Too little data to pinpoint cause of NZ beehive deaths

NZ apiarists unsure if vanishing bees signal 'colony collapse'

By Suze Metherell in Taupo

June 23 (BusinessDesk) - The sudden and devastating demise of honey bee hives, known overseas as colony collapse disorder, may threaten New Zealand's $5.1 billion apiculture industry, after thousands of colonies were lost over last spring.

North Island beekeepers spanning the Coromandel, Great Barrier, Wairarapa and Taranaki suffered significant losses with some reporting up to 95 percent of adult bees disappearing from hives. However, a lack of reporting to the Ministry for Primary Industries or the Environmental Protection Agency meant there was no certainty about whether the sudden collapses were linked, the New Zealand Apiculture Conference in Taupo heard.

The comments came during a panel session including Dr Oksana Borowik, a commercial beekeeper and geneticist, Don Macleod, a pesticide consultant who works with the National Beekeepers' Association, and Dr Mark Goodwin, head of the honey bees and pollination unit at Plant & Food Research.

Borowik was the first to report a sudden departure of bees at her Coromandel hives between August and December. Hives were discovered with only 200 young worker bees, the queen and plenty of pollen and nectar for them to eat with few dead bees found near the hive. The remaining bees were riddled with Nosema Apis and Nosema Ceranae pathogens, which attack the honey bees' gut, as was a recently discovered pathogen, Lotmaria Passim, she said.

DNA testing by Gisborne-based dnature confirmed the presence of the pathogens.

None of the bees that left the hives had been collected, meaning little was known whether they carried pathogens, but it's understood nosema rapidly ages the bees, meaning they can leave the hive earlier, and also affects their homing abilities to return to the hive.

Speaking from the floor, a visiting US beekeeper told the conference the symptoms were very similar to the colony collapse disorder experienced by beekeepers in the US. In 2008, after reports of disappearing adult bees, the US Department of Agriculture's research unit surveyed 20 percent of the country's 2.44 million colonies. Surveyed beekeepers reported a total loss of about 36 percent of their honey bee colonies, up about 14 percent from the previous winter, according to the research on its website.

Colony collapse is the subject of international scientific debate, with the blame variously placed on climate change, pesticides, over-crowding or pests. The recent spate of unexplained bee deaths comes after New Zealand's wild bee colonies were effectively wiped out by the arrival of the varroa mite in 2000, which halved the country's pollination workforce.

When the panel asked the 400-strong conference how many had experienced hive deaths with symptoms described by Borowik and other Coromandel apiaries, roughly a quarter of the room raised their hands, but only one had actually reported the case. Macleod said to date MPI had only recieved 12 reports of hive deaths, and the agency was not necessarily able to help because of the uncertainty over the cause of death.

Goodwin said the government is now funding further investigation into the sudden deaths. He told the conference that correlation does not equal causation and because there was so little data it would be dangerous to jump to conclusions.

Macleod said the baseline for average hive deaths in a typical season is unknown, and New Zealand beekeepers didn't have a habit of talking about hive deaths.

Asian demand for manuka honey has seen the price for all New Zealand honey increase, amid a global honey shortage. Bees produced $187 million of exported honey in the June 2014 year, up 8 percent by volume and almost 30 percent by value on the previous year.

The number of registered beekeepers increased 12 percent in 2013/14 to 4,814, and is nearly back to pre-varroa levels. Meanwhile, total hive numbers reached 500,000, an increase of 55,000 on the previous year. About 750 commercial beekeepers accounted for more than 90 percent of those hives while hobby beekeepers, defined as owning 50 hives or fewer, numbered 4,590. In July last year, there were just 800 members across the two bee industry groups.

Representatives of New Zealand's fragmented bee industry are seeking government support to reintroduce commodity levies for honey and the creation of a single national body by April next year. The conference will consider industry unification, which may see the National Beekeepers Association and the Federated Farmers Bee Industry Group become a single body.

(BusinessDesk)

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