Musk duck Biziura lobata
Musk ducks are endemic to southern Australia, and are named after the distinct musky smell males excrete during the breeding sesason. Musk ducks show extreme sexual size dimorphism (males can be three times heavier than females) and are also recognisable by a leathery black lobe attached to the lower mandible.
Our research into musk ducks involved studying paternity in a population of musk ducks to explore the mating system and the function of male secondary sexual traits (i.e. lobe and musky smell). After assigning paternity to ducklings, we found only two out of seven males fathered all the ducklings in the five broods for which we could assign paternity. These males were territorial and heavier, had larger lobes and displayed more frequently than the other males. This demonstrates a polygynous mating system, which corresponds with previous field studies suggesting a lek mating system. In addition, skewed paternity distribution towards more ornamented and larger males suggests these traits evolved under sexual selection.
We also investigated the conservation genetics of musk ducks, which occur in two geographically isolated populations (eastern and western Australia). We compared genetic variation at both coarse and fine scales. We found significant genetic structure between eastern and western populations, suggesting these populations diverged near the end of the Pleistocene. There was little genetic structure between populations within eastern Australia.
This research formed part of a PhD carried out by Dr. Patrick-Jean Guay, entitled “Behavioural ecology and conservation genetics of the Musk Duck (Biziura Lobata)”. Patrick-Jean is now a lecturer in Biomedical Sciences at Victoria University, Melbourne.
More information about this research can be found in these publications:
Guay, P-J, Chessor, RT, Mulder, RA, Afton, AD, Paton, DC & McCracken, KG (2010). East-west genetic differentiation in Musk Ducks (Biziura lobata) of Australia suggests late Pleistocene divergence at the Nullarbor Plain. Conservation Genetics 11: 2105-2120. Full text
Guay, P-J & Mulder, RA (2007). Skewed paternity distribution in the extremely size dimorphic musk duck (Biziura lobata). Emu 107: 190-195. Full text
Guay, P-J & Mulder, RA (2005). Isolation and characterisation of microsatellite markers in musk duck (Biziura lobata: Aves), and their application to other waterfowl species. Molecular Ecology Notes 5: 249-252. Full text
Photo: David Kleinert