Flexibility in the foraging strategies of spiders

Abstract

Although many spiders build prey-capture webs, spider foraging strategies include species that, instead of building webs, deploy silk in other ways for prey capture. Additionally, there are species that capture prey, either by ambush or by active pursuit, without making notable use of silk in the process. There are striking examples of predatory specialisation from spiders, particularly among the Salticidae, suggesting that assumptions about adaptive trade-offs, in which the small nervous systems of spiders might constrain their cognitive or sensory abilities, need to be carefully evaluated. Predatory versatility, whereby an individual spider adopts a conditional strategy with which it classifies prey into diverse categories, illustrates that an individual spider may be a poly-specialist, because it is polyphagic and at the same time it is highly specialised on more than one prey type. More generally, individual flexibility in spider behaviour has important implications concerning the cognitive capacities of predators that orchestrate their strategies using small nervous systems. Introduction. At first glance, characterising spider foraging might appear straightforward. All spiders are predators, and most frequently the spider's prey is an insect. All spiders produce silk, which is often put to use as part of their predatory arsenal. Yet a closer look reveals staggering diversity - and it is not just variation between species that contributes to this diversity, as we also need to address variation within single species and even within individual spiders.