Why are so many yellowjackets buzzing around Southeast Michigan?

They induce fear. They're aggressive. And for some people, they pose a serious health risk.

Many people's instinct is to swat and run away from those black-and-yellow bugs that have a really painful sting, but this year it seems there are a lot of yellowjackets everywhere.

But why?

Dion DeGennaro, president of Sergio's Pest Control, says the increase in yellowjackets in Southeast Michigan is due to multiple factors, but mainly to trophallaxis.

"The past couple of years, we were up over 30% each year, so in recent memory, it has gotten a lot worse than 10 years ago," DeGennaro said. 

DeGennaro says yellowjackets are having a hard time finding food, which is a sweet liquid created by bee larvae, which is why they are preying on sugary human food.

"I'm scared of them," said Liliana Boggenes, who was eating her cider doughnuts in a parking lot because she was afraid to go near yellowjackets.

"They want your food, and they won't leave," said Janet Armil, who still remembers when she was stung by a bee when she was 7 years old.

While you can't always avoid these bugs in public, DeGennaro has some tips to steer clear of the stingers at home, especially when tending your gardens and lawns.

"They can nest in the ground, in the gap between bricks or siding, or they can build a physical nest in a bush," DeGennaro said.

The holes in the ground are the size of a quarter. DeGennaro says to avoid running your lawn mower near the holes or hives.

Doing so can actually aggravate them.

While stores sell sprays and traps, DeGennaro advises you call an expert because one hive can house thousands of yellowjackets.