Culex erraticus

(Dyar & Knab, 1906)

Erratic Mosquito

Culex erraticus is a mosquito in the Culicidae, subgenus Melanoconion. It is a documented of virus (EEEV) and West Nile virus, with females exhibiting aggressive biting toward birds, mammals, amphibians, and reptiles. The species shows distinctive seasonal -shifting behavior, feeding primarily on ectothermic hosts during warmer months and shifting to endothermic hosts during cooler periods. It has been observed as in gopher tortoise burrows in Florida and in swamp elsewhere.

Culex (Melanoconion) erraticus by the Smithsonian. Used under a CC0 license.

Pronunciation

How to pronounce Culex erraticus: //ˈkjuː.lɛks ɛˈræ.tɪ.kʊs//

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Habitat

Swamp and wetlands; in Florida, have been documented in gopher tortoise (Gopherus polyphemus) burrows. Females lay in floating clusters called egg rafts on the edges of aquatic plant leaves, including Eichhornia crassipes, Salvinia molesta, Salvinia minima, and Lemna minor.

Distribution

Southeastern United States (widespread in Florida, rare in northeastern states), ranging north to Connecticut and Ontario, west to Nebraska, and south through Mexico, Central America, and South America; also present in southernmost California and the Caribbean.

Seasonality

Active year-round in warmer regions; in Florida, overwinter in gopher tortoise burrows from October through February, with peak abundance increasing when falls below 12 hours daily. from sites occurs in March.

Diet

Females bloodfeed on birds, mammals, amphibians, and reptiles; males feed on nectar. Blood meal analysis has confirmed including gopher tortoises, white-tailed deer, alligators, chipping sparrows, and northern parulas.

Host Associations

Gopherus polyphemus - / blood Primary for females in Florida burrows; may serve as or diluting host for
white-tailed deer - blood Confirmed via blood meal analysis
American alligator - blood Confirmed via blood meal analysis; may serve as long-term virus
chipping sparrow - blood Confirmed via blood meal analysis; migratory may influence arboviral transmission dynamics
northern parula - blood Confirmed via blood meal analysis
yellow-crowned night heron - blood Frequently targeted avian in Alabama
great blue heron - blood Frequently targeted avian in Alabama

Life Cycle

Overwinters as . Females lay in floating egg rafts on aquatic vegetation. Developmental stages include egg, larva, pupa, and adult. In temperate regions, winter severity influences timing of seasonal shifts and reproductive .

Behavior

Exhibits activity. Females demonstrate opportunistic feeding with temporal shifts in selection throughout the season. In Florida, enter gopher tortoise burrows for when decreases below 12 hours, remaining from October through February; occurs in March when photoperiod increases. Blood-feeding activity decreases during overwintering period.

Ecological Role

of virus (EEEV) to humans and horses; bridge vector for EEEV between enzootic and cycles. Naturally infected with West Nile virus (WNV) and suspected vector. Vector of Plasmodium floridense, a of reptiles. Serves as for parasitic water mites (Arrenurus spp.), which attach primarily to second abdominal segments.

Human Relevance

Public health concern due to potential transmission of EEEV and WNV to humans and livestock. Aggressive biting females can be nuisance pests. Management targeting in gopher tortoise burrows during winter months may be more effective, though must balance tortoise conservation needs.

Similar Taxa

Culiseta melanuraBoth are EEEV ; Cs. melanura is the primary enzootic vector while Cx. erraticus serves as bridge vector. Cs. melanura specializes on birds, whereas Cx. erraticus shows broader range including reptiles and mammals.
Culex quinquefasciatusBoth Culex , but Cx. quinquefasciatus is primarily urban, breeds in dirty water, and bites at night; Cx. erraticus is associated with swamps, wetlands, and tortoise burrows with activity and distinctive seasonal -shifting.

More Details

Arboviral Overwintering Mechanism

The use of gopher tortoise burrows by Cx. erraticus may contribute to arboviral persistence through winter. Long-lived reptiles like gopher tortoises and alligators can sustain high for extended periods, potentially serving as that re-infect emerging mosquitoes in spring.

Climate Change Implications

Winter severity has been shown to predict timing of shifts, with 93% of variation explained by chill accumulation. Global warming may alter these patterns, potentially extending periods of mammalian feeding and transmission risk.