BEHAVIORAL AND ENDOCRINE MECHANISMS OF REPRODUCTIVE SUPPRESSION IN SERENGETI DWARF MONGOOSES

Behavioural, demographic and endocrine data were collected from a wild population of dwarf mongooses, Helogale parvula, in Serengeti National Park, Tanzania. The data show that subordinate females are reproductively suppressed by a complex of endocrine and behavioural mechanisms, while subordinate males are reproductively suppressed primarily by behavioural mechanisms. Subordinate females have (1) low baseline oestrogen levels, (2) low mating rates, and (3) low peak oestrogen levels during mating periods. Subordinate males (1) have low mating rates, and (2) are the recipients of increased aggression during mating periods, but (3) have androgen levels indistinguishable from those of dominants, both during and away from mating periods. Mechanistic differences between the sexes suggest that the selection pressures favouring reproductive suppression may also differ between the sexes. © 1992 The Association for the Study of Animal Behaviour.