Submitted to: Journal of Chemical Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/1/2004
Publication Date: 9/1/2004
Citation: Zhang, Q., Chauhan, K.R., Erbe, E.F., Vellore, A.R., Aldrich, J.R. 2004. Semiochemistry of the goldeneyed lacewing Chrysopa oculata (Neuroptera: Chrysopidae): Attraction of males to a male-produced pheromone. Journal of Chemical Ecology. 30(9):1831-1853. Interpretive Summary: Lacewings, especially green lacewings (Chrysopidae), are some of the most common predators of aphids and other soft-bodied insects and, because of their commercial availability and resistance to insecticides, chrysopids are among the most commonly released predators for augmentative biological control. While green lacewings are increasingly being released for biocontrol, methods are still needed to retain the predators near augmentation sites and/or to attract wild predators to target areas. Here we demonstrate that the reported attraction of lacewings to chemicals from the catnip plant is actually coincidental to the fact that males of certain lacewings produce an odor (pheromone) that matches a minor chemical component of catnip oil. The pheromone, the first identified for this kind of insect, attracts other male lacewings, and may draw female lacewings to the vicinity. These findings should be of interest to scientists studying chemicals affecting predator behavior, and may be of practical utility in manipulating natural or artificially augmented populations of lacewings for enhanced biological control.
Technical Abstract: Antennae of males and females of the goldeneyed lacewing, Chrysopa oculata, responded to four compounds extracted from the abdominal cuticle of males: nonanal, nonanol, nonanoic acid, and 1R,2S,5S,8R-iridodial. No volatiles were detected from the abdominal cuticle of the females. Thoracic extracts of both sexes contained antennally active 1-tridecene and inactive skatole. Iridodial was the only male-specific compound that exhibited significant attraction to Co. oculata males. A weak attraction of males was also found to nepetalactol (an aphid sex pheromone component), which may be due to the 5% iridodial present in the synthetic sample as an impurity. A plant volatile, methyl salicylate, synergized attraction to iridodial, whereas 1-tridecene was antagonistic. No females were caught in the entire study. Co. oculata males possess numerous elliptical epidermal glands on the 3rd-8th abdominal sternites, which are likely the pheromone glands. Another lacewing species, Chrysoperla rufilabris, did not produce male-specific volatiles or possess the type of gland presumed to produce pheromone in Co. oculata males, but (Z)-4-tridecene was identified as a major and antennally active compound from thoracic extracts of both sexes. Thus, 1R,2S,5S,8R-iridodial is now identified as a male-produced male-aggregation pheromone for Co. oculata, the first pheromone identified for lacewings.