Effects of UV-B radiation on fitness related behaviors of the sea urchin Strongylocentrotus intermedius

Ozone depletion induced by anthropogenic gases has been increasing the transmission of solar ultraviolet-B radiation (UV-B, 280–315 nm) through the atmosphere, which may impact the fitness of marine invertebrates in intertidal and shallow waters. To our knowledge, however, the responses of fitness related behaviors to UV-B radiation at different intensities have been rarely studied in marine invertebrates. For the first time, the present study investigated the effects of exposure of one hour to UV-B radiation at different intensities on foraging behavior, Aristotle’s lantern reflex and righting behavior of the sea urchin Strongylocentrotus intermedius. Exposure of one hour to UV-B radiation at 10 μW/cm2 significantly reduced foraging behavior. An intensity dependent effect of exposure to UV-B radiation was found in the duration of the Aristotle’s lantern reflex. Exposure to UV-B radiation at 20 μW/cm2 for one hour significantly reduced the duration of the Aristotle’s lantern reflex, but 10 μW/cm2 did not. There was no significant difference of righting response time among sea urchins exposed to 0, 10 and 20 μW/cm2 for one hour. To test potential carryover effects, the behavioral traits were re-measured three days later. We found significant carryover effects of UV-B radiation on foraging time and righting response time, but not on the duration of the Aristotle’s lantern reflex. The present study indicates that a brief exposure of one hour to UV-B radiation can significantly affect the duration of Aristotle’s lantern reflex, righting response time and foraging behavior of a sea urchin, although the immediate impacts and carryover effects were highly trait dependent. This study provides new information into the behavioral responses of marine invertebrates to exposure to UV-B radiation. Future studies should be carried out to investigate long-term carryover effects of UV-B radiation on behavioral and physiological fitness related traits.