The environment is changing globally in an accelarating pace. All organisms have to cope with these changes and it far from known how and if they will be able to do so. Environmental changes can occur gradually or sudden and drastic. In recent years a growing number of studies showed that evolutionary and ecological processes can occur at similar time scales in many organisms. The project “Sex in the Sea” aims to explore the influence of the biotic and abiotic environment on sexual selection in marine copepods and its potential feedback on population dynamics. Sexual selection in plankton is a fairly unexplored field, but several studies report courtship dances and other behaviors that resemble sexually selected behaviors of higher organisms. One aim of this study is to identify and measure sexual selection inthese organisms. This task is far from trivial, even in bigger and wellstudied animals (see Klug et al. 2010). We use a combination of experimental and modeling methods to figure out what the biological and physical conditions are in which mate choice and mate competition could arise. Individuals in the marine environment have to escape predators, find food and find mates. Mate finding can be particulary difficult when densities are low. In some species of copepods the males follow pheromone trails of the females, which increases their chances of meeting up. This trails can be influenced by the chemical and physical environment. Besides the chemical environment the density and the adult sex ratio influences encounter rates, and thereby the costs and benefit ratio of mate choice.
Copepods use spermatophores to transfer their sperm. These packages are commonly thought of as quite costly to produce. However in our lab cultures we find individuals with several attached spermatophores, which might indicate that under certain conditions the price cannot be high enough or that it is quite cheap after all.