Dietland MÜLLER-SCHWARZE
Department of Environmental and Forest Biology, College of Environmental Science and Forestry,
State University of New York; 1, Forestry Drive, Syracuse, NY13210 USA
The beaver is a territorial, monogamous mammal. A family consists of a breeding pair, and their young of the present and the previous year. Two year-olds disperse to available sites along streams or lakes, usually 2 - 15 km from their natal colony. Beaver are nocturnal and communicate chemically by secretions placed on scent mounds they construct from mud. The two secretions are castoreum and anal gland secretion (AGS).
We have asked 1) what information is contained in these scent marks; 2) who are they addressed at; 3) what ecological function do they serve; 4) what is the structure of the chemical signal; and 5) what chemical compounds account for the behavioral activity.
In our bioassay, we place the secretion, compound or mixture to be tested on an artificial scent mound in an occupied beaver territory and record the responses by tagged beaver of known sex and age.
It now appears that castoreum provides a general territorial signal with little systematic variation, while AGS is sex- and individual-specific (1). The former inhibits colonization (2) while the latter aids in kin recognition. Both are suited to serve in regulation of intercolony interactions, and ultimately, population regulation.
The active cues in both secretions comprise many compounds. Mixtures of castoreum constituents are the more active, the more compounds they contain (3). AGS activity may depend on fewer compounds (1). A large proportion of active compounds are phenolics (4) and monoterpenes(5).
Literature