Aerospace-foraging bats eat seasonably across varying habitats

Recent research has confirmed the efficiency of insectivorous bats as pest suppressors, underlining the ecological services they offer in agroecosystems. Therefore, some efforts try to enhance bat foraging in agricultural landscapes by acting upon environmental factors favouring them. In this study, we monitored a Miniopterus schreibersii colony, in the southern Iberian Peninsula. We intensively sampled their faeces and analysed them by metabarcoding to describe how the bent-winged bat diet would change with time, and to test whether their most-consumed prey would seasonally depend on different landscapes or habitats. Our results confirm that M. schreibersii are selective opportunist predators of moths, dipterans, mayflies, and other fluttering insects, shifting their diet to temporary peaks of prey availability in their foraging range, including both pest and non-pest insects. Supporting our hypothesis, throughout the year, M. schreibersii consume insects linked to diverse open habitats, including wetlands, grassland, diverse croplands, and woodland. The importance of each prey habitat varies seasonally, depending on their insect phenology, making bats indirectly dependent on a diverse landscape as their primary prey source. Bats' predation upon pest insects is quantitatively high, consuming around 1610 kg in 5 months, of which 1467 kg correspond to ten species. So, their suppression effect may be relevant, mainly in patchy heterogeneous landscapes, where bats' foraging may concentrate in successive outbursts of pests, affecting different crops or woodlands. Our results stress that to take advantage of the ecosystem services of bats or other generalist insectivores, keeping the environmental conditions they require to thrive, particularly a heterogeneous landscape within the colony's foraging area, is crucial.