Vekhnik V.A., Vekhnik V.P., Rozentsvet O.A., Bogdanova E.S. 2019. Possible relations between reproduction of the yellow-necked mouse (Sylvaemus flavicollis) and oak yield // Russian J. Theriol. Vol.18. No.1: 33–42 [in English].
Victoria A. Vekhnik [firstname.lastname@example.org], I.I. Sprygin Zhiguli State Nature Biosphere Reserve, Zhigulyovskaya str. 1, Bakhilova Polyana Village, Samara Oblast 445362, Russia; Vladimir P. Vekhnik [email@example.com], I.I. Sprygin Zhiguli State Nature Biosphere Reserve, Zhigulyovskaya str. 1, Bakhilova Polyana Village, Samara Oblast 445362, Russia; Olga A. Rozentsvet [firstname.lastname@example.org], Institute of Ecology of the Volga River Basin of RAS, Komzina str. 10, Togliatti, Samara Oblast 445003, Russia; Elena S. Bogdanova [email@example.com], Institute of Ecology of the Volga River Basin of RAS, Komzina str. 10, Togliatti, Samara Oblast 445003, Russia.
ABSTRACT. Some species of mammals can reproduce in anticipation of future food abundance based on different ecological mechanisms. During 2017–2018 we studied the reproduction of a common abundant species, the yellow-necked mouse Sylvaemus flavicollis, in oak communities during the maturation of acorns to determine if the timing of reproduction has a predictive character. We observed a moderate yield oak year and a high yield oak year. At the very beginning of acorn growth, the share of females in oestrus was maximal, and no pregnant females were found. During the maturation of acorns, the proportion of females in oestrus gradually decreased. The share of males with reproductive activity also decreased during the census. In 2018, the sexual activity of the males was considerably higher than that in 2017, what can point on its role in the regulation of the intensity of reproduction. Thus, we found that mating and pregnancy in a large proportion of the mice during the autumn peak of reproduction, began at the beginning of acorn ripening, due to females feeding on immature seeds during pregnancy and lactation, eliminating a delay between forage yield and rodent reproduction. By the time the acorns were completely ripe and fell, the most of juveniles became independent, and a portion of the young females became sexually mature. So, the dependency of reproduction from the flow of acorns maturation was revealed instead of any prediction. A possible reason for this synchronization is the composition of the diet and, in particular, the contents of lipids and fatty acids. During the maturation of acorns, the proportion of triacylglycerols, the main constituents of body fat in animals, increases considerably, which can increase the survival rate of juveniles.
KEY WORDS: Sylvaemus flavicollis, reproduction, Quercus robur, Zhiguli Mts., lipids, synchronization.