Gens (behaviour)

In animal behaviour, a gens (pl. gentes) is a race of host-specific brood parasite. Brood parasites, such as cuckoos, which use multiple host species to raise their chicks, evolve different gentes, each one specific to its host species. This specialisation allows the parasites to lay eggs that mimic those of their hosts, which in turn reduces the chances of the eggs being rejected by the hosts.

The exact mechanisms of the evolution and maintenance of gens is still a matter of some research, however, it is believed that in cuckoos, gens-specific properties are sex-linked and lie on the W chromosome of the female. Male cuckoos, which have no W chromosome, are able to mate with females of any gens, and thereby maintain the cuckoo as one species.

References

• Gibbs et al. (2000), Genetic evidence for female host-specific races of the common cuckoo, Nature 407, 183-186
• Davies, N. (2000) Cuckoos, Cowbirds and other Cheats. T. & A. D. Poyser: London ISBN 0-85661-135-2
• Dawkins, R. (1982) The Extended Phenotype. Oxford University Press: Oxford ISBN 0-19-288051-9