Big bats binge bad bugs: Variation in crop pest consumption by common bat species

Abstract

As generalist predators, insectivorous bats exploit fluctuations in prey distribution and abundance. A more nuanced understanding of the influence of bats on arthropod pests requires documentation of the pest species bats consume and of the conditions associated with variation in rates of pest consumption. Here, we used high-throughput metabarcoding of DNA extracted from bat feces to investigate diets of 180 bats representing three Vespertilionidae species common to the southeastern US, a region dominated by agriculture and pine plantations. We detected 23 species of agricultural pests in bat diets, including pests responsible for severe economic damage, such as Helicoverpa zea, Spodoptera frugiperda, Chloridea virescens and Chrysodeixis includens. Incidence of pest consumption was high: 61% of all bats had consumed at least one agricultural pest species, with each bat consuming an average of 1.7 pest species. The likelihood of consumption of pests to row crops and the average size of pests consumed varied by bat species, with a large foliage-roosting species (Lasiurus seminolus) consuming a greater variety of pest species and pest species larger in size than smaller crevice, cavity, and cave roosting bat species (Nycticeus humeralis, Myotis austroriparius). Likelihood of pest consumption also varied among sampling periods (season) and among bats of different sizes (as reflected by wing length and mass). Overall, likelihood of pest consumption was higher in the late summer season than during spring or early summer, and higher among larger bats than smaller bats. Bat characteristics and seasonality were generally more effective than geographic features and weather conditions in predicting pest consumption patterns. Strategies for enhancing pest consumption services by bats in agroecosystems should strive to maintain and enhance diverse bat populations on a landscape scale by protecting and augmenting roost structures appropriate for each species. Our finding of widespread pest consumption by bats contributes to mounting evidence worldwide of the important role bats play in agricultural systems and highlights the value of incorporating bat conservation into integrated pest management programs globally.