Submitted to: Journal of Chemical Ecology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/27/2006
Publication Date: 10/1/2006
Citation: Zhang, Q., Schneidmiller, R.G., Hoover, D., Young, K., Welshons, D., Margaryan, A., Aldrich, J.R., Chauhan, K.R. 2006. Male-produced pheromone of the green lacewing, Chrysopa nigricornis (Neuroptera: Chrysopidae). Journal of Chemical Ecology. 31:2163-2176. Interpretive Summary: Predators are important natural enemies of a multitude of pest insects, and marshalling predators against pests is a desirable alternative to insecticidal control. Among the most important predators of aphids and other small insects are the so-called green lacewings. We discovered that a common green lacewing in the western U. S. is powerfully attracted to the same chemical earlier found to attract an abundant lacewing in the eastern U. S. Thus, a single chemical (that can be simply derived from the commercially available catnip plant) can be used to attract lacewings all across North America. A new attractant system for green lacewings is being developed at Sterling International, Inc., so that gardeners and commercial growers alike will be able to naturally induce female lacewings to lay eggs among pest infestations for enhanced biological control. Scientists studying chemicals affecting predator behavior will also be interested in these research results.
Technical Abstract: Gas chromatographic-electroantennographic detection (GC-EAD) analysis showed that male antennae of the green lacewing, Chrysopa nigricornis Burmeister, the most common lacewing species in the Pacific Northwest of the U.S.A., consistently responded to two compounds in thoracic extracts of the conspecific males: 1-tridecene and (1R,2S,5R,8R)-iridodial. These compounds were not detected from extracts of the abdominal cuticle, and no other antennally active compounds were found from the abdominal samples. In field-trapping experiments, traps baited with the EAD-active compound, iridodial, alone were not only strongly attractive to males of the golden-eye lacewing C. oculata Say, but also significantly attracted in large numbers of C. nigricornis males (both western and eastern forms), to a lesser extent, conspecific females (in late summer or early fall), plus another Chrysopa species, C. coloradensis Banks. Iridodial was recently identified as the male-produced aggregation pheromone from C. oculata, the first pheromone identified for lacewings. Methyl salicylate, reported as an attractant for both sexes of C. nigricornis and C. oculata along with many other beneficial insects, was inactive by itself at the concentration tested in our study, but showed a slightly synergistic effect on some occasions when combined with iridodial. However, methyl salicylate alone and its binary blend with iridodial seemed to attract the hoverfly, Metasyrphus americanus (Weidemann). 2-phenylethanol, a reported attractant for Chrysoperla carnea (Say), did not capture any green lacewings. Field testing clearly indicated that the lacewing pheromone, iridodial, loaded onto either rubber septa or as a binary blend with methyl salicylate in polyethylene bags could last at least 5 weeks in the field during the mid-summer season, the latter dispenser being 5-6 times more attractive to C. nigricornis than the former dispenser. Based on this study, a new attractant system for green lacewings is being developed at Sterling International, Inc. for both domestic and international markets.