Bat Foraging Activity and Insect Abundance in Relation to Foraging Activity on Baylor University Campus
The relationship between bats and urbanization is not yet well understood. Whereas bats are nocturnal and generally operate in darkness, insects tend to be drawn to illumination at nighttime. For this project, the relationships between bats and light and insects and light were being studied to determine how foraging activity of bats and insect abundance in an urban setting might vary in connection to different levels of artificial lighting. Echolocation signals were recorded over four weeks each night from 1900 hours to 0700 hours for five consecutive nights using ultrasonic detectors. The twelve locations on the Baylor University campus fall into groups of four based on the average nighttime light intensity due to the artificial lighting: low, medium, or high intensity. Insect abundance was tested once per week at each sampling location using non-toxic glue traps. To analyze the echolocation data, we utilized a program SONG SCOPE 4.0.7. An analysis of variance (ANOVA) revealed that bat foraging activity is significantly related to light intensity, and that foraging activity was higher in areas with higher light intensity (P < 0.0001). ANOVA of the insect abundance data showed that insect abundance was not significantly impacted by light intensity (P < 0.733).