Trombidiformes

Trombidiformes is an order of mites within the subclass Acari. It is one of the two major lineages of Acari, the other being Sarcoptiformes. Members of Trombidiformes display vast diversity in form and lifestyle, from free-living predators to plant feeders and external parasites.

The order includes many well-known groups and families, such as Trombidiidae (red velvet mites), Trombiculidae (chigger mites), Tarsonemidae (tarsonemid mites), Phytoseiidae (predatory mites used in biocontrol), and Tetranychidae (spider mites). Collectively, Trombidiformes comprises tens of thousands of described species across hundreds of families, occupying a wide range of habitats.

Morphology and life cycle: like other mites, adults typically have four pairs of legs, while the larval stage has three pairs. Members of Trombidiformes show great variation in size and morphology, with many having elongated bodies or ornate coloration. Reproduction is sexual, though some species exhibit parthenogenesis.

Ecology: Trombidiformes occupy soils, leaf litter, on plants, and in animal habitats, with some aquatic representatives. They can be free-living predators, phytophagous mites feeding on plant tissues, or parasites on invertebrates or vertebrates. Several species are agricultural pests, notably many Tetranychidae (spider mites) and Tarsonemidae, while Phytoseiidae mites are widely used as biological control agents against pest mites.

Taxonomy: The group has a long and complex taxonomic history, with ongoing revisions using morphological and molecular data. It remains a major focus of acarology due to its ecological and economic importance.