Where would we be without bees? – New Zealand Herald

Dr Ashley Mortensen is one of a team of scientists at Plant & Food Research looking at honey bees and pollination. Image / Supplied.

Honey bees threat overstated but new research is protecting colonies.

New Zealand scientists are using huge helium balloons to carry traps for honey bees at mating sites so they can analyse the catch to see how many carry a mite called varroa.

Watch the video here:

Video / Supplied by P&FR.

The mite is one of the major threats to honey bee health and this 'sky fishing' will help tell how healthy the colonies in the area are, says Plant & Food Research scientist, Dr Ashley Mortensen.

Varroa is one of the biggest issues facing honey bees round the around the world; the mite feeds on honey bees and carries a variety of bee diseases that often, if left untreated, result in colony death.

The Plant & Food Research team has been actively working with beekeepers on how best to manage varroa in colonies since the mite first came to New Zealand in the early 2000s monitoring the amount of varroa in colonies, testing existing methods of treating colonies, and developing new treatments against varroa.

Myths surrounding honey bees (all the bees are dying and, by implication from food shortages, so will we) have more to do with hyperbole, says Mortensen.

"Our food supplies do currently rely on honey bees many of our common fruits, vegetables and seed crops are pollinated by managed honey bees. But there are more than double the number of colonies in New Zealand now compared to 10 years ago, so the idea that we're losing honey bees as a resource is just not accurate."

Mortensen is one of a team of people at Plant & Food Research dedicated to understanding the roles of honey bees and other insects in crop pollination, as well as helping beekeepers ensure the health of their colonies.

"Pollination is a key contributor to our $60 billion of food exports," says Mortensen. "Without pollination, plants don't produce fruit or seed.

"A lot hinges on having healthy pollinators in the field at the right time. Honey bees are currently the only pollinator widely managed as part of the farming system."

Bee Biology & Productivity team leader Dr James Sainsbury says: "Honey bee colonies need to be managed to ensure they stay healthy and free from disease and to ensure the impact on our native ecosystems is minimised, much the same as farmers manage cow and sheep stocks."

Colony health is a big focus for Sainsbury's team but that health is not only impacted by pests and diseases. The size and composition of the colony can also determine its productivity. However, little is known about the ideal make-up of a colony for specialised jobs such as pollinating cherries in early spring, pollinating kiwifruit grown under nets, producing monofloral mnuka honey or a combination of any of these.

Plant & Food Research is collaborating with Queensland University of Technology and the University of Otago to determine the ideal colony age and demographics to encourage the maximum number of workers to forage for pollen and/or nectar.

"By getting more bees out foraging, more pollen gets moved between flowers," says Sainsbury, "and more nectar gets brought back to the hive for honey-making. If a colony is structured to optimise those activities, the colony becomes more productive and more valuable to the beekeeper and, in the case of pollination, the grower as well."

Another Plant & Food Research project is trying to determine the best way to manage honey bees to pollinate crops grown under cover or in glasshouses.

"More crops are being grown under cover, to protect from weather events or to create longer growing seasons in climate-controlled environments," says Sainsbury. "As a rule, honey bees like space foraging 3km or more from their hive so we need to understand whether it's possible to manipulate the behaviour of a colony to focus on pollination in a confined space."

While honey bees are plentiful, land use change is having an effect on the 28 species of bee that are native to Aotearoa New Zealand. Of these, 27 are not found elsewhere and several are now threatened with extinction.

Most have evolved to feed on the nectar of native plants, including mnuka, a hugely desired resource for beekeepers who focus on producing honey - mnuka honey can sell for up to $5000 per kg overseas. These native bees, as well as other insects, are also pollinating crops. Research has shown boosting pollination with wild pollinators can contribute gains of up to $3000 per hectare.

"Native insects are important parts of our food production system," says Dr Brad Howlett, leader of Plant & Research's Beneficial Biodiversity team. "They may be better pollinators for some of our crops than honey bees if we can find ways to manage them.

"Unfortunately, they've been largely ignored historically, so we're only now beginning to understand how they're contributing, how we can encourage more of these species onto our farms and orchards, and the impact farming and land use change is having on the native insect population."

Howlett believes more research is needed about the role native bees play in the ecosystem and how farming practices might affect them.

Mortensen says: "We just don't know enough about our native bees and whether they'll react the same way as honey bees to many of our farming practices. We're trying to create a testing standard to assess the impact of agrichemicals on native bees as well as honey bees."

"There's so much more we need to learn about our native insects in Aotearoa New Zealand," says Mortensen. "When we say Save the Bees, we need to be thinking beyond honey bees and find ways to save our native species too."

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Where would we be without bees? - New Zealand Herald