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Mosquitoes

Twenty-four mosquito species in six genera occur in Lake County. Each mosquito has its own preferred larval habitat, seasonality, and blood meal hosts. Mosquitoes undergo complete metamorphosis: egg, larvae, pupae, and adult. The first three of these stages are spent in the water.

Egg Stage

Depending on the species, mosquito eggs are laid singly or in rafts either on the water’s surface or on something solid that will eventually be under water.  A female mosquito deposits 50 - 200 eggs.  In the summer, the eggs can hatch into larvae in 2-3 days. Only unmoving water with organic material can support developing mosquito larvae, so females lay their eggs in tree holes that fill with rain water, tide water pools in salt marshes, sewage effluent ponds, irrigated pastures, rain water ponds, and horse troughs.  Mosquitoes will also lay eggs in “backyard habitats” like unmaintained swimming pools and water features.  Any container that holds water continually for a week may be a suitable habitat for a female to lay her eggs, even pet water dishes and overflow reservoirs beneath potted plants.

Larval Stage

Larvae grow through 4 instars or stages, shedding their hard outer skin each molt so the larvae can grow to the next stage. Larvae breathe air through a tube called a siphon that pokes through the water’s surface.  They have a well-developed head with mouth brushes that filter algae, bacteria, and other microorganisms out of the water. The larval stage lasts between 4-14 days depending on water temperature and mosquito species. After growing to a 4th instar, the larva transforms into a pupa.

Pupal Stage

The pupal stage for a mosquito is the equivalent of the cocoon stage for a butterfly; this is where the larval mosquito transforms into an adult mosquito. Pupae do not grow so they do not eat.  They breathe through a pair of siphon tubes at the water surface similar to the larvae. Once development is complete, the adult mosquito emerges from the pupal case.

Adult Stage

Three days after a female mosquito emerges from the pupal case she is ready to take a blood meal. It takes about three days, depending on temperature, for the blood meal to be digested and eggs to develop. Male mosquitoes do not take blood because they do not need to produce eggs. Because they need energy for flight and other activities, both male and female mosquitoes feed on plant nectar and other sugar sources. During summer, mosquitoes complete a full metamorphosis (from egg to adult), in approximately 7-10 days.  If you add the approximately three days it takes for the female to harden and find a host and the three days it takes for eggs to develop, the time from egg-to-egg is approximately two weeks.

Mosquitoes of Lake County

Scientific NameCommon Name
Aedes bicristatusSnowpool mosquito
Aedes fitchiiSnowpool mosquito
Aedes increpitusSnowpool mosquito
Aedes melanimonIrrigated pasture mosquito
Aedes nigromaculisIrrigated pasture mosquito
Aedes sierrensisWestern treehole mosquito
Aedes vexansInland floodwater mosquito
Anopheles franciscanusNo common name
Anopheles feeborniWestern malaria mosquito
Anopheles occidentalisNo common name
Anopheles punctipennisWoodland malaria mosquito
Culex apicalisNo common name
Culex bohartiBohart's mosquito
Culex erythrothoraxTule mosquito
Culex pipiensNorthern house mosquito
Culex stigmatosomaBanded foul water mosquito
Culex tarsalisWestern encephalitis mosquito
Culex territansNo common name
Culex thriambusNo common name
Culiseta incidensCool weather mosquito
Culiseta inornataLarge winter mosquito
Culiseta particepsNo common name
Orthopodomyia signiferaWhite-lined mosquito
Coquillettidia perturbansCattail mosquito

Invasive Aedes mosquitoes

Three invasive mosquito species, Aedes aegypti (yellow fever mosquito), Aedes albopictus (Asian tiger mosquito), and Aedes notoscriptus (Austrialian backyard mosquito) have become established in California in recent years.

As of June 2021, no invasive Aedes mosquitoes have been detected in Lake County.  The District’s surveillance program includes methods that specifically target these two species.

These species share many similarities; they are:

  • small, black-and-white mosquitoes
  • bite aggressively during the day, especially in shaded areas of the yard
  • lay eggs in containers (like buckets, roof gutters, used tires, wheelbarrows, children’s toys, canoes and other boats stored in yards, tarps, and other common backyard containers)
  • have eggs that can remain dry for years and hatch when flooded
  • can transmit Zika, dengue, chikungunya, West Nile, and other viruses.

More information about these invasive mosquitoes, including a map that shows their current range in California, is available from the California Department of Public Health’s Aedes aegypti (yellow fever mosquito) and Aedes albopictus (Asian tiger mosquito) page https://www.cdph.ca.gov/Programs/CID/DCDC/Pages/Aedes-aegypti-and-Aedes-albopictus-mosquitoes.aspx