Many species of Sancassania are habitat generalists and are not specialized for a particular phoretic host. Phoretic deutonymphs can be found on a variety of insects, diplopods, and millipedes, but they are most common on scarabaeid beetles.
Habitat generalists feed primarily on wet decomposing organic material and fungi. Some species are agricultural and stored product pests. Unspecialized generalists are known from bee nests, commonly from the European honey bee: Sancassania sphaerogaster (= S. mycophaga auct. non Mégnin) and S. rodionovi (=S. berlesei auct. non Michael) from hives of the European honey bee Apis mellifera. Sancassania rodionovi has also been reported from a nest of the carpenter bee (Xylocopa flavipes). Unidentified species of Sancassania have been sampled from nests of Apis cerana and the halictid bee Lasioglossum leucozonium.
A few lineages are specialists. Sancassania boharti is associated with the alkali bee Nomia melanderi. The presumed subgenus Ctenocolletacarus is associated with ground-nesting stenotritid bees of the genus Ctenocolletes and provides sanitary services to host nests. Many Sancassania species are obligate associates of scarabaeid beetles; they are phoretic on the beetle as deutonymphs and feed on the beetle carcass after the host death. Species of the nidicola-species groups specialize in feeding on fruiting bodies of large mushrooms and probably also their mycelium growing underground.
A biological account of Sancassania boharti can be found in Cross and Bohart, 1969. Phoretic deutonymphs of Sancassania boharti are usually found on the metasomal integument, crowded into the intersegmental spaces, where they pattern themselves into partially overlapping layers, their orientation opposite to that of the bee, and where they may be hidden from casual observation. Because these mites are found on the metasoma (dorsally in females and ventrally in males), sometimes on structures modified for copulation, this species is most likely to effect venereal transfer.
Additional observations on Sancassania boharti are available from Eickwort, 1979 and Eickwort, 1994. In nest cells these mites may occur on feces deposited by bee larvae, but they are especially abundant in cells containing dead bees and moldy provisions. The mites burrow through and tear apart the provision masses, consuming pollen, fungi, and dead brood. There is, however, no evidence that the mites kill the brood; they are presumably scavengers that take special advantage of food resources in cells in which brood fail to develop. Deutonymphs are facultatively produced and are phoretic on bees that develop in other cells; it is probable that these deutonymphs move through the soil to locate their hosts in the nest burrows.