Behavioral Diversity of Predatory Arboreal Ants in Coffee Agroecosystems

Abstract

Abstract Aspects of predator assemblages that alter predator effects on prey have received extensive recent attention. Among other mechanisms, differences in behavior or resource use within predator trophic levels may enhance predator effects on prey, especially if effects of each predator species differ with environmental conditions. We address whether three common ant species (Azteca instabilis F. Smith, Camponotus textor Forel, and Crematogaster spp.) are functionally unique in coffee agroecosystems, asking if each species differs in (1) cooperative foraging behavior, (2) responses to experimentally introduced herbivores, and (3) responses to pest outbreaks. Furthermore, we examined the behaviors and effects of each ant species under different conditions by varying herbivore species, herbivore size, and herbivore density and carrying out observations in different seasons. Ant species significantly differed in foraging behaviors, in effects on individual herbivores, and in responses to pest outbreaks in terms of both type and time of response to herbivores. The behaviors and effects of each ant species differed in the dry and wet seasons and for different herbivore species and sizes. Although A. instabilis generally removed more larvae and more quickly removed larvae, this was not the case under all conditions. The data presented thus support that common ant species in coffee agroecosystems are behaviorally diverse in their responses to herbivores under different conditions. We discuss the implications of these differences in ant behaviors for enhancement of predatory function in light of both multipredator effects and in terms of the potential importance of predator diversity.