Trichodectidae

Definition

A family of chewing lice (order Psocodea, parvorder Trichodectera) that are obligate ectoparasites of mammals. Members possess broad, dorsoventrally flattened bodies with strong mandibles adapted for feeding on hair, skin debris, and occasionally blood. Trichodectidae are distinguished from the related family Philopteridae (bird lice) by host association and subtle morphological differences in antennae and abdominal chaetotaxy. The family includes species of veterinary and conservation concern, such as the dog louse *Trichodectes canis*, which can vector the tapeworm *Dipylidium caninum*.

Etymology

From Greek tricho- (hair) + dektes (biter), with family suffix -idae

Example

*Trichodectes canis* on domestic dogs and *Bovicola bovis* on cattle are economically significant trichodectids; heavy infestations cause dermatitis, reduced weight gain, and hide damage in livestock.

Related Terms

• Phthiraptera
• Psocodea
• chewing louse
• Philopteridae
• Ectoparasite
• Vector
• Trichodectes canis
• Bovicola

Usage Notes

Formerly treated as a suborder or infraorder within Phthiraptera; modern phylogenomics places Trichodectidae within Psocodea, rendering 'Phthiraptera' paraphyletic. The family is morphologically conservative, making species-level identification rely on host association and subtle genitalic differences. Not to be confused with the similarly named fungal genus Trichoderma (Hypocreaceae).