Macrochelidae

Genus Guides

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Macrochelidae is a of predatory mites in the order Mesostigmata. The family is primarily associated with ephemeral, nutrient-rich such as animal , where they prey on , oligochaete worms, and . on flying insects—particularly dung beetles and flies—enables between temporary resource patches. Some have been developed as agents for pest management.

Macrochelidae by (c) Alexis Tinker-Tsavalas, some rights reserved (CC BY), uploaded by Alexis Tinker-Tsavalas. Used under a CC-BY license.Macrocheles by (c) Drepanostoma, some rights reserved (CC BY), uploaded by Drepanostoma. Used under a CC-BY license.Macrocheles by (c) Emmett Collins-Sussman, some rights reserved (CC BY), uploaded by Emmett Collins-Sussman. Used under a CC-BY license.

Pronunciation

How to pronounce Macrochelidae: /ˌmækroʊˈkiːlɪdiː/

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Identification

Macrochelidae can be distinguished from other Mesostigmata by the combination of an undivided shield with at least 28 setae pairs, genital shield with accessory , and the characteristic peritreme looped around the stigma. The presence of an arthrodial brush on the movable cheliceral digit is a key diagnostic feature. Males are identified by their shield configuration (holoventral or divided).

Images

Appearance

females possess an undivided shield bearing at least 28 pairs of setae. The sternal shield carries three pairs of setae; the genital shield bears one pair of setae with conspicuous accessory beneath the lateral margins. The ventrianal shield typically has 1–5 pairs of setae in addition to circumanal setae. The peritreme is usually looped around the stigma. The movable cheliceral digit usually has a well-developed arthrodial brush at its base. Adult males are similar but exhibit either a holoventral shield or separate sternigenital and ventrianal shields.

Habitat

Primary are ephemeral, organic-rich substrates: animal (coprophilous lifestyle), forest litter, decaying plant debris, beach wrack, and animal nests. Dung deposits represent the most extensively documented habitat, offering high prey and shelter but requiring mechanisms due to their temporary nature.

Distribution

. Documented from all major biogeographic regions including North America, Europe, South America (Colombia, Brazil), Southeast Asia (Indonesia: Bali, Sumatra, West Java, West Papua), and Australia.

Diet

Predatory. Prey includes oligochaete worms, , , and arthropod larvae. Most are within their patches.

Host Associations

Life Cycle

Development includes , larva, , deutonymph, and stages. Phoretic is typically performed by adult females, though males and nymphs may also engage in this . Some exhibit thelytoky (production of female offspring from unfertilized eggs) or (production of male offspring from unfertilized eggs) in addition to .

Behavior

is the defining behavioral : mites actively seek, attach to, and ride on insects to disperse from depleted resources to new patches. Attachment triggers include chemical and behavioral cues specific to host . During phoresy, mites cease feeding and development. females are the primary stage. Phoretic specificity varies phylogenetically, with terminal showing stronger host commitment than early-derivative lineages.

Ecological Role

that regulate of and other microinvertebrates in and decaying organic matter. Contribute to nutrient cycling in ephemeral . Serve as prey for larger arthropods within the same microhabitats.

Human Relevance

agents: Macrocheles robustulus is commercially available for management of pest insects including flies and . Macrocheles muscaedomesticae has been investigated for control of flies. Forensic relevance: some associated with human corpses in Europe, indicating potential utility in forensic acarology.

Similar Taxa

  • ParasitidaeAlso predatory mesostigmatic mites associated with ephemeral ; distinguished by divided shield and different setal counts
  • LaelapidaeShare order Mesostigmata and some overlap; distinguished by genital shield and lack of arthrodial brush on

More Details

Phoresy definition and debate

The phoretic relationship of Macrochelidae has been central to defining itself. Farish and Axtell (1971) used Macrocheles muscaedomesticae to redefine phoresy as temporary attachment with cessation of feeding and ontogenesis for purposes. Alternative hypotheses (accidental boarding, obligate , phagophily) have been proposed for some associations but are not supported for the majority of macrochelid- relationships.

Reproductive plasticity

The exhibits multiple reproductive modes: , thelytoky (Geholaspis, Macrocheles), and (Glyptholaspis, Holostaspella, Macrocheles). This flexibility may facilitate of ephemeral by single females.

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Sources and further reading