Colouration of the orb-web spider Gasteracantha cancriformis does not increase its foraging success
2012
Gawryszewski, F.M. | Motta, P.C.
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.
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