Testing the behaviour of Australian brushtail possums (Trichosurus vulpecula) to candidate semiochemicals from conspecifics’ urine

Abstract

The Australian brushtail possum (Trichosurus vulpecula) is a prolific introduced mammalian pest. Current pest control methods involve traps and poisons, but are proving to be ineffective long term solutions. As semiochemical lures are thought to be more attractive than food-based lures at low densities, researchers are attempting to utilize semiochemicals for kill traps. The objectives of this thesis were to create a testing protocol for use in a research colony of possums and use that protocol to test the attractiveness of semiochemicals found in possum urine that had been positively associated with possum attraction and interest in urine.. I hypothesised that there would be an observer effect present in the colony due to the nature of the colony husbandry protocols. There was no statistically significant observer effect present in the colony for eating, interaction, sitting, grooming or enclosure use (front or back). However, there was a trend (across the colony) that sitting and grooming increased in the presence of an observer. From these results, I designed an active presentation protocol for testing semiochemicals. I predicted that the most attractive compounds would belong to the acids and alcohol chemical groups. Overall there was no statistically significant difference between the semiochemicals. However, when taken individually there was clear evidence that five of the semiochemicals (belonging to the ketone, alcohol and phenol chemical groups) were more attractive than their control and the standard lure. It has been shown in this thesis that the attractiveness of semiochemicals can be tested in a small research colony. However, limits on colony size greatly reduce statistical power. For future studies, I would recommend increasing the sample size or instead developing field-based bioassays capable of being repeated across a greater number of sites, populations and therefore, individual possums.