Submitted to: Southwestern Naturalist
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/3/2010
Publication Date: 3/1/2011
Citation: Gillam, E.H., Westbrook, J.K., Schleider, P.G., McCracken, G.F. 2011. Virtual bats and real insects: Effects of echolocation on the mating behavior of corn earworm moths, Helicoverpa zea. Southwestern Naturalist. 56:103-107. Interpretive Summary: The corn earworm is a major pest that attacks the fruit of corn and cotton, and many other row crops. Corn earworm adults (moths) fly to mate and lay eggs, which become the next generation of pests that infest local and distant fields. New methods are needed to disrupt mating of corn earworm moths, and consequently reduce pest infestations and crop losses. This study examines the effects of artificial bat calls in a field setting on mating behavior of corn earworm moths, an insect that is known to perceive and respond evasively to bat calls. Artificial bat calls were broadcast over corn and cotton fields in an area where moths and bats were abundant. Collections of moths in corn and cotton fields, and in traps baited with a sex attractant were conducted in treated (with artificial calls) and untreated (without artificial calls) plots. The number of moths captured was not affected for either crop by artificial bat calls. Although this may be due to inadequacies of the artificial bat calls or the response parameters used, it also is possible that moths do not reduce mating activity even when perceiving a high risk of predation.
Technical Abstract: This study examines the effects of simulated ultrasound in a field setting on the mating behavior of corn earworm moths, Helicoverpa zea (Lepidoptera: Noctuidae), an insect that is known to perceive and resond evasively to the echolocation calls of bats. Complex, realistic echolocation signals were broadcast over crop fields of corn and cotton in an area where the moths and bats were abundant. Field collections of free-flying moths and pheromone trapping of male moths were conducted to replicate one-acre treatment (with artificial calls) and control (without artificial calls) plots. The number of moths captured was not affected in either experiment by the presence of the artificial bats. While this may be due to inadequacies of the artificial bat signals, it also is possible that moths did not reduce reproductive activity even when uhder a high perceived risk of predation. Discrepancies amont the results of previous studies on the effects of echolocation on mating activities of tympanate moths are discussed in terms of immediate versus longer-term behavioral responses of moths to the risk of predation.