Australia is probably the last country in the world not to have Varroa mite.
We are extremely fortunate being an island nation. However, with increased trade and travel and reduced biosecurity funding and resolution, it is a case of when and not if Varroa mite arrives.
Varroa mites—one of the most serious threats to honey bees worldwide—are infiltrating hives by smelling like bees, according to a new study appearing in Biology Letters.
The parasites were originally found on Asian honey bees (Apis cerana), but later began infesting and killing European honey bees (Apis mellifera).
European honey bee is a major pollinator for our pome and stone fruit crops. There are very significant wild honey bee colonies and a very important industry managing honey bee hives and pollination services.
The ongoing discussion world-wide about the effects of the chemical group 4A Neo-nicotinoids and bee health may be a case for, there is ‘no perfect poison’.
The Asian honey bee in Australia
Unfortunately Asian honey bees were first detected in the Cairns region in 2007 and as of October 2012 was established across 500,000 hectares in far north Queensland.
Varroa mites naturally occur on Asian bees. Varroa destructor is considered the most damaging parasite of honey bees in the world today, but only occur on some strains of Asian bees.
The mite found on the strain of Asian bees to the immediate north of Australia is Varroa jacobsonii which was thought not to reproduce on European honey bees (Apis mellifera) and therefore not pose a threat.
Chemical camouflage
This new study shows that Varroa mites were able to switch honey bee hosts by switching their scents—a form of chemical camouflage.
For chemical camouflage we think of squid and chameleons with their colour-changing camouflage. Sex pheromones used in mating disruption of codling moth and Oriental fruit moth are well known.
However, fooling socially sophisticated insects, such as honeybees, requires the faux scents to be incredibly accurate.
This is because the complex society of bees comprises tens of thousands of individuals divided by a sophisticated caste system.
(continues next month)
See this article in Tree Fruit June 2015
