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Ventral view of the contact surface of palps and forelegs of a female G. anthracina climbing upwards on a vertical surface of glass. Mainly claw tufts make contact with the glass (arrows).
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Tarantulas are large spiders with adhesive setae on their legs, which enable them to climb on smooth vertical surfaces. The mechanism proposed to explain adhesion in tarantulas is anisotropic friction, where friction is higher when the leg pushes than when it pulls. However, previous studies and measurements of adhesion in theraphosids were perform...
Context in source publication
Context 1
... climbing upwards, palps, legs I and II touched the surfaces only with part of the claw tufts ( Fig. 3), while leg pair IV touched the surface with the distal portion of tarsal scopulae and only in rare cases with claw tufts (Fig. 4A,B). Leg IV was more extended than the resting legs. This pattern was observed in all species on glass as well as on Teflon. When climbing on, legs III usually touched the surface with part of the claw tufts ...
Citations
... Wolff and Gorb (2015) analyzed climbing ability of hunting spider assemblages in microhabitats with differentiated vertical distribution and surface roughness. The phenomenon of footpad adhesion has also been studied in wandering spiders (Ctenidae; Niederegger andGorb 2006, Frost et al. 2018) and theraphosid tarantulas (Theraphosidae; Pérez-Miles et al. 2015, Silva et al. 2021. Pérez-Miles et al. (2015) showed that tarsal scopula and claw tufts produce friction forces acting in the opposite directions. ...
... The phenomenon of footpad adhesion has also been studied in wandering spiders (Ctenidae; Niederegger andGorb 2006, Frost et al. 2018) and theraphosid tarantulas (Theraphosidae; Pérez-Miles et al. 2015, Silva et al. 2021. Pérez-Miles et al. (2015) showed that tarsal scopula and claw tufts produce friction forces acting in the opposite directions. ...
... Studies of adhesive pads in spiders were mostly conducted because of varying capabilities of spiders to climb sloping and vertical surfaces and move on different types of substrata , Gasparetto et al. 2009, Foelix et al. 2012a, Wolff and Gorb 2012a, Niederegger 2013, Pérez-Miles et al. 2015, Frost et al. 2018, Goetzke and Federle 2021, Poerschke et al. 2021, Silva et al. 2021. However, relationships between tarsal morphology and environmental preferences of these animals were rarely analyzed. ...
The ventral surfaces of tarsi in spiders in the infraorder Mygalomorphae group play a key role in locomotion and burrow and nest construction. In our research, we analyzed the diversity of setae and patterns of sculpturing on tarsi in three species with different life strategies: a burrowing spider Brachypelma smithi (F. O. Pickard-Cambridge, 1897), a ground-dwelling spider, Pterinochilus murinus Pocock, 1897, and a arboreal spider, Poecilotheria regalis Pocock, 1899. We showed the presence of three types of setae on the ventral side of tarsi: plumose setae, short-haired spiniform setae, and spirally striated setae. Plumose setae were differentiated within a tarsus and their apical sections among the studied species, while the microtriched ensiform and spirally striated setae did not differ. All setae were characterized by a similar structure. Little differentiation was observed in the number and location of setae on the tarsi of the studied species. Spirally striated setae were absent in the burrowing spiders. In contrast, the shape and size of the sculpturing pattern varied among the studied species. The greatest differentiation was found in the burrowing and ground-dwelling spiders, while the smallest differentiation was found in the arboreal spider. We discuss our findings in relation to preferred habitats, the biology of the spiders, and adaptation of sculpturing and setae on spider feet to surface type. The morphology and diversity of setae and sculpturing patterns on the ventral side of tarsi in P. murinus was reported for the first time.
... Force measurements on scopula hairs in Aphonopelma seemanni (Theraphosidae) and Cupiennius salei (Ctenidae) confirmed that they are anisotropic and produce higher shear forces in the pushing direction (Niederegger and Gorb 2006). Moreover, it has been shown for bird spiders that during locomotion, tarsal scopula hairs are used for pushing, whereas pretarsal claw tufts are used for pulling and adhesion (Pérez-Miles et al. 2015). ...
Many spiders and insects can perform rapid jumps from smooth plant surfaces. Here, we investigate how jumping spiders ( Pseudeuophrys lanigera and Sitticus pubescens ) avoid slipping when accelerating. Both species differed in the relative contribution of leg pairs to the jump. P. lanigera accelerated mainly with their long third legs, whereas their short fourth legs detached earlier. In contrast, S. pubescens accelerated mainly with their long fourth legs, and their short third legs detached earlier. Because of the different orientation (fourth-leg tip pointing backward, third-leg tip pointing forward), the fourth-leg tarsus pushed, whereas the third-leg tarsus pulled. High-speed video recordings showed that pushing and pulling was achieved by different attachment structures. In P. lanigera , third-leg feet made surface contact with setae on their distal or lateral claw tuft, whereas fourth-leg feet engaged the proximal claw tuft, and the distal tuft was raised off the ground. S. pubescens showed the same division of labour between proximal and distal claw tuft for pushing and pulling, but the claw tuft contact lasted longer and was more visible in the fourth than in the third legs. Experimental ablation of claw tufts caused accelerating spiders to slip, confirming that adhesion is essential for jumps from smooth substrates.
... Within the Mygalomorphae, the Theraphosidae are characterized by the presence of specialized adhesive setae on distal segments of the legs (metatarsi and tarsi). These structures facilitate the locomotion and allow them to climb on vertical smooth surfaces including glass, and they also participate in the prey capture (Pérez-Miles et al. 2015, 2017. These setae, when arranged in a kind of brush on the ventral surface of tarsi and partially or totally on the metatarsi, are called scopulae; when present on the tip of the leg, under the claws, the adhesive setae are slightly longer and are called claw tufts (Fig. 1). ...
... These differences were correlated with microhabitat preferences and abilities to adhere to smooth surfaces. Arboreal theraphosids have more developed wide scopula with longer setae of similar structure as terrestrials, but no differences in adhesion properties were found in comparison with terrestrial species (Pérez-Miles et al. 2015). Wolff and Gorb (2015) demonstrated that in araneomorphs adhesive pads have an important role for locomotion and species with such structures are dominant on the arboreal upper strata while microhabitat surface (bark or leaves) seem to be less important than height. ...
... In studies that focused on the adhesion forces of the adhesive pads in spiders, the direction of friction and the mechanism of climbing and descending provided clear evidence of the joint and complementary participation of claw tufts and scopulae in locomotion and prey capture (Kesel et al. 2003;Niederegger and Gorb 2006;Wolff and Gorb 2012a, 2013Pérez-Miles et al. 2015, 2017. ...
Theraphosid tarantulas are large spiders that bear dense hairy adhesive pads on the distal parts of their legs: scopula and claw tufts. These structures allow them to climb on vertical smooth surfaces and contribute to prey capture. While adult females and juveniles remain most of the time in their burrows, adult males actively walk searching for females during the reproductive period. Adhesion and locomotion thus play important roles in the ecology and reproduction of these animals. In this paper, we review the current state of the knowledge on adhesion and locomotion in tarantulas, focusing on functional and evolutionary morphology.
... Scopulae and claw tufts consist of thousands of specialized setae that are apically broadened and cover the ventral surfaces of tarsi metatarsi and the tips of the legs under the paired claws (Pérez-Miles et al. 2015). These setae are oriented at a greater angle to the leg axis than covering setae (Pérez-Miles et al. 2015). ...
... Scopulae and claw tufts consist of thousands of specialized setae that are apically broadened and cover the ventral surfaces of tarsi metatarsi and the tips of the legs under the paired claws (Pérez-Miles et al. 2015). These setae are oriented at a greater angle to the leg axis than covering setae (Pérez-Miles et al. 2015). Setae of scopulae and claw tufts are covered on their distal part by setules with spatulashaped endings, which increase adhesion. ...
... Setae of scopulae and claw tufts are covered on their distal part by setules with spatulashaped endings, which increase adhesion. They have a very similar structure but differ in length and density (Foelix et al. 2012b;Pérez-Miles et al. 2015). ...
Tarantulas are large spiders with adhesive setae on their legs, which enable them to climb on smooth vertical surfaces. The mechanism proposed to explain adhesion in tarantulas is anisotropic friction, where friction is higher when the leg pushes compared to when it pulls. The static friction of live theraphosid spiders on different surfaces and at different inclines was measured and compared between burrowing and arboreal species to test the hypothesis of higher friction in arboreal tarantulas. We analyzed the complementary participation of claw tufts and scopulae of anterior and posterior legs when the tarantula climbs. We also considered the morphology of scopulae and claw tufts setae and compared with similar structures in other families. Adhesive setae, as well as some other setae types found on ventral tarsi are described and characterized. The adhesive face of setae varied in the orientation in different parts of the tarsi, and this variation is more conspicuous in the spiders that have only claw tufts or scopulae. The mechanics of climbing in association with the biological characteristics of the species are analyzed. We discuss the association of adhesive scopulae and claw tufts with burrowing/cursorial mygalomorphs as within Theraphosidae, as was suggested for free-hunter spiders. The morphology, functions, and evolution of scopula and claw tufts are discussed in this chapter.
... The setae of scopulae and claw tufts are covered on their distal, lamellar part by microtrichii (setules) with spatula-shaped endings, which increase adhesion (Wolff, Nentwig, and Gorb, 2013;Perez-Miles, Perafan, and Santamaria, 2015). Spatulae are plate-like termini of the setulae, providing the contact surface for van der Waals attraction in adhesion. ...
... Several authors (Dunlop, 1995;Foelix, 2011;Foelix, Rast, and Peattie, 2012;Niederegger, 2013) proposed that when the tarantulas walk on vertical glass they only use claw tufts for adhesion, while the tarsal and metatarsal scopulae are used for hunting. Perez-Miles, Perafan, and Santamaria (2015) reported that tarsal scopulae could also participate in locomotory adhesion. Foelix, Rast, and Peattie (2012) studied the adhesion of some tarantula species on glass and found that arboreal species show better adhesion than terrestrial ones. ...
The study focused on the specialised tarsal setae of tarantulas Avicularia metal-lica and Heteroscodra maculata, and the fibrous and non-fibrous material produced by them. When irritated spiders moved along smooth, perpendicularly-oriented glass walls not covered in silk, the claw tuft setae, located at the tips of the tarsal segments, left behind footprints containing two types of fibrous material. Using electron scanning microscopy, it was discovered that these represent fragments of parallelly oriented bundles of hollow fibres forming the shafts of the setae and their lateral branches (1), as well as clusters of contracted nanofibrils which aggregated at the ends of these fibres (2). During climbing, this fibrous material was detected both on the substratum on which the spiders were moving, and also on their claw tuft setae. The climbing activity of irritated tarantulas is also associated with the secretion of a fluid which dries on contact with air. This secretion acts as an adhesive and facilitates the movement of tarantulas on smooth surfaces, but while doing so it also glues together the distal, lamellar parts of the groups of setae which are in contact with the substratum during climbing. There are no such claw tuft setae morphological changes observed in undisturbed tarantulas, moving freely around their tube-like shelters and on the surfaces of objects covered with silk which they have produced. The sources of the air-drying secretion are probably the tubular fibres forming the shafts of pretarsal setae. The bundles of hollow fibres are an example of a system that produces secretions via a surficial pathway. The spinnerets and silk-producing glands associated with them, located in the opisthosoma, represent a system that produces silk via a systemic pathway. However, the results of observational studies have not confirmed the ability of tarantulas' feet to produce silk fibres of the same, or at least similar ultrastructure to that of the silk fibres produced by the activity of spinnerets and spinneret-associated silk glands.
... In order to study locomotion of Theraphosidae and other groups of spiders, one must consider the scopulae and claw tufts, which are adhesive devices on their legs. These structures could play an important role in locomotion, both on level ground and while climbing (Niederegger & Gorb, 2006;Foelix, 2011;Spagna & Peattie, 2012;Wolff, Nentwig & Gorb, 2013;Wohlfart et al., 2014;Lapinski, Walther & Tschapka, 2015;Pérez-Miles, Perafán & Santamaría, 2015;Wolff & Gorb, 2015;Pérez-Miles et al., 2017). Most of the species of Mygalomorphae (72%) have adhesive setae and they usually display cursorial lifestyles (Wolff, Nentwig & Gorb, 2013;Pérez-Miles et al., 2017). ...
... Most of the species of Mygalomorphae (72%) have adhesive setae and they usually display cursorial lifestyles (Wolff, Nentwig & Gorb, 2013;Pérez-Miles et al., 2017). However, the contribution of these features with respect to climbing is subject to controversy (Pérez-Miles, Perafán & Santamaría, 2015;Pérez-Miles et al., 2017). Pérez-Miles, Perafán & Santamaría (2015) analyzed the role of the adhesive setae of different species to improve locomotion on level ground and at different gradients of incline using both glass and Teflon as substrate for their trials. ...
... However, the contribution of these features with respect to climbing is subject to controversy (Pérez-Miles, Perafán & Santamaría, 2015;Pérez-Miles et al., 2017). Pérez-Miles, Perafán & Santamaría (2015) analyzed the role of the adhesive setae of different species to improve locomotion on level ground and at different gradients of incline using both glass and Teflon as substrate for their trials. As expected, they determined that glass contributed to higher levels of friction than Teflon (Roth & Willis, 1952;Pérez-Miles, Perafán & Santamaría, 2015). ...
Background
The mechanics and energetics of spider locomotion have not been deeply investigated, despite their importance in the life of a spider. For example, the reproductive success of males of several species is dependent upon their ability to move from one area to another. The aim of this work was to describe gait patterns and analyze the gait parameters of Eupalaestrus weijenberghi (Araneae, Theraphosidae) in order to investigate the mechanics of their locomotion and the mechanisms by which they conserve energy while traversing different inclinations and surfaces.
Methods
Tarantulas were collected and marked for kinematic analysis. Free displacements, both level and on an incline, were recorded using glass and Teflon as experimental surfaces. Body segments of the experimental animals were measured, weighed, and their center of mass was experimentally determined. Through reconstruction of the trajectories of the body segments, we were able to estimate their internal and external mechanical work and analyze their gait patterns.
Results
Spiders mainly employed a walk-trot gait. Significant differences between the first two pairs and the second two pairs were detected. No significant differences were detected regarding the different planes or surfaces with respect to duty factor, time lags, stride frequency, and stride length. However, postural changes were observed on slippery surfaces. The mechanical work required for traversing a level plane was lower than expected. In all conditions, the external work, and within it the vertical work, accounted for almost all of the total mechanical work. The internal work was extremely low and did not rise as the gradient increased.
Discussion
Our results support the idea of considering the eight limbs functionally divided into two quadrupeds in series. The anterior was composed of the first two pairs of limbs, which have an explorative and steering purpose and the posterior was more involved in supporting the weight of the body. The mechanical work to move one unit of mass a unit distance is almost constant among the different species tested. However, spiders showed lower values than expected. Minimizing the mechanical work could help to limit metabolic energy expenditure that, in small animals, is relatively very high. However, energy recovery due to inverted pendulum mechanics only accounts for only a small fraction of the energy saved. Adhesive setae present in the tarsal, scopulae, and claw tufts could contribute in different ways during different moments of the step cycle, compensating for part of the energetic cost on gradients which could also help to maintain constant gait parameters.
... Tarsal insect attachment usually implies directionality, i.e., the friction forces depend on the sliding direction, which is a major feature ensuring controllability, i.e., the ability of the tarsi to rapidly attach to and detach from a variety of surfaces. Whereas such behaviour has mainly been demonstrated for smooth tarsal attachment systems [19,49,50], little such evidence exists for hairy systems [51][52][53]. As expected, in both the investigated Nicrophorus species, the friction forces of the fore tarsi increase in the pull direction corresponding to the alignment and the apical structure of the tenent hairs. ...
Our aim was to compare friction and traction forces between two burying beetle species of the genus Nicrophorus exhibiting different attachment abilities during climbing. Specifically, the interaction of adhesive hairs and claws during attachment with respect to various surface properties was investigated by using a 2 × 3 experimental design. Traction force was measured for two different surface energies (hydrophilic vs hydrophobic) varying in roughness from smooth to micro-rough to rough. Nanotribometric tests on single legs were also performed. The external morphology of the attachment devices investigated by scanning electron microscopy suggested higher intra-specific (intersexual) than inter-specific differences. Whereas differences between the two species in traction force were high on smooth surfaces, no differences could be detected between males and females within each species. With claws intact, both species showed the highest forces on rough surfaces, although N. nepalensis with clipped claws performed best on a smooth surface. However, N. nepalensis beetles outperformed N. vespilloides, which showed no differences between smooth and rough surfaces with clipped claws. Both species demonstrated poor traction forces on micro-rough surfaces. Results concerning the impact of surface polarity were inconclusive, whereas roughness more strongly affected the attachment performance in both species. Nanotribometric analyses of the fore tarsi performed on micro-rough and rough surfaces revealed higher friction in the proximal (pull) direction compared with the distal (push) direction. In these experiments, we detected neither differences in friction performance between the two species, nor clear trends concerning the influence of surface polarity. We conclude that the investigated morphological traits are not critical for the observed interspecific difference in attachment ability on smooth surfaces. Furthermore, interspecific differences in performance are only clear on smooth surfaces and vanish on micro-rough and rough surfaces. Our results suggest that even subtle differences in the adhesion-mediating secretion in closely related species might result in qualitative performance shifts.
... The morphology of sticky setae, functions, mechanics and association with lifestyle was exhaustively studied (Homann 1957;Foelix and Chu-Wang 1975;Hill 1977;Rovner 1978;Kesel et al. 2003Kesel et al. , 2004Niederegger andGorb 2006, Varenberg et al. 2010;Foelix 2011;Foelix et al. 2012;Keane et al. 2012;Gorb 2012a, b, 2015;Niederegger 2013;Wohlfart et al. 2014;Lapinski et al. 2015;Pérez-Miles et al. 2015); these studies mostly focused on Araneomorphae. However, fine structure and function of adhesive setae in mygalomorphs are severely understudied. ...
... Considering the morphology, it is expected that distal setae produce adhesion when the leg pulls while proximal setae produce adhesion when the leg pushes. This hypothetical mechanism is congruent with the observations of Pérez-Miles et al. (2015) but differs from results by Niederegger and Gorb (2006) who found higher adhesion on scopula when the leg pushes in the theraphosid Aphonopelma seemanni. Rovner (1978), Foelix et al. (1984), Pekar et al. (2011 and Eggs et al. (2015) proposed the participation of scopulae in prey manipulation in Araneomorphae but some characteristics we found in Mygalomorphae at first question this function. ...
... Pulling adhesion is expected in claw tufts or the extreme of tarsal scopula, so these features could be involved in both prey capture and adhesion for locomotion. When the spider climbs vertically upward, the adhesion may be produced by apical adhesive setae of forelegs pulling and proximal scopula of hind legs pushing (Pérez-Miles et al. 2015) with a similar dynamics as proposed by and Wohlfart et al. (2014), for Cupiennius (Keyserling 1877). Inversely, when the locomotion is oriented downward, anterior scopulae push and posterior claw tufts (or distal scopulae) pull. ...
Mygalomorphae spiders have several cuticular structures, such as stridulating, sensory and urticating setae, which offer great potential for phylogenetic studies. Spiders of the subfamily Theraphosinae have stridulating setae that aid in group taxonomy, having been found in numerous genera including: Acanthoscurria Ausserer, 1871, Aguapanela Perafán, Cifuentes & Estrada-Gomez, 2015, Citharacanthus Pocock, 1901, Cyrtopholis Simon, 1892, Grammostola Simon, 1892, Hemirrhagus Simon, 1903, Lasiodora C. L. Koch, 1850, Longilyra Gabriel, 2014, Pamphobeteus Pocock, 1901, Phormictopus Pocock, 1901 and Theraphosa Thorell, 1870. Some distinct bristle-like setae were examined using scanning electron microscopy with the following objectives: (1) to sample and describe the diversity of setae on the coxae and trochanters of representatives of the subfamily Theraphosinae; and (2) to code morphological characters useful for phylogenetics. We used a previously published phylogenetic matrix, with modifications to those characters that scored stridulatory setae, and analyzed these data using parsimony with implied weighting. Setae of the same type were found in Acanthoscurria, Brachypelma Simon, 1891, Cyrtopholis, Phormictopus and Theraphosa (claviform stridulating setae). A second type, which we name velvet stridulating setae, emerged as an autapomorphy of the genus Lasiodora, and spiniform stridulating setae were recovered as an autapomorphy of the genus Pamphobeteus. Some other setae similar to those of Lasiodora, named plumose stridulating setae, were found in Nhandu Lucas, 1983, Proshapalopus Mello-Leitaõ, 1923, Pterinopelma Pocock, 1901 and Vitalius Lucas, Silva & Bertani, 1993. © 2018 American Museum of Natural History. All rights reserved.
... The morphology of sticky setae, functions, mechanics and association with lifestyle was exhaustively studied (Homann 1957;Foelix and Chu-Wang 1975;Hill 1977;Rovner 1978;Kesel et al. 2003Kesel et al. , 2004Niederegger andGorb 2006, Varenberg et al. 2010;Foelix 2011;Foelix et al. 2012;Keane et al. 2012;Gorb 2012a, b, 2015;Niederegger 2013;Wohlfart et al. 2014;Lapinski et al. 2015;Pérez-Miles et al. 2015); these studies mostly focused on Araneomorphae. However, fine structure and function of adhesive setae in mygalomorphs are severely understudied. ...
... Considering the morphology, it is expected that distal setae produce adhesion when the leg pulls while proximal setae produce adhesion when the leg pushes. This hypothetical mechanism is congruent with the observations of Pérez-Miles et al. (2015) but differs from results by Niederegger and Gorb (2006) who found higher adhesion on scopula when the leg pushes in the theraphosid Aphonopelma seemanni. Rovner (1978), Foelix et al. (1984), Pekar et al. (2011 and Eggs et al. (2015) proposed the participation of scopulae in prey manipulation in Araneomorphae but some characteristics we found in Mygalomorphae at first question this function. ...
... Pulling adhesion is expected in claw tufts or the extreme of tarsal scopula, so these features could be involved in both prey capture and adhesion for locomotion. When the spider climbs vertically upward, the adhesion may be produced by apical adhesive setae of forelegs pulling and proximal scopula of hind legs pushing (Pérez-Miles et al. 2015) with a similar dynamics as proposed by and Wohlfart et al. (2014), for Cupiennius salei (Keyserling 1877). Inversely, when the locomotion is oriented downward, anterior scopulae push and posterior claw tufts (or distal scopulae) pull. ...
We studied the morphology of scopula, claw tufts and a scopula-like feature (pseudoscopula) of tarsi on representatives of all Mygalomorphae spider families. The pseudoscopula is constituted by groups of non-microtriched conical setae. The taxonomic distribution of all these features was studied and mapped on a recent phylogeny of Mygalomorphae and the association of them with the lifestyles of the spiders was analyzed. Adhesive setae, as well as some other setal types found on ventral tarsi are described and characterized. The adhesive face of setae varied in the orientation in different parts of the tarsi, and this variation is more conspicuous in the spiders which only have claw tufts or scopula. We found an association of adhesive scopulae and claw tufts with burrower/cursorial or thin wafer lid trapdoor mygalomorphs as suggested for free hunter spiders, but we found that the pseudoscopula is associated with males of some trap-door and some weavers mygalomorphs. The presence of pseudoscopula widely extended among Mygalomorphae seems to be ancestral for the infraorder. The setal morphology of pseudoscopula suggests chemosensorial function; sparse chemosensory setae were also found in almost all Mygalomorphae. The morphology, functions and evolution of scopula, claw tufts and pseudoscopula are discussed.
... The research on these species covered several topics of reproductive biology, testing various hypotheses related to sexual selection, sexual communication, and reproductive isolation ( Costa et al. 2015). Other aspects such as locomotion and adhesion have also been studied in this group ( Pérez-Miles et al. 2015). Behavioral research in wolf spiders in Uruguay has been focused on two species as the main models: Schizocosa malitiosa ( Tullgren, 1905) and Allocosa senex ( Mello-Leitão, 1945). ...
Natural history collections are essential tools for development in biological
research. Since the nineteenth century, arachnological collections in the
Neotropics have been collaborating to carry out research on spiders and human
resource training. In many cases, they have been the starting point of several research
fields and the first steps allowing the development of arachnological studies in many
Latin American countries. An important part of the future production of arachnological
knowledge is deposited in these collections. They preserve critical data
about the natural history of Neotropical spiders in several areas of knowledge, such
as taxonomy, systematics, ecology, ethology, and biogeography. The present chapter
is focused on the historical, present, and future perspectives of Neotropical
arachnological collections and their contribution to spider research. We also discuss
the main role that araneological collections will play in the future of knowledge of
Neotropical spider diversity and its conservation.
