Mate-searching behaviors in the freshwater calanoid copepod Leptodiaptomus ashlandi

We examined the mate-searching behaviors of the freshwater calanoid copepod, Leptodiaptomus ashlandi, collected from Lake Michigan. The copepods were observed using a 3D optical system to obtain simultaneous front and side views. Males showed significant increases in their swimming speed while pursuing females in 7 out of 14 pre-mating interactions. Females did not show any alterations in their swimming speeds. Males did not swim to females directly nor did they follow the female swimming paths. These results indicate that male L. ashlandi find their females in a manner that is different from either freshwater cyclopoids or the marine calanoids. Therefore, different species may have different behaviors to enhance the encounter probability for mating and to recognize mates.