Possums will evolve to resist 1080 poison – expert

The study found opossums in Western Australia developed resistance to 1080 after natural exposure to the toxin on native plants.

Although New Zealand possums were native to south-eastern Australia, this discovery has led to some concern that New Zealand possums will become resistant to the poison.

This was stated by study co-author Professor Steve Trewick. Morning report possums in western Australia are about 160 times more tolerant of 1080 than possums in eastern Australia.

“Most possums that were introduced into New Zealand and released came from south-eastern Australia and Tasmania, so possums in that area are largely intolerant to 1080.”

Trewick said many plants in Western Australia had very high levels of natural 1080 designed to protect their leaves, and possums had become resistant over time.

This could lead to control of New Zealand’s possum population through repeated use of 1080.

“Evolution happens all the time,” Trewick said.

“What we do know is that possums in New Zealand will develop resistance to any lethal compound they are exposed to.”

Trewick said that in New Zealand, opossums have been repeatedly exposed to very high doses of 1080, which causes a high mortality rate, but not 100 percent mortality.

“It is poisoning survivors who may have genetic variations that contribute to their survival.”

While there was no direct evidence that New Zealand possums developed resistance to 1080 temperatures, there was also no data showing how many opossums survived exposure to 1080 temperatures.

“Using 1080 is very difficult. If you put too much 1080 in your bait for better kill, you will discourage possums because they can detect the 1080.

“The new study provides a platform because we have identified genetics that may well be involved in toxin resistance.”

Trewick said a new program was starting in New Zealand to search for toxin resistance genes in the local population.

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