the TDT curves and the thermal mortality in the field. Open microhabitats posed acute heat challenges that were better withstood by the thermotolerant butterfly, P. rapae, where the species mainly laid their eggs. Despite being more thermosensitive, P. napi was predicted to present higher survivals than P. rapae due to the thermal buffering provided by their selected microhabitats. However, its offspring could be more vulnerable to host‐plant scarcity during summer drought periods. Overall, the different interaction of the butterflies with microclimatic and host‐plant variation emerging at fine scales and their different thermal sensitivity posed them contrasting heat and resource challenges. Our results contribute to setting a new framework that predicts insect vulnerability to climate change based on their thermal sensitivity and the intensity, duration, and accumulation of their heat exposure.
The impact of habitat disturbance on butterfly species assemblage in the Afrotropical
region was studied by investigating inter-habitat community variation of butterflies.
Distinct butterfly species assemblages were found across surveyed habitat types, with
1554 adult butterflies of 126 species from five families recorded. The Primary forests
had the highest species diversity and a higher dissimilarity between the Secondary
and Plantation Forests. Of the 126 species recorded, 80 species were unique to one
habitat. We provide new insights into butterfly ecology in the region, which can inform the development of conservation strategies to protect these ecosystems.
We used a 12-year survey of butterflies in 24 parks in Marseille (South-East France), to highlight the overall decline of butterfly biodiversity (richness, abundance, diversity) in this Mediterranean city. This study confirms the importance of the urban gradient in the composition and structure of butterfly communities with a clear difference between the city centre and the outskirts. The study also highlights the preponderant role of local factors. While the distance from the natural environment remains a major factor, nectar resources and habitat diversity are local factors that can positively drive biodiversity. In contrast, management, as currently practised, has a negative effect on biodiversity. This implies that management, nectar resources and habitat diversity in parks are the key action levers at local scale. Thus, our results show that the response is not linear, from the most urban to the least urban, but seems to be closer to a patch/mosaic structure according to the importance of local factors. The long-term survey shows that butterfly communities show a simplified pattern: generally, parks on the outskirts tend to resemble those of the intermediate level and parks of the intermediate level tend to resemble those of the city centre. The long-term survey shows that butterfly communities have lost in complexity with the loss of Mediterranean species probably linked to the disappearance of their host plants. Finally, this long-term study suggests that it is possible to influence biodiversity through management with direct action in the management of green spaces.
Aims
The aim of this study was to determine the butterfly diversity in Okomu National Park, Nigeria in order to make available information on butterfly species in this protected areas.
Background
Butterflies are a taxonomically important group for predicting the health of the environment.
Objective
In order to establish butterfly abundance and distribution in Okomu National Park, a temporal variation study was conducted for a period of twenty-four months (July 2012 to June 2014).
Methods
Eight transects (Disturbed habitat (DIS), Forest Edge/Plantation (FE/P), Moderately Open Forest (MOF), Forest Along Road/Moist Patches (FAR/MP), Riparian Habitat (RIP), Closed Canopy (CC), Shrub (SHR) and Grassland (GRA) were mapped out from the four ranges (Igwonwan, Arakhuan, Julius Creek and Babui) from visual level of disturbance and degree of canopy closure for transect walk, butterfly net and baited trap methods of butterfly sampling. Environmental variables (temperature, relative humidity, and rainfall) were concurrently sampled with butterflies.
Results
A total of 143 species and 6,310 individuals of butterflies were obtained from the families; Nymphalidae, Papilionidae, Pieridae, Lycaenidae, and Hesperiidae. Nymphalid (3103: 49.2%) and Pieridae (2269: 36.0%) predominated and Hesperiidae was recorded low (8: 0.1%). Significant differences were observed in the abundance of butterflies in the transects (p< 0.05). Rainfall was positively correlated with butterfly abundance. Butterfly abundance was higher in rainy season compared to dry season except in RIP where a reverse trend was observed. Abundance was higher in FAR/MP (1633: 25.9%) and MOF (1251: 19.8%) compared to other transects, and was lowest in SHR (295: 4.7%).
Conclusion
It can be concluded that butterfly in Okomu forest is abundant and stable, and as such continuous effort is required to conserve butterfly flora and fauna in this park.
Grazing generally benefits grassland biodiversity as it prevents shrub and tree succession. However, too intense
grazing may have negative effects for example many grassland insects. EU-subsidies for grazing of some habitats,
aimed at promoting biodiversity, still require a relatively intense grazing, and could therefore have negative
consequences for some species. We quantified how such grazing affects habitat quality for the marsh fritillary
butterfly, and how this influence its colonization-extinction dynamics and persistence. Specifically, we studied a
metapopulation on Gotland (Sweden), where the marsh fritillary occupies unfertilized calcareous grassland with
a naturally slow succession. We quantified the difference in larvae autumn nests between grazed and ungrazed
habitat, and used this difference to adjust the ‘effective area’ of 256 habitat patches in a 50 km2 landscape. We
then parameterized a metapopulation model based on the occurrence pattern of the adult butterfly, and simulated
future population development under different grazing regimes. The results showed that ungrazed habitat
harbored 4.8 times more nests than grazed habitat. Reducing the ‘effective area’ of grazed patches accordingly
increased the local extinction probability and decreased colonization. Grazing all suitable habitat reduced the
occupancy by over 80%, while no grazing increased the occupancy by up to 40%, based on projections of future
dynamics. Current grazing is clearly too intense, and EU-subsidies are here, thus, a conservation measure with
negative consequences for a threatened butterfly. To prevent this, subsidies for grazing need to be more flexible
and better adapted to the prevailing soil conditions and requirements of the target species.
In this study we assessed microhabitat and host plant preferences of Aporia crataegi (Linne 1758) larvae in the field. The study was conducted in the submediterranean part of Slovenia, at the edge of the limestone region Kraški rob, where this species is widespread. The larvae were most abundant on blackthorn (Prunus spinosa L.) and the com-mon hawthorn (Crataegus monogyna Jacq.), and infrequent on the rosehip (Rosa sp.) and rock cherry (Prunus mahaleb L.). Smaller shrubs with greater exposure to sun appeared to be preferred and larvae constructed their nests on outer branches of plants. The thermophilic nature of larvae was evident by the low and sheltered position of the nests, although in P. spinosa, which is more thermophilic than C. monogyna, they were positioned somewhat higher. As the nests and larvae occur mostly on plants growing in warmer microhabitats, larvae that had overwintered can take advan-tage of the quicker development of buds and leaves in early spring. The rocky ground below and around the occupied plants was often covered with grass, suggesting the need for cooler and warmer microclimate during hot summers and cold winters with strong winds, respectively. Densities of larvae and nests were positively but non-significantly correlated to density of host plants; however, in later suc-cessional stages, where host plants are most abundant, open and sunny microhabitats that can provide opportunities for larvae to warm up are lacking. The revival of the traditional management practices with extensive grazing with late and only occasional mowing may slow down the overgrowing process, leaving spiny host plants abundant and in close proximity to the nectaring sources for the adults.
Many species adapted to alpine and montane meadow ecosystems are at risk of extinction. The skipper Pyrgus ruralis lagunae Scott is a mountaintop butterfly restricted to San Diego County, CA, a federally listed endangered species, and is in imminent risk of extinction. Historically, P. r. lagunae was found in the Laguna and Palomar mountains. We did not detect the skipper in the Laguna Mountains, and the species has likely been extirpated from this area, which represents half of its historical range and is the type locality. We studied three populations on Palomar Mountain. Skippers primarily occupied areas close to creeks or in adjacent ravines at two nongrazed sites. The third site is grazed by cattle, and skippers were found close to the forest edge. At nongrazed locations, creek areas had higher cover of intermediate-height vegetation, more bare ground, and more flowers compared with unoccupied areas of the same meadow. The vegetation at occupied and unoccupied areas within the grazed meadow were similar. Even so, skippers occupied areas with more bare ground as well as greater species richness of flowering plants. A grazing exclosure was previously installed in an attempt to protect and enhance skipper habitat, but skippers did not use the dense grasslands that developed inside the exclosures. Contrary to the prevailing theory, protection from grazing did not improve skipper habitat. This illustrates how management based on inadequate biological information can hinder well-intentioned conservation efforts.
The reproductive systems of males and females are generally constant in form within butterfly species. Males provide sperm as well as accessory gland substances for transferring to females. During copulation, a single spermatophore including sperm is structured in the bursa copulatrix of females. The bursa copulatrix can contain a full-size spermatophore or remnants of several spermatophores. The sperm to be used for fertilisation is stored in the spermatheca of females, not in the spermatophore. The female oviposition system is essentially a paired structure with two ovaries. Fertilisation takes place in the common oviduct as the sperm pass along this duct and enter the egg. Sperm dimorphism occurs in butterflies. An eupyrene spermatozoon, the normal sperm that can fertilise an egg, is transferred to the female as bundles in the spermatophore. A bundle consists of 256 eupyrene spermatozoa. The apyrene spermatozoon, however, has no nucleus and does not have fertilisation ability. After copulation, both types of spermatozoa move out of the bursa copulatrix, and then arrive at the spermatheca to be stored until oviposition. The spermatheca does not enlarge relative to the stored spermatozoa, suggesting the number of spermatozoa stored is limited. Therefore, the success of sperm migration from the spermatophore to the spermatheca is primarily critical for the reproductive success of the males.
Female oviposition decisions in insects may strongly affect offspring growth and survival, and thus determine population performance. In this study, we examined oviposition site selection in the xerophilous ecotype of the endangered myrmecophilous butterfly Phengaris (=Maculinea) alcon (Lepidoptera, Lycaenidae) in Estonia, at the northern distribution margin of both the butterfly and its host plant, Gentiana cruciata L. Egg distribution on individual host plants appeared to be highly uneven: plants carrying high egg loads contrasted to a high proportion of host plants without any or with a few eggs. Host plant use for oviposition was strongly dependent on plant characteristics and environmental context. Host plant height relative to the surrounding vegetation rather than the absolute height of host plants was a key factor determining the use of particular host plant individuals for oviposition. In particular, plants protruding above surrounding vegetation had a higher probability of being used for oviposition, and carried more eggs. Additionally, the number of eggs laid on individual host plants was positively associated with the presence of flowers and the number of shoots. More aggregated host plants received fewer eggs than those with less conspecifics around. Feeding damage by wild herbivores, found in a substantial proportion of the butterfly’s host plants, strongly reduced the number of eggs on individual plants. Our results underline the need to assure that butterfly’s host plants do not become overgrown by surrounding vegetation. Best practices for opening vegetation around host plants may need further studies that explicitly account for butterfly’s host ants—their abundance in relation to vegetation height and their response to opening vegetation.
Context
Evidence-based nature conservation focuses on ecological facts and the incorporation of knowledge on the ecology of species, including its entire life cycle. In butterflies, imagos and its larvae often demand specific and diverging micro-habitat structures and resources. In consequence, ecological requirements of the imaginal and pre-imaginal stage have to be taken into consideration to conduct effective conservation management.
Objective
Here we analyse ecological pre-requisites of imagos and larvae for two lycaenid butterfly species, the common blue Polyommatus icarus and the adonis blue Polyommatus bellargus. Both butterfly species occur in calcareous grasslands and mainly depend on two plant species at our study site, the horseshoe vetch Hippocrepis comosa and bird’s-foot trefoil Lotus corniculatus. These plant species serve as nectar sources and larval host plants for the two butterfly species.
Methods
First, we assessed the occurrence of imagines and larvae of the two butterfly species and recorded various micro-habitat characteristics, like the number of flower buds of the two main host plants, the surrounding vegetation height, percentage of bare soil, availability of shadow, and the distance to and geographic direction of thickets at respective sites. In a second step we took high resolution aerial pictures from our study area using an unmanned aerial vehicle (drone). Based on these aerial pictures and the information on the larvae´s habitat preference from our field observations, we trained a habitat suitability model to identify micro-habitat structures suitable for larvae of the two butterfly species.
Results
We found that abundance of imagos is positively correlated with flower bud density of the two host plants. Low vegetation height and high proportion of bare soil (but not flower bud density) positively influence egg oviposition. The calculated habitat suitability models predict the occurrence of high quality larval habitats with high prediction power (AUC = 0.72).
Conclusions
This combined data set consisting of field observations, high resolution aerial pictures taken from an unmanned aerial vehicle, and models underline that (1) species with complex life cycles may request more than one habitat niche, depending its stage of development, and (2) high resolution aerial pictures taken from drones provide valuable background data to generate habitat suitability models—even on a micro scale but covering larger parts of a landscape.
Extremely long proboscides of insect flower visitors have been regarded as an example of a coevolutionary arms race, assuming that these insects act as efficient pollinators for their nectar host plants. However, the effect of proboscis length on generalized or specialized flower use remains unclear and the efficiency of butterfly pollination is ambiguous. Neotropical Hesperiidae feature a surprising variation of proboscis length, which makes them a suitable study system to elucidate the role of extremely long-proboscid insects in plant-pollinator networks. The results of this study show that skippers with longer proboscides visit plant species with deep-tubed flowers to take up food, but do not pollinate them. Skippers equipped with extremely long proboscides seldom include short-tubed flowers in their diet nor visit more plant species than those with shorter proboscides. Our observations indicate that the extremely long-proboscid skippers steal nectar from their preferred nectar host plants, Calathea sp., instead of contributing to their pollination. Finally, we discuss the impact of nectar robbery by these butterflies on their nectar host plants and their legitimate pollinators, euglossine bees.
Historical data sources on abundance of organisms are valuable for determining responses of those organisms to climate change and coincidence of changes amongst different organisms. We investigate data on the general abundance of Lepidoptera over an 89 year period 1864-1952. We related abundance to monthly mean temperature and precipitation and the winter North Atlantic Oscillation (NAO) index, and to numbers of migrants from an independent source. Abundances of Lepidoptera were significantly positively correlated with current year temperatures for May to September and November and significantly negatively correlated with temperatures in January. Numbers were also negatively correlated with rainfall for April and May and annual total of the current year and with August in the previous year. Abundance of Lepidoptera decreased significantly with. an increasing,winter NAO index. Increased overall abundance in Lepidoptera coincided significantly with increased numbers of migrants. The climate associations were very similar to those previously reported for butterfly data collected by the British Butterfly Monitoring Scheme; although warm and drier summers were generally beneficial to Lepidoptera populations, wet summers and winters and mild winters were not. We discuss the implications for Lepidoptera biology and populations in regions of Britain in the face of projected climate changes.
Both land use intensification and abandonment within grasslands lead to a homogenisation of vegetation structure. Therefore, specially structured microsites such as vegetation gaps with bare ground play an important role for species conservation within grasslands. Vegetation gaps are crucial for the establishment of low-competitive plant species and offer special microclimatic conditions essential for the development of the immature stages of many invertebrate species. The influence of small-scale soil disturbance in the form of mounds created by ecosystem engineers such as ants or moles on biodiversity is therefore of special scientific concern. The effects of mound-building species on plant species diversity have been extensively studied. However, knowledge on the significance of these species for the conservation of other animals is rare. In this study we analyse the importance of mounds created by the European mole (Talpa europaea) as an oviposition habitat for the small copper (Lycaena phlaeas) within Central European mesotrophic grasslands. Our study showed that host plants occurring at molehills were preferred for oviposition. Oviposition sites were characterised by an open vegetation structure with a high proportion of bare ground (with a mean coverage of about 50 %), a low cover of herbs and low-growing vegetation (mean height: 4.5 cm). Our study clearly illustrates the importance of small-scale soil disturbance for immature stages of L. phlaeas and the conservation of this species within mesotrophic grasslands. Mound-building ecosystem engineers, such as T. europaea, act as important substitutes for missing dynamics within mesotrophic grasslands by diversifying vegetation structure and creating small patches of bare soil.
Many butterfly target species are associated with early successional stages of grasslands. The Blue-spot Hairstreak, Satyrium spini (Denis & Schiffermüller, 1775), is a target species of grasslands. However, it feeds on Common Buckthorn (Rhamnus cathartica), which is associated with late successional stages of grasslands. If S. spini would also be restricted to late seral stages, there might be a management dilemma due to the contrasting requirements of S. spini and other target species. The aim of this study was to determine the oviposition preference of S. spini in calcareous grasslands, and to give management recommendations to promote this species. Therefore, we studied the oviposition microhabitats of S. spini at three representative patches of the Diemel Valley (Central Germany) by comparing environmental conditions on occupied and control host plants. In total we surveyed 1,889 host plants. Altogether we found 148 batches of S. spini on them containing 396 eggs. Most of the eggs were on plants that grew under the warmest conditions. Females preferred to lay eggs on small (< 1.3 m) shrubs of Rh. cathartica fully exposed to the sun growing on steep south- and west-facing slopes. This butterfly showed no difference in its preference for bushes growing in hedges or solitarily. About 80% of the batches of eggs were laid on the upper surface of a twig fork close to the surface of the ground (< 1 m). Our study showed that S. spini is a species characteristic of mid-successional stages of calcareous grasslands. The survival of suitable habitats for S. spini depends on regular management. To achieve this we recommend traditional rough grazing with sheep and goats, which creates open grasslands with small Rhamnus plants. In addition, the shrubs in tall hedges bordering calcareous grasslands should be subjected to cutting on a rotating basis.
The breakdown of the transhumant grazing system in the Spanish Pyrenees has led to a severe decline in the area of pastures. However, in the high mountain zone there are still large areas of species-rich grasslands. The aim of this study was to assess the oviposition preferences of the shrub-feeding Blue-spot hairstreak, Satyrium spini (Denis & Schiffermüller, 1775), in montane common pastures in the Spanish Pyrenees and recommend a way of managing these grasslands that favours this species. Our study showed that females of S. spini laid their eggs on Dwarf buckthorn (Rhamnus pumila Turra) and Alpine buckthorn (R. alpina L.), which are novel host plant records for Spain. A warm microclimate was of crucial importance for egg-laying. Occupied plants grew mostly at sparsely vegetated grassland sites where there were large patches of bare rocks, stones or gravel. Most egg batches were laid close to the ground and 75% consisted of only one egg. The number of batches per R. pumila plant was higher on east-, southand west-facing slopes than on north-facing slopes. Presence of eggs and the number of egg batches per R. pumila plant were best explained by a long sunshine duration. At high altitudes particularly warm microhabitats seem to be more important for S. spini than at lower altitudes in Central Europe. We assume that the preference for unusually warm microhabitats is explained by the cold climatic conditions near the altitudinal range limit of the species. That most of the eggs were laid singly and not in small batches as in Central Europe might be a risk-spreading strategy to cope with the harsh climatic conditions and the high inter-annual variation in weather conditions in the high mountain zone in the Pyrenees. The best way to maintain open grasslands for S. spini and other thermophilous grassland species in the high mountain zone of the Pyrenees is to use the traditional combination of sheep and cattle grazing.
Small-scale soil disturbance, such as animal mounds created by subterraneous ecosystem engineers are important microhabitats for species of conservation concern. There are many studies on the effects of ecosystem engineers on plant species diversity and soil properties, but the influence of such organisms on other taxa, such as insects, are rarely analyzed. In this paper, we demonstrate for the first time the role of molehills produced by the European Mole (Talpa europaea) (Linnaeus, 1758) as a larval habitat for a threatened butterfly species within central European calcareous grasslands. We selected the grizzled skipper (Pyrgus malvae) (Linnaeus, 1758) as a study species as previous studies revealed that it prefers warm and open microhabitats for oviposition. Our study clearly showed that host plants occurring on or in the close vicinity of molehills were regularly occupied by immature stages of P. malvae. Occupied host plants at these disturbed sites were characterized by a more open vegetation structure with a higher proportion of bare ground or stones and a lower cover of the herb layer compared with available host plants (control samples). Among molehills those were preferred that had the highest cover of host plants, especially Agrimonia eupatoria. Molehills are important larval habitats for P. malvae in calcareous grasslands on deeper soils. At these sites succession occurs rapidly and the amount of bare ground is usually low, even when they are managed. In contrast to other known breeding sites in calcareous grasslands, molehills with a high cover of host plants provide ideal conditions for the successful larval development of P. malvae: (i) sufficient food during the larval period and (ii) warm microclimatic conditions.
High-mountain endemics with very restricted ranges are likely to have a high risk of extinction under the various scenarios of global warming. Endemic to the high mountains of the St Katherine Protectorate in South Sinai (Egypt), the Sinai Hairstreak Satyrium jebelia is just such a species. For the first time, its population size was estimated and its distribution and that of its larval food plant (Rhamnus dispermus) were mapped. The total world population in 2012 was estimated to be 1,010 individuals, perhaps divided into six smaller sub-populations of varying size. Its moderate dispersal ability and the relatively close proximity of the sub-populations may indicate metapopulation structure, but more data are needed. Aspects of host-plant and habitat quality were significant predictors of the presence of Sinai Hairstreaks on individual trees. No immediate threats are evident except global warming: if current climate-change predictions for Egypt are correct, the quality of habitat and plant diversity will decrease in the St Katherine Protectorate, with obvious long-term conservation implications.
As pre-hibernating larvae of the marsh fritillary (Euphydryas aurinia) have limited mobility essential resources need to be available at a very local scale. We surveyed larval webs (2011–2013), the host plant devil’s bit scabious (Succisa pratensis) (2012), and derived variables from digital orthophotos and digital elevation models (Normalized Differenced Vegetation Index, accumulated sun hours, slope, aspect) to explain the presence–absence and abundance of larval webs at three different spatial grain sizes (5 × 2.5 m, 10 × 10 m, 25 × 25 m) across seven study sites in northern Jutland, Denmark. Two-component hurdle models indicated that host plant abundance was the only important predictor of presence–absence and abundance of larval webs across the seven sites. The strength of the host plant effect on larval web prevalence increased when enlarging spatial grain size. For presence–absence (and less for abundance), the effect of host plants on larval webs varied across study sites. Using mixed effects models, we additionally analysed presence–absence of larval webs (in 1 × 1 m plots) in relation to detailed host plant measurements (abundance and size), vegetation height, and environmental variables (soil temperature, air temperature and soil moisture) across four of the sites. This showed that larval webs were located in the densest parts of the host plant patches. Given the low mobility of pre-hibernating larvae (
1. ‘Ecological fitting’ is the process whereby the suites of traits an organism carries from previous evolutionary relationships are used to enable colonisation of novel environments or resources.
2. The concept has much explanatory power in studies of novel host associations, particularly when data suggest a deviation from optimal foraging theory, but is often overlooked in studies of herbivore host selection behaviour in favour of evolutionary hypotheses.
3. In the present study, the concept was used to explain the unusual host selection behaviour of the New Zealand endemic oligophagous butterfly Lycaena salustius Fabricius, the larvae of which feed on endemic Polygonaceae species and the introduced and closely related Fagopyrum esculentum Moench.
4. In field cage oviposition choice assays involving only endemic plants, females preferred to oviposit on the rare Muehlenbeckia astonii Petrie. However, the novel host F. esculentum was overwhelmingly preferred in an additional greenhouse assay. In larval no‐choice performance assays, fitness indicators were variable for the novel host.
5. This imperfect relationship between oviposition preference and larval performance is discussed as a possible example of ecological fitting and highlights the potential use of the concept as an explanatory tool in novel host selection behaviour studies.
The adults’ mobility and oviposition preferences of Zerynthia cassandra have been studied for the first time, with the aim of integrating auto-ecological information into recommendations for the habitat’s management of this species. Results of our mark-release-recapture study have highlighted that Z. cassandra is a strictly sedentary species, since detected movements only occurred over very short distances (≤200 m) and mainly within the species’ reproductive habitat (i.e. around Aristolochia rotunda stands), with males moving further than females. Our study shows that the main oviposition habitat of Z. cassandra is found where A. rotunda plants are growing in large stands; sites where plants growing in half to full sun and mostly oriented to the south are preferred. The distance of deposited eggs from the plants’ roots was narrowly correlated with the plants’ length. Eggs were deposited singly, mainly on the underside of leaflets. Management strategies necessary for improving the most important habitat features for the conservation of this species are suggested.
Understanding the factors that determine habitat quality is vital to ensuring appropriate habitat management. The main objective of this study was to assess the microhabitat preferences of egg-depositing females of the Grizzled Skipper (Pyrgus malvae) in calcareous grasslands of the Diemel Valley (Central Germany) for defining habitat quality. Based on this knowledge, we make management recommendations for the conservation of this threatened species. P. malvae generally preferred open and warm oviposition sites. However, there were considerable differences in the environmental conditions, depending on the selected host plant. On the small Potentilla tabernaemontani plants that grew in sparse vegetation with low-growing turf, mostly only one egg was found per plant. In contrast, occupied Agrimonia eupatoria host plants were larger and more prominent, regularly having more than one egg, and grew at sites with a taller and denser vegetation. The observed oviposition pattern reflects a trade-off between microclimate and food availability: Usually, occupied P. tabernaemontani plants grow under favourable microclimatic conditions. However, during hot years the risk of desiccation is high, leading to food shortage. In contrast, A. eupatoria generally provides more biomass, thrives on deeper soils and the vegetation has a cooler microclimate: hence, food shortage is somewhat unlikely. To meet the described habitat requirements of P. malvae, traditional rough grazing by sheep and goats seemed to be the most appropriate land management strategy. The re-introduction of coppicing in woodlands, particularly adjacent to calcareous grasslands, would also be beneficial.
The large copper butterfly, Lycaena dispar batavus, a subspecies of much conservation interest, is host-specific to the great water dock, Rumex hydrolapathum, but little is known of the relationship between herbivore and host in wild populations. This study investigated the distribution of both R. hydrolapathum plants and L. d. batavus eggs in four different habitat types within the Weerribben National Park, The Netherlands, during the summer of 1993. As expected, host plant distribution strongly influenced that of its herbivore. Further, both species had significantly aggregated distributions, and that of R. hydrolapathum was in agreement with the negative binomial model. Host plant selection for oviposition showed no significant relationship with physical plant characteristics, such as plant height and the number of leaves, and at the scale studied, habitat type was of only limited influence. The possible influence of the vegetational architecture surrounding host plants is discussed.
The time schedule of mate-locating behavior in the male satyrine butterfly Lethe diana was studied. Males displayed territorial behavior only in the afternoon, but it was not known whether they attempted to locate mates in the morning. In order for males of most butterfly species to mate with a virgin female, it would be most effective to initiate mate-locating behavior in the morning, when synchronous eclosions occur. Males of L. diana flew patrols in the morning and displayed territorial behavior in the afternoon. The cost of territorial behavior is probably less than that of patrolling, as territorial flights are shorter than those when patrolling. The temporal switching of mate-locating behavior is theoretically favored, since the reproductive value of females decreases later in the day, when males perform the less costly mate-locating behavior. Thus, the diurnal switching of male mate-locating behavior may be an adaptive strategy in response to the rapid decline in the reproductive value of females over the course of a day.
Data are presented which confirm previous findings that sympatric mimicry complexes dominated by unpalatable Neotropical ithomiine butterflies (Nymphalidae: Ithomiinae) are vertically stratified by height of flight. Flight height of ithomiine species is positively correlated with the height of their larval host-plants. Thus members of a mimicry complex utilize host-plants of similar heights. Non-mimetic British woodland butterflies also show a positive relationship between flight height and host-plant height, which suggests that the relationship is independent of mimicry. I propose that female butterflies fly at heights which maximize the probability of encountering their larval host-plants, and that males fly at similar heights to females in order to maximize the probability of encountering potential mates. Female butterflies probably encounter plants of similar heights to their larval hosts more frequently than they encounter plants of other heights. I suggest that butterfly species may therefore be more likely to make host shifts to plant species of a similar height to their current host-plants. Finally, I discuss how the relationship between flight height and height of larval host-plants, coupled with microhabitat-dependent selection on colour pattern, could lead to the evolution in sympatry of vertically stratified mimicry complexes.
1. The thermal environment at the scale in which most species exist is largely unknown, and thus the majority of physiological models is based on meteorological measures of ambient temperature.
2. The use of artificial neural networks in ecological analysis is promoted by using them to model microhabitat temperature.
3. The performance of conventional multiple linear regression is compared with that of artificial neural networks in predicting the temperature profiles of two different microhabitats using ambient temperature, solar radiation, and wind speed as input (independent) variables.
4. In both cases, the artificial neural networks showed a lower mean absolute residual error than multiple linear regression (0.95 °C compared with 1.41 °C, and 0.29 °C compared with 0.50 °C) and a higher correlation ( r ² ) between predicted and observed values (0.832 compared with 0.668, and 0.884 compared with 0.670).
5. An artificial neural network developed to include a microhabitat patch description based on height within patch, substrate, and four classes of per cent vegetation cover performed well ( r ² = 0.933, prediction error 95% confidence limits =± 2.5 °C).
6. It is suggested that artificial neural networks are more appropriate than conventional regression‐based approaches for estimating microhabitat temperature.
1. Habitat requirements and occurrence patterns of three species of burnet moths ( Zygaena filipendulae , Zygaena lonicerae and Zygaena viciae ) were studied at different life stages and different scales on the Baltic island of Öland, Sweden.
2. Larvae of all three species were more likely to occur in small‐scale patches (i.e. 1 m ² ) with a greater cover of their most important host plants, Lotus corniculatus , Trifolium medium / pratense , or Vicia spp., than were pupae or adults, and were also observed on significantly larger than random plants. Pupation of Z . filipendulae took place in taller vegetation than preferred by feeding larvae and adults.
3. Adults of all species preferred different nectar plants of Asteraceae and Dipsacaceae , growing in sunny conditions.
4. A large‐scale analysis of occupancy patterns was made, evaluating the relationship between burnet occurrence and the area of meadows and pastures within 10 × 10 km grid cells in Sweden. All three species showed a significant positive relationship with the area of semi‐natural grassland. The area required for a 50% probability of burnet occurrence was 454 ha for Z . filipendulae , 925 ha for Z . lonicerae and 2055 ha for Z . viciae .
5. Conservation work should aim at preserving and restoring open areas rich in the respective host plants and nectar sources, with light grazing or mowing late in the season. At the landscape scale, burnet moths were favoured by a high density of semi‐natural grassland and management priorities should be directed to these regions.
Egg placement by herbivorous insects is an important step in their interaction with their host plants, and is the result of processes operating at different spatial and temporal scales. Although several studies have examined egg-placement patterns at different scales, this has rarely been achieved simultaneously using a multi-scale hierarchical approach. We studied egg placement in a rare European butterfly, Iolana iolas, whose larvae specifically feed on seeds of plants of the genus Colutea, using a hierarchical approach and Generalised Linear Mixed Modelling. The study was carried out in 2002 and 2003 in a ca 60 km2 area in southern Madrid province, Spain, where the host plant, Colutea hispanica, has a highly fragmented distribution. We monitored in detail 132 plants in 24 patches and estimated the abundance of butterflies over the whole reproductive period of C. hispanica. We measured phenological, morphological and landscape variables potentially affecting egg-placement at three hierarchical levels: fruit, plant and host plant patch. Using egg presence–absence on mature fruits as the response variable, we found that eggs were more likely to be laid on fruits aged 1–2 weeks at the middle of the flowering period (fruit level), on large plants with a small number of shoots at the base (plant level), and in well connected host plant patches (patch level). Our results suggest that egg-placement is a process determined by factors operating at different levels: fruit, plant and host plant patch. Because egg-placement studies are often made with spatially correlated data, neglecting their intrinsic hierarchical nature could lead to equivocal conclusions.
1. Predictions on species richness and incidence of species are made using data for three scales of mapping from the Greater Manchester butterfly atlas; for the whole of the conurbation (2 km×2 km scale) and for two sample areas centred on the Mersey Valley (1 km×1 km scale; 1 ha scale). Predictions are based on data for recording effort, altitude, biotopes, host‐plants and nectar resources.
2. Data for Greater Manchester indicate that substantial shortfalls may occur in recording butterfly species for atlases despite the fact that butterflies are generally easily identified and well supported with recorders. Shortfalls tend to be larger for species with fewer records, indicating that some species may be more easily overlooked than others.
3. The results demonstrate that targeting squares for re‐survey is necessary and feasible. The predictions have other valuable research applications, the most important of which is being able to assess the accuracy of distribution maps, to correct them, and to make projections of distribution changes.
4. Predictions may be enhanced by improvements to mapping in three ways: (i) Collecting data on recording effort. Variation in recording effort typically accounts for differences in species richness and incidence of species more than any other variable; (ii) Collecting data on biotopes and specific resources. The present results are promising and demonstrate that the collection of environmental data linked to a suitable sampling frame could facilitate knowledge of the distribution of species over extensive areas that remain under‐recorded; and (iii) Distinguishing between breeding individuals and vagrants. Vagrancy is a problem associated both with species and scale. Although species vary substantially in their capacity to migrate beyond their habitats, the effect of vagrancy on distribution maps becomes an increasingly large problem as the grain of mapping (size of recording units) decreases. It is suggested that over‐recording can be a problem, particularly when mapping is fine‐grained.
We analysed the habitat preferences of adult stages and oviposition electivity of Melitaea aurelia in calcareous grasslands in the Diemel Valley (central Germany) to assess the key factors for successful management. Egg-laying
and adult habitats of M.aurelia were more or less congruent. Oviposition electivity at the host plant (Plantago media) was best explained by a combination of host plant quantity and vegetation structure. Habitat quality, isolation and patch
area explained 86% of the current patch occupancy of M. aurelia. With M. aurelia preferentially inhabiting transitional vegetation types, management requires a balance between abandonment and disturbance.
Disturbances provide open soil that facilitates germination of the host plant Plantago media. On the other hand, immature and adult stages of M.aurelia perform best on calcareous grasslands with a high amount of host plants and low disturbance intensity. Traditional rough
grazing regimes seem to be the most favourable tool for developing the necessary spatial and temporal heterogeneity in patches.
The best results may be achieved by rotational grazing where only a subset of inhabited patches is grazed intensively each
year. Our analysis of patch occupancy indicates that it would be desirable to restore patches in close proximity to occupied
sites.
We studied the oviposition and larval habitat preferences of the Niobe fritillary (Argynnis niobe) in the dunes of the east Frisian Island Langeoog (German North Sea). By ascertaining habitat quality we are able to assess
the minimum habitat size for populations of A. niobe in dune islands. The preferred oviposition and larval habitats were best characterised by a combination of (1) host-plant
abundance, (2) host-plant quality and (3) vegetation structure. The oviposition and larval habitats of A. niobe were characterised by low-growing vegetation with bare ground and a warm microclimate. In contrast to the also common V. tricolor ssp. curtisii, the leaves of the host plant V. canina showed a lower C/N ratio, suggesting that differences in plant quality may account for host-plant use. A. niobe seems to depend on very large areas of potential larval habitat, thus explaining its ongoing decline in the increasingly
fragmented Central European landscape. Our data indicate that grass encroachment is a major threat for A. niobe in coastal dunes due to its negative impact on microclimate and violet germination. Mosaic top-soil removal and low-intensity
grazing should be suitable tools to promote rejuvenation of V. canina.
The ecological effects of fire management, especially regarding arthropods are poorly investigated. Burning in winter was
assumed to pose a threat to butterfly species hibernating as larvae. To assess the impact of prescribed burning on population
viability, we analysed larval-habitat preferences of the highly endangered, xero-thermophilous butterfly Hipparchia fagi in vineyards of the Kaiserstuhl region (southern Germany). Microhabitat preference analyses for mature larvae and egg-laying
females revealed a preference of H.fagi for Bromus erectus-dominated communities with sparse vegetation coverage and a distinct tuft growth of the host plant B.erectus on microclimatically benefited slopes. We explain the preference of B.erectus by a preference of vegetation structure. The grass tufts offer a suitable climatically buffered living space for larvae.
Egg deposition took place on dry substrate at positions of high solar radiation, thus adapted to hot and dry microclimate.
As the larval habitat was sparsely vegetated as well as generally legally protected, fire management was not applicable and
therefore not affecting the populations. We think it is conceivable that H.fagi, occurring here at its northern range limit, might expand its larval habitat into denser, combustible B.erectus stands in the course of global warming. A change in habitat preferences would necessitate a re-evaluation of management options.
Maritime ringlet butterflies (Coenonympha nipisiquit McDunnough), an endangered species in Canada, inhabit salt marshes, which consist of microhabitat mosaics with varied larval
survival rate. These microhabitats may influence the movement and reproductive behaviors of females, which in turn may affect
population dynamics. I recorded behaviors and locations of females every minute with a GPS rover and calculated their move
lengths and turning angles. Move lengths did not change in response to microhabitats, although turning angles became larger
near bodies of water with sparse vegetation. Females spent a longer time in one location and oviposited more often where the
principal larval host, Spartina patens (Aiton) Muhl., is abundant, regardless of larval survival rate. Older females tended to initiate flight more readily than
younger females and spent more time flying and nectaring. Younger females were more fecund and spent a longer time at one
location. Because young females tend to be less mobile and more fecund, the majority of oviposition should take place near
eclosion sites. However, some eggs will be laid away from microhabitats favorable to larval survival when older females become
mobile and move out of their natal microhabitats. Because it seems to have little potential to colonize new habitat on its
own, monitoring population dynamics and habitat quality will be crucial for the persistence and recovery of this rare species.
ResearchGate has not been able to resolve any references for this publication.