Yellow Jackets (Vespula) are the most aggressive stinging insects in the state. They are famous for their "swarming" defense and their love for sugary drinks in late summer.
The LookThey are bright yellow and black. Unlike honey bees, they are hairless and shiny.
The WaistThey have a very thin "wasp waist" that separates their thorax and abdomen.
The FlightThey have a rapid, side-to-side hovering pattern. If you see a yellow insect flying in a straight line, it’s likely a bee; if it’s "dodging" around, it’s a yellow jacket.
Nesting HabitsIn Utah, they are primarily ground-nesters. They often take over abandoned rodent burrows or holes in rock walls. They also nest behind siding or in the eaves of homes.
The Autumn ShiftIn the spring, they eat protein (caterpillars). In the fall, their diet shifts to sugar. This is why they become "aggressive" around soda cans and fruit during September.
Social DefenseIf you step near their nest, they don't just send one guard; they send the whole colony. They can sting multiple times without dying.
Why are they so mean in late summer?The colony is at its peak population (up to 5,000!), and their food source is running low. They are hungry and protective, which makes for a dangerous combination.
Can I just plug the hole in the ground?Never. If you plug the entry hole to a yellow jacket nest in your siding or ground, they will simply chew a new way out—often leading them into your living room.
Do they die in the winter?The workers and the old queen die. Only the new, fertilized queens survive by hiding under logs or in house attics to start again in the spring.
