Impact of artificial lights on foraging of Neotropical insectivorous bats

Abstract

Studies from the temperate zones have shown that artificial lights can either deter insectivorous bats by disorienting them and increasing exposure to predators, or attract them by providing concentrations of prey, depending on the life history of the species in question. This study looked at insectivorous bat responses to light pollution in the tropics for the first time. Bat echolocations were recorded at 11 pairs of light and dark sites in premontane and lower montane forest of Monteverde, Costa Rica. Bat foraging activity was higher at artificially lighted sites (mean ± standard error 123.64 ± 34.77 recorded echolocations per night) than dark sites (mean ± standard error 49.64 ±12.00 recorded echolocations per night), but species richness was not statistically different between sites. While the majority of bat species increased their activity in response to light, Myotis pilosatibialis and an unidentified bat were only recorded in dark sites, suggesting that like temperate bats, tropical species are differentially impacted by artificial lights. Increased light pollution in the tropics concentrates some species around human inhabited areas while harming others via habitat fragmentation, potentially shifting community structure.