UC Santa Cruz

Agroecosystems benefit from biological control services, yet predatory activity by natural enemies, like ants, can be highly spatio-temporally variable. Heterogeneity in perennial coffee agroecosystems is not driven by the crop itself, but rather climate at the regional scale and managed shade trees and herbaceous plant layers at the local scale. We examined the effects of both inter-annual seasonal and microhabitat variation on the predatory function of ground-foraging ants on a globally disruptive coffee pest, the coffee berry borer (Hypothenemus hampei). During the dry and rainy seasons, we measured prey removal rates of the borer by ants across three distinct litter treatments. We found significantly higher rates of prey removal during the dry season and, to a lesser extent, in plots with greater leaf litter and lower soil temperatures. Our results indicate that both large scale processes like inter-annual seasonal variation in climate and small-scale differences in microhabitat refugia can influence pest predation activity by natural pest control agents in coffee agroecosystems.