This genus includes nearly 100 species with diverse ecologies. They are common inhabitants in beetle galleries, ant colonies, bumble bee nests, stored products, insect cultures, rotting fruit, flowers, and soil.
Among Proctolaelaps, there is a group of species recorded only from bumble bee nests (Proctolaelaps bombophilus, P. longanalis, P. longisetosus, P. ornatus, and P. sibiriensis). In contrast to most generalist species of Proctolaelaps with multidentate fixed chelicerate digits, the bumble bee species display fixed chelicerate digits with just a few teeth, and they lack the typical ventral process (mucro) on the movable digit. The disparity in cheliceral morphology may suggest a different type of and/or more specialized feeding.
Other species associated with bees include habitat generalists Proctolaelaps pygmaeus found in nests of bumble bees and honey bees and Proctolaelaps bickleyi found, among other habitats, in honey bee hives. In addition, one species, Proctolaelaps scolyti, normally associated with bark beetles, has been recorded from Apis mellifera.
Proctolaelaps pygmaeus is an example of a cosmopolitan habitat generalist that can be found in soil, decomposing plant material, bulbs, moss, stored food, under bark, and nests of small mammals, bumble bees, and honey bees. This species may be predatory on small arthropods, but is also a fungivore, and unlike most similar mites, it is able to ingest solid matter (fungal conidia, arthrospores, hyphae, or yeast). There is circumstantial evidence that it can attack humans and that the results can be severe enough to cause extensive papular dermatosis (reviewed by Halliday, 1997). Feeding on both animal prey (small mites) and fungi has been confirmed in laboratory experiments for Proctolaelaps bulbosus (Galvao et al., 2011). Proctolaelaps regalis, which is normally an omnivore species that feeds on fungi and microarthropods, could also prey on eggs, larvae, and pupae of Drosophila by rapid cheliceral thrusting (Houck et al., 1991).
Other species are more specialized. For example, feeding on nectar of tropical flowers and dispersing on hummingbirds, butterflies, or honey possums has been seen (Dusbabek et al., 2007; Guerra et al., 2010). Proctolaelaps nauphoetae is a true parasite of the cockroach Nauphoeta cinerea (Blattidae); it inserts its chelicerae through the cuticle of its host and feeds on the hemolymph.