Effects of nymphal diet and adult feeding on allocation of resources to glassy-winged sharpshooter egg production

Authors: Sisterson, Mark; Stenger, Drake

Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/2018
Publication Date: 10/3/2018
Citation: Sisterson, M.S., Stenger, D.C. 2018. Effects of nymphal diet and adult feeding on allocation of resources to glassy-winged sharpshooter egg production. Environmental Entomology. 47:1173-1183. https://doi.org/10.1093/ee/nvy094.
DOI: https://doi.org/10.1093/ee/nvy094

Interpretive Summary: The glassy-winged sharpshooter is an invasive insect capable of transmitting the bacterial pathogen Xylellela fastidiosa to grapevine. Introduction of the glassy-winged sharpshooter to California resulted in epidemics of Pierce’s disease of grapevine in two grape growing regions of California. In response, an area-wide suppression program was initiated that relies on application of insecticides. In this study, effects of juvenile diet on timing and magnitude of glassy-winged sharpshooter egg production were evaluated. While juvenile diet affected adult size and development time, juvenile diet did not affect time to first oviposition or quantity of mature eggs available at time of first oviposition. Results suggest that the nutritional resources required for egg production were gained by females during the first week after adult emergence via adult feeding. Identifying periods where resource acquisition is critical for glassy-winged sharpshooter egg production will aid in predicting glassy-winged sharpshooter population dynamics and may suggest novel targets for control.

Technical Abstract: The glassy-winged sharpshooter is an invasive insect capable of transmitting the bacterial pathogen Xylella fastidiosa. Pre-oviposition periods of laboratory reared glassy-winged sharpshooters are variable. Here, two questions were addressed: does nymphal diet affect pre-oviposition period and how do allocation patterns of resources differ for females that produce eggs versus females that do not? Nymphs were reared on one of three host plant species: cowpea, sunflower, or sorghum. Half of females were sacrificed at emergence. The remaining adult females were held on cowpea, a host plant species known to support egg maturation via adult feeding. Females were sacrificed on the day of first oviposition or after 9 weeks if no eggs were deposited. Females reared as nymphs on sorghum had longer development times and were smaller (head capsule width and hind tibia length) than females reared as nymphs on cowpea and sunflower. However, nymphal diet did not affect percentage of dry weight that was lipid at emergence. Further, nymphal diet did not affect time to deposition of the first egg mass or total number of eggs matured at time of first oviposition. Egg production reduced allocation of resources to insect bodies, with body lipid content decreasing with increasing egg production. In general, females increased wet weight 1.4 fold during the first week after adult emergence, with wet weights plateauing over the remaining 9 weeks that adults were monitored. Thus, it seems reasonable to hypothesize that resources required for egg production were acquired via adult feeding during the first week after adult emergence.