Sex-Specific Regulation of Marking Behavior by Sex Hormones and Conspecifics Scent in Tree Shrews (Tupaia belangeri)

Abstract

HOLST, D. v. AND F. EICHMANN.Sex-specific regulation of marking behavior by sex hormones and conspecifics scent in tree shrews (Tupaia belangeri).PHYSIOL BEHAV 63(2) 157–164, 1998.—In tree shrews (Tupaia belangeri), both males and females mark their surroundings with urine and skin gland secretions. In this study we examined in standard tests the modulation of marking behavior of male and female tree shrews by hormones and chemical signals of conspecifics. Males mark more frequently than females in the absence of conspecific scent. Female scent elicits only low marking responses in both sexes. Male scent stimulates marking of both sexes, with a much higher response in females. Increasing amounts of male scent result in a corresponding increase in marking by females. In contrast, male marking is maximally stimulated by low scent concentrations of male conspecifics, whereas higher scent concentrations inhibit male marking. Gonadectomy diminishes male marking activities under all scent conditions, whereas in females only the response to male scent is reduced. In unscented cages, the low marking activities of castrated males and intact females are stimulated by treatment with testosterone or estradiol. In the presence of male scent, however, only testosterone, but not estradiol, stimulates marking of castrated males. Marking of intact males or females is not increased by either hormone. As this study shows, external (scent of conspecifics) and internal factors (sex hormone levels) interact to regulate tree shrews’ marking behavior in a sex-specific manner. These results are discussed with respect to the sex-specific contexts and functions of tree shrews’ marking behavior.