Erythraeidae

Robineau-Desvoidy, 1828

Subfamily Guides

5

Erythraeidae is a of predatory mites in the order Trombidiformes. are free-living, fast-running with long legs adapted for pursuit. Larvae are of various arthropods, including harvestmen, spiders, bees, and grasshoppers, using a stylostome to feed on body fluids. These mites are typically oval, relatively large for mites, reddish in color, and densely hairy. The family belongs to the superfamily Erythraeoidea within the diverse group Parasitengona, which includes velvet mites, chiggers, and water mites.

Lasioerythraeus by (c) Sam Kieschnick, some rights reserved (CC BY), uploaded by Sam Kieschnick. Used under a CC-BY license.Leptinae by (c) mark-groeneveld, some rights reserved (CC BY), uploaded by mark-groeneveld. Used under a CC-BY license.Leptinae by (c) Derek Hennen, some rights reserved (CC BY), uploaded by Derek Hennen. Used under a CC-BY license.

Pronunciation

How to pronounce Erythraeidae: /ˌɛɹɪˈθɹeɪɪˌdiː/

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Identification

Distinguished from related microscopically by the presence of a single claw on the tibia of the palp. The combination of oval body, dense hairiness, reddish coloration, and exceptionally long first and fourth legs separates from most other mite families. Larvae can be identified by their parasitic association with and the presence of a stylostome for feeding.

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Appearance

Oval, relatively large mites, usually reddish-colored and densely hairy. Legs are long, especially the first and fourth pairs, adapted for running. Possess either one or two pairs of . Microscopic examination reveals a single claw on the tibia of the palp, distinguishing them from related .

Habitat

occupy diverse terrestrial . Some , such as Abrolophus, deposit on sun-exposed rocks. The Balaustium has been observed cruising pavement for windblown pollen in spring. Larval habitats are determined by distribution.

Distribution

Worldwide distribution with records from Europe, Asia, Africa, Australasia, North America, and South America. Documented from Iran, Colombia, Spain, France, Italy, Serbia, Sicily, Ukraine, Montenegro, China, and Guatemala. In North America, molecular evidence suggests well over 100 in the U.S. and Canada alone, many undescribed.

Seasonality

active in spring in temperate regions. Spiderlings parasitized by erythraeid larvae emerge in autumn and overwinter, suggesting larval activity in late summer to autumn.

Diet

are free-living . Larvae are that feed on body fluids and dissolved tissues of using a stylostome.

Host Associations

Life Cycle

Complex typical of Parasitengona with parasitic larvae and predatory . Larvae bite a hole into the and use a stylostome to feed. After engorgement, larvae detach and develop through inactive stages (calyptostatic) to become free-living predatory adults.

Behavior

are fast runners using long legs for pursuit of prey. Males perform a circular dance before depositing , even without females present. During this dance, males deposit a secretion trail containing a that facilitates rediscovery by the male and likely by females. Multiple spermatophores are deposited at single locations; older spermatophores are pushed to the substrate when new ones are added. Up to 24 spermatophores may be deposited within 2 hours in culture conditions.

Ecological Role

function as in terrestrial . Larvae act as that may influence . Some have been investigated for potential as agents.

Human Relevance

Generally not medically important to humans directly. Some parasitize bees, including honey bees, which may have implications for apiculture. Bright red species in the Balaustium are regularly noticed by the public in spring. Serve as bioindicators due to their specific requirements and sensitivity to environmental conditions.

Similar Taxa

  • TrombidiidaeAlso in Erythraeoidea; larvae are of arthropods. Distinguished by microscopic characters of the palp tibia claw structure.
  • Trombiculidae (chiggers)Also in Parasitengona with parasitic larvae, but larvae feed on vertebrates rather than arthropods, and are morphologically distinct.
  • Hydrachnidae (water mites)Also in Parasitengona but adapted to freshwater; are aquatic with morphological adaptations for swimming rather than running.

More Details

Taxonomic diversity

The contains 62 , including Abrolophus, Balaustium, Charletonia, Erythraeus, and Leptus. Many remain undescribed, particularly in North America where molecular evidence suggests over 100 species in the U.S. and Canada alone.

Reproductive biology

structure includes three protein secretions: Secretion I envelops sperm, Secretion II forms the stalk, and Secretion III forms the crown. Secretions harden through oxidative conversion of sulfhydryl groups to disulfide bonds, prevented from premature hardening by an oily secretion from the accessory gland.

Research significance

Erythraeidae, along with other Parasitengona, are important for understanding the evolutionary transition from terrestrial to aquatic in mites. They serve as models for studying complex evolution and indirect sperm transfer mechanisms.

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Sources and further reading