Red-capped Robin Petroica goodenovii
Our research into the red-capped robin focused on two main areas: (1) how parental quality is correlated with biased sex allocation; and (2) relationship between plumage colour and genetic reproductive success. When we examined the relationship between parental quality and sex allocation, we found that maternal quality was strongly related to sex allocation. We also found some paternal correlates, involving age and the source of paternity. We found that biased sex allocation is maintained by differing production costs of each sex and the genetic benefits to females of producing sons when fertilised by high-quality males.
Our second study was one of the first to explore the relationship between carotenoid-based plumage colour and genetic reproductive success. We found males with the highest within-pair reproductive success during the first season moulted into the most colourful plumage at the conclusion of that season. However, these colourful males did not go onto attain the highest reproductive success during the subsequent breeding season while displaying this plumage. Instead, variation in male reproductive success was explained by male body condition and age. This indicates that the information value from colourful plumage is unpredictable.
This research into red-capped robins formed part of a PhD carried out by Dr. Damian Dowling, entitled “Behavioural ecology of the red-capped robin”. Damian is now an Australian Research Fellow at Monash University, Melbourne.
More information about these studies can be found in these papers:
Dowling, DK & Mulder, RA (2006). Combined influence of maternal and paternal quality on sex allocation in red-capped robins. Journal of Evolutionary Biology 19: 440-449. Full text
Dowling, DK & Mulder, RA (2006). Red plumage and its association with reproductive success in red-capped robins. Annales Zoologici Fennici 43: 311-321. Full text
Dowling, DK, Adcock, GJ & Mulder, RA (2003). Novel polymorphic microsatellite markers for paternity analysis in the red-capped robin (Petroica goodenovii: Aves). Molecular Ecology Notes 3: 517-519. Full text
Photo: Catherine Payne