Pest-regulation service of the coffee berry borer (Hypothenemus hampei) in agroforestry systems

The coffee berry borer (CBB) is one of the main pests affecting coffee production leading to significant yield losses. Pest control service within agroforestry systems (AF) results from complex biotic and abiotic interacting components. Factors explaining regulation of the CBB can interact with each other and have potential antagonistic effects. This explains many contradictory results for studies focusing on the impact of few factors on a single response variable. This is particularly true with the effect of shade on the CBB (Morris et al, 2018). This factor can directly affect CBB development but also indirectly by affecting the community of natural enemies. Studying this pest-regulation service requires therefore a systemic ap-proach. Here we developed structural equation models describing the interactions within these systems. Using data from three complex AF in Nicaragua and from an experimental farm in Costa Rica, we assessed the effects of environmental conditions and agricultural practices on the CBB, and on the diversity and abundance of predaceous ants (Fig 1). The area occupied by coffee-associated trees, the thermal amplitude and the shade were negatively related to CBB. Ant diversity and abundance were negatively related to coffee density, and positively related to CBB. While our results on a systemic scale confirm the potential of AF to provide a pest control and interesting management alternatives, it also reveals the difficulty of studying this service.