Identification of Sex Pheromone Components for the Click Beetles Melanotus piceatus Blatchley and Melanotus insipiens (Say) (Coleoptera: Elateridae).

Little is known about the semiochemicals that mediate the reproductive behavior of click beetles, the Elateridae. Research over the past two decades has begun to fill this gap, with: (1) the discovery of sex attractants for a number of pest and non-pest species, and (2) subsequent studies toward development of semiochemically-based pest management approaches and conservation initiatives for pests and non-pests, respectively. We used chemical, electrophysiological, and behavioral studies to identify, synthesize, and field test female-produced sex attractant pheromones of two North American elaterid species, Melanotus piceatus and M. insipiens. We identified two possible pheromone components for each species using coupled gas chromatography-mass spectrometry analyses of extracts of ovipositors of females: (2Z,6E)-farnesyl acetate and (2E,6E)-farnesyl acetate for M. piceatus, and decyl octanoate and decyl butanoate for M. insipiens. Subsequent coupled gas chromatography-electroantennogram detection analyses indicated that antennae of males were responsive to only one of the two compounds for each species: (2Z,6E)-farnesyl acetate for M. piceatus, and decyl butanoate for M. insipiens. In field trials, (2Z,6E)-farnesyl acetate and decyl butanoate as single components attracted males of M. piceatus and M. insipiens, respectively. In both species, most male beetle flight activity occurred from May through June. Identification of the sex pheromones of these species will provide useful tools to study their biology, while further expanding our knowledge of the types of compounds to be expected in the sex pheromones of related species.