While the global decline of honeybees in general has caught most headlines, Asian honeybees seem to have vanished in the city of Townsville, Australia since their last nest was destroyed in November. Most of the hives were destroyed after forager bees were found carrying the varroa jacobsoni, a relative of the destructive varroa mites. The varroa jacobsoni is believed to be a less harmful relative of the varroa parasite, but it may adapt over time to become a more harmful pest.
Varroa mites are one of the honeybee’s several stressors and were discovered in the Asian honeybee hive in Townsville. Until now, Australia had been free of varroa mites, which are known to cause billions of dollars’ worth of damage to agriculture worldwide. As per the Australian Department of Agriculture, 65 percent of Australian crops rely on the honeybee population and the crops they pollinate. If varroa mites are established in Australia, they could cause an estimated $70 million loss in crop industries.
The Australian Honeybee Industry Council (AHBIC) said that the Department of Agriculture staff were carrying out floral sweeping. According to the Northern Australian Quarantine Strategy (NAQS), floral sweep netting is the most efficient sampling method to confirm the presence of Asian honeybees. Floral sweeping has been proposed as the key surveillance technique to provide early detection of exotic pest bees. Along with floral sweeping, department staff also used helium balloons to check for male Asian honeybee drones.
Ashley Bunce, director of the varroa mite response for Townsville, hoped the balloon plan would help find more Asian honeybees and to see if there had been any other incursions. “Essentially, it’s a large helium balloon attached to some fishing line, and it has some lures which has the female sex pheromone, which attracts the male bees out,” Bunce said. After the drones are caught, they are put into an ethanol solution and tested for potential varroa mites. According to Bunce, they can also do a genetic analysis on the drones. The analysis can help determine if the drones are related to any other nest in the area or if there’s a new nest they need to harness.
Trevor Weatherhead, executive director of the AHBIC, stated that local beekeepers have “commenced the second round of checking managed hives by either alcohol washes, sugar shakes, or drone brood uncapping. Tests to date have been negative for varroa jacobsoni.” However, department staff are still taking precautions and were distributing leaflets to Townsville residents asking them to look out for the Asian honeybee. “If [the varroa mite] starts to then spread Australia-wide, there’ll be implications Australia-wide, so we certainly don’t want it to establish in the Townsville area,” Weatherhead said.
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