Wild Jobs: Katydid Wrangler Rhett Hartman

Q: Why do katydids sing?

A: Katydids are green, they’re shaped like leaves, and they’re active at night — they’re basically invisible. That’s great for avoiding predators, but it makes it tough to find mates. Males sing so females can find them.

Q: What do their songs sound like?

A: Some katydids sound like a gushing faucet. Others sound like a sprinkler: pssst ... pssst ... pssst. Males make sound by rubbing their wings together.

Q: What do you hope to learn about katydids?

A: Lots of males sing at the same time. I want to know what signals go into a female’s brain to make her choose one male’s song instead of another’s.

Q: How can you tell what goes into a female’s brain?

A: Katydids hear the same way we do. Sound goes into their ears. It’s converted to electricity. The electricity travels through nerves to their brain. I put wires on katydids so I can graph the electrical signals as they move through their nerves.

Q: What does the graph look like?

A: We make lots of graphs, but one looks like squiggly lines. You can learn a lot from those squiggles, though.

Q: Like what?

A: I learned that with one kind of katydid, a female’s nerves filter out some signals before they ever reach her brain. These signals come from males who sing a fraction of a second after other males. But if the signal never reaches her brain, then she never actually “hears” the late singers. So, the late singers may not get many girlfriends.