Here’s why yellow jackets are more aggressive in the summer
Jul 16, 2025, 9:00 AM | Updated: 11:35 am
When this time comes, certain species become more aggressive to protect their food and gardeners become more likely to be stung by a wasp. (Canva)
(Canva)
SALT LAKE CITY — More people say they’re seeing lots of yellow jackets, or wasps, this summer, but one University of Utah professor says he hears that comment every year.
Biology professor Jack Longino teaches a course on bugs and insects every fall. He says in the springtime, yellow jackets are more cautious because there are fewer wasps in the colony, but that changes as we get into mid-to-late summer.
“They get incredibly brazen,” Longino explained. “They lose that risk aversion and they’ll sort of risk everything to get that morsel of hot dog from you.”
Longino says yellow jackets and other bugs are considered cold-blooded, so the heat might impact how quickly their colonies grow.
“If the season is extra hot, it could just sort of accelerate that process so that the colony grows faster, gets larger numbers faster,” Longino explained. “So that predictable increase and abundance of aggressiveness could come earlier and earlier in the season.”
Longino says yellow jackets are annual bugs; only the queen makes it through the winter with her larvae. He says the workers are hungrier and more aggressive in the summer and fall as they try to bring back more food for their queen.
Longino says wasps aren’t as bad as they seem though and help get rid of pests in the garden.
Related: How to prevent being stung by a wasp
