Abstract:
Ansell’s mole-rat, Fukomys anselli, is a social subterranean mammal and exhibits an extreme
reproductive division of labour. Reproduction in the colony appears to be restricted usually to a
single female. Complete colonies captured throughout an entire calendar year were euthanased
and the histology of the gonads and plasma hormone concentrations were measured in
reproductive and non-reproductive members of both sexes. In males, the circulating levels of
testosterone were highest in the reproductive male. The mean testes mass for male corrected for
body mass was lower than that of the non-reproductive male. However, the mean testes volume
of reproductive males was greater than that for the non-reproductive males and the seminiferous
tubule diameter was greater in reproductive males. Reproductive females characteristically
possessed corpora lutea of ovulation and pregnancy in their ovaries and this was met with much
elevated progesterone concentrations in these females. In contrast, non-reproductive females
showed a complete range of follicular genesis, but they did not possess corpora lutea of ovulation
or pregnancy, in turn they show depressed progesterone concentrations. The current available
evidence suggests that in Ansell’s mole-rats, the non-reproductive males and females refrain
from sexual activity by being subordinate and moreover related to the breeding pair.
