Male Colorado potato beetles alter search behavior in response to prior female presence on potato plants

Authors: Weber, Donald; Duan, Jian; Haber, Ariela

Submitted to: Journal of Pest Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/12/2019
Publication Date: 1/21/2020
Citation: Weber, D.C., Duan, J.J., Haber, A.I. 2020. Male Colorado potato beetles alter search behavior in response to prior female presence on potato plants. Journal of Pest Science. 93:595-604.

Interpretive Summary: Colorado potato beetle (CPB) is a key pest of potato in North America and Eurasia, and notorious for its evolution of pesticide resistance to many modes of action. Detailed knowledge of the pheromones of this pest could serve to manipulate their behavior as a component of potato integrated pest management. Here, we evaluated the response of male beetles on potato plants that had been exposed to females only, males only, mixed-sex groups, or no beetles (clean plants). Results of our study showed that males had characteristic active searching behavior and also spent about three times longer on female-exposed foliage, compared to either male-exposed or clean leaves. The findings indicate presence of a persistent female-produced pheromone, the discovery of which will be the subject of future research. Results should be of interest to pheromone and potato researchers and pest managers.

Technical Abstract: Colorado potato beetle (Leptinotarsa decemlineata; Coleoptera: Chrysomelidae) is a widespread key pest of nightshades of the temperate northern hemisphere. Its evolution of multiple pesticide resistance will continue as a threat to potato and other crops if chemical control is relied upon for potato pest management. An integrated approach including semiochemicals and other non-pesticidal tactics is essential to sustainable management. A volatile aggregation pheromone produced by male adult beetles is attractive to both females and males. Also, earlier research indicates that males respond to a yet-unidentified female-produced sex pheromone. We investigated male Colorado potato beetle behavior on potato plants that had been exposed to females only, males only, mixed-sex groups, or no beetles (clean plants). During observation, these plants hosted no beetles except for the single experimental male beetle. These males (previously mated or unmated) responded very differently to female-exposed plants, spending longer time on plants, and undertaking characteristic active searching behavior, exploring more leaves per plant and moving more rapidly between leaves. When presented with a three-way choice, males spent about three times longer on the female-exposed foliage, compared to either male-exposed or clean leaves. Searching parameters differed between mated and unmated males, but both showed similar reactions to female-exposed plants; there was no statistical interaction between male mated condition and plant treatment. Results indicate presence of a persistent female-produced pheromone strongly influencing male searching behavior and between-plant movement.