Insectivorous bats provide more pest suppression services than disservices - a case study in China

Many studies have investigated the role of insectivorous bats as natural enemies of agricultural pests. However, insectivorous bats have a broad diet, and whether their prey species are beneficial or harmful is unknown; thus, accurately assessing the services provided by bats is challenging. In China, most people, including farmers and plant protection workers, have an insufficient understanding of the ecological value of bats in biological control. Therefore, we collected the fecal samples of 10 bat species from three different sampling sites located in Guizhou Province, China, and conducted DNA metabarcoding to determine the diet composition of bats. We also categorized the prey species from the diet of bats as harmful or beneficial, based on previous studies, and recorded the industries they affect. Our results showed that the 10 bat species consumed prey from 19 orders and 96 families; most of them being lepidopterans. Among 564 total prey species recorded, 390 (69.15%) were pests and 28 (4.96%) were beneficial insects. Among them, 326 (57.80%) were agriculture or forestry pests, such as globally present Cotton bollworm (Helicoverpa armigera) and Beet armyworm (Spodoptera exigua). These results indicated that insectivorous bats have more beneficial effects than harmful effects, especially in the context of agriculture and forestry, as they suppressed very few beneficial arthropod mesopredators. By comparing the differences in the diet of I. io in different regions, we found that bats present in different regions can provide different predation services. Our study showed that insectivorous bats provide excellent pest suppression services in various industries and regions. It might be helpful for increasing awareness among people and bat conservation in China and other regions.