NIWA ecologists catch on to a bug's life

Kneeling in the mud under the cover of trees, covered in anoraks, sandflies and dedication, three scientists are looking out for the little guy.

Kneeling in the mud under the cover of trees, covered in anoraks, sandflies and dedication, three scientists are looking out for the little guy.

As part of a stream experiment by NIWA, freshwater ecologists Dr Richard Storey and Brian Smith and interns Maurice de Wit and Neils Groot have spent the last two months running around for freshwater insects.

The experiment is thought to be a world first but had a simple execution. The scientists loaded rocks into controlled pools of flowing freshwater; some had rocks poking out above the surface, some had none.

"There's not too many people in the world focused on insect egg laying," Storey said, "but we think it's a fairly important element in riparian stream restoration."

A sticky paste lathered on the protruding rocks caught insects, allowing scientists to see what was landing to spawn. The point was to learn whether insects preferred streams which provided landing opportunities, so they could lay their eggs. The larvae would develop into tasty fodder for birds, thereby providing a diverse and sustainable habitat.

"What insects do is provide food for other organisms, so you get fantails and swallows eating them. The quality of a stream isn't just about what we see," Smith said.

The experiment was one of two planned and ended last week. Storey said the first round, while not a failure, hadn't yielded the results they had hoped for on first glance. "It may be that the polarised light on the stream alongside was more attractive than what was going on over here," he said.

He said they'd make some adjustments and run a second round starting before Christmas. "We want to understand the ecology of as many species as we can."

Part of the experiment was a bug net hovering above the stream, which caught all in its path to reveal the kind of flying fish food that frequented the spot. Smith was pleased to find a stonefly in the murky cocktail, as they were one of the favoured dining options for trout. "These are the good good guys, this is your goal," he said.

Smith said a healthy stream was a diverse stream, rampant with snails, birds, fish and insects.

"The adults are a little bit overlooked. They may not be as charismatic as a kea or a kakapo but they are equally as important. It's all special so we need to look after it."

Results were transported back to NIWA's laboratory on the University of Waikato campus where they would be examined

- Story from Waikato Times.