Hives fall victim to plagues that could sting us all

Dr Mark Goodwin. Photo / Paul Estcourt

Bees face a widening range of threats to their existence - a prospect with profound implications for global food security, reports Catherine Masters

Mark Goodwin plucks yet another yellow German wasp out of the syrupy container put out to attract golden honeybees and squashes the intruder against the wooden table.

The HortResearch scientist does this over and over, using tweezers to put an end to the unsuspecting foreign wasps which keep landing and which are just another of the many enemies of the poor old ravaged and really quite seriously threatened honeybee.

Warnings about the demise of the honeybee are clocking up.

The varroa bee mite has already decimated them around the globe and now we keep hearing about a strange new phenomenon, known as colony collapse disorder in America, which is the latest threat to the humble little pollinator.

This disorder is known as Mary Celeste Syndrome in Britain because, like the famous ship found deserted in the ocean in the 1870s, bee-keepers return to what appeared to be healthy hives only to find them deserted.

The bees presumably fly away to die but no one is sure why.

All manner of theories are being mooted, from pesticides, to which bees are very sensitive, to failing nutrition and from over-farming to parasites and viruses.

The situation is serious in America. Latest statistics reveal a third of colonies have not survived the winter - for the fourth year in a row.

If this keeps happening, many experts - Goodwin included - say the consequences will be dire. Since bees are crucial in pollinating so many crops, from fruit and vegetables to clover for farm animals, the fear is a greatly reduced food supply.

But what of our bees and our food supply?

At the Ruakura Research Centre in Hamilton, HortResearch's Dr Mark Goodwin is the man who probably knows more about them than anyone else in the country.

He has good news - and very worrying news.

Colony collapse disorder has yet to reach our shores. But Goodwin says it almost certainly will.

And more bad news. The varroa bee mite, which burst on to the scene here in 2000 seems to be developing resistance to two of the three chemicals used to control it. This is very bad, says Goodwin. The potential destruction caused by colony collapse disorder aside, it is the varroa mite which occupies much of his thinking.

Bees have not been in good health worldwide for some time, he explains.

In recent years it's been a bit like the ancient plagues of Egypt, as one thing after another has assaulted them.

We didn't really know about varroa until about 1950 but since then the mite has spread around the world, with the exception of Australia - and that's only through luck.

Varroa mites are all over the North Island and are well established in South Island hives. They are in Hawaii and Papua New Guinea.

Goodwin predicts the mite will get to Australia soon.

"It's amazing how fast it's spread. In 50 years not only did it get to every country bar Australia, but to every beehive in every country."

The varroa is one of those pests which became a major problem when it jumped species.

It was co-existing harmoniously enough on the Asian honeybee, feeding only on male bees, but at some stage jumped across to other types of bee and in these it kills female bees - and thus colonies.

In the North Island there are about 200,000 bee colonies, but only because of chemicals.

"This last autumn, if people hadn't put chemicals in all of them, in every one, we might have 2000 [colonies] left alive by spring."

It is a sadness for this dedicated bee-fan that the insects can no longer survive without bee-keepers putting chemicals in their hives. He thinks they have become the only creature in the world where intervention by humans is needed in this way to keep them alive.

Goodwin jumps up to fetch a piece of cardboard to demonstrate the varroa problem.

The cardboard is covered in debris from a beehive, including many hundreds of what look like tiny sesame seeds.

These are varroa mites, killed by chemicals and collected from one of the hives for counting.

There are probably 1000 on the board, Goodwin estimates, which means this hive is not badly infected.

The record is 35,000 mites.

Varroa suck the blood out of the larvae and the adult bee like little vampires, yet the mite itself is not really the problem. Like the mosquito, which spreads malaria, the varroa mite spreads viruses to bees.

There have been other nasties, spread in similar ways. In the 1960s the tropilaelaps mite also jumped from Asian honeybees, but fortunately it is mainly restricted to Asia.

Others include the small hive beetle from Africa, a stomach parasite from Asia which jumped from its host species, and Europe has managed to unwittingly import an Oriental hornet.

A group of just three or four of these guys will set out to kill a whole honeybee colony in a day, sitting outside the hive and crunching the bees as they come out to defend themselves.

But it's another new virus, which emerged in 2002, that really concerns Goodwin. The acute paralysis virus was first found in Israel but has already spread to China, Australia and the United States. The Israeli Acute Paralysis virus has been implicated in colony collapse disorder in the US.

Though there is no proof, Goodwin favours the virus theory for the reason the bees are disappearing, saying the paralysis virus has been found in 95 per cent of colonies with colony collapse disorder.

Until there is proof, Goodwin stresses this is just a theory and as bees die from all sorts of things, there could be another reason, or combination of reasons.

Regardless, things are not looking good for the US or Europe - or for us, he adds, because we eventually get everything they get.

In the 10 years that we have had varroa, we have picked up another nasty known as deformed wing virus. This makes the wings of bees shrivel up; it is spread by the varroa mite.

"You can tell if a colony has a lot of varroa just by looking at the bees. There are these bees that can't fly because they've got these shrivelled-up wings, which is kind of sad."

We head out to the research station's beehives, about 36 out in a field near a compost dump.

Goodwin puffs some smoke into a hive to quiet the bees and pulls out a slat laden with honey, bees and larvae.

The hive has some white strips added, to release chemicals to kill varroa.

The bee team's research here used to be mostly about bees and some pollination, but since the arrival of varroa it's mostly about pollination and some bees, he says.

Varroa has skewed everything. HortResearch is commercially funded so has to go where the clients are most worried. Some of its work is on artificial pollination - trying to find a replacement for bees because some clients are worried there might not be bees one day.

In the past year HortResearch has worked on everything from avocados to carrots, radishes and kiwifruit.

It's also working on the varroa problem, trying to breed bees which are resistant to the mite and have had some positive results.

But even if the scientists solve varroa, and even if the reason for colony collapse disorder is nailed down and solved, recent history shows another problem will emerge.

In the meantime, Goodwin fears New Zealand, along with much of the world, is being a bit complacent about the threat to bees.

The honeybee is not native to New Zealand - there is a native bee which is seemingly unaffected by varroa - but it is a solitary critter and though it does pollinate, it would be unable to cope with the food supply demands.

The honeybee was introduced by settlers mainly to provide honey but when agriculture started taking off bees were needed in bigger numbers.

"They are simply crucial," he says. "Most of what we produce, almost all our fruit and a lot of our vegetable seeds, is produced by bees. Probably in NZ it's worth about $2 billion a year.

"And then with clover and pasture, it's all got to be pollinated. We're not sure how important bees are there but they are almost certainly important, so a lot of our agriculture, cattle and beef farming and sheep, depend on bees as well. They really underpin everything we do."

It would be catastrophic to lose them.

"You probably wouldn't buy an apple in the supermarket any longer."

Goodwin says most of the fruit we see today in the supermarket would disappear. "If it doesn't, it will be produced by someone with a paintbrush, pollinating. You can imagine the cost of that, the price would suddenly be 10 times what it is now."

The world won't come to an end without bees, but experts seem to be slowly waking up to the need for serious research.

The World Organisation for Animal Health recently announced it would propose research on bee mortality be intensified to better control and fight against the numerous emerging and already known diseases.

"Bees contribute to global food security and their extinction would represent a terrible biological disaster," says the group's director-general, Dr Bernard Vallat.

He's not wrong, says Goodwin, who has trouble even contemplating a world without bees.

"There will always be bees," he says, optimistically. "There just has to be. We've got no choice."

DANCING WITH BEES

Dr Mark Goodwin fell into studying bees when he was searching for a topic for his Masters thesis many years ago.

Since then, he's fallen in love with them.

For insects with a brain the size of a pinhead, they are so cool, he says.

They can be trained to fly to particular food sources and do the most amazing maths.

They will dance in the hive to indicate the direction and distance of a food source, taking gravity and the sun into account.

In his thesis, Goodwin showed that even on cloudy days, bees have a memory of where the sun was at a particular time the day before and dance accordingly.

Another scientist in the 1940s was able to train bees to fly around an eight-storey building to a food source.

The bees were able to somehow measure how far they flew in a certain direction and the angle of the sun, working out the resulting vector from the various paths and compensating for the movement of the sun. "It would take me half the day with my calculator and I'd probably get it wrong, yet they just do it- measure the distances, measure the angles, do the maths, do the trigonometry, all on the spot with a brain the size of a pin head."

The scientist admits he is pretty disappointed about the arrival of varroa, because his research passion is the "brainy" side of bees.

Now he spends most of his time working on how to keep them alive.

A SWARM OF KILLERS
1950s: The varroa bee mite (pictured right) is found to have jumped species, spreading around the world and killing millions of colonies.

1960s: The tropilaelaps mite also jumped species, but fortunately is mainly in Asia.

1970s: African killer bees began spreading, from Brazil to North America.

1980s: The small hive beetle from Africa, turned up in Florida and started devastating colonies. It has spread to other countries, including Australia.

2001: The microsporidian stomach parasite Nosema cerane, jumped its host species and is now throughout much of the world.

2002: A new virus, the Israeli Acute Paralysis virus, is found in China, Australia and in the United States where it is implicated in colony collapse disorder.