Ant community potential for pest control in olive groves: Management and landscape effects

Abstract Ants are important pest control agents in many agroecosystems worldwide. However, little is known about how management, landscape complexity, their interaction, and the ecological contrast generated by different agricultural practices affect their communities and the potential pest control they can provide. Here, we surveyed ant communities in 40 paired olive groves with different agricultural management regimes across 20 localities spanning a wide range of landscape complexity at the regional scale. We also conducted field experiments with dummy plasticine models and fresh prey to explore the ant potential to control the two main pests of the olive tree (olive moth and olive fly). In addition, we calculated an index, the Ant-community Predation Function (APF), which informs about the predation pressure exerted by ant communities over these pests. Results show that: a) the maintenance of herb cover at intermediate landscape complexity sites maximizes the abundance and potential for pest control by ants; b) the ecological contrast affects ant abundance and ant richness but does not impact the predation function; c) APF is a good measure of pest control potential at the community level; and, d) Tapinoma nigerrimum is an important ant species for pest control in our system, which seems little affected by local or landscape heterogeneity. The maintenance of herb cover, organic farming and a certain landscape complexity is beneficial for ant communities and increase their contribution to pest control in olive groves.