Discovery and field evaluation of sex pheromone components for the click beetle Melanotus verberans (LeConte) (Coleoptera: Elateridae)

Authors: Williams Iii, Livy; HALLORAN, SEAN - University Of California, Riverside; BAKER, PAUL - Clemson University; ETZLER, FRANK - Montana Department Of Agriculture; Lawrence, Lance; MILLAR, JOCELYN - University Of California, Riverside

Submitted to: Journal of Chemical Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/10/2024
Publication Date: 2/5/2025
Citation: Williams Iii, L.H., Halloran, S.T., Baker, P.D., Etzler, F.E., Lawrence, L.L., Millar, J.G. 2025. Discovery and field evaluation of sex pheromone components for the click beetle Melanotus verberans (LeConte) (Coleoptera: Elateridae). Journal of Chemical Ecology. https://doi.org/10.1007/s10886-025-01569-3.
DOI: https://doi.org/10.1007/s10886-025-01569-3

Interpretive Summary: Wireworms, the larvae of click beetles, are insect pests that inhabit the soil and feed on many staple crops such as potatoes and cereals. These pests have become increasingly problematic in North America in recent years, in part due to the lack of effective management strategies. Species-specific behavior-modifying chemicals have been used for more than 50 years for monitoring and management of insect pests of agriculture and human health. Such chemicals have been identified for a few click beetle species, which has led to their use in nationwide field testing of click beetle monitoring and management strategies. However, little is known about the insect-produced chemicals that mediate the reproductive behavior of the majority of these pests. An ARS scientist in collaboration with other researchers used chemical and behavioral studies to identify, synthesize, and field test the sex attractant of a click beetle that is an economically important insect pest of U.S. crops. Results indicated that two female-produced chemicals were strongly attractive to male insects of the same species, and did not appear to attract other species. Also, most male beetle flight activity occurred from April through May. Given that the sex attractant of this insect consists of two compounds that can be readily synthesized, its development for monitoring and management of this pestiferous click beetle is economically feasible.

Technical Abstract: Wireworms, the larval stage of elaterid beetles, are among the most serious soil-borne insect pests in the world. Wireworms feed on a variety of key crops, including small grains, maize, vegetables, fruits, sugar cane, sugar beets, potatoes, and sweet potatoes. Management of these pests is becoming increasingly problematic, in part due to knowledge gaps in their basic biology, which hinders development of effective crop protection strategies. In particular, little is known about the semiochemicals that mediate the reproductive behavior of these pests. Research over the past two decades has begun to fill this need, with: 1) the discovery of sex attractants for several of the key pest species, and 2) subsequent studies toward development of semiochemically-based pest management approaches. We used chemical and behavioral studies to identify, synthesize, and field test the sex attractant pheromone of adult Melanotus verberans, the larvae of which are important crop pests. In coupled gas chromatography-mass spectrometry analyses of extracts of ovipositors of females, five possible pheromone components were identified. Subsequent coupled gas chromatography-electroantennogram detection analyses indicated that male antennae were responsive to only two of these compounds, 13-tetradecenyl acetate and 13-tetradecenyl hexanoate. In field trials, neither compound alone was attractive, but a blend of the two was strongly attractive to conspecific male beetles, and did not attract other species. A two-year field study showed that most male beetle flight activity occurred from April through May. Because the sex pheromone of M. verberans consists of two compounds that can be readily synthesized, its development for integrated pest management should be economically feasible.