Colouration of the orb-web spiderGasteracantha cancriformisdoes not increase its foraging success

Abstract

The presence of conspicuous colouration in predators is puzzling because natural selection is expected to favour cryptic or disruptive colouration, making predators less detectable by prey. However, the prey attraction hypothesis proposes that conspicuous colour patterns in spiders increase their foraging success by luring prey. Using manipulative experiments we tested the prey attraction hypothesis for the three most common colour morphs of the orb-weaver Gasteracantha cancriformis (yellow, white, and black and white), as well as individuals painted black and individuals painted yellow. Contrary to our predictions, the black painted spiders had the highest number of damaged areas in webs (an indirect measure of foraging success). Black painted spiders were also observed more often consuming prey and with prey remains in the web, although the trend was not significant. Furthermore, there was no difference in the number of prey intercepted by webs of each spider colour and, in the laboratory, Drosophila melanogaster did not choose any of the spider colours preferentially. Our results suggest that colouration in G. cancriformis is costly or neutral in terms of foraging success. Alternatively, we propose that colouration in Gasteracantha could be an aposematic signal.

Jewelled spiders manipulate colour-lure geometry to deceive prey

“…I used the presence of new prey items and/or web damage as a measure of interceptions in the preceding time period [15,16]. While this may overestimate true interception rates as a result of abiotic confounds (e.g.…”

Technicolour deceit: a sensory basis for the study of colour-based lures

“…Our understanding of the function and evolution of colour lure systems is in its infancy, and most studies to date have explored the fundamental question of whether a given phenotype enhances foraging success (Blamires et al, 2012;Gawryszewski & Motta, 2012;Tso et al, 2007;Tso, Liao, Huang, & Yang, 2006;Vaclav & Prokop, 2006). This work has done much to dispel the idea that common luring groups, such as orb-web spiders, are essentially passive predators, and has proven particularly valuable in clarifying the ecology of colour lure systems.…”

A nocturnal cursorial predator attracts flying prey with a visual lure

“…The prey attraction function of spider body coloration, however, has only recently been discovered, mainly in the web-building spiders. Several web-building spiders increase the web interception rate of insects through brightly coloured body parts as has been shown in a diverse array of genera such as Argiope (Bush, Yu, & Herberstein, 2008) and Gasteracantha (Hauber, 2002) of the family Araneidae, Nephila of the family Nephilidae (Fan, Yang, & Tso, 2009;Tso, Lin, & Yang, 2004;Tso, Tai, Ku, Kuo, & Yang, 2002) and Leucauge of the family Tetragnathidae (Tso, Liao, Huang, & Yang, 2006), although a few studies do not support the visual lure hypothesis (Gawryszewski & Motta, 2012;Vanderhoff, Byers, & Hanna, 2008). In addition to web spiders, some cursorial spiders have also been demonstrated to visually lure prey.…”