The increased incidence of solar ultraviolet B (UVB) radiation has been proposed as an environmental stressor, which may help to explain the enigmatic decline of amphibian populations worldwide. Despite growing knowledge regarding the UV-induced biological effects in several amphibian models, little is known about the efficacy of DNA repair pathways. In addition, little attention has been given to the interplay between these molecular mechanisms with other physiological strategies that avoid the damage induced by sunlight. Here, DNA lesions induced by environmental doses of solar UVB and UVA radiation were detected in genomic DNA samples of treefrog tadpoles (Hypsiboas pulchellus) and their DNA repair activity was evaluated. These data were complemented by monitoring the induction of apoptosis in blood cells and tadpole survival. Furthermore, the tadpoles' ability to perceive and escape from UV wavelengths was evaluated as an additional strategy of photoprotection. The results show that tadpoles are very sensitive to UVB light, which could be explained by the slow DNA repair rates for both cyclobutane pyrimidine dimers (CPDs) and pyrimidine (6,4) pyrimidone photoproducts (6,4PPs). However, they were resistant to UVA, probably as a result of the activation of photolyases during UVA irradiation. Surprisingly, a sensory mechanism that triggers their escape from UVB and UVA light avoids the generation of DNA damage and helps to maintain the genomic integrity. This work demonstrates the genotoxic impact of both UVB and UVA radiation on tadpoles and emphasizes the importance of the interplay between molecular and sensory mechanisms to minimize the damage caused by sunlight.

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ResumoAnimais menos carismáticos são mais propensos a atropelamento: atitudes humanas em relação a pequenos animais nas estradas brasileiras. Estradas são fontes longas e intermitentes de diminuição da vida selvagem devido aos seus efeitos indiretos, como fragmentação de hábitat, ou seus efeitos diretos, como a constante mortalidade por atropelamentos. Assim, alguns estudos indicam que parte desses atropelamentos pode ser intencional e passível de ser evitada. Nós investigamos se diferentes grupos de pequenos animais apresentaram diferentes taxas de atropelamento e como o "carisma" afeta as chances de sobrevivência de um animal nas rodovias. Durante nosso experimento, nós quantiicamos as taxas de atropelamento de modelos de aranhas, serpentes, pintos e folhas de árvore (controle) em três rodovias de diferentes volumes de tráfego. Constatamos que serpentes e aranhas foram consistentemente atropeladas com maior frequência que os pintos e as folhas. Também observamos que os pintos foram os únicos modelos resgatados pelos humanos. Concluímos que as chances de sobrevivência dos pintos é a maior entre os modelos testados e isso se deve ao valor carismático atribuído a eles pelos seres humanos, em comparação a serpentes e aranhas. Sugerimos a veiculação de campanhas na mídia que visem a aumentar a conscientização do público quanto à conservação da vida selvagem como uma ferramenta útil para solucionar o problema do atropelamento intencional de pequenos animais. Palavras-chave:Aranhas; Conlitos com a vida selvagem; Conservação; Ecologia de estradas; Serpentes AbstractRoads are long and intermittent sources of wildlife loss due to their indirect effects, such as fragmentation of habitat, or their direct effects, such as constant mortality by run-over. Thus, some studies indicate that a portion of these run-over incidents may be intentional and could be avoided. We investigated whether various groups of small animals had different run-over rates and how "charisma" affects the survival chances of an animal on the roads. During our experiment, we quantiied run-over rates for models of spiders, snakes, chicks, and tree leaves (control) on three roads with different trafic volumes. We found out that snakes and spiders were consistently ran over with a higher frequency than chicks and leaves. We also observed that chicks were the only models rescued by human beings. We concluded that the survival chances of chicks are the highest among the models tested and this is due to the charismatic value attributed to them by human beings, when compared to snakes and spiders. We suggest the broadcasting of campaigns in the media to increase public awareness regarding wildlife conservation as a useful tool to solve the problem of intentional run over of small animals.

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