Painted Apple Moth find a new arrival

Thursday 2 June 2005

Testing confirms Painted Apple Moth find a new arrival.

Scientific testing using two different techniques indicates that that the Painted Apple Moth (PAM) trapped at an Otahuhu container facility on 5 May 2005 was a new arrival, and not a remainder of the population in West Auckland that sparked eradication measures in 2002.

While scientific testing using DNA had previously been difficult because of technical challenges the recent use of a different gene region has proved successful. Additionally the use of a forensic tool being developed at Otago University was recently identified as an alternative option. The results from both testing regimes indicate that the PAM male caught on 5 May 2005 was a new arrival.

Biosecurity New Zealand Eradication Programmes Manager Ian Gear said the latest testing compared the ratios of certain stable isotopes of the Otahuhu moth with previous captures in Auckland, Australia and with moths bred in the two colonies established to produce females as part of the Auckland eradication programme.

“Testing indicated the Otahuhu moth was significantly different to moths already in New Zealand, and most similar to the Australian moths. The results also indicated the Otahuhu moth had pupated in a climate significantly more arid that Auckland. Stable isotopes for the main Auckland population were reasonably consistent, but were significantly different to an Australian moth tested,” says Ian Gear.

“As well as saying the Otahuhu moth is significantly different, the results for hydrogen and carbon isotopes in particular gave us some spectacular indications of the potential of the technique. Carbon isotope values indicate the diet of the larvae, and there were two clearly distinct groups. One indicated a diet of foliage; the other indicated the artificial diet fed to the colonies held in containment. It was possible to establish that the two colonies shared a similar diet, but had a different water source.

“It really is a useful technique that has great potential. While the information needed to indicate a definite point of origin is not available at this stage, it will be possible to build a database that will just about tell us the moth’s suburb, street address and passport number,” says Ian Gear.

The forensic stable isotope testing was done by the Dunedin company Iso-trace New Zealand Limited.

ENDS

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