Acaroidea

Pronunciation

How to pronounce Acaroidea: /ˌæ.kəˈrɔɪ.di.ə/

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Summary

Astigmatina is a diverse clade of mites within Acariformes, characterized by soft bodies, varied ecological roles, and varying leg configurations in different life stages. Many are parasites, but others contribute beneficially to ecosystems.

Physical Characteristics

Astigmatan mites are usually soft-bodied and white to brownish in colour (rarely tan and well-sclerotised), ranging from 0.15 to 2.00 mm in length. They lack stigmatal openings, peritremes, or prodorsal sensilla. The gnathosoma is usually exposed, with 2-segmented chelicerae, typically chelate-dentate in shape. Larvae have six legs; nymphs and adults have eight legs. The genital opening varies by life stage, with one pair of genital papillae in the protonymph and two pairs in the tritonymph and adult.

Identification Tips

Mites in the Astigmata clade are characterized by their small size, soft body, lack of stigmata, and presence of exposed gnathosoma. Distinct life stages have different leg counts; larvae are hexapod while nymphs and adults are octopod.

Habitat

Astigmatina can be found in a variety of habitats including wet substrates like decaying plant tissue, dung, mud, and within human homes. They inhabit environments such as mammal nests, stored food areas, and are also found in bird nests.

Distribution

Astigmatina species are widely distributed, with some adaptations to specific environments, such as living in human homes or in populations that increase in agricultural soils after harvesting or manure application.

Diet

Astigmatina species have diverse diets. They can be microbe feeders, feed on organic material, or act as kleptoparasites. Some are obligate associates of bees while others consume plant material, fungi, or algae.

Life Cycle

Astigmatina undergo a metamorphosis with distinct life stages: larvae (hexapod), nymphs (octopod), and adults (octopod) with variations in reproduction and development stages such as the presence of deutonymphs that may be heteromorphic.

Reproduction

Males possess an aedeagus typically in a postcoxal position, while females have a secondary sperm-receiving structure known as a bursa copulatrix.

Ecosystem Role

Astigmatina play various roles in ecosystems, including being decomposers in organic material, living as parasites, and engaging in mutualistic relationships with bees.

Economic Impact

Astigmatina contribute to allergies and damage stored products in homes. They are also involved in pest management by preying on other plant pests such as armored scale insects.

Health Concerns

Some Astigmatina species are known for causing skin diseases such as scabies and mange in mammals.

Evolution

Astigmatina evolved from oribatid ancestors and has developed a wide range of ecological strategies compared to their predecessors.

Misconceptions

Astigmata members are often just seen as pest mites, underestimating their ecological roles and contributions to beneficial relationships with other species.

Tags

• mites
• Astigmatina
• ecology
• parasitism
• stored products