PARENT SESSION

Community Ecology 4 -- Session Chair: Marianna Wood-- Van Duzer Theater

CO-OCCURRENCE OF BAT FLIES ON NEOTROPICAL BATS: A NULL MODEL ANALYSIS. Carl W. Dick. Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA.

ABSTRACT- Ecologists debate whether species composition is predicated by deterministic rules of interspecific interactions. Assembly rules predict that species will co-occur less often than expected by chance, and those that do co-occur will differ morphologically. Streblid flies and their bat hosts provide an ideal system with which to test predictions of competition and coexistence ecology. Thirty-one species of Venezuelan bats were parasitized by two or more bat fly species. Abundance data of fly occurrence on hosts were analyzed using null models. Because co-occurring fly species are almost always of different genera and different morphologically, I predicted that fly species would co-occur no less often than expected by chance. Despite the different morphologies exhibited by co-occurring fly species, null model analyses revealed that fly species on 2-parasite hosts generally co-occur less often than expected by chance. However, on 3- and 4-parasite hosts, more cases of species co-occurrence were revealed. Furthermore, my study indicates that individuals of single species are found together more often than expected by chance. This means that 1) intra-specific assemblages of parasites are clumped, and 2) the degree of inferred inter-specific competitive interactions depends on the abundance of single fly species.

KEY WORDS: Assembly rules , Streblid flies