By Keith Perry
science reporter
Scientists are testing a method that could cull possums before they leave the mother's pouch.
A team at the Ruakura Agricultural Research Centre in Hamilton is investigating possum breast milk to try to cut the babies' chances of survival.
The researchers say possum milk contains vital antibodies that help
cubs to develop immunity against infections. By chemically disrupting the transfer of antibodies from the mother to the baby, scientists hope the weakened possum cubs will be unable to resist diseases and infections and die before they leave the pouch.
The scientists are also examining ways of introducing foreign antibodies into the mother's milk via bait that would interfere with the development of the young possums' sex organs, making them sterile at birth.
The scientists say that because the chemical would be specific to possum milk, it would be safer and cheaper to use than conventional poisons.
Biochemist Dr Fran Adamski said: "We have made significant progress in understanding how these antibodies are transferred to the possum pouch young via the mother's milk and we hope the findings could provide a new weapon in controlling possum numbers.
"Our research shows there are two key stages in the possum's development in line with other marsupials.
"The first stage is like gestation in other mammals, where the pouch possum receives very specialised milk containing high levels of these antibodies. The next stage is like a second birth for marsupials, when they leave the mother's pouch and go into late lactation where the mother's milk then becomes like that of other mammals such as a cow's.
"By this stage they are less vulnerable to biocontrol methods so our strategy is to target them in the first phase when they are receiving the milk with the large amounts of antibodies."
Researchers are working on 109 research projects for possum and bovine tuberculosis control at a cost of $15.5 million, with $5.3 million specifically for biocontrol of possums.
Kevin Smith of the Royal Forest and Bird Protection Society said his group was excited by the studies.
"There needs to be more research into better methods of possum control because existing poisons are really a stopgap until something more potent comes along."
Pictured: Dr Fran Adamski
