Submitted to: Environmental Entomology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/20/2009
Publication Date: 8/1/2009
Citation: Frank, D., Leskey, T.C., Bergh, C. 2009. Post-mating behavior of female dogwood borer (lepidoptera: sesiidae) in apple orchards. Environmental Entomology. 38(4):1219-1225. Interpretive Summary: The dogwood borer is an important wood-boring pest in apple orchards in eastern North America. In order to develop effective management strategies for this insect, one must understand the biology and behavior of the insect in the field. As the female is responsible for depositing eggs and creating new infestation sites within an orchard, understanding her behavioral repertoire is of particular importance. After mating, female dogwood borers seek egglaying sites within apple orchards with most of the foraging activity occurring in the late afternoon and early evening (from 500PM-700PM). Females were generally observed searching for egg-laying sites below the graft union of apple trees, as this is where most burr knot tissue, a favored host plant tissue, is found. Females also spent a large portion of their time resting between foraging and egg-laying bouts in the canopy of apple trees. Results of these studies will help facilitate development of effective management strategies targeting female dogwood borer.
Technical Abstract: The post-mating behavior of female dogwood borer, Synanthedon scitula (Harris) (Lepidoptera: Sesiidae), was examined in a young apple orchard planted on size-controlling rootstock in Virginia. All female dogwood borers captured while exhibiting casting flight near the base of trees were mated, based on the presence of a spermatophore. Surveys of female activity within orchards were conducted at regular intervals throughout the daylight hours, revealing a diel periodicity that peaked between 1700 and 1900 hours, with most females located below the graft union of trees. A transition matrix, based on 1108 behavioral sequences exhibited by 66 females, was used to produce a first-order Markov chain of behavioral events that occurred significantly more often than expected by chance. Casting flight, probing with ovipositor, and oviposition were the most frequent behaviors observed, representing 31.7, 30.0, and 18.1 percent of all behaviors recorded, respectively. Our observations revealed that 88, 99, 99 percent of casting flight, probing with the ovipositor, and oviposition, respectively, occurred below the graft union. Observed behaviors considered not directly related to oviposition site selection or oviposition included antennal grooming, non-casting flight, and resting, representing 1.3, 8.3 and 10.6 percent of all behaviors recorded, respectively. Mated females spent significantly more time resting than in other behaviors and significantly more time in that state within the apple tree canopy than on other parts of the tree. Results are discussed in relation to the influence of insect-host plant interactions on oviposition site selection by female dogwood borer.