2011 Annual Report
1a.Objectives (from AD-416)
To quantify the timing and abundance of the late-season arrival of migrant crop pest insects, and their impact on foraging behaviors and body condition of Brazilian free-tailed bats.
1b.Approach (from AD-416)
Several species of crop pest insects (corn earworm, fall armyworm, cabbage looper and stink bugs) will be collected daily from pheromone traps and blacklight traps to identify return (i.e., southward) migration events in central TX (Uvalde and College Station). Bats returning to Frio Cave (near Uvalde) from nightly foraging flights will be netted, and fresh fecal pellets will be collected. The fecal pellets will be analyzed to determine the presence of several insect species in the diet of bats. Temporal changes in the fecal DNA will be correlated with daily insect collections and weather conditions. Changes in timing, locations, and altitudinal distribution of feeding activity of bats will be documented in relation to movements and availability of crop pest insects.
This is a new project, with the goal of defining the relationships between migratory behavior of certain crop pest insects and the foraging activity and overall health of bats that prey on these insects. In FY 2011, late summer/fall daily captures of the corn earworm, fall armyworm, and cabbage looper (at Uvalde and College Station, Texas) showed that capture of corn earworm moths was an order of magnitude greater than that of cabbage looper moths; the magnitude of daily capture of fall armyworm moths was intermediate. Fall armyworm captures occurred later in the fall than was the case with corn earworm and cabbage looper moths. The lack of substantial capture of moths in traps baited with a mixture of feeding attractant and feeding stimulant suggested either a lack of feeding response by the moths or a limited response to the bait and trap type. The average weight of Brazilian free-tailed bats in these localities was found to increase in synchrony with an increase in the number of trapped corn earworm moths. A second major increase in the average weight of bats was not associated with an increase in the number of trapped corn earworm moths; rather, this was associated with a dietary shift to feeding on other insect species including fall armyworm moths. Work under this project, as it progresses, will provide valuable information on the interactions and interrelationships between some major crop insect pests and the bats that consume these insects by the millions.
The ADODR of this project and the cooperator maintain regular communication by phone and e-mail, where progress of the work is discussed and evaluated, and where solutions to work impediments are developed. The ADODR and the cooperator periodically meet face-to-face (at scientific meetings, etc.) to discuss research priorities and the overall direction and progress of the work.