[Some features Microtus arvalis arvalis and Microtus arvalis obscurus behaviour in family groups in experiment]

Social behaviour and time bunget of Microtus arvalis arvalis and Microtus arvalis obscurus was studied in 34 sq m enclosures. 10 family groups of each chromosome form (totally 60 animals) were used for observations. The experiment consisted of four stages: setting of a new territory by the voles (I); behaviour of the voles on fsmiliar territory (II); putting an unfamiliar male (III) or an familiar female (IV) into the groups. Totally 1120 hours of observation were conducted. We compared time budgets of two vicariuos forms by calculating the duration of active moving, sitting outside the nest-boxes, grooming and foraging of the voles. Social behaviour of M.a.arvalis and M.a.obscurus was described by analyzing the total number and ratio of different types of interactions (investigating, amicable, aggressive, contact evasion and avoidance). Time burget and social behaviour of two chromosome forms differed notably. Exploratory behaviour and some forms of activity are more typical for M.a.obscurus. They were also more sociable and less aggressive than M.a.arvalis. Amicable interactions predominated in M.a.obscurus while investingating (neutral) contacts predominated in M.a.arvalis.