Location: Invasive Species and Pollinator Health
Project Number: 2030-22000-033-035-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Aug 1, 2024
End Date: Apr 30, 2025
Objective:
The objectives of this project are to: 1) complete the necessary paperwork to import the strain of the parasitoid Dolichogenidea gelechiidivoris from research cooperators in Spain, (2) collect and rear non-target lepidoptera in California and (3) conduct host-specificity testing of D. gelechiidivoris.
Approach:
During the FY24 performance period of this project, an initial representative selection of 24-35 species of North American non-target lepidoptera in the larval stage will be offered to experimental female D. gelechiidivoris in a series of two-tiered exposure studies, consisting of no-choice and choice tests. Ideally, laboratory testing will be conducted during spring-summer when these insects are naturally active in the field and can be reared in the lab. By design, no-choice experiments will evaluate the oligophagy of D. gelechiidivoris under maximum non-target exposure in quarantine conditions. The tomato pinworm, Keiferia lycopersicella, will be used as a positive control in tests. Keiferia lycopersicella has been present in California for at least 100 years, and laboratory experiments have demonstrated that D. gelechiidivoris will parasitize and successfully develop on K. lycopersicella larvae.
Data collection for all trials will include a measure of parasitoid offspring egg-adult development time; parasitoid offspring sex ratios; and levels of non-target host mortality caused by D. gelechiidivoris attack, including attempted parasitism, successful parasitism, and host-feeding. Timed visual observations or video recordings may be integrated into this tier to learn valuable behavioral information about the range, quality and duration of categorical contact interactions between D. gelechiidivoris and non-targets, including host inspection, host attack, and host rejection. At the completion of all no-choice testing, the group of non-targets whose mortality was not caused directly by D. gelechiidivoris will be excluded from further testing and placed in the no-risk category. The remaining group of on-target species attacked by D. gelechiidivoris will be included in choice testing trials to measure the host preference of D. gelechiidivoris when each non-target is offered in a paired combination with P. absoluta. P. absoluta larvae will be included in this second tier of testing as it is assumed that any problems in obtaining this target species will have been cleared by this point.
