Amphibians' response to the lunar synodic cycle-a review of current knowledge, recommendations, and implications for conservation

The way in which amphibians respond to the geophysical changes brought about by the lunar synodic cycle is a neglected area of their ecology, but one which has recently generated interest. Knowledge of how amphibians respond to lunar phase is of intrinsic interest and also may be important for conservation and monitoring of populations. We surveyed the literature on amphibians' responses to the lunar cycle and found 79 examples where moon phase in relation to amphibian behavior and ecology had been studied, across diverse amphibian taxa. Of the examples reviewed, most of them show some type of response to lunar phase, with only a few species being unaffected. We found that there is no significant difference between the numbers of species which increase, and those that decrease activity or reproductive behavior (including calling) during a full moon. The responses to the lunar cycle can not be generalized across taxonomic group, but instead are highly species specific and relate directly to the species' ecology. The primary reasons for changes in amphibian behavior in response to the lunar cycle appear to be temporal synchronization of breeding and predator avoidance. Responses to changes in prey availability, facilitation of visual signalling and use of lunar cues in navigation and homing are less prevalent but merit further investigation. Comparisons between studies are hampered by differences in field and analytical methods; we therefore make a number of recommendations for future collection and analysis of data related to lunar phase.