FACTORS AFFECTING BODY-MASS AND VENTRAL G LAND SIZE IN GREAT GERBIL (RHOMBOMYS OPIMUS) IN SOUTH-EASTERN KARAKUM DESERT

Three year studies of Rhombomys opimus on permanent test plots at the Repetek Reserve (Turkmenistan) permit to consider interrelations betwe en the body mass in adult males,and ventralgland size related to sex, age and season. Sexual dimorphism of both parameters has been revealed . Significant male-female differences in the body mass were registered in subadults and adults, while the gland surface area differed also i n juveniles. These parameters increase with age during the first year of gerbil's life, so that differences between three age categories are significant both in males and females. Seasonal variability of the pa ramaters was observed. In autumn the size of ventral glands in all adu lts is smaller than in spring, the portion of females with active glan ds being increased. All adult males possess active glands throughout t he whole year. The body mass in adult males doesn't differ by seasons, that in females it's higher in spring due to pregnancy. in various ye ars the mass of animals differs significantly, but the gland size does n't change.