You aren’t imagining it - the mosquitoes of Los Angeles have been bad this year.
For the third year in a row, L.A. ranked first on Orkin pest control’s Top Mosquito Cities List. The 2023 runners-up include Chicago, New York City and Atlanta.
“As far as abundance and biting pressure” — the frequency of incidences of mosquito bites — “it has [increased],” says Martin Serrano, operations manager for the Greater L.A. County Vector Control District.
Weather plays a key role in the mosquito surge. Rainfall from Tropical Storm Hilary created a perfect breeding ground for mosquitoes, which lay their eggs in standing water and damp earth. Throughout Southern California, swimming pools, ponds and backyard sources such as containers or buckets can become vectors for mosquito eggs and larvae.
“The rain provided a replenish of water into these pools. Some of these pools that are dry, obviously, they have a cement bottom, they’re going to hold water,” says Serrano.
With a changing climate, L.A.’s mosquito season — the period of time that mosquitoes can live and reproduce in an environment — is changing as well.
“[Southern Californian] winters are really short; we’re seeing the winter get shorter and shorter,” says Serrano. “Top mosquito season, depending on the weather, can be anywhere from March or April to mid-November.”
Over 50 species of mosquito live in California alone, according to Dr. Laura Melissa Guzman of the Ecological Data Science Lab at USC. The “ankle-biter,” or aedes mosquito, has been recently introduced to the L.A. area.
“There’s specifically one species of mosquito, aedes vexans, which is very cosmopolitan. It’s widespread across the world. And aedes vexans is able, if the soil is damp, they can breed. They can lay eggs in the soil,” says Guzman. Serrano also calls them “daytime biting mosquitoes.”
“We have had an influx of them since 2014,” says Serrano. Aedes can multiply in water sources as small as a bottle cap or wet potato chip wrapper. “During the summer, you don’t need much time for them to reproduce.”
Preventing mosquito populations from growing requires work, a lot of it in educating the general public. “The best thing people can do is reduce areas where mosquitoes can reproduce,” said Guzman, recommending that Angelenos get rid of water that they see has mosquito larvae. “They can also make sure that there’s no leaky outdoor faucets, things like that, so there’s no standing water.”
Freshman communications major Gillian Podell says that in New Jersey, where she’s from, mosquitoes are common. She’s observed fewer of the bloodsucking bugs in L.A.
“I haven’t gotten bitten here yet,” says Podell. But not everyone feels the same.
“I came out here [to L.A.] about nine years ago and never used to notice them before, but I feel like the last couple of years, I definitely have been getting bitten,” says Elise Dodge, a USC alumna. Dodge is from Michigan, where she says there are a lot of mosquitos. “I think it has gotten worse.”
Podell was surprised to learn that L.A. had been ranked so highly in Orkin’s list this year. Dodge agrees that L.A. ranking number one for mosquitoes in 2023 is “crazy.”
“It didn’t used to be buggy here,” says Dodge.
Mosquito bites are more than just annoying. The insects can transmit diseases to both humans and animals that are potentially deadly, such as West Nile Virus, St. Louis Encephalitis and canine Heartworm.
The state of California’s West Nile incidence report from earlier this month shows that six people died from “West Nile Virus-related fatalities” in 2023 so far. L.A. County’s first death from the virus this year was reported three weeks ago.
As of Sept. 22, there have been 153 human cases of West Nile Virus in California this year, already more than double the human cases of last year.
It’s not all bad news. Serrano says that the L.A. County Public Health Department has seen about 35-40% fewer mosquito samples that are positive for disease than last year. This year’s mosquito season, while full of an abundance of the bugs, may also end sooner than anticipated.
While a late summer made experts concerned that the mosquito season would continue through late fall this year, that doesn’t seem to be the case. “By all indications the weather is mild,” says Serrano. “It really depends on the weather and the elements.”
Photo courtesy of Jacopo Werther / CC BY 2.0