CANCELLED - Do herbivore-induced plant volatiles affect insectivorous bat activity in agricultural fields?

Background/Question/Methods

Bats are important pest control agents in agricultural systems worldwide. Tracking insect abundance spatially and temporally, bats can detect insect fluctuations and outbreaks. Yet, the underlying mechanisms that drive these foraging behaviors are unclear. It is well documented that plants respond to herbivore damage by emitting herbivore–induced plant volatiles (HIPVs), which influence many tri-trophic interactions. Notably, HIPVs can attract invertebrate and avian natural enemies that use the chemical cues to locate insect prey, but it is unknown if HIPVs are used by carnivorous mammals. Using a model crop system, soybean (Glycine max), in the mid-Atlantic US, our study asked three questions: 1) Which bat species are active in soybean fields?; 2) Is insectivorous bat activity affected by a) naturally occurring soybean HIPVs and/or b) synthetic soybean HIPVs (indole or farnesene); and 3) If so, which species are affected? Across soybean fields in the mid-Atlantic US, we created paired plots that were either HIPV plots (damaged plants or synthetic dispensers) or control plots (undamaged plants or empty dispensers). We measured bat activity using ultrasonic recorders and detected five species.

Results/Conclusions

The big brown/silver-haired bat (Eptesicus fuscus/Lasionycteris noctivagans) was the most active species group on the landscape, as anticipated. Yet, our results do not support our hypothesis that bats use HIPVs in soybean fields of the mid-Atlantic US, as bat activity did not significantly differ between control and HIPV plots (either natural or synthetic). However, the relationships among plants, herbivores, and natural enemies can depend on a variety of factors and conditions, and we hope this initial study on bats and HIPVs may serve as a roadmap for developing future bat–plant research.