Machilidae

Definition

A family of primitive, wingless insects in the order Archaeognatha, commonly called jumping bristletails. Members are characterized by an elongated, cylindrical body covered in tiny scales, a humped thorax, large compound eyes that often meet dorsally, and three caudal appendages (two cerci and a median epiproct). The approximately 450 described species are primarily ground-dwelling, found in leaf litter, rock crevices, and similar moist microhabitats, where they feed on algae, lichens, and decaying organic matter. They differ from the superficially similar silverfish (Zygentoma) by possessing the ability to jump by flexing the abdomen against the substrate, and by having eversible vesicles on the ventral abdomen for water absorption.

Etymology

From Machilis, the type genus (classical Greek machilos, possibly related to 'fighter' or 'warrior,' perhaps alluding to active movement), + -idae (family suffix).

Example

Petrobius brevistylis, a common littoral machilid of European rocky shores, tolerates salt spray and wave splash by seeking refuge in crevices during high tide.

Synonyms

• jumping bristletails (common name)

Related Terms

• Archaeognatha
• Zygentoma
• Thysanura (obsolete)
• cercus
• Epiproct
• Apterygote
• Microcoryphia
• Machilis
• Petrobius

Usage Notes

The family Machilidae is one of two extant families in Archaeognatha (the other being Meinertellidae). Formerly, Archaeognatha and Zygentoma were grouped together in the now-obsolete order Thysanura. Machilidae are distinguished from Meinertellidae primarily by the presence of scales on the legs and antennae (absent in Meinertellidae) and differences in the structure of the maxillary palps. The common name 'jumping bristletail' refers to the distinctive saltatorial escape response; 'bristletail' alone is sometimes used more broadly to include both archaeognathans and zygentomans. The family is cosmopolitan but most diverse in the Mediterranean region and southern hemisphere.