Learn about the Varroa lifecycle in under a minute
This excellent video was made by Dr. A.E. Latimer. You can also see how she made it.
Varroa in Australia
The history of the Varroa mite, specifically Varroa destructor, is intertwined with the evolution of honeybees. Varroa mites are parasitic arachnids that infest honeybee colonies, feeding on the “fat bodies” (the equivalent of a liver in bees) of both adult bees and developing bee brood. In the process, Varroa weakens the bees and transmit various bee viruses. This infestation can lead to colony collapse if left untreated.
The Varroa mite is believed to have originated as a parasite of Asian honeybee species, such as Apis cerana. These mites co-evolved with their original host bees and did not pose a significant threat to them. However, at some point, the Varroa mite jumped across to the Western honeybee species, Apis mellifera, which is the most common honeybee species kept by beekeepers worldwide. This switch allowed Varroa mites to spread beyond their original range in Asia. It is believed that the mites were inadvertently introduced to other regions through the global trade of honeybee colonies and beekeeping equipment. Recently, Varroa mites were discovered in Australia near Newcastle, NSW in June 2022. While successful eradication was achieved when previously discovered (in north Queensland in 2016 and 2019), this was not possible in Newcastle.
Beekeepers and researchers are in a constant battle with Varroa mites. Considerable effort has been spent on chemical treatments (miticides) to control mite infestations. However, over time, mites develop resistance to some of these chemicals, making control more challenging. The future of controlling Varroa is in the practice of Integrated Pest Management (IPM). Here, a number of different techniques including chemicals, physcial measure and bee breeding are all employed in concert to control mites on one hand; and, reduce the mite’s ability to adapt and build immunity.
Varroa mites continue to evolve because of their rate of reproduction (4-5 times that of the honeybee) and their unusual, imbred reproductive cycle that asists with their speedy adaptation.
The genetic history of Varroa mites is a complex interplay between their co-evolution with Asian honeybee species, their host switch to Western honeybees, and the ongoing efforts of beekeepers and researchers to combat their devastating effects. The battle against Varroa mites remains a significant challenge in modern beekeeping, highlighting the importance of sustainable IPM to protect honeybee populations.