Foraging Strategies of Cursorial and Ambush Spiders

Abstract

Food consumption in animals is a complex task with multiple steps. Choosing an adequate foraging site is the very first one, and involves not only the presence of prey and predators but also abiotic conditions. Because spiders are usually cannibalistic, conspecifics fall within these two categories in addition to being competitors. Specifically for ambush and cursorial spiders, the type of substrate is also very relevant because spiders often rely on substrate-borne vibrations to find their prey, and distinct substrates propagate vibrations differently. At this point or after contacting the prey, spiders have to decide whether or not to attempt capture. Such a decision involves profitability, prey defenses, and the physiological state of the spider. To capture prey, ambush and cursorial spiders may rely on web sheets, adhesive setae on the tips of the legs, glue-spitting, and venom directly injected from the fangs of the chelicerae. The actual mode of ingestion also varies among species. For almost every step from picking a foraging place to prey consumption, multiple sensory modalities may be used, such as vision, contact chemoreception, olfaction, detection of substrate-borne vibrations, and air displacement. Adequately choosing where to forage, properly detecting, choosing, capturing, and handling prey may have important fitness implications. In this chapter, we summarize the knowledge on these topics with regard to Neotropical cursorial and ambush spiders, detecting gaps and areas better covered within the topics above. Finally, we attempt to suggest promising model species to investigate these different steps of foraging in these animals.