Two ways to hide: predator and prey perspectives of disruptive coloration and background matching in jumping spiders

Abstract

Camouflage is used by prey to avoid detection by predators, and by predators to remain unseen by their prey. Effective camouflage can be achieved through background matching, where an animal matches the colours and patterns of the background or through disruptive coloration, where high-contrast markings disrupt the viewer's ability to detect the animal's shape. We used digital images to measure the body colour of two jumping spiders, Anasaitis sp. and Ilargus sp., and the substrate in which they were found (vegetation and leaf litter, respectively), in order to investigate their camouflage strategies. We evaluated the chromatic and achromatic contrast and the body patterns of spiders and both substrates modelling the perception of a bird (Cyanistes caeruleus) and a fly (Drosophila melanogaster) as potential predator and prey. Both Anasaitis sp. and Ilargus sp. were a good colour match to leaf litter in fly and avian vision; however, Ilargus sp. was a worse colour match to foliage than Anasaitis sp. Compared with its background, Anasaitis sp. also had far higher contrast stripes than Ilargus sp. We suggest that Anasaitis sp. is adopting a disruptive coloration, generalist strategy, whereas Ilargus sp. is adopting a background-matching strategy.