Sensory aspects of trail-following behaviors in the Asian longhorned beetle, anoplophora glabripennis

Authors: GRAVES, FERN - Pennsylvania State University; BAKER, THOMAS - Pennsylvania State University; Zhang, Aijun; KEENA, MELODY - Us Forest Service (FS); HOOVER, KELLI - Pennsylvania State University

Submitted to: Journal of Insect Behavior
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/18/2016
Publication Date: 10/27/2016
Citation: Graves, F., Baker, T., Zhang, A., Keena, M., Hoover, K. 2016. Sensory aspects of trail-following behaviors in the Asian longhorned beetle, anoplophora glabripennis. Journal of Insect Behavior. doi:10.1007/s10905-016-9587-8.

Interpretive Summary: The Asian longhorned beetle (ALB) is an invasive and xylophagous insect pest from Asia which has invaded the U.S. and Europe. ALB is highly polyphagous, attacking a wide range of hardwood trees, including those in the genera Acer, Salix, Populus, and Ulmus. It is estimated that 30% of all urban trees could potentially be lost if all urban environments in the contiguous U.S. were infested with this pest. In previous research, we have identified a female-produced sex trail attractant. In this study, we demonstrated that the maxillary and/or labial palps of the male beetle could be involved in trail pheromone detection via contact chemoreception. Understanding how male ALB detects the female-produced sex trail attractant and recognizing the behaviors associated with trail-following will help scientists and growers to reveal the mechanisms of this portion of the mate-finding process in this insect, as well as offering insights into trail-following behaviors of other insects. It will also enable scientists and growers to develop more reliable and efficient trapping systems to detect ALB infestation and monitor ALB populations for more efficient management of this pest.

Technical Abstract: Anoplophora glabripennis has a complex suite of mate-finding behaviors, the functions of which are not entirely understood. These behaviors are elicited by a number of factors, including visual and chemical cues. Chemical cues include a male-produced volatile semiochemical acting as a long-range sex pheromone, a female-produced cuticular hydrocarbon blend serving as a sex-identification contact pheromone, and a recently identified female-produced trail sex pheromone that is followed by mate-seeking males. However, the sensory appendages used to detect the trail sex pheromone and the location of any sensilla on these appendages are unknown. We evaluated the ability of virgin male A. glabripennis to follow a sex pheromone trail after removal of the terminal four antennal segments and/or the maxillary and labial palps using a two-choice behavioral bioassay. We also tested the ability of males to follow the trail sex pheromone using volatile pheromone cues only, without physical contact with the pheromone. Results suggest that the palps are primarily responsible for sensing the pheromone, with males lacking palps unable to respond behaviorally to the trail sex pheromone. Under the conditions of this study, males could not follow the sex pheromone trail without direct contact, suggesting that olfaction may not be involved in detection of this pheromone. However, we did not determine to what degree the trail pheromone chemicals would volatilize under our experimental conditions. This work is important in elucidating the behaviors and sensory structures involved in mate-finding by this species on a substrate, and these studies may help determine whether the trail sex pheromone has applications for monitoring and management.