What are mites and what kind of insects do they represent? - briefly
Mites are minute arachnids belonging to the subclass Acari, closely related to spiders and ticks. They are not insects but members of the class Arachnida.
What are mites and what kind of insects do they represent? - in detail
Mites belong to the subclass «Acari», a lineage within the class «Arachnida». They share the arachnid body plan of two main tagmata, the cephalothorax and abdomen, and possess four pairs of walking legs in the adult stage. Unlike true insects, which are classified under the class «Insecta» and have three pairs of legs, mites are more closely related to spiders and ticks.
Morphologically, mites exhibit a compact, often soft integument, chelicerae adapted for piercing, sucking, or grinding, and a gnathosoma that houses the mouthparts. Their dorsal shield, when present, may be heavily sclerotized, providing protection in harsh environments.
Key characteristics of the group include:
- Species richness exceeding 55 000 described taxa, with estimates of total diversity reaching several hundred thousand.
- Habitat versatility: soil, leaf litter, water bodies, plant surfaces, animal hosts, and stored products.
- Ecological roles: predators of small arthropods, scavengers decomposing organic matter, parasites feeding on vertebrate blood or plant sap, and mutualists in some symbiotic relationships.
Taxonomically, mites occupy the following hierarchy: Kingdom Animalia → Phylum Arthropoda → Subphylum Chelicerata → Class «Arachnida» → Subclass «Acari». Within «Acari», two major orders dominate: the Parasitiformes (including ticks and many predatory mites) and the Acariformes (encompassing diverse groups such as oribatid, astigmatid, and trombidiid mites).
The distinction from insects is evident at multiple levels. Insects possess a three‑segment thorax with three pairs of legs, compound eyes, and typically two pairs of wings. Mites lack wings, have a fused body plan, and develop through larval, nymphal, and adult stages, each bearing four pairs of legs after the larval phase. Consequently, mites represent a separate evolutionary lineage within arthropods rather than a subgroup of insects.