The Effect of Artificial Night Lighting on the Little Brown Bat (Myotis lucifungus).

Abstract

With increased human development, light pollution caused by artificial night lighting, has progressively become an ecological problem for a variety of species (Rich and Longcore, 2006). The concepts of light pollution and conservation are considered especially important for those species that are nocturnal. Bats, like other nocturnal species, could be at risk from the effects of artificial night lighting; however very few studies have investigated this. Depending on the surrounding environment, a bat changes it echolocation calls accordingly to avoid obstacles and also to forage for insect prey (Wund, 2006). We must consider that artificial night lighting may impact the use of echolocation in both in foraging and in orientation; changing the relative reliance on sonar and vision. We investigated the effects of light on echolocation and associated behaviors in this study. Sixteen Myotis lucifugus were captured from an attic of a resident of the Chautauqua Institution during the summer of 2010. Four randomized treatments were preformed for each bat by recording behavior and echolocation over 1 minute. Treatments were 1) 1 minute with the light off, 2) 1 minute with the light on, 3) 30 seconds light off and 30 seconds light on and 4) 30 seconds light on and 30 seconds light off. Behavioral results show significant difference in activity when the bats are exposed to a light on that then switches to lights off. This is in contrast to no significant difference in activity when the bats are exposed to a constant light treatment. We did not find differences in sonar call structure based on treatment. Our data demonstrate[s] that the little brown bat will have a slower response time to changing light conditions possibly because of the time [it] takes for light versus dark adaption, as well as their natural response to light and dark. We also suggest that the little brown bat has the ability to be plastic in their behavior as well as sonar in constant light conditions, enabling them to adjust accordingly and be successful in both sonar and behavior.