Recrudescence of sexual activity in a reproductively quiescent colony of the Damaraland mole‐rat (Cryptomys damarensis), by the introduction of an unfamiliar and genetically unrelated male—a case of incest avoidance in‘queenless’colonies

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Abstract
Colonies of the eusocial Damaraland mole‐rat, Cryptomys damarensis, are founded from a single reproductive pair of animals genetically unrelated 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, there is a strict incest avoidance and the colony remains reproductively quiescent. Reinstatement of sexual activity in a queenless colony may be brought about in the laboratory by the introduction of an unfamiliar and unrelated adult male.In the queenless colony under study, there 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. The youngest, but most dominant n on‐reproductive female became sexually active and subsequently became pregnant and hence acquired the position of reproductive female. The new reproductive female exhibited heightened progesterone (9nmols/mmol creatinine) and oestradiol (3000pmols/mmol creatinine) concentrations in the urine relative to the other non‐reproductive females. These hormone concentrations were indicative of a reproductively active female.Behavioural and hormonal data are presented to show that sexual activity can be re‐instated in queenless colonies of laboratory maintained mole‐rats by the introduction of unrelated male mole‐rats.
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