RECRUDESCENCE OF SEXUAL-ACTIVITY IN A REPRODUCTIVELY QUIESCENT COLONYOF THE DAMARALAND MOLE-RAT (CRYPTOMYS DAMARENSIS), BY THE INTRODUCTION OF AN UNFAMILIAR AND GENETICALLY UNRELATED MALE - A CASE OF INCEST AVOIDANCE IN QUEENLESS COLONIES
Ca. Rickard et Nc. Bennett, RECRUDESCENCE OF SEXUAL-ACTIVITY IN A REPRODUCTIVELY QUIESCENT COLONYOF THE DAMARALAND MOLE-RAT (CRYPTOMYS DAMARENSIS), BY THE INTRODUCTION OF AN UNFAMILIAR AND GENETICALLY UNRELATED MALE - A CASE OF INCEST AVOIDANCE IN QUEENLESS COLONIES, Journal of zoology, 241, 1997, pp. 185-202
Colonies of the eusocial Damaraland mole-rat, Cryptomys damarensis, ar
e founded from a single reproductive pair of animals genetically unrel
ated by common descent. All non-reproductive members of the colony are
progeny of this reproductive pair. In colonies where the reproductive
female has been experimentally removed or has died a natural death, t
here is a strict incest avoidance and the colony remains reproductivel
y quiescent. Reinstatement of sexual activity in a queenless colony ma
y be brought about in the laboratory by the introduction of an unfamil
iar and unrelated adult male. In the queenless colony under study, the
re was a marked change in social structure with an increase in Landau'
s index of linearity from 0.8 to 0.9 on introduction of the new male.
The unrelated male became a high ranking dominant reproductive male. T
he youngest, but most dominant non-reproductive female became sexually
active and subsequently became pregnant and hence acquired the positi
on of reproductive female. The new reproductive female exhibited heigh
tened progesterone (9 nmols/mmol creatinine) and oestradiol (3000 pmol
s/mmol creatinine) concentrations in the urine relative to the other n
on-reproductive females. These hormone concentrations were indicative
of a reproductively active female. Behavioural and hormonal data are p
resented to show that sexual activity can be re-instated in queenless
colonies of laboratory maintained mole-rats by the introduction of unr
elated male mole-rats.