The discerning predator: decision rules underlying prey classification by a mosquito-eating jumping spider

Abstract

SUMMARYEvarcha culicivora is an East African jumping spider that feeds indirectly on vertebrate blood by choosing blood-fed female Anopheles mosquitoes as prey. Previous studies have shown that this predator can identify its preferred prey even when restricted to using only visual cues. Here, we used lures and virtual mosquitoes to investigate the optical cues underlying this predatorʼs prey-choice behaviour. We made lures by dissecting and then reconstructing dead mosquitoes, combining the head plus thorax with different abdomens. Depending on the experiment, lures were either moving or motionless. Findings from the lure experiments suggested that, for E. culicivora, seeing a blood-fed female mosquitoʼs abdomen on a lure was a necessary, but not sufficient, cue by which preferred prey was identified, as cues from the abdomen needed to be paired with cues from the head and thorax of a mosquito. Conversely, when abdomens were not visible or were identical, spiders based their decisions on the appearance of the head plus thorax of mosquitoes, choosing prey with female characteristics. Findings from a subsequent experiment using animated 3D virtual mosquitoes suggest that it is specifically the mosquitoʼs antennae that influence E. culicivoraʼs prey-choice decisions. Our results show that E. culicivora uses a complex process for prey classification.

Negative Correlation between Ant and Spider Abundances in the Canopy of a Bornean Tropical Rain Forest

“…Future studies of the detailed mechanisms affecting the relative abundances of the two taxa in a particular place (tree) should consider the ant habit of establishing territories or exclusive spaces (Hölldobler & Wilson , Human & Gordon ), myrmecophily in spiders (Cushin ), spider visual acuity (which allows them to detect enemies at a distance; Hölldobler & Wilson , Zurek et al . , Nelson & Jackson , ), and the micro‐environmental conditions that limit behavior and survival.…”

Optical cues used in prey identification by a juvenile jumping spider, Yllenus arenarius (Araneae, Salticidae)

“…Rendered movies (swf format) were back projected (1400 × 1050 pixels) on to a screen using a SHARP XR-10X-L data projector. Data projectors with comparable properties of display were used in similar studies with other jumping spiders (Harland & Jackson 2002;Nelson & Jackson 2006, 2012b. The screen was situated about 100 mm from the projector lens.…”

“…E. culicivora was found to use even more complex algorithms in prey recognition than Portia. The spider was demonstrated to use female mosquito-specific cues, such as the mosquito's characteristic resting posture, the cues from a blood-fed female abdomen, cues from the thorax and head, specifically the mosquitoʼs antennae Nelson & Jackson 2006, 2012b.…”

Visual stimulus characteristics that elicit tracking and striking in the Praying Mantises, Parasphendale affinis (Giglio-Tos), Popa spurca (Stål), and Sphodromantis lineola (Burmeister)

“…This is evidenced by the similarities in the preyrecognition algorithms used by animals with very different brains, for instance, amphibians (Ingle, 1983;Roth, 1987;Ewert, 2004), the amphibious fish Periophthalmus koehlreuteri (Ewert, 2004), cuttlefish (Darmaillacq et al, 2004) and mantises (Kral and Prete, 2004). Even more interesting is the fact that creatures much smaller than mantises, for instance, the jumping spider Evarcha culicivora, can combine different subsets of category-specific stimulus elements into a coherent perception of a potential prey item (Nelson and Jackson, 2012; see also Harland and Jackson, 2000). Hence, the strategy of representing prey implicitly seems to be widespread.…”