Birds and bats differ in pest control pathways in fruit orchards: Intraguild and direct predation

Birds and bats are relevant natural enemies of pests in fruit crops. However, by preying also on arthropod natural enemies, they may act as intraguild predators that can lead to pest release. Disentangling how these two groups intervene in different ecological relationships is thus essential to understand their relative contribution and complementarity in pest control provision. We used dietary DNA metabarcoding to build tri‐trophic networks that account for direct and indirect interactions among top predators (birds and bats), mesopredators (spiders) and pests (insects) in apple and blueberry crops. To identify species closely linked to pests, we estimated modularity. To evaluate their topological and tri‐trophic role, we quantified their centrality and the extent of distinct predatory pathways in their diets (i.e. direct pest predation, intraguild predation or both). Finally, in the case of birds in apple crop, we tested if the topological and tri‐trophic role of species depended on their abundance, degree of insectivory and morphological traits. The network was modular in both crops, with birds and bats occupying distinct modules feeding on different prey. Bats tended to be more directly connected to pests than birds, which were more frequently involved in intraguild predation. Among birds in the apple crop, higher abundance increased direct pest predation, whereas greater insectivory favoured intraguild predation. Morphology further shaped topological position, with smaller species with less pointed wings demonstrating higher centrality values. Birds and bats showed different and complementary roles in pest control service, a pattern consistent among fruit crops. Both vertebrate groups were associated with different prey, and birds were more prone to promote pest release than bats, although such effect was weaker for common and less insectivorous species. Synthesis and applications . Our study highlights that by combining interaction networks, tri‐trophic cascades and species traits, we can better understand the role of species on the control of pests in fruit crops. In particular, our results point out that promoting bats and abundant birds may be an efficient strategy to enhance pest control in fruit orchards.