Biology

Propagation

Varroa destructor lives in balance with its original host Apis cerena, which is found in southern Asia and as far west as eastern Russia. In the latter area and towards the end of the 19th century, a change in host occurred: the varroa mite invaded the colonies of Apis mellifera imported to contribute to the subsistence of the inhabitants of this region. Through trade and the subsequent exchange of colonies, the mites have propagated over almost all of the planet. Only Australia and certain regions of central Africa and northern Europe have not yet fallen prey to varroatosis.

Behaviour

Varroa reproduce exclusively in the sealed brood cells of honey bees. Using transparent cells, Gérard Donzé was able to observe the entire reproductive cycle of the Varroa mite, which he described in two articles dealing with the reproduction and mating of the parasite.

A look under the cap: the reproductive behaviour of Varroa in the capped brood of the honey bee (PDF, 443 kB, 19.01.2017)
G. Donzé, P. Fluri, A. Imdorf (1998)

Remating in Varroa: for which purpose? (PDF, 143 kB, 19.01.2017)
G. Donzé, P. Fluri, A. Imdorf (1998)

Mathias Rickli and Gérard Donzé have filmed the key events in the life of a varroa mite family.
The film, which is in German or French, can be obtained from:
Geschäftsstelle BienenSchweiz, Jakob Signer-Strasse 4, CH-9050 Appenzell, Switzerland.

Having no eyes and living in the darkness of the colony and cell, varroa mites must rely on their sense of smell to navigate. This faculty was studied in detail at the Swiss Bee Research Centre to identify attractive substances - specifically, those produced by the brood - as a basis for control methods. The 'nose' of the Varroa mite is found on its legs, and the capabilities of this olfactory organ have been examined down to the cellular level. The possibility of trapping varroa mites during their search for a brood to infest was studied in the beehive.

Movements of the digestive tract of a Varroa destructor nymph

Time lapse recording of the melanisation process triggered by wounding a honey bee pupa with an insect pin. The same immune reaction results from a Varroa destructor bite.

An adult Varroa destructor slithered between the abdominal tergites of a honey bee. The mite drills a hole in the tegument joining the cuticular plates and sucks the underlying hemolymph (blood)

A Varroa destructor nymph looks for the feeding site (indicated by an arrow) on a honey bee pupa. Once she found the hole in the host’s cuticula, she starts feeding. Peristaltic movements of her digestive tract are visible through her cuticula.