Lyon, France: A tiny, blind, hairless subterranean rodent that lives in social colonies in the harsh, semi-arid conditions of Africa could shed light on stress-related infertility in humans, the 23rd annual meeting of the European Society of Human Reproduction and Embryology will hear.
Dr Chris Faulkes, a senior lecturer at the School of Biological & Chemical Sciences, Queen Mary, University of London, will tell the conference that the African naked mole-rat is at the extreme end of a continuum of socially-induced reproductive suppression among mammals, with other examples including primates such as marmosets and tamarins, mongooses and members of the dog family (such as wolves and jackals).
The naked mole-rat lives in colonies of between 100-300 animals, but only the queen reproduces, suppressing fertility in both the females and the males around her by bullying them.
Dr Faulkes said: The queen exerts her dominance over the colony by, literally, pushing the other members of the colony around. She shoves them to show whos boss. We believe that the stress induced in the lower-ranking animals by this behaviour affects their fertility. There appears to be a total block to puberty in almost all the non-breeding mole-rats so that their hormones are kept down and their reproductive tracts are under-developed.
Currently, we think that the behavioural interactions between the queen and the non-breeders are translated into the suppression of certain fertility hormones (luteinizing and follicle stimulating hormones). In the non-breeding females this has the effect of suppressing the ovulatory cycle, while in the non-breeding males it causes lower testosterone concentrations, and lower numbers of sperm. In most non-breeding males, sperm that are present are non-motile.
The queen also seems to exert control over the breeding males, so that concentrations of their testosterone are suppressed except when she is ready to mate.<
Contact: Mary Rice
European Society for Human Reproduction and Embryology