This research will use a combination of field observations, endocrine analyses, and "DNA fingerprinting" to determine the mechanisms and adaptive consequences of several reproductive phenomena that have been little-investigated in mammals. The study organisms is the dwarf mongoose, a small gregarious carnivore for which a substantial base of observational data and a population of individually-recognizable animals exist in the Serengeti National Park, Tanzania. In groups of these animals older dominant individuals suppress reproduction in younger, subordinate (but physiologically mature) animals, which are less likely to exhibit mating behavior, to conceive, or to bring pregnancies to term than are dominants. The PIs will use behavioral observations and analyses of urinary peptide and steroid hormones to document the stage(s) at which reproduction is suppressed. Genetic fingerprints will be used to determine maternity and paternity of offspring and thereby determine whether subordinates's breeding attempts are ever successful. Field demographic data will determine the effects of attempting reproduction on individual survival and future reproduction. A second reproductive phenomenon to be investigated is synchrony of estrus between subordinate and dominant females. DNA fingerprinting will be used to determine whether synchronously reproducing subordinates produce more surviving offspring than do asynchronous animals. Finally, subordinate females without young of their own nevertheless lactate and nurse the young of dominants. The endocrine status of lactating nonbreeders, as well as the effort of their lactation on components of their own and of dominant's fitness will be investigated.
