Discovery of foreign insects concerns scientist

1.00pm

A Nelson scientist's discovery of several previously undetected insects in urban areas has prompted a call for better surveillance.

Surveillance is usually targeted at specific pests that represent a major biosecurity threat to New Zealand, like the Asian gypsy moth.

Until recently, there has been no surveillance in urban areas that may harbour "sleepers" -- species that have become established but are not yet widespread.

While researching the presence of introduced insects in urban areas, Nelson Landcare Research scientist Richard Toft and his team found five previously undetected species.

They used a range of traps set up at Port Nelson, around the Warehouse distribution centre at Wiri in Auckland, and in suburban gardens in Christchurch, Nelson and Wellington.

Two new introduced beetles were discovered at Wiri, and three new fungus gnats (small flies), one of which is believed to have been here for more than 20 years, were found in suburban gardens.

It is not yet known what effect the gnats may have on native ecosystems.

At Port Nelson a new ant incursion was detected, reported to the Ministry of Agriculture and Forestry and subsequently eradicated.

Various other ant species were discovered for the first time in Nelson and other sites in the South Island.

Mr Toft said the research underlined the need for generalised urban invertebrate surveys.

"It is clear we need to be better aware of what insects are getting here. New Zealand has some of the strictest biosecurity measures in the world, but unless we search every square centimetre of every container, detecting all invaders at the border is simply not possible.

"We need better post-border surveillance to detect any invaders that have made it past the border, most likely into surrounding suburban areas."

Plans for future research include further identification of the insect specimens collected during the surveys, and developing surveillance techniques.

There will also be more work on some of the existing urban "sleepers" to determine their potential threat to the environment.

- NZPA