3.2. Where to find mites

Adult females are most easily found inside of capped worker and drone bee brood cells of infested colonies, where they reproduce. They do not appear to markedly favour either cell type for their reproduction. This is also the only place where nymphal stages can be found. To find a mother mite and her nymph offspring, simply uncap a bee brood cell of an infested colony and remove the developing bee inside. Tilt the entire comb so that the ambient light will be directed into a cell. Any mites present will be easily seen with the naked eye in the bottom of the cell or on the cell wall.

The presence of adult mites with offspring inside bee brood cells is clear evidence that they have reproduced and have not simply entered the bee cell after being transported (say on robbing bees) from another colony of a sympatric bee species, which might confuse host-specificity attributed to them. Male mites are best found inside of capped cells in which the developing bee is about to emerge or else in random collections of adult mites found moving on the surfaces of combs.

Adult Tropilaelaps mites are much more mobile than adult Varroa mites and can be seen moving quickly across the surface of infested brood combs. In this situation they are hard to collect. When they are not moving, they also become well camouflaged against the background colour of the wax combs and are hard to see. When the brood comb is lifted out of the colony into the open light mites also quickly enter open cells and remain still on the cell walls, where again, they are hard to see.

Adults of both sexes can also be found on the bodies of adult bees, but only in extremely low numbers, even in heavily infested colonies. This is probably because mites avoid adult bees as much as possible because they cannot feed on them and hence can only survive for a few days (Woyke, 1984; Wilde, 2000). Nevertheless, at some stage they have to move on to adult bees in order to disperse from the colony.