When a dreaded honeybee parasite was first detected in Australia in June 2022, evolutionary biologist Professor Alexander Mikhayev saw both a looming disaster and an unprecedented opportunity. He grabbed a vial of bee pheromones, a helium balloon and a butterfly net, and set off to find the places bees mate.
Varroa destructor is a poppy-seed-sized mite that feeds on honeybees and their larvae, and carries several deadly bee viruses. Where the parasite spreads, bee populations collapse soon after. Until 2022, Australia was the largest honeybee producing country still free of varroa mites.
When he realised government monitoring programs were only sampling managed bee hives and not the feral bee population, Mikhayev decided to take matters into his own hands.
From his base at the Australian National University in Canberra, Mikhayev drove all over New South Wales collecting as many bees as possible. He soon realised that truly seizing this opportunity to understand the genetics of varroa resistance would require a continent-wide monitoring program.
Now, as the destructive mite spreads across the country, Mikhayev is calling on citizen scientists to help the Australian Bee Observation Network. Volunteers are being provided with pheromones and instructions on how to collect drone bees.
Bees collected from the same sites repeatedly will help researchers observe the development of varroa resistance in real time. This research could prove crucial in mitigating the extensive damage the parasite is expected to inflict on Australian food systems, as honeybees are crucial pollinators for a variety of crops such as almonds, apples and blueberries.
Introduced honeybees are under threat in Australia from a newly arrived parasitic mite. Photo by Ricky Sproule.
Australia has thousands of native bee species, but varroa is not known to affect them. Honeybees, imported from Europe two centuries ago, are now naturalised all over the country, and both the feral population and commercial beehives play a key role in our food system. It is the population of wild, introduced bees that Mikhayev sees as an untapped reserve of genetic diversity.
Mikhayev hopes to track genetic changes in bee populations as the parasite makes its way across Australia.
“Genetic diversity is the raw material for evolution,” says Mikhayev.
Bees collected now, before the parasite reaches them, will be vital for understanding varroa resistant populations that emerge in the future.
If researchers only look at the genes of varroa-resistant populations, they are unable to determine which genes are responsible. “It’s like searching for a needle in a haystack statistically,” says Mikhayev.
Having samples from the same population, immediately before and after varroa resistance develops, will allow researchers to locate the genes responsible for resistance traits. These traits can then be bred into docile, domesticated populations of honeybees that are well-suited to beekeeping.
Neighbourhood bee watch
Mikhayev says participants in the national scientific project don’t need particular skills or experience to find bees in the mood to breed.
Drones and queens gather on warm days in “drone congregation areas” to mate, he says, which are usually 10 to 20 metres up in the air, above clearings surrounded by native vegetation.
Professor Alexander Mikhayev collecting wild honeybee drones. Image provided by ANU.
Volunteers collect stingless drone bees by tricking them into thinking they are approaching a mating queen. A vial of queen bee pheromones tied to a helium balloon causes the drones to gather, then lured closer to the ground and collected in butterfly nets.
“I realised I don’t have to be a professor to do this. School kids could do this… and it’s actually quite easy and quite fun,” says Mikhayev.
Because drones from many different hives will congregate at the same area many times a year, volunteers can collect samples from the same hives to give researchers insights into the parasite’s impact over time. Specimens are sent to Mikhayev’s Bee Lab at ANU for analysis.
A sting in the tale
Varroa was first identified by biosecurity officers at Newcastle Port in June 2022, but Mikhayev suspects it was likely in the country for as much as a year before then.
In February this year, the National Management Group (NMG), the federal body tasked with managing the varroa outbreak, abandoned efforts to eradicate the pest. The NMG has now transitioned to supporting beekeepers and the pollination industry to live with varroa.
Living with varroa will make beekeeping more difficult and more expensive. Beekeepers will now need to monitor their hives for varroa and regularly apply chemical control methods.
Victorian beekeeper John Edmonds has been keeping bees since he was 17. He has seen the rise of a handful of large companies that have begun to dominate Australian apiculture over recent decades.
John Edmonds has been keeping bees since he was 17 years old. Image provided by Edmonds Honey.
Edmonds thinks the arrival of varroa will only accelerate the consolidation of the beekeeping industry.
“The bigger beekeepers will get bigger, while the old blokes like myself will retire,” says Edmonds.
Mikhayev says New Zealand, where varroa arrived in 2000, may offer a window into the near future for Australia’s beekeepers. The extra labour and operating costs of managing varroa drove many small beekeepers in New Zealand out of business. Declines in the health and population of bees reduced crop yields for farmers and horticulturalists, said Mikhayev.
The Australian department of Agriculture Forestry and Fishing estimates that varroa will decrease national agricultural productivity by $70 million dollars a year.
The feral honeybee population in New Zealand has basically disappeared. Mikhayev says wild hives are still sometimes found in New Zealand, but it is not known whether these are small populations that have developed resistance, or recent escapees from managed hives.
Mikhayev has spoken to many small-scale beekeepers in the northern hemisphere who have refused to apply chemical treatments despite the warnings. “They come back to me and say, ‘see my bees are fine,’ then the bees are dead the next year.”
For Australian beekeepers, there are no alternatives to chemical control in the short term.
“Virtually all unmanaged bee colonies will die,” says Mikhayev.
Mapping the spread
Currently, the NSW Department of Primary Industries is maintaining a live map of reported varroa infestations. This map depends on reporting by beekeepers and does not include infestations of feral bee populations. The Citizen was unable to identify public mapping plans beyond the New South Wales borders.
Comprehensive mapping is needed to understand and slow the spread of the poppy-seed sized mite, which feeds on honeybees and their larvae. Photo by Piscisgate/ Wikimedia Commons.
The short-term goal of the Australian Bee Observation Network is to map the spread of the mite and its associated viruses through the feral bee population. This will help beekeepers plan the movement of their hives to slow the spread of the parasite.
The long-term goal is to support the development of varroa-resistant honeybees. The timing is crucial, as the parasite will quickly spread across the eastern states.
Mikhayev says it is likely already present in Victoria and Queensland. Western Australia, Northern Territory and Tasmania may remain varroa free for a few more years.
