PARENT SESSION
Contributed Oral Session 46: Predator - Prey Ecology: Communities and Environmental Impacts
Tuesday, August 9, 8:00 AM - 11:30 AM, Meeting Room 519 B, Level 5, Palais des congrès de Montréal
Asymmetric indirect interactions mediated by a shared parasitoid: A field test of the apparent competition theory.
Hambäck, Peter*,1, Stenberg, Johan2, Ericson, Lars, 1 Dept of Botany, Stockholm, Sweden2 Dept of Ecology and Environmental Science, Umeå, Sweden
ABSTRACT- This study reports on an asymmetric indirect interaction between two chrysomelid beetles, mediated by a shared parasitoid (Asecodes mento), where one species (Galerucella tenella) experiences higher and the other species (G. calmariensis) lower parasitization in mixed versus monospecific populations. This pattern, that also affects the species distribution, is a consequence of differences in life history characteristics. The inferior species (Gt) has a smaller body size, a lower fecundity, and sustains a lower parasitoid density compared with the superior species. This connection between life history characteristics and dominance in host-parasitoid systems corresponds to predictions from current community ecology theory, and provides a useful building-block in the development of a predictive theory of species dominance in presence of apparent competition.
Key words: host-parasitoid system, apparent competition, parasitoid selectivity, community ecology