Vulpeculin: a novel and abundant lipocalin in the urine of the common brushtail possum, Trichosurus vulpecula

Lipocalins are a family of secreted proteins. They are capable of binding small lipophilic compounds and have been extensively studied for their role in chemosignalling in rodent urine. Urine of the common brushtail possum ( Trichosurus vulpecula ) contains a prominent glycoprotein of 20 kDa, expressed in both sexes. We have isolated this protein and determined its primary sequence by mass spectrometry, including the use of metabolic labelling to resolve the leucine/isoleucine isobaric ambiguity. The protein sequence was identified as a lipocalin, and phylogenetic analysis grouped the protein with other marsupial lipocalin sequences in a phylogenetic clade distinct from established cross-species lipocalin sub-families. The pattern of expression in possum urine and the similarity in sequence and structure to other lipocalins suggests this protein may have a role in brushtail possum chemosignalling.

Building selection by the common brushtail possum (Trichosurus vulpecula)

ContextThe common brushtail possum (Trichosurus vulpecula) is a protected native species in Australia that can access buildings in urban areas and cause considerable damage or disruption to building occupants. Although several strategies to discourage this species from entering buildings have been recommended, few have been evaluated empirically. AimsOur study aims to analyse how landscaping and building construction influence occupancy of buildings by the common brushtail possum. MethodsWe collated reports of possums occupying 134 buildings over 12 years on the campus of The Australian National University (ANU), in the Australian Capital Territory (ACT). We used generalised linear modelling (GLM) to identify associations between the total number of reported possum-related incidents for buildings and a range of landscape and building characteristics. Key resultsControlling for the effect of building size, we found that the number of reported possum-related incidents in buildings was positively associated with the percentage of tree and shrub canopy cover within the calculated home-range buffer distance of 49m from buildings, length of canopy overhanging roofs and building age, and negatively associated with tree species richness and number of trees with natural hollows and nest boxes within 49m of buildings. There were likely to be more possum-related reports from buildings in areas where the dominant tree genus was native, buildings with parapets (walls extending above the roof), buildings with structures penetrating from the roof, buildings with tile roofs and gable roofs. ConclusionsA combination of suitable habitat surrounding buildings, suitable access to the roofs of buildings and weak points in building roofs (e.g. parapets, roof penetrations), makes them more vulnerable to occupancy by the common brushtail possum. Implications Our results provided clues for managing existing buildings, or designing new buildings, in a way that may reduce the likelihood of occupancy by the common brushtail possum. Our study also demonstrated how building-maintenance records can be used to address human–wildlife conflict over time.

Genetic viability of a reintroduced population of south-western common brushtail possum (Trichosurus vulpecula hypoleucus), Western Australia

This study focused on a reintroduced population of south-western common brushtail possum (Trichosurus vulpecula hypoleucus) to assess genetic variability and inform future management strategies. Individuals were translocated to Matuwa Kurarra-Kurarra Indigenous Protected Area, Western Australia, from four source populations, but subsequent monitoring has indicated a 50% reduction in population size from original founder numbers in the eight years since establishment. Tissue samples from three of the four source populations and an additional four comparative sites (n=140 animals total) were analysed using 13 microsatellite loci. Inbreeding was lower and heterozygosity was higher in the translocated Matuwa population than in two of the source populations studied, highlighting the benefits of promoting outbreeding through the use of multiple source populations in translocations. However, allelic richness at Matuwa is low relative to two of the source populations, suggesting the impact of population bottlenecks on genetic diversity, which was supported by significant allele frequency mode shift and Wilcoxon rank sign test for heterozygosity excess tests for genetic bottlenecks. Despite the genetic health of the population being stronger than predicted, this population is still at risk due to environmental factors, small size and fragmentation. This is the first study to document patterns of genetic diversity and to highlight issues with translocation for this subspecies and adds to the limited literature illustrating how outbreeding can be used for conservation purposes.

Uptake of ‘Eradicat’ feral cat baits by non-target species on Kangaroo Island

ContextPredation by feral cats (Felis catus) threatens a range of vertebrate species across Australia, and cat-free islands increasingly act as safe havens for biodiversity. A feral cat eradication program has begun on Kangaroo Island (4405km2) in South Australia, and poison baiting is likely to be one of the main methods used. Aims Here, we trial a non-toxic version of a cat bait, ‘Eradicat’, on western Kangaroo Island, to examine its potential impact on non-target species. MethodsNon-toxic baits containing the biomarker Rhodamine B were deployed across four sites in early August and late November in 2018, with bait take and consumption assessed both by remote cameras and by the presence of Rhodamine B in mammalian whisker samples taken post-baiting. Key resultsCats encountered baits on very few occasions and took a bait on only one occasion in August (<1% of 576 baits deployed). Non-target species accounted for over 99% of identifiable bait takes. In both seasons, >60% of all baits laid was taken by either the common brushtail possum (Trichosurus vulpecula), bush rat (Rattus fuscipes) or Australian raven (Corvus coronoides). In November, Rosenberg’s goanna (Varanus rosenbergi) and southern brown bandicoot (south-eastern subspecies; Isoodon obesulus obesulus), listed nationally as Endangered, also took baits (3% and 1% respectively). The Kangaroo Island dunnart (Sminthopsis fuliginosus aitkeni), listed nationally as endangered, approached a bait on only one occasion, but did not consume it. Evidence of bait consumption was visible in the whiskers of captured common brushtail possums (100% of post-baiting captured individuals in August, 80% in November), bush rats (59% in August and 50% in November), house mice (Mus musculus) (45% in November) and western pygmy-possums (Cercartetus concinnus) (33% in November). ConclusionsAlthough feral cat baiting has the potential to significantly benefit wildlife on Kangaroo Island, impacts on non-target species (particularly the bush rat and common brushtail possum) may be high. ImplicationsAlternative cat baits, such as those containing a toxin to which native species have a higher tolerance or that are less readily consumed by native wildlife, will be more appropriate.