Geographical variation in patterns of parentage and relatedness in the co-operatively breeding Ground Tit Parus humilis
Article first published online: 17 MAR 2011
© 2011 The Authors. Journal compilation © 2011 British Ornithologists’ Union
Volume 153, Issue 2, pages 373–383, April 2011
How to Cite
JOHANNESSEN, L. E., KE, D., LU, X. and LIFJELD, J. T. (2011), Geographical variation in patterns of parentage and relatedness in the co-operatively breeding Ground Tit Parus humilis. Ibis, 153: 373–383. doi: 10.1111/j.1474-919X.2011.01115.x
- Issue published online: 17 MAR 2011
- Article first published online: 17 MAR 2011
- Received 29 January 2010; revision accepted 2 February 2011. Associate Editor: Michael Sorenson.
- breeding biology;
The Ground Tit is a large parid species endemic to the Tibetan Plateau. Here we describe its genetic breeding system based on 2 years of fieldwork on a population from Damshung, Tibet. Genetic relatedness and parentage were analysed using 16 microsatellite markers and sex was determined with a marker on the Z and W chromosomes. We established that 16 of 75 families (21%) were assisted by one or occasionally two male helpers, which in most cases were young from a previous brood of one or both of the breeding adults. The helpers typically stayed with their families throughout the breeding season. Helpers never obtained any paternity in their own families, but one helper was identified as the sire in the only instance of extra-group (and extra-pair) parentage detected. Thus, the level of extra-group/extra-pair parentage appears to be very low in this Ground Tit population, and sharing of reproduction within family groups is apparently absent. Our results contrast with the findings from another Ground Tit population in Gansu, further northeast in China, with respect to both the number and sex of helpers and the division of parentage within and among family groups. In Gansu, helpers regularly produced offspring and both extra-pair and extra-group paternity as well as maternity (egg dumping) was common. Differences in family structure, philopatry, territoriality and potential inclusive fitness benefits can probably explain this contrast, and are likely to reflect the relative costs and benefits of co-operative breeding.