Hive talkin’: Bee genes could be key to honeybee survival

Nobody likes being buzzed by a bee, given the risk of a painful sting, but don’t be too quick to swat it. Bees play a vital role in the human food chain, pollinating the plants that provide us with food.

"Most people don't realise the importance of bees," says Gerard Coyne, who keeps honeybee hives. "It doesn't just come down to the honey we can produce; it is our food crops that rely on bees for pollination. More than half of the food we eat depends on bee pollination, " he says.

If bees disappeared, the first thing to go would be our fruits. Subsequently, as more crops failed, other animals would begin to go, says Coyne, who is chairman of the Native Irish Honey Bee Society.

This isn’t scaremongering: honeybees are in serious decline around the world.

Much of the blame is being placed on the Varroa mite, the nemesis of beekeepers everywhere. The mites latch on to bees, drawing out fluids and weakening them.

“The Verroa mite will debilitate the bees, leaving them more open to diseases,” says Prof Grace McCormack of NUI Galway’s school of natural sciences. “But the mite also seems to transmit viruses, and that is the real problem.”

An answer to this worldwide issue may well be hidden in the very honeybee you brush away from your outdoor picnic.

Some beehives in Ireland seem to be able to resist the mite – or at least to tolerate its presence. And the hunt is now on to find these bees and identify the genes that confer this resistance.

McCormack is heading a research programme with the strong support of members of the Native Irish Honey Bee Society., and the study will form part of a PhD thesis being pursued by Keith Browne.

The mites arrived in Ireland in 1998 and spread rapidly, wiping out honeybee hives across the island, says Coyne. Chemicals were used to contain mite infestations, but this was an incomplete answer, so beekeepers began to use breeding as a way to increase resistance.

The society was founded in 2012. One of its goals was to protect the native honeybee from disappearing completely due to crossbreeding. The society turned to McCormack and her group for help in this effort.

“We are assisting the society and are working in collaboration with them to see if we can have a breeding programme established to protect the native Irish bees,” McCormack says.

Browne, who won a Ryan Institute research scholarship, is focusing on bee genes and how they interact with the wider environment. He also received funding from the Irish Research Council.

“We are trying to do two things: establish a breeding programme with the aim of increasing the amount of honeybees in Ireland that have resistance to Varroa. In doing that, not only do you treat the mite, you give the bees greater disease resistance,” Browne says. “We are also trying to look for any wild Irish bees that might still exist in the environment.”

This second part will be a challenge, given the amount of crossbreeding that has taken place over the years since the Varroa mite arrived.

With this in mind, there is a citizen science aspect to the research. The public are being encouraged to watch for wild honeybee hives and to report their whereabouts to the research team.

People can use either the project's Facebook page (search for "The Bee Genes"), contact them on Twitter @thebeegenes, or report hives to the Native Irish Honey Bee Society by emailing pro@nihbs.org. The researchers stress how important this type of public input could be.

Tolerance genes

The study will depend on finding hives with tolerance or resistance to the mite, and then looking at the genetics of the bees in the search for tolerance genes.

“It is about finding the cause of Verroa tolerance, but certainly Verroa tolerance can be increased, no doubt,” says Browne.

He is also keen to study whether tolerance may be linked in any way to how and where the bees are foraging.

“We are looking for known traits but also to see if we can link bee tolerance and disease resistance to how the bees are using their local environment.”

Coyne is confident progress will be made and the native Irish honeybee can be protected. “Bees are tough. They have survived everything the environment has thrown at them,” he says.

“The worry we have is there are other diseases out there, like the small hive beetle. We have not got on top of the Verroa mite, and if this arrived it would be a problem.”

MITE LINK: DO IRISH HONEYBEES HAVE THE ANSWER?

Beekeepers on both sides of the Border have a central role to play in finding bees that tolerate the Verroa mite. They are being asked to count the number of mites clinging to a bee to gauge the level of hive infestation.

"There is huge expertise among the beekeeping community," says Prof Grace McCormack of NUI Galway. "We are asking beekeepers to do a Verroa count. You can actually see them."

The size of a mite compared with a bee is like the size of a fist to our bodies, she says.

The 30 or so beekeepers taking part use a sugar-sweet method to do the count. They put a given number of bees into a jar, add some powdered sugar and then shake them about gently.

The powder makes the mites fall off. Then, when the bees are released, the mites can be counted. It doesn’t harm the bees, which might be cross after the shaking, but getting to lick off the sugar is their reward for helping.

“The keepers are being asked to do a count twice a year and then to breed from those hives with the lowest Verroa count,” McCormack says.

There are 26 types of northern European honeybee, Apis mellifera mellifera, that have adapted to local conditions across northern Europe, and the Irish version is a tough one.

“It survives in the cold and wet and has adapted to this environment. We believe the environment has played a huge role in their adaptation,” she says.

It may be that resistance to the Varroa mite is a part of this adaptation, so understanding the genes it carries could help control the mite in other countries.