1. Bat Foraging Activity Increases
Near Bat Houses KRISTEN M. LEAR1, ELIZABETH BRAUN DE TORREZ2 1Department of Zoology, Ohio Wesleyan University, Delaware, OH, 43015, USA 2Department of Biology, Boston University, Boston, MA, 02215, USA
Introduction
Agriculture often uses chemicals for insect pest control.
Alternatives to chemical pest control:
▪ biological control
♦ predators or parasites (Borrer et al., 1989)
♦ vertebrate insectivores
Bats consume agricultural pest insects (Whitaker, 1995;
McCracken, 1996)
Anecdotal evidence of benefit (less chemical spraying) to
farmers with on-site bat colony (Murphy, 1993)
Bat houses used to attract bats
Is general bat activity and foraging activity higher near
bat houses?
Results
T-tests comparing near (15m) versus far (95, 175, 255m) showed significant differences for all measures (total passes: t18 = 4.6, p<0.001; feeding buzzes: t18 = 4.6, p<0.001; ratio feeding buzzes/total passes: t43 = 2.6, p<0.02).
ANOVA single factor, F(3, 86) = , p<0.001
Discussion
▪ General bat activity and foraging activity not directly correlated to distance from roost
▪ However, general bat activity and foraging activity are higher at near sites versus far sites.
▪ Supports use of bat houses on agricultural lands to attract bats so that they may serve as agents of biological pest control.
Figure 1: Mean of total passes (95% CI)
ANOVA single factor, F(3, 86) = , p<0.001
Methods
Monitored general bat activity and foraging activity with
Anabat II acoustic detector
Four minute recordings at 15 sites along transects
originating from bat house inhabited by Mexican
free-tailed bats (Tadarida brasiliensis)
▪ sites 15, 95, 175, and 255m from bat house
▪ recorded between 2200 and 0100
Recorded total bat passes and feeding buzzes
Compared site data using single-factor ANOVA and
t-tests (two-sample assuming unequal variances)
Figure 2: Mean of feeding buzzes (95% CI)
Literature Cited
Borrer, D. J., Triplehorn, C. A., Johnson, N. F An introduction to the study of insects, 6th edition. Saunders College Publishing, Forth Worth, Texas pp.
McCracken, G. F Bats aloft: A study of high-altitude feeding. Bats, 14(3):7-10.
Murphy, M Bats: A farmer’s best friend. Bats, 11:23.
Whitaker, Jr., J. O Food of the big brown bat Eptesicus fuscus from maternity colonies in Indiana and Illinois. American Midland Naturalist. 134:
ANOVA single factor, F(3, 86) = 1.521, p>0.5
Acknowledgements
We thank the National Science Foundation, Bat Conservation International, and the American Society of Mammalogists for funding and John and Jimma Byrd for use of their field house and pecan orchard.
Figure 3: Mean of feeding buzzes/total passes (95% CI)