Quick Dips

Bagging Bugs

A project looking at insect communities may tell us whether recently planted forests of exotic trees have comparable insect communities to those in ancient native forests. Theoretical ecologist Dr Simon Hodge is heading what is believed to be the most intensive study to date of fungal-breeding insects in New Zealand forests, aiming to produce an extensive list of arthropods, their fungal hosts and their preferred habitats.

It has been previously supposed that exotic forests support a less diverse range of insect species. However, preliminary research by Hodge and other New Zealand ecologists indicates a level of diversity in exotic forests that is similar to that found in native woodlands.

Since February, the scientists have collected insects from forests stretching across the middle of the South Island. These include native bush in the Okuti Valley (Banks Peninsula), beech forests in Lewis Pass and rimu forests on the West Coast. Pine and spruce forests were also sampled as were six restoration and conservation sites around Christchurch. The team plans to use statistical models to ascertain how successfully man-made and restoration forests preserve invertebrate species diversity.

"By comparing the diversity and similarity of fungal insect faunas we hope to develop an index, based on insects found in mature native forests, with which to compare other forest habitats" says Hodge.

Over 6,000 insects have been caught in 280 traps and now the task of sorting out the bugs begins, with the aim of completing the project by next autumn. There is also an applied aspect to the project.

"The research will strengthen associations between entomologists at Lincoln University and pest control workers at Landcare Research who are studying possum feeding ecology in beech forests," says Hodge. Insect remains have been found in possum stomachs and it is still unknown whether possums feed directly on forest insects -- and therefore pose a direct conservation threat -- or eat them while grazing on vegetation or fungi.