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Forrestfield, Australia

Spencer P.B.S.,Murdoch University | Woolnough A.P.,Vertebrate Pest Research Section
Livestock Science | Year: 2010

Camels are substantial providers of transport, milk, sport, meat, shelter, fuel, security and capital in many countries. In Australia there are estimated to be over a million individuals, and growing at more than 80,000 per year. Australian dromedary camels may therefore represent a considerable resource for the world's camel production herd. Here we document the structure and assess the genetic diversity over a very large sampling area (> 3 million km2). Using a total of 484 reproductive individuals belonging to six sampling locations of dromedary camel (Camelus dromedaries) we analysed 28 microsatellite markers to assess polymorphism in the Australian herd. Eighteen of these markers were polymorphic, producing a total of 185 alleles. Unlike camel breeds from elsewhere in the world, the classification of Australian camels into distinguishable breeds was not supported by the program STRUCTURE at the microsatellite level. Australian camels also showed very weak levels of sampling structure (and genetic diversity) suggesting a small historical founder size. © 2010 Elsevier B.V. All rights reserved. Source

Campbell S.,University of Melbourne | Campbell S.,Vertebrate Pest Research Section | Coulson G.,University of Melbourne | Lumsden L.F.,Arthur Rylah Institute for Environmental Research
Acta Chiropterologica | Year: 2010

The thermal environment of day roosts is considered one of the most influential factors affecting the survival, growth and reproduction of microbats. The use of torpor is a common energy saving strategy employed by microbats in temperate regions. The efficiency of entry into, and arousal from, torpor is governed by roost microclimate, primarily roost temperature. The large-footed myotis Myotis macropus roosts in both tree cavities and a man-made tunnel at Yan Yean reservoir in Victoria, Australia. We investigated the thermal properties of both roost types in comparison to available tree cavities and ambient temperature over four time periods from October 2003 to May 2005. Tree cavities and tunnel roosts remained significantly warmer at night, cooler during the day, and were more stable than ambient temperatures. In addition, roost tree cavities were significantly cooler between 10:0013:00 h compared to available tree cavities, and there was a trend for roost tree cavities to be slightly warmer at night and slower to reach maximum temperature relative to available tree cavities during the breeding season (OctoberJanuary). In contrast, there was little difference in roost and available tree cavity temperatures outside of the breeding season (AprilMay). Temperatures inside tunnel roosts were more stable and were significantly cooler during the afternoon compared to roost tree cavities during both the breeding and non-breeding seasons. Myotis macropus may actively trade-off the enhanced thermoregulatory benefits of warm roosts for reduced predation risk associated with the tunnel roosting environment. © Museum and Institute of Zoology PAS. Source

Rollins L.A.,University of New South Wales | Rollins L.A.,Deakin University | Whitehead M.R.,University of New South Wales | Whitehead M.R.,The Australian National University | And 5 more authors.
Current Zoology | Year: 2015

Although population genetic theory is largely based on the premise that loci under study are selectively neutral, it has been acknowledged that the study of DNA sequence data under the influence of selection can be useful. In some circumstances, these loci show increased population differentiation and gene diversity. Highly polymorphic loci may be especially useful when studying populations having low levels of diversity overall, such as is often the case with threatened or newly established invasive populations. Using common starlings Sturnus vulgaris sampled from invasive Australian populations, we investigated sequence data of the dopamine receptor D4 gene (DRD4), a locus suspected to be under selection for novelty-seeking behaviour in a range of taxa including humans and passerine birds. We hypothesised that such behaviour may be advantageous when species encounter novel environments, such as during invasion. In addition to analyses to detect the presence of selection, we also estimated population differentiation and gene diversity using DRD4 data and compared these estimates to those from microsatellite and mitochondrial DNA sequence data, using the same individuals. We found little evidence for selection on DRD4 in starlings. However, we did find elevated levels of within-population gene diversity when compared to microsatellites and mitochondrial DNA sequence, as well as a greater degree of population differentiation. We suggest that sequence data from putatively nonneutral loci are a useful addition to studies of invasive populations, where low genetic variability is expected. © 2015 Current Zoology. Source

Rollins L.A.,Deakin University | Rollins L.A.,University of New South Wales | Woolnough A.P.,Transport and Resources | Woolnough A.P.,Vertebrate Pest Research Section | And 9 more authors.
Molecular Biology and Evolution | Year: 2016

Mitochondria are critical for life, yet their underlying evolutionary biology is poorly understood. In particular, little is known about interaction between two levels of evolution: between individuals and within individuals (competition between cells, mitochondria or mitochondrial DNA molecules). Rapid evolution is suspected to occur frequently in mitochondrial DNA, whose maternal inheritance predisposes advantageous mutations to sweep rapidly though populations. Rapid evolution is also predicted in response to changed selection regimes after species invasion or removal of pathogens or competitors. Here, using empirical and simulated data from a model invasive bird species, we provide the first demonstration of rapid selection on the mitochondrial genome within individuals in the wild. Further, we show differences in mitochondrial DNA copy number associated with competing genetic variants, which may provide a mechanism for selection. We provide evidence for three rarely documented phenomena: selection associated with mitochondrial DNA abundance, selection on the mitochondrial control region, and contemporary selection during invasion. © The Author(s) 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. Source

Spencer P.B.S.,Murdoch University | Giustiniano D.,Murdoch University | Hampton J.O.,Murdoch University | Gee P.,Rural Solutions | And 4 more authors.
Journal of Wildlife Management | Year: 2012

The dromedary camel (Camelus dromedarius) is a significant invasive species in Australia. It is an unusual pest species that is of large body size with relatively low fecundity compared with other pest species. Camels are highly adapted to the arid regions that characterize a large proportion of Australia and occupy an almost completely undisturbed area of ≥3 million km 2. They have no history of invasion elsewhere in the world. Despite this, their population has been expanding at approximately 80,000 camels per annum, with the most recent estimate of population size around 1,000,000 individuals. We employed a landscape-genetic approach to evaluate the population structure and molecular ecology of Australian camels. We combined mitochondrial control region sequence (n = 209 animals) with 18 microsatellite markers to profile over 800 adult camels to identify the presence of a single panmictic population. We showed that demographically defined neighborhoods for wild camels are about 200 km; this value was supported by home range estimates. Distances greater than this display no pattern of isolation by distance across the Australian continent. The result is the largest single geographical population so far recorded for an invasive species in Australia. This pattern may be explained by the impressive and near-nomadic dispersal pattern of camels, in combination with an unpredictable environment virtually devoid of barriers to movement and predatory suppression. Although it is technically feasible, the reality is that it would not be economically or politically viable to have continental eradication of wild camels in Australia because of the vast size and movement dynamics of the camel population. As such, we advocate a change away from an expensive solution to an intractable reduction program (that is almost entirely focused on protection of biological refugia) and moves to include cultural, economic, and biodiversity asset protection for the management of this most unorthodox of invasive species. © 2012 The Wildlife Society. Source

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