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Bushinger, Scott J.*, Bryant W. Buchanan, and Sharon E. Wise. 2003.


Visual prey detection by red-backed salamanders, Plethodon cinereus, under ?black? light



Student Research

When conducting behavioral studies on animals such as amphibians, it is important to consider the visual capabilities of the study animal and how those capabilities might affect the experimental design. Some authors have suggested that individuals of Plethodon cinereus (red-backed salamanders) cannot detect visual stimuli under ?black? light (mostly UV + some ?white? wavelength energy) and that ?black? light may be used in experiments to simulate darkness. We tested the hypothesis that salamanders cannot detect visual stimuli under ?black? light by comparing salamander responses to artificial prey under four lighting treatments: ?white? light (high intensity), ?white? light (low intensity), ?black? light, and darkness. Artificial prey (a black square on a white background) were presented to the salamanders using an optomotor apparatus, which moved the prey at a rate of about 0.75 cm/sec. We recorded the time required for salamanders to orient toward prey (a visual response) under each of the four lighting treatments. Our preliminary results suggest that red-backed salamanders orient toward prey much faster under ?black? light and high and low intensity white light than in total darkness, suggesting that salamanders are capable of detecting visual cues under ?black? light. Therefore, we propose that it is inappropriate to use ?black? light as the light source in experiments in which visual cues are to be eliminated (as in total darkness). Because ?black? lights produce both UV and ?white? wavelengths, more experiments are needed to determine whether or not these salamanders are capable of detecting visual cues under UV wavelengths alone.
* UC class of 2003