krombeini found with Osmia lignaria of North America, (the Blue Orchard Mason Bee).

Pollen mites do not feed on bees, but rather their provisions, and are harmful because they consume the food resources and starve or stunt the developing larvae; there is evidence that pollen mites also directly harm the egg by puncturing it.

Both their feeding habits and their size differs significantly from Varroa destructor, the mite very harmful to the European Honey Bee.

A mason bee, upon emerging from its nest, may be burdened by hundreds of hitchhiking pollen mites.

Because accurate identification of different pollen mite species is exacting and microscopic, and several host bees are in commerce and shipped regularly, it is likely that Ch.