Lifespans of Fur Color Morphs in Polymorphic Populations of the Mole Vole and the Hypothesis of Adaptive Polymorphism

Different lifespans were for the first time demonstrated for three (brown, bicolor, and black) fur color morphs in ten mole vole populations of the Volga, Ural, and Trans-Ural regions. With the longest lifespan of 5 years in the species, morphs that numerically dominate in a population can live 1–4 years longer than accompanying morphs. Spearman’s correlation coefficient between the longest lifespan of the morphs and their proportion in the population was R sp = 0.81 ( p < 0.0001). A number of morphological and functional features were identified in the color morphs. The findings are of general biological significance, confirming the hypothesis of adaptive polymorphism. Evolutionary and ecological mechanisms whereby selective advantages develop in morphs (as probable ecomorphs) are possible to evaluate using the morphs as a natural model of the initial step of sympatric form development in different parts of the range.