Lifetime reproductive success in two secondary hyperparasitoid wasps, Lysibia nana and Gelis agilis

Lifetime reproductive success in two secondary hyperparasitoid wasps, Lysibia nana and Gelis agilis

Terrestrial Ecology

General information on earlier student projects below - updates with supervisor Jeff Harvey!

Hyperparasitoids are insects that develop on, or in another parasitoid species. Secondary hyperparasitoids attack primary parasitoid hosts (usually their cocoons) that have already emerged from the secondary herbivore host. In spite of their potential importance in affecting the dynamics of plant-herbivore-parasitoid systems (over three trophic levels), little is still known about the biology and life-history of secondary hyperparasitoids (in the fourth trophic level).

This project aims to examine lifetime reproductive success (fecundity) in two species of solitary, secondary idiobiont hyperparasitoids that attack fully cocooned pre-pupae of the same primary parasitoid host. Cotesia glomerata is a primary parasitoid that attacks young larvae of cabbage white butteflies, including Pieris brassicaeLysibia nana is a secondary hyperparasitoid that only attacks C. glomerata and a few related parasitoids species. Gelis agilis is a more generalistic hyperparasitoid than L. nana, and is also a primary parasitoid of many other hosts in nature. Although C. glomerata is well studied, and considered to be an important biological control agent of pierid butterflies, virtually nothing is known about its complex of secondary hyperparasitids.

Preliminary experiments compared developmental strategies in the two hyperparasitoids (Applied Entomology and Zoology). Some additional data on reproductive success in L. nana has also been obtained and can be incorporated into the students results. In the proposed experiments, the student will monitor offspring production in both hyperparasitoid species over the course of their lifetime. Because both hyperparasitoids exhibit different biological charcteristics, the data generated will greatly enhance our understanding of both life-history evolution in these fascinating insects as well as factors that permit co-existence in the field. It is planned that the results of the experiments will be written up and submitted as a manuscript to a peer-reviewed journal.

All insects are currently cultured in both Wageningen University (Dept. of Entomology) and the Netherlands Institute of Ecology.