ARS | Publication request: Morphological characterization of the antennal sensilla of the dogwood borer (Lepidoptera: Sesiidae)

Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 18, 2010
Publication Date: November 20, 2010
Citation: Frank, D.L., Leskey, T.C., Bergh, C.J. 2010. Morphological characterization of the antennal sensilla of the dogwood borer (Lepidoptera: Sesiidae). Annals of the Entomological Society of America. 103(6):993-1002.

Interpretive Summary: Dogwood borer has become an important wood-boring pest of apple trees planted on dwarfing or size-controlling rootstocks due to their tendency to produce burr knot tissue. Burr knot tissue is a favored oviposition site by female dogwood borer, and subsequent, larval feeding can eventually lead to tree girdling and death. We characterized the size of male and female dogwood borer antennae and the types of sensory structures present on them. Significantly, more segments were present on the female antennae, though the length and width of individual segments were larger on males. Seven types of sensory structures were present on both male and female antennaes, though significantly more of six sensory types were present on the female antennae. This study will enhance our ability to resolve the electrophysiological and behavioral responses of females to host plant volatiles. Ultimately, a better understanding of the mechanisms involved in host-finding and oviposition acceptance behaviors will create opportunities to assess the possibility of using plant-derived compounds for the monitoring or management of female dogwood borer in apple orchards or managed urban landscapes.

Technical Abstract: The external morphology of the dogwood borer antennae and their sensilla was investigated using light and scanning electron microscopy. Male and female antennaes were clavate before tapering to an apical point and consisted of three main segments; the scape, pedicel, and flagellum. Although, there was no significant difference in the length of the flagellum between genders, the number of flagellomeres was significantly greater in females than in males, and the length and width of individual flagellomeres was significantly greater in males than in females, except near the distal end of the antennae. The antennal flagellum of both male and female dogwood borer contained seven sensillum types: auricillica, basiconica, chaetica, coeloconica, squamiformia, styloconica, and trichoidea (3 subtypes). The mean number of sensilla basiconica did not differ between female and male antennaes, but all other sensillum types were significantly more abundant on the female antennae. The morphology and purported function of each sensillum type are discussed in relation to the host and oviposition site finding, and acceptance behaviors exhibited by dogwood borer.