PDF(Pubmed)
Abstract：
Melanism, the process of heavier melanin deposition, can interact with climate variation at both micro and macro scales, ultimately influencing color evolution in organisms. While the ecological processes regulating melanin production in relation to climate have been extensively studied, intraspecific variations of melanism are seldom considered. Such scientific gap hampers our understanding of how species adapt to rapidly changing climates. For example, dark coloration may lead to higher heat absorption and be advantageous in cool climates, but also in hot environments as a UV or antimicrobial protection mechanism. To disentangle such opposing predictions, here we examined the effect of climate on shaping melanism variation in 150 barred grass snakes (Natrix helvetica) and 383 green whip snakes (Hierophis viridiflavus) across Italy. By utilizing melanistic morphs (charcoal and picturata in N. helvetica, charcoal and abundistic in H. viridiflavus) and compiling observations from 2002 to 2021, we predicted that charcoal morphs in H. viridiflavus would optimize heat absorption in cold environments, while offering protection from excessive UV radiation in N. helvetica within warm habitats; whereas picturata and abundistic morphs would thrive in humid environments, which naturally have a denser vegetation and wetter substrates producing darker ambient light, thus providing concealment advantages. While picturata and abundistic morphs did not align with our initial humidity expectations, the charcoal morph in N. helvetica is associated with UV environments, suggesting protection mechanisms against damaging solar radiation. H. viridiflavus is associated with high precipitations, which might offer antimicrobial protection. Overall, our results provide insights into the correlations between melanin-based color morphs and climate variables in snake populations. While suggestive of potential adaptive responses, future research should delve deeper into the underlying mechanisms regulating this relationship.
摘要：
Melanism,更重的黑色素沉积过程，可以在微观和宏观尺度上与气候变化相互作用，最终影响生物体的颜色进化。虽然与气候相关的调节黑色素产生的生态过程已经得到了广泛的研究，很少考虑黑色素的种内变异。这种科学差距阻碍了我们对物种如何适应快速变化的气候的理解。例如,深色可能会导致更高的热量吸收，并且在凉爽的气候下是有利的，而且在炎热的环境中作为紫外线或抗菌保护机制。为了解开这些相反的预测，在这里，我们研究了气候对意大利150条条纹草蛇（Natrixhelvetica）和383条绿鞭蛇（Hierophisviridflavus）的黑色素变化的影响。通过利用黑色素形态(黑曲霉中的木炭和picturata，木炭和淡淡的H.viridiflavus）和汇编2002年至2021年的观察结果，我们预测H.viridiflavus中的木炭形态将优化寒冷环境中的热吸收，同时在温暖的栖息地内提供保护，使其免受过度的紫外线辐射；而picturata和abundisic变体会在潮湿的环境中茁壮成长，自然有更密集的植被和更湿润的基质，产生更暗的环境光，从而提供隐藏优势。虽然picturata和断断续续的形态与我们最初的湿度预期不符，黑曲霉的木炭形态与紫外线环境有关，建议防止有害太阳辐射的保护机制。H.viridiflus与高沉淀有关，这可能会提供抗菌保护。总的来说,我们的研究结果为黑色素颜色形态与蛇种群气候变量之间的相关性提供了见解。虽然暗示了潜在的适应性反应，未来的研究应该更深入地研究调节这种关系的潜在机制。
