Abstract: Artificial night lighting (or ecological light pollution) is only now gaining attention as a source of long-term effects on the ecology of both diurnal and nocturnal animals. The limited data available clearly indicate that artificial light can affect physiology and behaviour of animals, leading to ecological consequences at the population, community, and ecosystem levels. Aquatic ecosystems may be particularly vulnerable to such effects, and nocturnally breeding animals such as frogs may be especially affected. To address this potential, we quantify the effects of artificial light on calling and movement behaviour in a rural population of male green frogs (Rana clamitans melanota (Rafinesque, 1820)) during the breeding season. When exposed to artificial light, frogs produced fewer advertisement calls and moved more frequently than under ambient light conditions. Results clearly demonstrate that male green frog behaviour is affected by the presence of artificial light in a manner that has the potential to reduce recruitment rates and thus affect population dynamics.

Abstract: 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.

Abstract: Ultraviolet (UV) vision exists in several animal groups. Intuitively, one would expect this trait to be favoured in species living in bright environments, where UV light is the most present. However, UV sensitivity, as deduced from sequences of UV photoreceptors and/or ocular media transmittance, is also present in nocturnal species, raising questions about the selective pressure maintaining this perceptual ability. Amphibians are among the most nocturnal vertebrates but their visual ecology remains poorly understood relative to other groups. Perhaps because many of these species breed in environments that filter out a large part of UV radiation, physiological and behavioural studies of UV sensitivity in this group are scarce. We investigated the extent of UV vision in Caudata, the order of amphibians with the most nocturnal habits. We could recover sequences of the UV sensitive SWS1 opsin in 40 out of 58 species, belonging to 6 families. In all of these species, the evidence suggests the presence of functional SWS1 opsins under purifying selection, potentially allowing UV vision. Interestingly, most species whose opsin genes failed to amplify exhibited particular ecological features that could drive the loss of UV vision. This likely wide distribution of functional UV photoreceptors in Caudata sheds a new light on the visual ecology of amphibians and questions the function of UV vision in nocturnal animal species.