Bats as suppressors of agroforestry pests in beech forests

Forest ecosystems are fundamental to the conservation of global biodiversity and human wellbeing, hosting high numbers of species worldwide, and providing essential regulatory, provisioning, and cultural ecosystem services. The increasing impact of drivers of environmental changes such as climate change and biological invasions endangers forests, often acting synergically with forest pests, whose effects are exacerbated. Within this context, forest bats may represent key ecosystem service providers by consuming pests such as defoliating and fruit-damaging arthropods, yet their actual role has been so far neglected. Here we pursued the hypothesis that forest bats will be important suppressors of agroforestry pest insects. We analysed the diet of two forest specialists, Barbastella barbastellus and Plecotus auritus, occurring in syntopy in beech forests of Central Italy, by adopting molecular tools. The diet of the two bat species differed significantly: only 52 out of 71 and 69 prey taxa identified in the diet of B. barbastellus and P. auritus, respectively, were shared between the two bat species. Individual bats preyed, on average, upon 10 insect taxa, and pests were especially frequent in the diet of P. auritus (up to 85% of prey eaten by an individual bat). Such pests included both agricultural and forest-damaging insects, some of which pose serious threats to agroforestry systems. This highlights the importance of preserving animal diversity in forests for the benefit of this ecosystem type as well as of the surrounding habitats, such as farmland.