Parasitoid wasps benefit from shade tree size and landscape complexity in Mexican coffee agroecosystems

Abstract

Increased agricultural intensification has led to a decrease in biodiversity and the deterioration of important agricultural ecosystem services, such as biological control. Parasitoid wasps are important biological control agents for many crop pests, and augmenting their abundance and diversity may confer significant economic and environmental benefits. We investigated how management practice, landscape composition, and biotic and abiotic environmental components affect the parasitoid community in coffee farms of Chiapas, Mexico. Local variables pertaining to vegetation structure and diversity, Azteca sericeasur (keystone ant species) presence, and abiotic factors such as synthetic chemical usage and altitude were quantified. Additionally, the landscape composition was assessed for different land uses at both 250m and 500m radii. Utilizing generalized linear mixed-effect models (GLMM), we found that both local and landscape factors affected the parasitoid community. At the local scale, the proximity of A. sericeasur nests benefited parasitoid abundance and diversity, whereas different measures of vegetation structure had both positive and negative effects on parasitoid richness, abundance, and diversity. At the landscape scale, we found neighboring intensively managed farms to have an adverse impact on parasitoids. Surprisingly, parasitoids were also positively influenced by increasing altitude and the use of synthetic pesticides. Our findings indicate that the studied agricultural matrix supports a diverse parasitoid community, and that properly managed vegetation structure and increased landscape complexity may augment natural parasitoid communities. Thus, conservation management should take into account environmental complexity at multiple scales.