Does cold weather mean no more mosquitoes?

Mosquitoes slow down during winter, prefer 50 degrees, above

SAN ANTONIO – While mosquitoes always tend to remain quiet in the cold-weather months, the insect seems to be in fewer numbers this winter compared to previous years. 

South Texas has seen a colder-than-average winter, including some stretches of below-freezing weather. 

"It's normal that we'd see fewer mosquitos, just because it's just too cold for them to move," said Molly Keck, a Texas Agrilife entomologist. 

When it comes to insects, temperature thresholds are important. 

"For every insect, there's a temperature that prevents them from being able to fly," Keck said. 

For bees and mosquitoes, that magic number is generally around 50 degrees. At that temperature, mosquitoes start to shut down and wait for a warm stretch of weather. Their sweet spot is 80 degrees and above, which means mosquitoes may start buzzing again as soon as late February.  

For now, mosquitoes just hide.

"They can either dig in the soil and find a warm spot, or they find pockets of air that are warmer," Keck said. "They're able to find, on sunny days, pockets of warm weather where they can start moving around and being a bit more active."

Keck's explanation disproves a common misconception that insects "freeze off" and die.  

"We just don't get cold enough for long enough in Texas, or really anywhere in the United States to really kill mosquitoes," she said.

In fact, mosquitoes can survive winters in Alaska, where their eggs are even more capable of surviving deep freezes.  

Kech also said that Zika virus cases are down.  

"We really didn't see many cases at all, like we expected to see in 2017. (In) 2016 it exploded," she said.

While it is still too early to make a correlation, Keck believes mosquito prevention efforts may be helping reduce the number of cases.

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