PARENT SESSION
Oral Session #71: Animal Population Ecology. Presiding: J. Dooley.
Thursday, August 9, 2001. 1:00 PM to 4:15 PM. Hall of Ideas J.

Competition and coexistence between insect parasitoids.

Bonsall, Michael¹, ¹

ABSTRACT- The role of life-history characteristics on the persistence and coexistence of insect parasitoids that compete for a single, limiting host resource are explored empirically and theoretically. I present long-term time series and manipulative experimental results from a Drosophila - parasitoid assemblage (Drosophila subobscura, Asobara tabida and Leptopilina heterotoma). I demonstrate how parasitoid demographic characteristics (e.g. adult longevity) trade-off against larval competitive ability to mitigate the effects of interspecific competition and promote coexistence. Theoretically, I explore, using a structured population model, how wasps partition the limiting resource through shared and exclusive rights to different host classes and how uninvadable community structures emerge from an understanding of demographic trade-offs and competitive ability. The role of limiting similarity, niche partitioning and transient dynamics on the organisation of parasitoid guilds are explored in the light of these theoretical and empirical results.

KEY WORDS: Interspecific Competition, Invasion Dynamics, Limiting Similarity, Transients