1. Center for Marine Science, University of North Carolina Wilmington, Wilmington, North Carolina 28403 USA
2. Department of Biology, Saginaw Valley State University, Saginaw, Michigan 48710 USA
3. Laboratory for Sensory Ecology, J. P. Scott Center for Neuroscience, Mind and Behavior, Department of Biological Sciences, Bowling Green State University, Bowling Green, Ohio 43403 USA and University of Michigan Biological Station, 9133 East State Street, Pellston, Michigan 49769 USA