Plant-based contraceptive bait for possums
Plant-based contraceptive bait for possums a step closer
The humble spud has been used to demonstrate that vegetable baits that reduce possum fertility are feasible, and may one day join a range of possum control tools.
Landcare Research and Marsupial Cooperative Research Centre scientists have completed contained laboratory trials using potatoes grown by the Boyce Thompson Institute for Plant Research in the United States, a world leader in developing plant-based vaccines. Possums were fed chunks of potato containing a foreign protein - in this case, an inactive part of a protein from a bacterium. Antibodies to the foreign protein were found in the possums* blood, gut and reproductive tracts. This means that the antibodies permeated throughout the possums* systems.
The result is a boost for Landcare Research and the Marsupial CRC*s plans for a similar trial, that would involve feeding possums carrots that contain a protein called ZP3, from the coating of the female possum*s eggs. Scientists believe the carrots will act as a vaccine that tricks possums* immune systems into believing the eggs are foreign bodies, and making antibodies against them. This method is called immunocontraception, as possums are essentially immunised against conceiving. The programme leader, Dr Phil Cowan, says the potato trial results are encouraging news for his team, which is aiming ultimately for a 60 to 70 percent reduction in possum fertility from the use of immunocontraceptive baits. *We*re very excited, because the positive results show great potential for the use of plants as a delivery system for the biological control of possums. We can now proceed with the carrot trial with confidence*.
Dr Cowan says successful development of immunocontraception should be a useful and humane addition to current possum control measures, which depend on poisons. *We hope the immunocontraceptive baits will slow the rate at which possum populations rebuild after poisoning. This means control will be needed less frequently, resulting in less environmental contamination, and reduced risk to non-target species*.
Dr Cowan also says the plant baits themselves will be environmentally friendly.
*They will be processed so that they cannot grow or spread genetic material to other plant life. Also, the parts of the possum protein contained in the carrots will be specific to marsupials, and should not affect other animals*.
The carrots will be grown in the US, and subject to approval from ERMA and MAF, will arrive in New Zealand in the new year, in time for the new possum breeding season. Feeding trials with the carrots will be held in strict containment.
For more information, please contact: Phil Cowan Landcare Research Palmerston North ph (06) 350 3806
Janine Duckworth Landcare Research Lincoln ph (03) 325 6701 x2279