Morphological phylogeny of cobweb spiders and their relatives (Araneae, Araneoidea, Theridiidae)

Agnarsson, Ingi

doi:10.1111/j.1096-3642.2004.00120.x

Cited by 252 publications

(422 citation statements)

References 186 publications

(394 reference statements)

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“…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.

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334

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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 ...

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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

334

368

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“…Such vibrations are common in courting Achaearanea (e.g. observations of Lubin [28]) and may be generated by abdominal vibrating, tremulation or stridulation, as stridulatory devices are common in theridiid spiders [29]. Male spiders, on entering the female's web, also spend up to several minutes approaching the female and tapping her legs and body.…”

Section: Discussionmentioning

confidence: 99%

Assassin bug uses aggressive mimicry to lure spider prey

Wignall

Taylor

2010

Proc. R. Soc. B.

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Assassin bugs (Stenolemus bituberus) hunt web-building spiders by invading the web and plucking the silk to generate vibrations that lure the resident spider into striking range. To test whether vibrations generated by bugs aggressively mimic the vibrations generated by insect prey, we compared the responses of spiders to bugs with how they responded to prey, courting male spiders and leaves falling into the web. We also analysed the associated vibrations. Similar spider orientation and approach behaviours were observed in response to vibrations from bugs and prey, whereas different behaviours were observed in response to vibrations from male spiders and leaves. Peak frequency and duration of vibrations generated by bugs were similar to those generated by prey and courting males. Further, vibrations from bugs had a temporal structure and amplitude that were similar to vibrations generated by leg and body movements of prey and distinctly different to vibrations from courting males or leaves, or prey beating their wings. To be an effective predator, bugs do not need to mimic the full range of prey vibrations. Instead bugs are general mimics of a subset of prey vibrations that fall within the range of vibrations classified by spiders as 'prey'.

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“…The spiders of this family are kleptoparasitic and araneophagous and build webs of diverse architecture (Exline & Levi 1962;Elgar 1993;Agnarsson 2004). In India, this family is represented by 43 species (Platnick 2013).…”

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confidence: 99%