About Coquillettidia perturbans (Walker, 1856)
Coquillettidia perturbans is a species of mosquito that has been recorded on every continent except Antarctica. It is a known vector of West Nile virus and Eastern equine encephalomyelitis. Its geographic range is increasing as its feeding area grows. It occurs throughout the United States, with a mainly southern distribution, and it feeds preferentially on mammals. C. perturbans is most commonly found in low-elevation areas with high vegetation, warm summers and high air humidity. These conditions support a swamp-like habitat that supports the growth of cattails (Typha latifolia) and Juncus sp., which C. perturbans prefers to support optimal larval and pupal development. Water quality is also an important factor for Coquillettidia species: the water must have no current, neutral pH, low salt concentration, and a low level of suspended particulate matter. The species' distribution is expanding because of its increasing feeding range and resulting disease transmission. C. perturbans lays eggs as an egg raft in marsh or swamp habitat. Each egg raft usually contains around 100 eggs, which generally hatch after several days, depending on environmental temperature. Larvae and pupae have a modified abdominal segment that can pierce the inner gaseous tissue (aerenchyma) of aquatic plants in this environment, such as cattails (Typha latifolia) and Juncus sp. This piercing gives them access to the plant's aerenchyma to breathe, allowing larvae and pupae to take in atmospheric oxygen without needing to stay near the water surface. This avoids the risks of predation and exposure to insecticides. C. perturbans goes through four aquatic larval instars. Pupal development can last from a few hours to a few weeks, depending on climate. Cold weather can lengthen the larval period to several months. The pupal stage can also range from a few hours to several weeks depending on environmental climate. Approximately 24 hours after an adult emerges from the pupal case, its wings finish hardening and are fully expanded, enabling flight. The full life cycle takes around seven to sixteen days to complete. If the species enters a hibernation stage, adults can live up to five or six months.
