| abstract | The ability of several acaridid species to colonize and feed in diff erent nutritional substrates, such as grain crops, oil seeds, damaged vegetables, mixed fodder, hay and straw from the mangers and litter of livestock keeping places, litter, ambrosia and dead bees from beehive bottoms, is investigated. Species-specifi c diff erences in indices of domination and occurrence, and of Sorensen and Jaccard coeffi cients of similarity of species compositions on diff erent substrates are related not only to the nutritional inequality of these substrates, but also to the mite ability to grind them and to absorb these substrates through intracellular, contact and cavitary digestion using certain hydrolytic enzymes. |