Three new invasive species of mosquitoes have recently spread to Southern California. Residents across the state have been reporting a higher number of mosquito bites, especially on the lower body, than in previous years. These new species have caused the increase in bites.

The newcomers are close relatives of some of the mosquito species that currently reside in Southern California. They are Aedes notoscriptus, Aedes aegypti, and Aedes albopictus, which is also known as the Asian tiger mosquito. These species do not fly long distances and have spread due to the unintentional transportation of their eggs.

Unlike native mosquitoes, the new species are more aggressive. They bite during the day, as opposed to only being active during the morning and the evening. The newcomers are much smaller than most other mosquitoes. Their hosts can’t see them because of their size, so they are more difficult to spot and swat away. This causes them to be less afraid to bite. The new species tend to target the feet, ankles, and shins when biting humans; they are less likely to be noticed when landing on the lower body than on the upper body. Several people have reported that recent mosquito bites are causing more severe swelling and itching than usual bites. Director of Community Affairs for the Greater Los Angeles Vector Control District Kelly Middleton explains that “we react to [the new mosquitoes’ bites] worse” than bites from mosquitoes native to Southern California because “our immune system is not used to them.”

As of now, the invasive mosquitoes haven’t reportedly spread any diseases. However, the three new species possess the ability to transmit dangerous viruses such as Zika, yellow fever, and dengue fever. Director of Communications for the Orange County Mosquito and Vector Control District Lora Young says that the concern “is more the possibility of disease.” Although no serious cases of mosquito-borne diseases have been reported, “there is now a possibility of those because we have the mosquito that can spread them.”

In order to lessen the likelihood of a mosquito-borne disease epidemic, vector control officials advise people to prevent the mosquitoes from spreading. According to Young, “These [mosquitoes] are really backyard breeders,” meaning that the new mosquitoes tend to breed in backyards or areas with similar conditions. Backyards often contain sources of standing water, such as puddles, water-filled containers, and pet water dishes. Mosquitoes find these locations appealing to lay eggs in. The easiest and most effective way to prevent mosquito breeding is to ensure that all sources of still water outdoors are eliminated. There is an extremely low chance that the invasive mosquito species will leave Southern California, but helping reduce the spread of mosquitoes will prevent the problem from becoming worse.