I am investigating the conspicuousness costs of expressing colourful secondary sexual traits in terms of predation risk and access to prey. My model system consists of two species of Calopteryx damselflies, which express wing coloration, a species- and sex-specific sexually selected trait. The damselflies are predated in Scandinavia by a passerine bird, the white wagtail. The damselflies feed for example on small dipterans, so I use Drosophila as a model species.

 

I am using electrophysiology in the damselfly eye, spectrophotometry, and receptor noise modelling of vision to ascertain how discriminable the damselfly wings are against natural patchy backgrounds, under the vision system of each species.

 

My first results show that wing coloration can be antagonistically selected by predators and prey, through its costs on the damselfly’s conspicuousness. Moreover, this antagonistic selection can be sex-dependent, with males paying a much larger cost. I also found clear differences between the two damselfly species.

 

The estimates of predation risk in natural populations of both damselfly species suggest that one species is commonly more predated than the other, and that males are more predated than females. I am currently investigating in more detail why birds choose upon one species or sex, by performing behavioural experiments in the laboratory. I am also exploring the implications of expressing a conspicuous trait in hunting success. Finally, I am also studying the intraspecific communication within Calopteryx species, since males might use a flickering cue based on the wing coloration during courtship.