Abstracts (first author)
Context-dependent plasticity of reproduction in the common goby (Pomatoschistus microps)
Reproduction in animals can be highly variable with characters like reproductive rates and reproductive success being affected by numerous abiotic and biotic factors. Different populations of one species usually experience different kinds of such external influences. Likewise, there are often temporal changes in the environment, e.g. in the course of the progressing breeding season. By differentially affecting reproduction in males and females this social and population ecological context can also determine the direction and strength of sexual selection. While most research on sexual selection thus far has ignored this background, this study is specifically addressing the interactions between reproduction, sexual selection and its natural context, using the common goby (Pomatoschistus microps) as a model species. This small marine fish has exclusive paternal care, a resource-based mating system and plastic sex roles. Additionally, it occurs throughout the Baltic Sea and its distribution thus naturally stretches over steep environmental gradients. In this study, we investigated how different seawater temperatures and adult sex ratios affect reproduction, the operational sex ratio and intra- and intersexual competition in a controlled laboratory experiment. We found that warmer water led to higher reproductive rates in both sexes. However, this increase was much higher in males. Other preliminary results show larger clutches and higher reproductive rates under female-biased conditions. This study thus helps to further our understanding of the context-dependency of reproduction and we will discuss how this ultimately affects sexual selection.