The unusual breeding system of the Australian Brush-turkey
We investigated the breeding system and genetic population structure of the Australian Brush-turkey using microsatellite markers.
Population history
The Australian Brush-turkey (Alectura lathami) lives in rainforests along the coast and inland on the North East corner of Australia. The descendant of this species were once found in the ancient land mass of Gondwana and their nearest extant relatives are found in Papua New Guinea and South America.
Today the species is found from the Cape York Peninsula in the north down to Gosford, New South Wales in the South.
The Australian Brush-turkey is threatened by habitat destruction and is now locally extinct in some of its pre-European range. Individuals spend most of their time on the ground but do roost in trees at night.
Genetic analysis of population structure
Genetic markers are required to study the population structure and parentage but no published microsatellite markers are available for this species.
We therefore created an Australian Brush-turkey microsatellite-enriched genomic library, successfully isolated almost 100 microsatellite sequences and validated a marker set suitable for investigating parentage and population structure of Australian Brush-turkeys (Martins et al. 2013).
We used these markers to investigate of the genetic population structure and the breeding systems of the Australian Brush-turkey by DNA profiling 60 individuals collected at 6 sites across the range of the species.
Breeding system
Males can be distinguished from females by the colour and size of the wattle and their call. Australian Brush-turkeys belong to the Megapodiidae family which is the only bird family that does not use body heat to incubate its eggs (Jones and Goth, 2008).
A single male will build an incubation mound of leaf litter and other decomposing organic material in which several females lay about 18-24 eggs (Jones 1988). The incubation temperature leads to biased sex ratios, as is observed in reptiles (Goth & Booth, 2005).
Genetic analysis of the breeding system
An early study based on minisatellite loci suggested that the mound-owning male is not the father of all the offspring which have been incubated in his mound (Birks, 1997). The microsatellite markers we developed (Martins et al. 2013) were used to investigate the breeding systems of this species.
The first set of samples were collected during 2010-11 but the poor weather during the breeding season (Winter 2010-February 2011) meant that additions samples of family groups were required.
Personnel
Filipa Martins
Dr. Gavin Horsburgh
Project supervisors
Dr Deborah Dawson (d.a.dawson@Sheffield.ac.uk)
Collaborator
Professor Darryl Jones (Griffith University, Australia)
Funding
Filipa Martins visited Sheffield during 2011 from the Faculty of Sciences of the University of Lisbon to complete the laboratory work which was funded by a Leonardo Da Vinci Scholarship.
Further reading
Birks S (1997) Paternity in the Australian brush-turkey, Alectura lathami, a megapode bird with uniparental male care. Behavioural Ecology 8, 560–568.
Goth A & Booth DT (2005) Temperature-dependent sex-ratio in a bird. Biology Letters, 1, 31–33.
Jones DN (1998) Construction and maintenance of the incubation mounds of the Australian Brush-turkey Alectura lathami. Emu, 88, 210–218.
Jones DN, Dekker RWRJ and Roselaar CS (1995) The Megapodes. Oxford University Press Inc., New York
Jones DN & Goth A (2008) Mound-builders. Australian Natural History Series, CSIRO Publishing, Melbourne
Martins FMS, Dawson DA, Horsburgh GJ, Timmons S, Jones DN (2013) Microsatellite loci characterised in a megapode, the Australian brush-turkey Alectura lathami. Conservation Genetics Resources, 5, 1179–1184.