Biological observations are available for Anoetus halictonida, associated with Halictus rubicundus, and an undescribed species of Anoetus associated with Lasioglossum lineatulum (Eickwort, 1979; Eickwort, 1994):
Phoretic deutonymphs attach to the host's wings. On female bees they also often attach in shingle-like rows to metasomal tergum I or II, while on males they may occur on the venter of the head, thorax, and sometimes the metasoma. Phoretic deutonymphs move from their phoretic host onto the provision mass in a new cell, and transform into tritonymphs that soon molt into adults.
The adult females stay on the provision mass and swell greatly. The males remain very small and crawl onto the dorsum of the female when the host larva is about half grown. It is possible that these males develop rapidly from the first unfertilized eggs laid by the females, perhaps skipping all nymphal instars, and then mate with females of the parental generation. The inseminated females then lay fertilized eggs, all of which develop into females.
Those female eggs are laid on the bee nest cell wall and bee larvae, and mite larvae and protonymphs feed on the surfaces of the bee larvae and pupae, apparently consuming microorganisms; they do not harm the bees upon which they feed. Mite protonymphs begin to appear when the bee larva pupates, when they crawl on the pupa, especially ventrally. Molting to phoretic deutonymphs begins about half way through the pupal stadium. Phoretic deutonymphs preferentially cluster on the pupa's dorsal propodeal surface and about the wing bases. They transfer to the adult bee when it emerges. Deutonymphs remain on their female hosts while the hosts hibernate, and they detach from host bees as new cells are constructed in the spring.
In addition, field observations and laboratory experiments on Anoetus associated with halictid bees of the genus Megalopta showed that mites reduce fungal infestation of the nest cells, thus decreasing bee mortality (Biani et al., 2009).