Dear Hudson,
The other day I walked into a cloud of gnats. I love insects, but it was unpleasant to have all those critters fly into my whiskers.
I asked my friend Rich Zack what they were doing. He’s an insect scientist at Washington State University.
He told me that most insects are individualistic. They don’t usually fly together in groups—unless they need to mate or travel. Then, some insects form a group called a swarm.
“The purpose of the adult insect is to mate,” Zack said. “They have short lives—so short that a lot of them don’t even feed as adults. So, the mating period is very important to them.”
That’s what my gnats were doing.
The conditions outside were just right, so a bunch of male gnats showed up in the same place. When female gnats got there, it was easy for them to find a mate—because everybody was together.
Some insects bring gifts to a swarm. Zack told me that dance flies may show up carrying a piece of prey or even a pretty rock or leaf. They’re hoping a female dance fly will think they’re strong and clever. Maybe she’ll pick them to mate.
A few insects do everything a little differently. They’re social. They always live together in colonies. That includes all ants and termites as well as some bees and wasps. Some of them form swarms, too.
Sometimes ants and termites send out individuals with wings to mate. Most of them die after that, but a few chew off their wings and go find a new place to live. That will be a new colony.
Honey bees also swarm to mate or form a new colony—but they keep their wings. You might even see a bee keeper catching a swarm of honey bees. Then they put the swarm into a new home.
Sometimes a swarm is less about meeting someone and more about going somewhere. Some insects migrate. They move from one place to another with the seasons. Monarch butterflies can fly a whopping 3,000 miles from the place they’re born to the place they spend winter. Some people call that swarm a “kaleidoscope” because it’s so colorful.
Some grasshoppers form a giant swarm that gets a special name, too. It’s sometimes called a plague.
Normally, these grasshoppers live alone and act chill. But if conditions are just right—like heavy rain after a dry period—they have tons of babies. If those babies bump into each other, it triggers a change in their brains. They transform into locusts. They’re bigger and stronger than regular grasshoppers. They’re brightly colored. And they eat everything. A swarm of locusts can gobble up an entire farm in just a few hours.
The other time you might see a group of insects flying together is near a porch light or street lamp. Lots of insects hang out around lights. But they’re not doing anything together. They happen to be in the same place, but they’re minding their own buzz-iness.
Sincerely,
Dr. Universe