title: Bats track and exploit changes in insect pest populations.
abstract: The role of bats or any generalist predator in suppressing prey populations depends on the predator's ability to track and exploit available prey. Using a qPCR fecal DNA assay, we document significant association between numbers of Brazilian free-tailed bats (Tadarida brasiliensis) consuming corn earworm (CEW) moths (Helicoverpa zea) and seasonal fluctuations in CEW populations. This result is consistent with earlier research linking the bats' diet to patterns of migration, abundance, and crop infestation by important insect pests. Here we confirm opportunistic feeding on one of the world's most destructive insects and support model estimates of the bats' ecosystem services. Regression analysis of CEW consumption versus the moth's abundance at four insect trapping sites further indicates that bats track local abundance of CEW within the regional landscape. Estimates of CEW gene copies in the feces of bats are not associated with seasonal or local patterns of CEW abundance, and results of captive feeding experiments indicate that our qPCR assay does not provide a direct measure of numbers or biomass of prey consumed. Our results support growing evidence for the role of generalist predators, and bats specifically, as agents for biological control and speak to the value of conserving indigenous generalist predators.
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, Tennessee, United States of America. gmccrack@utk.edu
authors.forename: Gary F
authors.initials: GF
authors.lastname: McCracken
authors.forename: John K
authors.initials: JK
authors.lastname: Westbrook
authors.forename: Veronica A
authors.initials: VA
authors.lastname: Brown
authors.forename: Melanie
authors.initials: M
authors.lastname: Eldridge
authors.forename: Paula
authors.initials: P
authors.lastname: Federico
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Kunz
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000818:Animals; D002685:Chiroptera; D017753:Ecosystem; D005243:Feces / Q000737:chemistry; D005247:Feeding Behavior; D005819:Genetic Markers / Q000235:genetics; D009036:Moths / Q000235:genetics; D010572:Pest Control, Biological / Q000379:methods*; D016133:Polymerase Chain Reaction; D011157:Population Dynamics; D013045:Species Specificity
chemical_list: D005819:Genetic Markers