Scientists bugging out about fall in insect numbers

Scientists in New Zealand are concerned by a new German study, which revealed an alarming fall in the number of flying insects like butterflies and bees.

The results have long-term implications for pollination and the food chain - however bug researchers aren't sure of the cause.

Insects make up two-thirds of all life on earth. They pollinate plants, enrich our soil, and provide food for larger animals in the food chain.

However New Zealand's 'bug man' Ruud Kleinpaste is concerned - a German study found a 75 percent drop in the number of flying insects over a 27 year period.

"Bugs basically run this planet. They look after everything that we value," he says.

It's a trend in many countries. Scientists are unsure what's causing the decline, but the use of pesticides and herbicides is one possible target.

Experts believe human behaviour is having an impact.

"Humans are getting a little bit too popular on this planet, and it has an effect everywhere. This defornation or this impact on our biodiversity seems to be going on with birds, lizards, and now insects," he says.

Bucking the trend here in New Zealand - the population of the honey bee - it's seen rapid growth over the last 10 years.

For farmers who rely on them for crop pollination, it's estimated bees contribute about $5 billion a year to the country's economy.

"There are ways that we can circumvent the loss of insects. Our lives would be so worse off if we had to control every little thing that these insects are doing for us," says Dr Jenny Jandt, from the Otago University Zoology Department.

They're also promoted as a good high-protein food source for the world's growing population, another reason scientists are keen to work out just what's causing their decline.