Location: Beneficial Insects Introduction Research Unit
Project Number: 8010-30400-001-038-I
Project Type: Interagency Reimbursable Agreement
Start Date: May 1, 2026
End Date: Sep 30, 2027
Objective:
The goal of this research is to continue evaluations of Dryinus sinicus for biological control of spotted lanternfly. The objectives include (1) investigating the effect of different temperatures on the parasitism rate and the parasitoid’s offspring fitness (development time, survival, sex ratio, body size, etc.); and (2) examining the effects of different host plants (mixed) on the parasitism and fitness of both host and parasitoid. In addition, we will (3) complete additional studies to further improve simple storage methods of D. sinicus. These studies will be done in close collaboration with APHIS project partners.
Approach:
Objective 1: Temperature effect on parasitism, survival, offspring development.
We will investigate the effect of different temperatures (20, 25, and 30 °C) on parasitism rate, life-time fecundity, predation, voltinism (univoltine, biovoltine or multivoltine) and parasitoid offspring fitness (development time, survival, sex ratio, body size). Given the reproductive season of this parasitoid occurs during early summer, we will consider only middle and high temperature effects and look at the potential of lab manipulation for multivoltine (multiple generations per year) rearing of this parasitoid. The main purpose of this study is to develop improved rearing methods. If sufficient wasps are available, we will add two more temperatures (15 and 35 °C), and test and compare one-week fecundity and predation across all temperatures, and temperature effect on the parasitoid’s survival and development. These temperature range tests may also help us to develop climatic niche models to predict the potential range of this parasitoid.
Objective 2. Host plant effects. In the past year, we investigated the effects of host plants (TOH vs grapes) on the parasitism rate and host-feeding (foraging efficiency) in no-choice tests. Preliminary results showed no significant effect of host plant on parasitism or host feeding, but female wasps developed from hosts reared on grape are smaller than those from hosts reared on TOH. It is unclear whether these young nymphs developed from grape plants are smaller than those from TOH; therefore, it is unknown whether the parasitoid’s body size and sex ratio are directly or indirectly affected by the host plant. We will conduct two experiments to further investigate these results. First, we will determine the host’s preference and fitness on the two different plants in a choice test (walk-in chamber, 23 °C). Second, we will determine the parasitoid’s preference for host plants in a choice test and offspring fitness of the parasitoids (chamber, 23 °C).
Objective 3. Improving simple rearing and cold-storage methods of D. sinicus.
We will continually improve simple methods of rearing D. sinicus and stockpiling cocoons. We will figure out the conditions (temperature, host stage) for improved parasitism and offspring fitness as well as percentage of female offspring. All cocoons produced prior to ramping down for the season for overwintering will be stored at 20 °C 16L:8D and 40-60% RH. Any emerging wasps (second generation) within the same year will be used for rearing or experiments. All remaining cocoons will be examined to determine the status (dead or alive) and developmental stage and live cocoons will then be placed at 15°C for one week, followed at 10°C for another week before they will be held at 5 °C (complete dark) in vials inside a 100% RH humidity box for 3 months during the wintering season.