After rainy LA winter, mosquitoes will swarm as weather warms

Hosted by

Brian Brown, entomology curator of the Natural History Museum of Los Angeles, encourages Angelenos to be more forgiving of bloodthirsty pests. “If you could see a mosquito under a microscope, you'd think it's one of the most beautiful things you'd ever seen,” he says. Photo by Shutterstock.

Southern California’s extra-rainy winter brought some much-needed water to the parched region. But it also might mean Angelenos will be busting out the bug spray more this spring and summer, as swarms of mosquitoes hatch in warm and moist conditions. 

LA’s population of the bloodthirsty creatures has already been on the rise for at least a decade, due to warming weather and an influx of invasive species like Aedes aegypti and Aedes albopictus. 

But experts say these mosquitos, which can lay their eggs in water-filled containers as small as a bottle cap, will find breeding conditions better than ever this year, simply because there will be more standing water left over from the rain. 

“They lay their eggs on the sides of these [water-filled] containers, and even if they dry out, once they’re wet, those eggs can hatch,” says Steve Vetrone, director of scientific-technical services for the Greater Los Angeles County Vector Control District. “This [rain] is creating a much bigger problem for us in many backyards, which really haven't been a big problem in the past.”

Vetrone says the county has been keeping a database of thousands of unmaintained backyard pools, which were dry previously, but may have collected water during the winter deluge. 

He says when one of these pools is reported, technicians typically try to either empty it out, or treat it with chemicals that eradicate mosquitoes in their larval stage. 

For those who don’t have pools, he still recommends remaining vigilant about other sources of backyard water, like rain barrels or planters. 

“We can't be everywhere all the time,” he says. “If they notice something even as small as a plant saucer, [Angelenos should] be sure that they're dumping that water out there and not leaving any water standing.”

Since mosquitoes can spread diseases like West Nile Virus, it’s also critical for Angelenos spending time outdoors to protect themselves with bug spray. Wearing long pants and sleeves can also help, even though it might not be pleasant as temperatures rise. 

Brian Brown, entomology curator at the Natural History Museum of Los Angeles, says this protection is increasingly necessary during the day.

“These new varieties like the Aedes aegypti and Aedes albopictus, these urban feeders, are active during the day too,” he says. “So you can just step outside your door — I do sometimes — and I get nailed by one of these mosquitoes right away. They don't fly around your head and buzz and whine, they just land directly in and start biting.”

But, while mosquitoes often get a bad rap, Brown says we should remember to cut them at least a little slack — they’re an important part of the food chain, and they’re just doing what they know how to do best — sucking blood. 

“They're out there trying to gather enough energy in order to reproduce,” says Brown. “We all know that if insects like mosquitoes disappeared, then the world would be in terrible condition — it wouldn't be able to function.”



  • Dr. Brian Brown - entomology curator, Natural History Museum of Los Angeles
  • Steve Vetrone - director of scientific-technical services for the Greater Los Angeles County Vector Control District