Mosquitoes

Mosquito Quick Facts
  • Over 3,500 species of mosquitoes in the world, 53 in California, 13 in the Coachella Valley.
  • Only females take a blood meal; they need blood protein to develop their eggs.
  • Mosquitoes use exhaled carbon dioxide, body odor, temperature and movement to target humans, other mammals and birds.
  • Females can lay 100-300 eggs.
  • Mosquito-borne diseases kill more people than any other single disease factor.

The mosquito is a highly effective and deadly vector for human disease agents. The tiny insect has played a powerful role in spreading viruses such as West Nile, St. Louis encephalitis, western equine encephalitis, dengue, and Zika.

In the Coachella Valley, we regularly detect 13 mosquito species. The species of greatest public health concern in the valley are the Culex tarsalis, Culex quinquefasciatus and the Aedes aegypti. These species are capable of transmitting micro organisms that cause disease in people.

Culex tarsalis

Culex tarsalisThe western encephalitis mosquito, Culex tarsalis, is the most important indigenous species in the valley and the primary vector of St. Louis encephalitis (SLEV), western equine encephalomyelitis (WEE) and West Nile virus (WNV). This mosquito breeds year round with two distinct peaks: In March/April and in late September/October. Cx. tarsalis prefers to feed on birds, but readily attacks people, horses, and cattle.

Culex quinquefasciatus

culex_quinqThe southern house mosquito, Culex quinquefasciatus, is a nuisance to residential communities from Palm Springs to the Salton Sea. Larvae breed in foul or highly polluted waters, typically in artificial containers, fish ponds, septic tanks, catch basins, waste treatment ponds, and neglected swimming pools. Birds are its principal blood meal source; however they will attack humans and invade homes. This mosquito has been found infected with encephalitis virus (eg., SLEV, WEE, and WNV) in California, but its role in the natural transmission of these viruses is considered to be secondary to that of Culex tarsalis in rural situations. In urban environments, Cx. quinquefasciatus is often the primary WNV vector.

Aedes aegypti
aedesThe yellow fever mosquito, Aedes aegypti, is an invasive mosquito species in the Coachella Valley and is capable of transmitting serious viruses, such as chikungunya, dengue, yellow fever, and Zika. It was first detected in the valley in 2016. The District is working proactively to reduce the chances of mosquito-to-human transmission. In addition to our routine surveillance program, the District is actively monitoring for invasive Aedes mosquito species and carrying out enhanced surveillance and control activities as per the District Invasive Mosquito Species Response Plan in an effort to eliminate them.

Life Cycle – about a week

The life cycle of a mosquito from egg to adult can be completed in less than a week, depending on water temperature and the species of mosquito. Eggs deposited on water surfaces usually hatch within a day or so, while those deposited in soil can hatch months or even years later depending on water availability. On average the female usually deposits from 100 to 150 eggs at a time. Over the life course the female mosquito may deposit three to four batches of eggs.

Mosquito Life Cycle

The life cycle of a mosquito from egg to adult can be completed in less than a week, depending on water temperature and the species of mosquito. Eggs deposited on water surfaces usually hatch within a day or so, while those deposited in soil can hatch months or even years later depending on water availability. On average the female usually deposits from 100 to 150 eggs at a time. Over the life course the female mosquito may deposit three to four batches of eggs.

That's why it's important to dump and drain all standing water where mosquitoes lay their eggs. Learn what you can do to prevent mosquitoes and mosquito bites with these Prevention Tips.