Hunting efficiency and predation risk shapes the color-associated foraging traits of a predator

Abstract

When animals forage or court their behaviors are often constrained by factors such as predation risk. Predator--prey interactions govern the evolution of many behavioral and morphological traits. However, animals with foraging or courtship tightly linked to morphology cannot make quick behavioral adjustments when encountering a dilemma. In this study, we investigate how opposing pressures of maximizing prey intake and minimizing predation risk shape the morphology-associated foraging traits of a sit-and-wait predator. Recently, the conspicuous body colorations of certain orb-weaving spiders have been demonstrated to be attractive to both insect prey and predators. In this study, we performed field manipulations to assess how visual luring signals of such predators trade off opposing pressures of feeding and surviving. We created dummies made of cardboard to test how changing size of conspicuous signal affected attractiveness to prey and predators. Dummies mimicked the coloration pattern and chromatic properties of giant wood spider Nephila pilipes. We found that dummies were similarly attractive to prey and predators as real spiders were. Uniformly yellow colored dummies attracted significantly more prey than those dummies that mimicked the color pattern of N. pilipes. However, such dummies also attracted far more hymenopteran predators. Our findings indicate that current morphology-associated foraging traits of certain animals do not necessarily provide the best feeding performance but reflect a trade-off between opposing pressures of foraging intake and predation risk. Copyright 2009, Oxford University Press.