Do male jumping spider display colors function as sensory traps to avoid cannibalism?

Lauren Gawel, Michelle Brock, Lisa Anne Taylor; Department of Entomology and Nematology, University of Florida

Abstract
Evolution of male ornamentation is often driven by sexual selection. Male color patterns may act as ‘sensory traps’ that exploit already-existing color biases in females that spill over from other contexts. In jumping spiders, many males display bright colors like those used by prey to warn of toxicity (e.g., red patches and black-and-white stripes). We hypothesized that since females are expected to avoid bright colors, males with black and white striped facial patterning would have a lower risk of being attacked by females; therefore, they would also have a lower risk of cannibalism by females. We tested this hypothesis using the jumping spiders Habronattus trimaculatus and Phidippus regius. Males display black-and-white stripes on their faces and front legs, respectively (directed at cryptically-colored females). If these stripes function as a sensory trap, we would expect females to avoid attacking black and white striped prey. To test this, we presented spiders with termites that had colored ‘capes’ adhered to their abdomens (black, white, or black-and-white striped). Results showed that the spiders attacked striped termites (and black termites) at significantly lower levels than the white termites. This is consistent with our hypothesis that black-and-white patterns in male displays might effectively reduce cannibalism risk. While studies of sensory traps have been done in other animals, our study takes a novel approach examining the balance between attracting a female and avoiding risks associated with courtship.