Meeting Abstract
Global light pollution is increasing worldwide, nearly doubling over the past 25 years. The encroachment of artificial light into remaining dark areas threatens to disturb natural rhythms of wildlife species. Artificial light impacts the behavior of insectivorous bats in numerous ways, including changing foraging behavior and altering prey selection. It is often suggested that bats should forage more commonly on moths, or on larger moths, relative to other available prey around artificial light, likely due to a higher energetic payoff. In a manipulative field experiment, we measured plasma &beta-hydroxybutyrate concentrations from 4 species of insectivorous bats in naturally dark and artificially lit conditions to investigate effects of light pollution on fueling rates (a proxy of foraging success). &beta-hydroxybutyrate increases predictably in both captive and free-living bats after feeding and can thus be used to measure foraging intensity. Contrary to predictions, fueling rates did differ consistently between experimental conditions for any species. In general, fueling rates at lit sites were highest early in the night followed by a decrease, while the opposite was the case at unlit sites. Our results, building on others, demonstrate that bat-insect interactions may be more nuanced than the common assertion that moth consumption increases around lights. Our work highlights the need for greater mechanistic understanding of bat-light interactions to predict which species will be most affected by light pollution, and to more effectively craft management strategies to minimize unnatural shifts in prey selection caused by artificial lights.
