CHEMICAL SIGNALS INVOLVED IN SPACING BEHAVIOR OF BREEDING FEMALE BANKVOLES (CLETHRIONOMYS-GLAREOLUS SCHREBER-1780, MICROTIDAE, RODENTIA)

In order to study the mechanism involved in the seasonal territorialit y of breeding bank voles, the social behavior and scent marking of pai red females were observed throughout a reproductive cycle. Initially u nfamiliar females were kept in large laboratory pens provided with ind ividual burrows. After a brief period of hostility, females behaved in a friendly manner towards each other, sharing the same nest even in t he presence of a male and until the middle of pregnancy. They scarcely marked with urine. Continuous olfactory assessment appeared to play a n important role in maintaining the friendly interactions. In late pre gnant and lactating females, on the contrary, the odor of a familiar f emale triggered aggressiveness and scent marking with urine and probab ly with flank glands. These reactions may be interpreted as spacing be havior. Moreover, the interaction between females may inhibit reproduc tion in one of them. These results are discussed in relation with the available ecological data.