Bee deaths raise fears of colony collapse

A beekeeper tends a hive.

A beekeeper tends a hive.

Scientists are responding to early reports of more honey bee colony losses on the Coromandel and in Waikato during autumn and winter, the symptoms of which they fear are consistent with a phenomenon known as colony collapse disorder (CCD), which has decimated honey bee populations in North America and Europe.

Last spring beekeepers on the western side of the Coromandel reported the mysterious disappearance of thousands of colonies of bees, resulting in estimated production losses of between 40 and 65 per cent of their honey crop.

Bees swarm around hives.

Bees swarm around hives.

Similar unexplained bee losses occurred in the Raglan region, Wairarapa and central North Island.

One of New Zealand's leading scientists on honey bees and crop pollination, Dr Mark Goodwin, head of Plant and Food Research's bee unit, said the clinical symptoms of these latest losses were consistent with colony collapse disorder.

"That doesn't mean it's the same cause, but the outward expression of it ticks all the boxes of colony collapse disorder," he said.

A honey bee collecting pollen.

A honey bee collecting pollen.

"The symptoms look very similar, bearing in mind that the cause of these bee losses may be something completely different."

Colony collapse disorder has never been positively identified in New Zealand.

"We are getting reports that colonies are dying already and we're nowhere near spring," Dr Goodwin said. "Reports are coming from the same area of the Coromandel affected by colony collapses last spring and further afield in the Waikato."

"We had hoped (losses) would be just confined to spring but in the autumn Coromandel people were reporting colonies dying from the same symptoms as last spring."

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"But these are the ones we know about," he said. "For every one we know about, as we learnt from the last occurrence, there will probably be a whole lot we don't know about."

Last week Dr Goodwin and a molecular biologist were en route to the Coromandel to check hives in the centre of the latest outbreak for levels of pathogens believed to be linked to CCD.

Initially they were looking for hives with high levels of Nosema Ceranae and Lotmaria passim, two newly discovered pathogens that attack the gut of honey bees.

"We need hives that we can guarantee have high levels of Nosema ceranae and Lotmaria passim. They did last spring so we think there's a good chance they will again this year," he said.

Researchers believe colony collapse is caused by a combination of factors that may include these two pathogens. However, they say the pathogens may not be the immediate cause of death, but an effect of something else that weakens the bees and makes them susceptible to the pathogens.

For research purposes scientists may use a product routinely used in many countries overseas to control Nosema ceranae, a treatment that is not currently registered for use in New Zealand.

If it is effective, Dr Goodwin said the industry will have to decide if it wants to make the treatment available in this country. That process is expensive and may take months before it is registered and available for use by beekeepers.

"We still don't know what the cause is and if we don't know what the cause is, it's very hard to offer beekeepers solutions," he said.

He is also seeking industry support to co-fund his research, which is initially being financed through core funding from Plant and Food Research.

"At the moment we're mainly concentrating on the centre of the outbreak, but we would like to be able to reach much further afield," he said.

"We want to expand it to see if pathogens are the cause of colony collapse. We need to monitor a much larger number of colonies to determine if there's a relationship between the levels of Nosema ceranae and Lotmaria passim and life and death."

Dr Goodwin said what is happening on the Coromandel will affect any organisations that rely on bees for pollination or honey crops and is also likely to be of interest to scientists working in the Northern Hemisphere.

 - Stuff


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