Meeting Abstract
Within intertidal ecosystems smaller organisms in high density populations face predation from larger organisms and competition from similarly sized organisms. As a result, they may experience a trade-off between foraging and sheltering. Across North America Carcinus maenas, or the European green crab, is an invasive species. The behavior of juvenile green crabs is understudied. We previously found that smaller juvenile crabs (5-10 mm carapace width, CW) spent a larger proportion of their time sheltering than larger juveniles (20-25 mm CW). Since green crabs are known to be cannibalistic at high densities, we hypothesized that the difference in sheltering behavior between small and large juveniles might change with the presence of a conspecific predator (30-40 mm CW). In an artificial setting, crab behavior was studied through video analysis. Preliminary data suggest that small crabs in the presence of conspecific predators allocate more time to sheltering. Large crabs in the presence of conspecific predators spent more time foraging. A shift in behavior of smaller individuals in the presence of predator may provide information on tradeoffs and conflicts individuals experience within a population. Understanding conspecific prey behavior in the presence of a predator may lead to a better understanding of demographical conflicts within C. maenas and potentially other decapods.
