Characterizing substrate-borne vibrational mating signals produced by pear psylla, Cacopsylla pyricola (Hemiptera: Psyllidae)

Authors: JOCSON, DOWEN - Washington State University; GONZALES, MARK - Washington State University; Horton, David; BEERS, ELIZABETH - Washington State University; OELLER, LIESL - Washington State University; CROWDER, DAVID - Washington State University

Submitted to: Journal of Insect Behavior
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/6/2023
Publication Date: 10/10/2023
Citation: Jocson, D.M., Gonzales, M.T., Horton, D.R., Beers, E., Oeller, L.C., Crowder, D.C. 2023. Characterizing substrate-borne vibrational mating signals produced by pear psylla, Cacopsylla pyricola (Hemiptera: Psyllidae). Journal of Insect Behavior. https://doi.org/10.1007/s10905-023-09839-2.
DOI: https://doi.org/10.1007/s10905-023-09839-2

Interpretive Summary: Pear psylla is the primary insect pest of pears in North America and continues to be difficult to manage using standard insecticide-based control programs. Like other psyllid species, male and female pear psylla locate one another for mating by use of acoustic signals. This trait could make this species susceptible to control through mating disruption by saturating orchards with a synthesized version of the live signal. However, the acoustic signals of this species have yet to be described, nor is it clear how environmental factors such as temperature affect the live signal. We show that different seasonal forms of psylla produce slightly different signals, and that temperature further affects characteristics of the live signal, especially that of the male insect. These results are the first description of the acoustic signals for this species. Our results will help in developing an effective synthetic mimic of the live signal for use eventually in an acoustically based program of mating disruption.

Technical Abstract: Tactics that manipulate insect behavior are a component of many pest management strategies. Pheromones are widely used for mating disruption for example, although few studies have assessed disrupting other forms of communication. For pests that use acoustic signals to locate mates, characterizing the signals across variable environments is the first step to using mating disruption. Here we characterized the mating signals of male and female pear psylla (Cacopsylla pyricola) and assessed whether temperature and presence of conspecific individuals altered the male signal characteristics. Pear psylla is a candidate for mating disruption as females overwinter before emerging in the spring and using substrate-borne signals to locate mates; if these first matings can be disrupted populations could be suppressed. We show winterform and summerform male psylla songs both contain a group of chirps followed by a trill, while females respond with chirps. Summerform and winterform male song trills differed significantly in peak frequency (Hz), likely because males of each form called at different temperatures. For both forms, the call peak frequency had a positive linear relationship with temperature. Males were also more likely to sing when they had previously encountered females compared to naïve males. Our results show acoustic signals can be characterized across different life stages of a pest and a range of environments. Studies that advance our understanding of insect acoustic communication will promote development of novel behaviorally-based management tactics.