Baker, B. J., & Richardson, J. M. L. (2006). The effect of artificial light on male breeding-season behaviour in green frogs,Rana clamitans melanota. Can. J. Zool., 84(10), 1528–1532.
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.
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Buchanan, B. W. (1993). Effects of enhanced lighting on the behaviour of nocturnal frogs. Animal Behaviour, 45(5), 893–899.
Abstract: Biologists studying anuran amphibians usually assume that artificial, visible light does not affect the behaviour of nocturnal frogs. This assumption was tested in a laboratory experiment. The foraging behaviour of grey treefrogs, Hyla chrysoscelis, was compared under four lighting conditions: ambient light (equivalent to bright moonlight, 0·003 lx), red-filtered light (4·1 lx), low-intensity 'white' light (3·8 lx), and high-intensity 'white' light (12·0 lx). The treatments were chosen to correspond to standard methods of field observation of frog behaviour. The foraging behaviour of frogs in the four treatments was observed using infra-red light that was invisible to the frogs. The ability of the frogs to detect, and subsequently consume prey was significantly reduced under all of the enhanced light treatments relative to the ambient light treatment. Thus, the use of artificial light, within the visible spectrum of the frogs' eyes, can influence the outcome of nocturnal behavioural observations. These results lead to the recommendation that anuran biologists use infra-red or light amplification devices when changes in frogs' visual capabilities may influence the conclusions drawn from a study.
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Deng, K., Zhu, B. - C., Zhou, Y., Chen, Q. - H., Wang, T. - L., Wang, J. - C., et al. (2019). Mate choice decisions of female serrate-legged small treefrogs are affected by ambient light under natural, but not enhanced artificial nocturnal light conditions. Behavioural Processes, in press, 103997.
Abstract: Artificial light at night (ALAN) is a widespread anthropogenic stimulus that can significantly alter nocturnal animals’ behavior, from migration to foraging to vocal communication. In the present study, we tested the hypothesis that the mate choice decisions of female serrate-legged small treefrogs (Kurixalus odontotarsus) were influenced by ambient light intensity. Standard two-speaker phonotaxis tests were conducted in a sound attenuating chamber. We set four light conditions (I-IV, from low to high) based on a range of light intensities from the maximum natural light at night (i.e., full moon) to that of the actual calling sites, which had artificial light. Contrary to our prediction, female frogs showed a preference for calls on the bright side in treatment I when they were exposed to identical stimuli. However, females preferred longer calls on the dim side to shorter calls on the bright side in this treatment. In addition, there were no significant effects of choice side, light treatment or their interaction on leave time or choice time. Our results suggest that females are more attracted to mates in bright light under natural nocturnal light conditions, but the preference for longer calls is not altered in serrate-legged small treefrogs.
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Gaston, M. S., Pereyra, L. C., & Vaira, M. (2018). Artificial light at night and captivity induces differential effects on leukocyte profile, body condition, and erythrocyte size of a diurnal toad. J Exp Zool A Ecol Integr Physiol, in press.
Abstract: Light pollution or artificial lighting at night (ALAN) is an emerging threat to biodiversity that can disrupt physiological processes and behaviors. Because ALAN stressful effects are little studied in diurnal amphibian species, we investigated if chronic ALAN exposure affects the leukocyte profile, body condition, and blood cell sizes of a diurnal toad. We hand-captured male toads of Melanophryniscus rubriventris in Angosto de Jaire (Jujuy, Argentina). We prepared blood smears from three groups of toads: “field” (toads processed in the field immediately after capture), “natural light” (toads kept in the laboratory under captivity with natural photoperiod), and “constant light” (toads kept in the laboratory under captivity with constant photoperiod/ALAN). We significantly observed higher neutrophil proportions and neutrophils to lymphocytes ratio in toads under constant light treatment. In addition, we observed significantly better body condition and higher erythrocyte size in field toads compared with captive toads. In summary, ALAN can trigger a leukocyte response to stress in males of the diurnal toad M. rubriventris. In addition, captivity can affect the body condition and erythrocyte size of these toads.
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Grant, R., Halliday, T., & Chadwick, E. (2013). Amphibians' response to the lunar synodic cycle--a review of current knowledge, recommendations, and implications for conservation. Behavioral Ecology, 24(1), 53–62.
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.
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