Meeting Abstract

P1.77  Friday, Jan. 4  Costs and benefits of aerial predation in dragonflies PANDIT, MM*; WEILAND, TJ; SWITZER, C; IWASAKI, JM; COMBES, SA; Indiana University Bloomington; Middlebury College; Harvard University; Harvard University; Harvard University mpandit@indiana.edu

Predator-prey interactions are a major driving force in evolution, affecting the fitness of both participants. For prey, escape is essential; but for predators, the potential benefit of a successful capture is offset by the energetic cost of pursuit and the risk of failure. Many ecological studies have documented capture success rates of predators pursuing different types of prey, and biomechanical studies have examined the dynamics of predator-prey encounters. However, few studies have combined these approaches to gain insight into the relative costs and benefits to predators of pursuing different types of prey. In this study, we examined aerial predation in Libellulidae dragonflies pursuing four different types of dipteran prey (fruit flies, mosquitoes, houseflies and deerflies) in an outdoor artificial habitat. We quantified capture success rates and estimated energetic cost by analyzing 3-D high speed videos of predation encounters to determine the time from takeoff to capture, as well as the total distance traveled from the perch. We asked how the cost-benefit relationship changes when dragonflies pursue different types of prey, and compared trials from five species of dragonflies to determine whether the relative difficulty of catching certain types of prey is universal, or whether particular dragonflies are specialized for catching particular prey. We found that capture success varies between dragonflies, with larger species generally being more successful predators. However, the gross parameters of the interaction (time and distance to capture) are determined primarily by the type of prey, which may place larger predators at an energetic disadvantage in some situations.