INTERAND INTRA-POPULATION VARIABILITY IN FUR COLORING OF THE SUBGENUS SYLVAEMUS INHABITING THE NORTHERN MACROSLOPE OF THE CENTRAL CAUCASUS
Sylvaemus sylvaticus L. are widespread and numerous on the northern macroslope of the Central Caucasus, with their natural habitats also ranging from the semi-desert zone to the subalpine highlands. They have been known to display a high degree of phenotypic plasticity and are extremely morphologically-variable, particularly when it comes to their fur color. There is a wide variety of shades in the coloring of the back and the belly, as well as the size and shape of their pectoral spot. So far there has been insufficient data acquired on the fur color and the size and shape of their pectoral spot of the wood mice, residing in a high-altitude environment of the Caucasus Mountains. The material gathered for this investigation has been the result of the field studies of the subgenus Sylvaemus sylvaticus L. of the Central Caucasus. For the first time, a phenotypic and geographical study of the fur coloring of the wood mice has been carried out, with their age range factored in as well, on the basis of the extensive factual material collected in their natural habitat of the northern macroslope of the Central Caucasus, it being a unique environment of high-altitude belt structure of mountain ecosystems. The research has been conducted on three biotopes in the steppe zone and two biotopes in the subalpine belt of the Elbrus area, which vary in terms of the presence or absence of forest cover. We have examined three patterns of back fur coloring: brown, light brown, and gray-brown and two patterns of belly and hind leg coloring: dark and light. Thus, twelve patterns of fur coloring with the presence or absence of a pectoral spot in the subgenus Sylvaemus sylvaticus L. that inhabit the northern macroslope of the Central Caucasus are described. The research findings indicate that a combination of brown back, light paws and belly dominate in fur color, which is more than 60% in the area in question. The largest number of individuals with a pectoral spot or with small brushstroke-like spots of various shapes and intensity has been recorded in the steppe zone, with the maximum of 14% in the individuals of the Kurp population.