Mating behavior and effects of light on the fairy shrimp Branchinella kugenumaensis (Ishikawa, 1895): vision dominated mating system

Large branchiopods face time constraints in reproduction efficiency due to their living in temporary environments. Efficiency on mate locating is especially important for their population sustaining. Light has been demonstrated as an important factor influencing mating success for anostracans, but detailed information is lacking. Branchinella kugenumaensis tends to aggregate at water surface. We hypothesized that this tendency is related to a necessity of light for mating. We observed Branchinella kugenumaensis mating behavior, which contained 6 elements: orientation, station taking, amplexus, intromission, copulation and disengagement. In addition, we compared the first 3 elements of behavioral responses of focal males toward three types of potential mates (receptive females, non-receptive females, and other males) in both light and dark conditions. We found that light effects were significant in all 3 behavioral elements, regardless of potential mate types. Therefore, we suggest that male B. kugenumaensis relies on vision to assess potential mates