Macropus Fuliginosus Research Articles

Regeneration failure threatens persistence of Persoonia elliptica (Proteaceae) in Western Australian jarrah forests

The severe disruption of herbivore relationships can result in catastrophic, demographic consequences for plant populations. We investigated the potential roles of herbivory, fire and their interaction, in the observed long-term regeneration failure of Persoonia elliptica R.Br. (Proteaceae), an understory tree species of fire-prone jarrah (Eucalyptus marginata Sm.) forests in southwestern Australia. Seed production, storage and viability were assessed, as was seedling recruitment in both the presence and absence of fire (a potential germination cue), using experimental herbivore exclosure plots. We also sought to determine the ‘herbivory zone’ (height) within which P. elliptica was susceptible to browsing. Herbivores, primarily the western grey kangaroo, preferentially consumed leaves of P. elliptica up to a browsing height of 1.5 m. Viability of fresh seeds was low at ca. 39 % and rapid viability loss was observed in the soil seed bank, with only ca. 5 % of seeds remaining viable for >1 year. Germination was restricted almost solely to burned areas and survival of recruits to the confines of herbivore exclosures. We suggest that an increase in the primary herbivore, combined with low viable seed supply, is the likely cause of continuing regeneration failure in this species. The slow growth of the species suggests that without intervention, seedlings and juvenile plants will be unable to escape the herbivory zone. Management actions to facilitate recruitment might best focus on the combination of managed fires to break seed dormancy, followed by fencing to protect seedlings from large herbivores.

The seroprevalence and factors associated with Ross river virus infection in western grey kangaroos (Macropus fuliginosus) in Western Australia.

A serosurvey was undertaken in 15 locations in the midwest to southwest of Western Australia (WA) to investigate the seroprevalence of Ross River virus (RRV) neutralizing antibodies and factors associated with infection in western grey kangaroos (Macropus fuliginosus). The estimated seroprevalence in 2632 kangaroo samples, using a serum neutralization test, was 43.9% (95% CI 42.0, 45.8). Location was significantly associated with seroprevalence (p<0.001). There was a strong positive correlation between seroprevalence and the average log-transformed neutralizing antibody titer (r=0.98, p<0.001). The seroprevalence among adult kangaroos was significantly higher than in subadult kangaroos (p<0.05). No significant association was observed between seroprevalence and the sex of kangaroos (p>0.05). The results of this study indicate that kangaroos in WA are regularly infected with RRV and may be involved in the maintenance and transmission of RRV.

Newborn care: what we can learn from the kangaroo mother.

The word “kangaroo” comes from the Guugu Yimithirr word “gangurru,” which refers to gray kangaroos [Macropus fuliginosus (Western); Macropus giganteus (Eastern) (1)]. The name was first written as “Kanguru” on July 12, 1770 by Sir Joseph Banks (1743–1820), who was with the famous Captain James Cook (1728–1779) at the modern Cooktown in Australia, while they were repairing their ship – the HMS Endeavour damaged on her historic voyage to the Great Barrier Reef (2). The language of the indigenous people of Cooktown is Guugu Yimithirr. The brobdingnagian joey (infant kangaroo) crawls over the mother kangaroo’s fur in approximately 3 min to arrive at the mother’s pouch, which contains four teats to feed the baby; milk of different chemical compositions are provided to the esurient joey by the different quad-teats (3, 4). The mother kangaroo seems to have little interest in her newborn at first, but the joey stays in the pouch feeding and growing – eventually leading to a powerful, henotic bond between mother and baby. The young kangaroo joey first absquatulates the pouch for a few minutes at 198 days of life and then abscises at an average of 235 days at an average weight of 4–5 kg. Though outside the mother’s pouch, the baby (infant) will suckle for another 4 months until a year of age. This joey has a close vinculum with its mother for sometime thereafter due to the healthy touching that the pouch-suckling milieu created (3, 4). Koala (Phascolarctos cinereus) mothers have developed the same feeding technology over the millions of years of their evolution leading to a successful bond between this mansuetudine mother and her bonhomie baby who like all marsupial newborns is called a joey (5, 6). Though the kangaroo mother figured out the best way to feed and bond with her joey millions of years ago, it took Homo sapiens much longer to learn about caring for its newborn and to be taught this “kangaroo” care (7). Modern neonatology has developed over the past few centuries and has acquired amazing technology in the twenty-first century (7). However, it was not until 1978 that Dr. Edgar Rey Sanabria, professor of neonatology, established “kangaroo care” for premature and low-weight newborns in Bogota, Colombia; his apercu on premature infants was in response to overcrowding and lack of resources in his hospital (8, 9). Professor Sanabria received the World Health Organization (WHO: Geneva, Switzerland) Sasakawa Health Prize in 1991 for his idea and work suggesting that physical closeness between the premature newborn and the mother in a skin-to-skin contact might make up for lack of modern newborn services and resources such as incubators. Indeed, if it worked for marsupials and other animals for millions of years, how about the human newborn?

Sedation of western grey kangaroos (Macropus fuliginosus ocydromus) with tiletamine-zolazepam

AbstractIt is sometimes necessary to restrain kangaroos (Macropus spp) for veterinary treatment or in the course of scientific research, but the associated stresses may induce capture myopathy in wild kangaroos. Judicious use of injectable sedatives can reduce the risk of capture myopathy. Zoletil®, a proprietary mixture of tiletamine and zolazepam, is reported to have a wide safety margin, a small dose volume, and be quick acting for a range of animals. We investigated the dose-response relationship of Zoletil® in 26 western grey kangaroos (Macropus fuliginosus ocydromus). All kangaroos were recumbent within 5-10 min of intramuscular injection with mean (± SD) Zoletil® of 4.55 (± 0.98) mg kg−1. Mean (± SD) time to recovery varied between individuals, 2.07 (± 0.41) h over all occasions, and was independent of dose rate. For animals that were assessed on multiple occasions, mean (± SEM) time to recover was reduced from 2.25 (± 0.09) h on the first occasion to 2.15 (± 0.10) h on the second occasion and 1.81 (± 0.11) h on the third. Since kangaroos sedated with Zoletil® are vulnerable to predation and injury during recovery, we believe they should be supervised until they are able to fend for themselves.

Wildlife management aims and ecological processes: A case study of kangaroos

ABSTRACTWildlife management can be for conservation, sustainable utilization, and pest control. This study describes broad‐scale patterns in the annual population growth rate (r) in 2 large mammals that are the focus of wildlife management, namely the western gray (Macropus fuliginosus) and the red kangaroo (M. rufus). The study also aims to determine the processes that generate the patterns, in particular weather and harvesting. The mean annual population growth rates were not different from zero (r ∼ 0) consistent with no long‐term trends and the stated kangaroo management aims of conservation and sustainable utilization. The frequency distributions of r were broadly consistent with the published data for several other small and large mammals. Western gray kangaroo population dynamics were weakly related to prior rainfall (and the prior Southern Oscillation Index, SOI) and harvesting. Population dynamics of red kangaroos were most related (ω1 = 0.53, R2 = 0.16) to the prior SOI, and to a lesser extent to prior rainfall and harvesting however the relationships were weak. Hence, the management aims were achieved but the ecological processes behind them describing the effects of weather and harvesting are unclear at the large landscape scale. © 2014 The Wildlife Society.

Inter‐ and intraspecific effects of body size on habitat use among sexually‐dimorphic macropodids

Body size affects key life‐history parameters including dietary requirements and predation risk. We examined these effects on diel habitat use in a community of three sexually‐dimorphic macropodid marsupial species: western grey kangaroo Macropus fuliginosus, red‐necked wallaby M. rufogriseus and swamp wallaby Wallabia bicolor. In particular, our study seeks evidence of these effects operating concurrently at the intra‐ and interspecific levels. We used radio‐tracking to quantify habitat use and characterised each used location by recording the cover of plant functional groups and the presence of plant species. During nocturnal foraging periods we predicted that smaller animals (between and within species) should use habitats with higher‐quality forage, which is often less abundant, than larger animals, as metabolic demand scales with body size. During diurnal resting periods we predicted that smaller animals (between and within species), being more vulnerable to predation, should use greater concealment cover than larger animals. Western grey kangaroos and swamp wallabies behaved as predicted during foraging periods, but red‐necked wallabies did not, using more open, poorer‐quality habitats than expected. Only western grey kangaroos showed a within‐species effect on habitat use: the relatively smaller females foraged in higher‐quality patches. Habitats used by animals during the resting period generally offered greater concealment cover than those used during the foraging period, but there were no clear body size effects on the density of vegetation used. In our system, body size alone could not explain all of the observed patterns, suggesting that there may also be individual differences in habitat requirements influenced by factors such as reproductive costs, predation risk and social facilitation.

Reproductive Implications of Exposure toToxoplasma gondiiandNeospora caninumin Western Grey Kangaroos (Macropus fuliginosus ocydromus)

Australian marsupials are thought to be particularly vulnerable to pathologic impacts of Toxoplasma gondii, and they may be similarly affected by Neospora caninum. Pathology due to either organism could be expressed as reduced female reproductive performance. We studied adult female western grey kangaroos (Macropus fuliginosus ocydromus) from suburban Perth, Western Australia, between May 2006 and October 2008. We used indirect fluorescent antibody tests to look for evidence of exposure to T. gondii and N. caninum in M. fuliginosus ocydromus and tested the association between their reproductive performance and a positive test result. Although 20% of plasma samples collected from 102 female kangaroos were positive for T. gondii and 18% were positive for N. caninum, we found no association between positive results and reproductive performance. Further study will be required to clarify if, and under what circumstances, T. gondii and N. caninum are pathogenic to macropod marsupials.

Further characterisation of two Eimeria species (Eimeria quokka and Eimeria setonicis) in quokkas (Setonix brachyurus)

The identification and characterisation of novel Eimeria species has largely been based on sporulated oocyst and sporocyst morphology, the host species and the geographical range. Variation in the size and shape of Eimeria oocysts across their host range however, make the identification and characterisation of novel species using traditional methodologies alone problematic. The use of molecular markers and phylogenetic analysis has greatly advanced our ability to characterise Eimeria species and has recently been applied to understand evolutionary relationships among Eimeria species from Australian marsupials.In the present study, Eimeria species isolated from quokkas (Setonix brachyurus) captured from Two Peoples Bay, Bald Island and Rottnest Island, Western Australia, were morphologically identified as Eimeria quokka and Eimeria setonicis. Both Eimeria species were identified as being polymorphic in nature with regards to sporulated oocyst and sporocyst morphometrics. Phylogenetic analysis using 18S rRNA and COI (cytochrome c oxidase subunit 1) genes, grouped E. quokka and E. setonicis within the Eimeria marsupial clade together with Eimeria trichosuri from brushtail possums, Eimeria macropodis from tammar wallabies (Macropus eugenii) and several unidentified macropod Eimeria species from western grey kangaroos (Macropus fuliginosus). This study is the first to characterise E. quokka and E. setonicis by molecular analysis, enabling more extensive resolution of evolutionary relationships among marsupial-derived Eimeria species.

Muscular anatomy of the tail of the western grey kangaroo, Macropus fuliginosus

The western grey kangaroo, Macropus fuliginosus, is a large-bodied kangaroo that engages in pentapedal locomotion at low speeds and bipedal hopping at high speeds. The tail is thought to have functional roles in both of these modes of locomotion. In pentapedal locomotion the tail acts as a ‘fifth limb’ to support the body weight together with the forelimbs while the hind limbs are drawn forward. The tail has also been suggested to have a role as a counterbalance during bipedal hopping. On the basis of these functional roles for the tail in locomotion, the caudal musculature of the western grey kangaroo was dissected and described in this study. The arrangement of the caudal musculature showed particular adaptations for the role of the tail in both pentapedal locomotion and bipedal hopping.

Comment optimiser les résultats de l’ostéotomie d’allongement du calcaneus dans le traitement du pied plat valgus de l’adolescent ? Analyse critique d’une série de 19 cas

Western grey kangaroos (Macropus fuliginosus melanops) are large, foregut fermenting herbivores common to Australia's southern woodlands and shrublands, but they extend well into semiarid habitats at the north-eastern edge of their range. At this range boundary, western grey kangaroos occupy open chenopod (saltbush) shrubland, along with Australia's other large native kangaroos, as well as with extensive pastoral stock, primarily the wool-breed merino sheep. In this habitat, within a large naturally vegetated enclosure (16 ha), western grey kangaroos grazing sympatrically with merino sheep spent much of the day resting under shade trees, and fed mainly during the evening and early morning, mainly on grasses and flat-leaved chenopods. On this diet, western grey kangaroos had water turnovers similar to those of red kangaroos, at 1.1 L d−1. Sheep, however, used 7.7 L of water each day. Thus, although the sheep were twice the average body mass of kangaroos, the sheep used more than seven times as much water. This level of water use by sheep was almost half that previously reported for sheep at the same site feeding mainly on salt-laden chenopods (ca. 12 L d−1), but was consistent with other studies showing lower water usage by sheep feeding on trees and low-salt shrubs; foregut (rumen) contents of our sheep comprised 35% tree browse. Overall, our data do not support suggestions that western grey kangaroos are limited mainly by water at this arid range-boundary. Notably, the western grey kangaroos’ feeding behaviours were consistent with those of other arid-zone kangaroos, highlighting distinctive differences in the ecological physiology of the foregut fermenting kangaroos and the ruminant sheep.

Water use and feeding patterns of the marsupial western grey kangaroo (Macropus fuliginosus melanops) grazing at the edge of its range in arid Australia, as compared with the dominant local livestock, the Merino sheep (Ovis aries)

Western grey kangaroos (Macropus fuliginosus melanops) are large, foregut fermenting herbivores common to Australia's southern woodlands and shrublands, but they extend well into semiarid habitats at the north-eastern edge of their range. At this range boundary, western grey kangaroos occupy open chenopod (saltbush) shrubland, along with Australia's other large native kangaroos, as well as with extensive pastoral stock, primarily the wool-breed merino sheep. In this habitat, within a large naturally vegetated enclosure (16ha), western grey kangaroos grazing sympatrically with merino sheep spent much of the day resting under shade trees, and fed mainly during the evening and early morning, mainly on grasses and flat-leaved chenopods. On this diet, western grey kangaroos had water turnovers similar to those of red kangaroos, at 1.1Ld−1. Sheep, however, used 7.7L of water each day. Thus, although the sheep were twice the average body mass of kangaroos, the sheep used more than seven times as much water. This level of water use by sheep was almost half that previously reported for sheep at the same site feeding mainly on salt-laden chenopods (ca. 12Ld−1), but was consistent with other studies showing lower water usage by sheep feeding on trees and low-salt shrubs; foregut (rumen) contents of our sheep comprised 35% tree browse. Overall, our data do not support suggestions that western grey kangaroos are limited mainly by water at this arid range-boundary. Notably, the western grey kangaroos’ feeding behaviours were consistent with those of other arid-zone kangaroos, highlighting distinctive differences in the ecological physiology of the foregut fermenting kangaroos and the ruminant sheep.

Behavioural responses of free‐ranging western grey kangaroos (Macropus fuliginosus) to olfactory cues of historical and recently introduced predators

AbstractPredation risk influences foraging decisions and time allocation of prey species, and may result in habitat shifts from potentially dangerous to safer areas. We examined a wild population of western grey kangaroos (Macropus fuliginosus) to test the efficacy of predator faecal odour in influencing time allocated to different behaviours and inducing changes in habitat use. Kangaroos were exposed to fresh faeces of a historical predator, the dingo (Canis lupus dingo), a recently introduced predator, the red fox (Vulpes vulpes), a herbivore (horse, Equus caballus) and an unscented control simultaneously. Kangaroos did not increase vigilance in predator‐scented areas. However, they investigated odour sources by approaching and sniffing; more time was spent investigating fox odour than control odours. Kangaroos then exhibited a clear anti‐predator response to predator odours, modifying their space use by rapidly escaping, then avoiding fox and dingo odour sources. Our results demonstrate that wild western grey kangaroos show behavioural responses to predator faeces, investigating then avoiding these olfactory cues of potential predation risk, rather than increasing general vigilance. This study contributes to our understanding of the impact of introduced mammalian predators on marsupial prey and demonstrates that a native Australian marsupial can recognize and respond to the odour of potential predators, including one that has been recently introduced.

Sexual selection on forelimb muscles of western grey kangaroos (Skippy was clearly a female)

Studies of sexual selection have tended to concentrate on obvious morphological dimorphisms such as crests, horns, antlers, and other physical displays or weapons; however, traits that show no obvious sexual dimorphism may nevertheless still be under sexual selection. Sexual selection theory generally predicts positive allometry for sexually selected traits. When fighting, male kangaroos use their forelimbs to clasp and hold their opponent and, standing on their tail, bring up their hind legs to kick their opponent. This action requires substantial strength and balance. We examined allometry of forelimb musculature in male and female western grey kangaroos (Macropus fuliginosus) to determine whether selection through male-male competition is associated with sex differences in muscle development. Forelimbs of males are more exaggerated than in females, with relatively greater muscle mass in males than the equivalent muscles in females. Furthermore, while muscles generally showed isometric growth in female forelimbs, every muscle demonstrated positive allometry in males. The significant positive allometry in male forelimb musculature, particularly those muscles most likely involved in male-male combat (a group of muscles involved in grasping: shoulder adduction, elbow flexion; and pulling: arm retraction, elbow flexion), clearly suggests that this musculature is subject to sexual selection. In addition to contributing to locomotion, the forelimbs of male kangaroos can also act as a signal, a weapon, and help in clasping, features that would contribute towards their importance as a sexually selected trait. Males would therefore benefit from well-developed musculature of the arms and upper body during competition for mates.

Intraspecific variation in femoral cross-sections: Sex and age variation in the quokka (Setonix brachyurus) and the western grey kangaroo (Macropus fuliginosus)

Intraspecific variation in femoral cross-sections: Sex and age variation in the quokka (Setonix brachyurus) and the western grey kangaroo (Macropus fuliginosus)

Paternally inherited genetic markers reveal new insights into genetic structuring within Macropus fuliginosus and hybridisation with sympatric Macropus giganteus

There are several aspects of biology in which the contribution of males and females is unequal. In these instances the examination of Y chromosome markers may be used to elucidate male-specific attributes. Here, male dispersal patterns and genetic structuring were examined using four Y-microsatellite loci in 186 male western grey kangaroos, Macropus fuliginosus, from throughout the species’ trans-continental distribution. In addition, 52 male grey kangaroos were examined to investigate hybridisation between M. fuliginosus and the eastern grey kangaroo, Macropus giganteus, in their region of sympatry in eastern Australia. Detected Y chromosome diversity was low, resulting from low effective male population size due to skewed sex ratios and a polygynous mating system. As expected, male dispersal was high across the range. However, the Lake Torrens–Flinders Ranges region appears to have significantly restricted male movement between eastern and central/western Australia. There was little evidence to suggest that other barriers (Nullarbor Plain and Swan River Valley) previously identified by nuclear and mitochondrial DNA marker studies restrict male movement. Hence, the admixture events previously identified may be associated with high male dispersal. Within the region of sympatry between M. fuliginosus and M. giganteus in eastern Australia, four M. giganteus individuals were found to possess M. fuliginosus Y-haplotypes. These results confirm the occurrence of hybridisation between male M. fuliginosus and female M. giganteus. Additionally, the introgression of M. fuliginosus Y-haplotypes into M. giganteus populations indicates that at least some male hybrids are fertile, despite evidence to the contrary from captive studies. This study has provided insights into the male contribution to population history, structure and hybridisation in M. fuliginosus, which were not predicted by comparisons between biparentally and maternally inherited markers. This highlights the importance of direct examination of the Y chromosome to provide novel insights into male-mediated processes, especially where the contribution of the sexes may differ.

Food Forensics in the Human and Pet-Food Industry: Use of a Simple Technology to Identify Commercially Important Species of Kangaroos from Western Australia

Kangaroos are internationally recognised and iconic wildlife. There are four species that are commercially harvested for human and pet meat in an industry worth more than US$150 million per year. Highly regulated controls govern the number, and the species that can be removed each year as many species undergo natural cycling in population number in response to stochastic fluctuations, such as rainfall (where populations generally increase) and periods of drought (decline in population numbers). At times when populations are too low, seasonal closures do not allow the harvesting of those species. This is when illegal killing is most detrimental and there is currently no method or comparative database to identify commercial game-meat kangaroo species. Here we generated a simple and discriminatory test that uses sequence data from mitochondrial DNA capable of differentiating amongst all the largest species of kangaroos (the wallaroo, western grey, eastern grey, and red kangaroo) in Australia. We present these data and we also include 18 suspected kangaroo sample seizures that formed the basis for the unambiguous, simple and relatively fast identification of seized kangaroo meat samples.

Molecular characterization of Eimeria species in macropods

A total of 597 faecal samples were collected from western grey kangaroos (Macropus fuliginosus), Euros (M. robustus), red kangaroos (M. rufus) in Western Australia and Eastern Grey Kangaroos (M. giganteus) from Victoria and screened for the presence of Eimeria by PCR at the 18S ribosomal RNA (rRNA) locus. The overall prevalence was 24.3% (145/597). At the 18S rRNA locus, sequences were obtained for 25 of the 145 positives. Phylogenetic analysis indicated that all the macropod-derived Eimeria species grouped in a separate marsupial clade that included Eimeria trichosuri from brushtail possums. At least 6 different clades were identified within the marsupial isolates and many of the genotypes identified are likely to be valid species, however morphological and biological data need to be collected to match sequences to previously characterized Eimeria species or identify if they are new species.

Anin situvertebrate bioassay helps identify potential matrices for a predator‐based synthetic management tool

AbstractTo assist management and conservation needs, researchers have called for active kairomones to be elucidated and synthesized directly from animal exudates. However, the existing literature does not provide guidance on how to initiate this complex process. To our knowledge, composite synthetic predator scents that incorporate multiple compounds to accurately mimic the natural signal have not been produced. One approach to improve the accuracy of synthetics is to identify and recombine all major infochemicals within a benign solvent. Therefore, we tested 2 natural, pre‐existing matrices for their potential as vehicles for delivery of a predator scent, dingo (Canis lupus dingo) urine, which causes a startle reaction among western gray kangaroos (Macropus fuliginosus), and avoidance by European foxes (Vulpes vulpes). We compared 2 putative backbone matrices—aged (3‐yr old) dingo urine from a previously active lot, and 10% methanol—to a distilled water control. We used a novel fence‐crossing assay to observe kangaroo interactions with both solvents and a negative control. Our assay allowed us to control for high feeding motivation by testing compounds away from the food source. We determined that neither free‐ranging kangaroos nor European red foxes were adversely affected by either treatment matrix. Foxes were, however, attracted to the aged dingo urine, and were often observed scent‐rolling in the inactive substance. Our results suggest that dilute methanol could be a possible matrix for predator‐scent applications for kangaroos, while aged scents may act as an attractant for nontarget species, particularly canids. © 2012 The Wildlife Society.

Impact of Pleistocene aridity oscillations on the population history of a widespread, vagile Australian mammal, Macropus fuliginosus

AbstractAim Climatic fluctuations during the Pleistocene have shaped the population structure of many extant taxa. However, few studies have examined widespread species inhabiting the Australian continent, where periods of increased aridity characterized the Pleistocene. Here we investigate the phylogeography and population history of a widespread and vagile southern Australian marsupial, the western grey kangaroo (Macropus fuliginosus).Location Southern Australia.Methods We examined the variation of the mitochondrial DNA (mtDNA) control region from 511 individuals of M. fuliginosus sampled throughout their transcontinental distribution. Maximum likelihood and Bayesian analyses were used to investigate the phylogeography and coalescence analyses were then used to test hypothesized biogeographical scenarios.Results The combined results of the phylogeographical and coalescence analyses revealed a complex evolutionary history. Macropus fuliginosus originated in the south‐west of the continent, with north‐western and south‐western populations subsequently diverging as a result of vicariance events during the mid‐Pleistocene. Subsequent arid phases affected these populations differently. In the north‐west, the expansion and contraction of the arid zone resulted in repeated vicariance events and multiple divergent north‐western mtDNA subclades. In contrast, the south‐western population was less impacted by climatic oscillations but gave rise to a major transcontinental eastward expansion.Main conclusions Macropus fuliginosus exhibits the genetic signature of divergence due to unidentified barriers in south‐western Western Australia, while previously identified barriers across southern Australia appear to have had little impact despite evidence of a broad‐scale range expansion prior to the Last Glacial Maximum (LGM). This pattern of localized expansion and contraction is comparable to unglaciated regions in both the Northern and Southern Hemispheres. Furthermore, this study indicates that despite the potential similarities between Northern Hemisphere glaciation and the activation of dune systems in the Australian arid zone, both of which rendered large areas inhospitable, the biotic responses and resultant phylogeographical signatures are dissimilar. Whereas a limited number of major geographically concordant refugia are observed in glaciated areas, the Southern Hemisphere arid zone appears to be associated with multiple species‐specific idiosyncratic refugia.

Ross River virus - at the interface between humans, animals and the environment

Ross River virus (RRV) is the most common cause of mosquito-borne illness in Western Australians. The virus is maintained in nature principally via transmission between competent mosquito vectors and native (marsupial) vertebrate hosts, although humans are suspected of being amplifiers of RRV in some situations. The influence of prevailing environmental conditions on the ecology of RRV has been extensively documented. Indeed, monitoring of environmental variables, together with vector mosquito populations and infection rates with RRV, now provides effective early warning of elevated levels of RRV activity in several different regions of Australia. Serosurveys provide convincing evidence that western grey kangaroos (WGK; Macropus fuliginosus) are commonly infected with the virus in south-west coastal regions of Western Australia. There is also evidence of seroconversions in WGKs coinciding with outbreaks of human disease. Such outbreaks have been preceded by favourable environmental conditions for breeding of WGKs, presumably leading to an increase in numbers of non-immune individuals in the environment. More recently, GIS analyses of clusters of human cases of RRV has shown a relationship between proximity of residence to mosquito and WGK habitat and risk of RRV disease. These findings indicate that monitoring of seroprevalence to RRV in vertebrate hosts of RRV, such as the WGK, may assist in predicting outbreaks of RRV disease and for determining whether strategies to manage natural host populations in close proximity to human habitation may be worth further consideration.