Web forms and the phylogeny of theridiid spiders (Araneae: Theridiidae): Chaos from order

Eberhard, William G.; Agnarsson, Ingi; Levi, Herbert W.

doi:10.1017/s1477200008002855

Cited by 83 publications

(94 citation statements)

References 67 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Moreover, both theridiids and linyphiids spin highly 3-dimensional webs that allow escape from common predators of orb spiders, especially parasitic wasps (4). Finally, although the evolution of extreme stereotypy in spinning behaviors appears to have been a crucial prerequisite for the transition from substrate defined sheet webs to architecturally defined aerial orbs, subsequent loss of that stereotypy may then allow continued diversification of web shape and thus occupation of novel niches (62,63). In other words, like the orb architecture itself, stereotypy of spinning behaviors is not an evolutionary end point but rather a stepping stone that allows for new web architectures to evolve.…”

Section: Discussionmentioning

confidence: 99%

Reconstructing web evolution and spider diversification in the molecular era

Blackledge

Scharff

Coddington

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

343

374

View full text Add to dashboard Cite

The evolutionary diversification of spiders is attributed to spectacular innovations in silk. Spiders are unique in synthesizing many different kinds of silk, and using silk for a variety of ecological functions throughout their lives, particularly to make preycatching webs. Here, we construct a broad higher-level phylogeny of spiders combining molecular data with traditional morphological and behavioral characters. We use this phylogeny to test the hypothesis that the spider orb web evolved only once. We then examine spider diversification in relation to different web architectures and silk use. We find strong support for a single origin of orb webs, implying a major shift in the spinning of capture silk and repeated loss or transformation of orb webs. We show that abandonment of costly cribellate capture silk correlates with the 2 major diversification events in spiders (1). Replacement of cribellate silk by aqueous silk glue may explain the greater diversity of modern orb-weaving spiders (Araneoidea) compared with cribellate orb-weaving spiders (Deinopoidea) (2). Within the ''RTA clade,'' which is the sister group to orb-weaving spiders and contains half of all spider diversity, >90% of species richness is associated with repeated loss of cribellate silk and abandonment of prey capture webs. Accompanying cribellum loss in both groups is a release from substrate-constrained webs, whether by aerially suspended webs, or by abandoning webs altogether. These behavioral shifts in silk and web production by spiders thus likely played a key role in the dramatic evolutionary success and ecological dominance of spiders as predators of insects.Araneidae ͉ behavioral evolution ͉ cribellate silk ͉ orb web ͉ speciation S piders are exceptionally diverse and abundant in terrestrial ecosystems. In contrast to megadiverse orders of insects, evolutionary diversification of spiders is not coupled with major trophic shifts. All spiders are predators of arthropods, and spiders are dominant consumers at intermediate trophic levels (1, 2). Spider diversification is instead linked to key innovations in silk use (3-7). For instance, the araneoid orb web (Fig. 1) with stretchy capture spirals, coated by adhesive viscid silk secretions, provides access to abundant flying insects (3,8). However, many spiders produce cribellate silk, a radically different dry adhesive that adheres to prey, using van der Waals interactions and hygroscopic forces (9). Some cribellate spiders also construct aerial orb webs, whereas most spin sheet-like webs on the substrate (Fig. S1) or have abandoned capture webs altogether. Furthermore, the most diverse families within ''orb-weavers'' (Orbiculariae) no longer build orb webs, but instead spin aerial sheet webs (Linyphiidae) or cobwebs (Theridiidae) (Fig. S2). Thus, discovering the pattern of evolution of web spinning behaviors is essential for understanding spider diversification.Orb webs possessing dry cribellate capture spirals are architecturally similar to those spun from aqueous viscid silk ( Fig. 1 ...

show abstract

Section: Discussionmentioning

confidence: 99%

Reconstructing web evolution and spider diversification in the molecular era

Blackledge

Scharff

Coddington

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

343

374

View full text Add to dashboard Cite

show abstract

“…Theridiids exhibit extreme diversity in morphology, ecology, and behavior, and show a particularly diverse array of web types, from simple to complex (Arnedo et al 2004;Agnarsson 2004;Eberhard et al 2008). Despite important recent advances in the systematics and classification of the family (e.g., Arnedo et al 2004;Agnarsson 2004), generic relationships are not completely understood, and some theridiid genera are poorly delimited and probably para-or polyphyletic (Arnedo et al 2004).…”

Section: Introductionmentioning

confidence: 99%

“…Most genera of the subfamily Spintharinae present a modified web. The genera Spintharus, Episinus and Thwaitesia build a web with an "H"-like shape, while Chrosiothes builds a sheet-like web, presumably because of a specialization for their prey (Eberhard 1991;Agnarsson 2004;Eberhard et al 2008). Although all genera present sexual dimorphism in size, behavior differs considerably among genera.…”

Section: Introductionmentioning

confidence: 99%

Phylogenetic relationships of the comb-footed spider subfamily Spintharinae (Araneae, Araneoidea, Theridiidae), with generic diagnoses and a key to the genera

Durán-Barrón

Contreras‐Ramos²

2013

Zootaxa

View full text Add to dashboard Cite

The monophyly of Spintharinae is supported in agreement with previous analysis of Theridiidae by Agnarsson and Arnedo et al. We study the relationships of the genera within Spintharinae. Fourteen species in the genera Chrosiothes, Episinus, Spintharus, Stemmops, and Thwaitesia constituted the ingroup, while five species from the genera Euryopis and Dipoena (Hadrotarsinae), as well as Latrodectus and Steatoda (Latrodectinae), served as outgroup taxa. The character matrix included 49 morphological characters. Parsimony analyses using several character weighting strategies supported the monophyly of Spintharinae with Stemmops as sister to a clade that includes the remaining ingroup taxa. Chrosiothes emerged as sister to Episinus + Spintharus + Thwaitesia which formed a polytomy. The equally weighted, successive weighted, and preferred implied weight topologies, were all logically consistent. A key to the genera of Spintharinae and diagnoses for each genus are given.

show abstract

“…Orb-webs are spun only by members of the Orbiculariae. Furthermore, several derived families of Orbiculariae spin different web types, such as the cobwebs of the Theridiidae (Coddington and Levi, 1991;Eberhard et al, 2008). Planar orb webs contain major ampullate radii that only are in contact at the center of the web.…”

Section: Introductionmentioning

confidence: 99%

Evolution of supercontraction in spider silk: structure–function relationship from tarantulas to orb-weavers

Boutry

Blackledge

2010

Journal of Experimental Biology

109

View full text Add to dashboard Cite

SUMMARYSpider silk is a promising biomaterial with impressive performance. However, some spider silks also 'supercontract' when exposed to water, shrinking by up to ~50% in length. Supercontraction may provide a critical mechanism to tailor silk properties, both for future synthetic silk production and by the spiders themselves. Several hypotheses are proposed for the mechanism and function of supercontraction, but they remain largely untested. In particular, supercontraction may result from a rearrangement of the GPGXX motif within the silk proteins, where G represents glycine, P proline and X is one of a small subset of amino acids. Supercontraction may prevent sagging in wet orb-webs or allow spiders to tailor silk properties for different ecological functions. Because both the molecular structures of silk proteins and how dragline is used in webs differ among species, we can test these hypotheses by comparing supercontraction of silk across diverse spider taxa. In this study we measured supercontraction in 28 spider taxa, ranging from tarantulas to orb-weaving spiders. We found that silk from all species supercontracted, except that of most tarantulas. This suggests that supercontraction evolved at least with the origin of the Araneomorphae, over 200 million years ago. We found differences in the pattern of evolution for two components of supercontraction. Stress generated during supercontraction of a restrained fiber is not associated with changes in silk structure and web architecture. By contrast, the shrink of unrestrained supercontracting fibers is higher for Orbiculariae spiders, whose silk contains high ratios of GPGXX motifs. These results support the hypothesis that supercontraction is caused by a rearrangement of GPGXX motifs in silk, and that it functions to tailor silk material properties.

show abstract

Web forms and the phylogeny of theridiid spiders (Araneae: Theridiidae): Chaos from order

Cited by 83 publications

References 67 publications

Reconstructing web evolution and spider diversification in the molecular era

Reconstructing web evolution and spider diversification in the molecular era

Phylogenetic relationships of the comb-footed spider subfamily Spintharinae (Araneae, Araneoidea, Theridiidae), with generic diagnoses and a key to the genera

Evolution of supercontraction in spider silk: structure–function relationship from tarantulas to orb-weavers

Contact Info

Product

Resources

About