Photo: Peter Young / Fisheye Films
A study has found that West Australian brushtail possums have developed resistance to 1080 after natural exposure to the toxin in local plants.
While New Zealand's possums were from south eastern Australia, the discovery had caused some concern about New Zealand possums becoming resistant to the poison.
Study co-author Professor Steve Trewick told Morning Report the possums in western Australia are about 160 times more tolerant to 1080 than the possums from eastern Australia.
"Most of the possums that were brought to New Zealand and released came from south east Australia and Tasmania, so an area were the possums are mostly not tolerant of 1080."
Trewick said many of the plants in Western Australia have very high levels of natural 1080, developed to protect their leaves and the possums have become resistant over time.
This could lead to implications with controlling New Zealand's possum population by repeatedly using 1080.
Researchers find possums could develop resistance to 1080
"Evolution is on all the time," Trewick said.
"What we know is that possums in New Zealand will evolve resistance to whatever lethal compound they are exposed to."
Trewick said in New Zealand, possums were repeatedly exposed to very high doses of 1080 that causes high levels of mortality, but not 100 percent mortality.
"It's the survivors of the poisoning events that are the ones that may have genetic variation that favours their survival."
While there was no direct evidence New Zealand's possums were developing resistance to 1080, there was also no data to show how many possums were surviving 1080 exposure.
"It's very tricky with 1080 usage. If you put too much 1080 in your bait, which would ensure a better kill rate, then you put the possums off because they can detect 1080.
"The new research creates a platform because we have identified the genetics that may well be involved in that toxin resistance."
Trewick said a new programme is starting in New Zealand to look for those toxin resistant genes in the local population.
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