PARENT SESSION
Poster Session 29: Predator / Prey Ecology
Thursday, August 11, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal

Intra-specific variation of a morphological inducible defense in the hypotrich ciliate Euplotes.

Kratina, Pavel^*,1, Altwegg, Res¹, Anholt, Bradley ¹, ¹ University of Victoria, Victoria, BC, Canada

ABSTRACT- Predation is ubiquitous in nature. Natural selection has driven the development of an array of defense mechanisms, which can be always present (constitutive) or only expressed in the presence of a predator cue (inducible). In this study we investigated the magnitude of morphological inducible defenses in response to predator density and its variability among clones. We exposed 15 clones of the hypotrich ciliate Euplotes to four densities of the turbellarian predator Stenostomum virginianum in laboratory microcosms. We measured the relationship between Euplotes cell width (inducible defense) and predator density for each clone. The results indicate that Euplotes gradually increased its cell width with predator density. Although this trend was similar for all clones, two clones expressed lower inducibility both in terms of absolute body width and level of induction (body width increase). This finding confirms the existence of interclonal variability in the magnitude of inducible defense. This variation will provide the raw material to study community effects of inducible defense, such as the ability to stabilize predator-prey dynamics.

Key words: inducible defense, Euplotes, predator-prey relationship