Male Impact on Female Reproductive Performance of the Larval Tephritid Parasitoid Diachasmimorpha tryoni (Hymenoptera: Braconidae)

Authors: RAMADAN, MOHSEN - State Of Hawaii; Wang, Xingeng

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/5/2021
Publication Date: 4/26/2021
Citation: Ramadan, M.M., Wang, X. 2021. Male impact on female reproductive performance of the larval tephritid parasitoid Diachasmimorpha tryoni (Hymenoptera: Braconidae). Journal of Economic Entomology. https://doi.org/10.1093/jee/toab063.
DOI: https://doi.org/10.1093/jee/toab063

Interpretive Summary: The Mediterranean fruit fly, one of the world’s most destructive invasive pests of fruit crops, invaded Hawaii during the last century and has caused severe economic losses and hindered export of tropical fruits. Several natural enemies have been introduced into Hawaii for biological control of medfly. The parasitic wasp Diachasmimorpha tryoni has been mass reared and released to help control medfly in Hawaii and other regions. We investigated male wasp reproductive performance and its role in female reproductive success, and showed that synchronizing male mating with female emergence from fly pupae maximized mating success. Mating reduced the potential lifetime fecundity of females, but multiple matings increased female offspring overall. Our results will help to improve mass rearing and augmentative releases of this important biological control agent against medfly.

Technical Abstract: Diachasmimorpha tryoni (Cameron) (Hymenoptera: Braconidae) is a larval parasitoid that has been massreared for augmentative biological control against the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) in Hawaii and other regions. To improve performance of female wasps in biological control programs, we conducted a series of experiments to investigate male wasp reproductive performance and its role in female reproductive success. The results showed that D. tryoni males remained close to the emergence (release) site following release. Males emerged earlier than females and male’s capacity to inseminate females reached the highest level (inseminated 9.2 ± 0.4 females/day) on the second day after eclosion in synchronization with female emergence peak; allowing males encountering most receptive females to enhance their mating success. Mating rates under normal rearing conditions (200 pairs per cage) reached optimum 100% insemination after 5 d. However, oviposition experience prior to mating impaired female’s receptivity as a percentage of inseminated females reduced to 17.5 ± 4.8%, while 70.0 ± 4.1% females without prior oviposition experience accepted mating. Mating reduced male’s survivorship and the potential lifetime fecundity of females, although multiple mating increased percentage of female offspring. Overall, influence of male density on the female oviposition rate and offspring sex ratio was not detected under captive rearing conditions. These results suggest that local and early mating is important for male’s reproductive success and females must be allowed to mate before they are exposed to hosts or released in the field to achieve their full reproductive potential.