Argasid

Argasid is the adjective used for the soft ticks of the family Argasidae, within the order Ixodida. The family includes several genera, most notably Argas, Ornithodoros, and Otobius. Soft ticks differ from hard ticks (Ixodidae) in several features: they have a leathery, flexible body without a hard dorsal shield; their mouthparts are usually not visible from the dorsal surface; many species feed briefly and repeatedly rather than forming a single prolonged blood meal.

Life cycle and feeding: Eggs hatch into larvae with six legs, followed by four nymphal instars and finally adults. Many argasids feed rapidly, often taking meals lasting minutes, and may endure long intervals without feeding. Some species feed on sleeping hosts and at roosts, nests, or sheltered sites.

Ecology and behavior: Argasid ticks occupy sheltered microhabitats such as bird nests, bat roosts, caves, rodent burrows, and poultry houses. They parasitize birds, bats, and mammals, including occasionally humans. They are generally less host-specific than many ixodids and can persist in environments with intermittent host contact.

Medical and veterinary importance: Several argasid species are vectors of relapsing fever spirochetes in humans and animals, and others transmit avian spirochaetosis or act as pests in poultry facilities. Otobius megnini, the spinose ear tick, is a well-known argasid parasite of domestic animals.

Distribution: Argasid ticks have a broad global distribution, especially in warm climates. Different species are adapted to caves, nests, or shelters, with regional variation in host preference and disease associations.