VARROA Where did it come from?

VARROA What is it?

Varroa is parasitic mite of honeybees. The tiny mite lives and feeds on larvae and adult bees.

Latin name

Varroa jacobsoni

Size

The female has a diameter of about one millimetre. Male mites are much smaller.

Appearance

Female shiny, red-brown and elliptical in shape with four pairs of legs. Male mites are white in colour and spend their lives inside capped brood cells.

VARROA Where did it come from?

Varroa was first named in 1904 by Dr Oudemans in Indonesia. He identified it on one of the Asian honeybee species, Apis cerana. This species is the natural host of Varroa: the bees the mites have developed host-predator relationship which allows the continued survival of both species. In the long term, it would not benefit the mites to completely wipe out their host species.

Our current problems with Varroa in Apis mellifera colonies began when humans moved European Apis mellifera into Asia. Varroa mites spread from Apis cerana colonies into Apis mellifera colonies.

Unlike Apis cerana, Apis mellifera has not evolved in the presence of the mite. Therefore Apis mellifera has not developed any defence mechanisms against Varroa. Colonies of Apis mellifera can be completed destroyed by the mite, unless the beekeeper takes some action to control mite numbers.

The effect of Varroa on Apis mellifera is not always the same. For example in Central and South America, some populations of Africanized honeybees seem able to survive in the presence of the mite. The effect of Varroa infestation is also somehow related to the viruses carried by the mites and honeybees.

VARROA Where is it now?

Movement by humans of colonies of Varroa-infested Apis mellifera led to the spread of Varroa around the world. In 1987 Varroa was found in the USA, in 1990 it was found in Canada, in 1992 it was found in the United Kingdom (and in 1997 here in Monmouth!) The only remaining major beekeeping areas without Varroa are now Australia and New Zealand, and most of Africa {as far as we know). In Europe only Ireland remains Varroa-free.

VARROA in South Africa

Varroa jacobsoni has now been confirmed present for the first time in sub-Saharan Africa. It was identified in the Western Cape, South Africa in August 1997.

References GAUTIER,D (1997) South African Bee Journal. 69: LEAR,E (1998) Personal communication

It may take three or more years before there are sufficient numbers of mites present in honeybee colony for them to be detected. If one colony in an apiary becomes infested with Varroa, all colonies in the apiary will become infested.