Life Cycle of Varroa Destructor

The life cycle of the Varroa destructor (Varroa mite) has two main phases. The first phase is when it reproduces in sealed brood cells. The second phoretic phase is when it lives on adult bees.

After a fertilized female mite invades a honey bee brood cell, it starts its reproductive stage before the bees cap it. The developing bee pupa has the mite located between its second sternites. The mite pierces the cuticle to feed on the fat body tissue.

About 60 to 70 hours after the invasion, the mite starts laying eggs. It first lays a male egg, which has one set of chromosomes. It then lays female eggs, which have two sets of chromosomes, every 30 minutes.

A single foundress mite typically undergoes 3–7 reproductive cycles during her lifespan, producing up to 30 eggs. The eggs exhibit distinct characteristics: an oval, flattened morphology, reddish-brown coloration, and a length of 1–1.2 mm.

In the phoretic phase, adult mites attach to adult bees, mainly nurse bees. They use special claws to hold on and feed on hemolymph through thin membranes. This mobile phase facilitates colony-to-colony transmission via drifting or robbing behaviors.

The mite's success in reproducing depends on timing with the host's pupal development. It especially prefers drone brood because they have longer capping periods. The mite also needs to avoid hygienic bee behaviors, like uncapping and removing brood. The efficiency of this life cycle causes mite populations to double every 4-6 weeks under ideal conditions.