Picking the right spot: crab spiders position themselves on flowers to maximize prey attraction

Abstract

AbstractIn plant-pollinator interactions, pollinating insects provide reproductive service to plants and receive food rewards. Flowers advertise the presence of nectar or pollen through various characteristics, including visual displays. In daisies (Chrysanthemum frutescens), the center of the inflorescence appears as a UV-absorbing bull's-eye that attracts pollinators, for example honeybees. Thomisus spectabilis crab spiders occupy daisies and prey on honeybees. They typically position themselves on the lingulate florets of daisies and create a color contrast that deceives honeybees. Honeybees prefer daisies with a T. spectabilis on the lingulate florets to vacant daisies. In contrast, when offered the choice between a vacant daisy and a daisy whose center was covered by a T. spectabilis, honeybees preferred the vacant daisy. Similarly, honeybees were deterred by daisies whose center was covered by lingulate daisy florets making a rectangle about the size of a T. spectabilis. Covering the lingulate florets of daisies by a rectangle of lingulate daisy florets, however, neither attracted nor repelled honeybees. Honeybees seem to rely on the visibility of the daisy center to locate food reward and, by positioning themselves on the lingulate florets of daisies, T. spectabilis exploit these sensory biases of prey.