Why Yellowjacket Wasps Are Aggressive

Why Yellowjacket Wasps Are So Aggressive in Summer

When summer starts to wrap up, yellowjacket wasps become one of the most noticeable—and annoying—insects buzzing around backyards. But why are yellowjackets so plentiful and aggressive in mid to late summer? Here's the low-down, explained in a way that makes sense.

1. Colonies Grow Huge by Late Summer

In spring, a single queen starts a tiny yellowjacket nest. As the weeks warm up, the colony explodes in size. By mid to late summer, there can be 4,000-5,000 workers, and the nest may hold 10,000-15,000 cells. That big colony means a lot more wasps—and a lot more chances for stings and trouble around people.

2. Their Food Needs Change

In spring and early summer, yellowjacket workers hunt protein (other insects, bits of meat) to eat and provide for their larvae. In return, the larvae release a sweet, sugary liquid that the adult wasps drink for energy. This swap keeps yellowjacket wasps closer to their nest and less visible to people.

3. Food Gets Scarce and They Get Hangry

As summer turns to late summer, the colony changes. The queen lays fewer eggs, so there are fewer larvae making that sugary reward. Now the adults are short on quick energy. Hungry workers start foraging outside the nest for sugar anywhere they can find it—spilled soda, fruit, desserts, barbecue sauces, even hummingbird feeders. That's why yellowjackets seem pushier around people and food in late summer and early fall.

4. They Defend Their Nests Fiercely

Yellowjackets use alarm pheromones to call in help when they feel threatened. That means if someone or something disturbs their nest—even by accident—they can swarm quickly and attack together. Vibrations from lawn mowers, weed trimmers, or even footsteps over a buried nest can set yellowjackets off. Sudden movements—or crushing one by accident—can trigger them too. Yellowjackets have smooth stingers, allowing them to sting multiple times. So, when wasps attack, you can be stung dozens of times in a matter of seconds, and they may chase you if you run.

Safety Tips from Palmetto Exterminators

• Keep food and drinks covered when outside.

• Seal garbage cans and clean up spilled food right away.

• Trim back areas around the home to reduce hiding spots for nests.

If you spot a nest near your house, contact Palmetto Exterminators for safe, professional removal.