This episode is sponsored by Fabulous, an app that helps you form healthy habits that stick.

You can check out the link in description to get a free one-week trial and 25% off a Fabulous subscription! [♪ INTRO]. Bees buzzing from flower to flower is a lovely and familiar sound.

But while the wing-whirring of adult bees is commonplace, when was the last time you heard a baby bee? The buzzing of adult bees comes from the high-speed flapping of their wings, which baby bees lack. But in at least one species of bee, larvae just love to play the drums.

And the reason why is actually… kind of terrifying. Scientists in Switzerland studying the solitary bee species Hoplitis tridentata were surprised to hear faint drumming sounds coming from brood cells within the stems of certain plants. Adult female bees make these nests by chewing into the stems of a variety of plants like thistle, mugwort, and wormwood.

There, they’ll lay up to a few dozen eggs and leave some food for when they hatch. The researchers were surprised because, well, very few people had ever documented sound production in larval bees before. In a 2021 article published in the Journal of Hymenoptera Research, the researchers described hearing two distinct kinds of sounds coming from within the stems of plants containing mason bee brood cells.

One was a quiet tapping sound, just loud enough for human ears to pick up, while the other was a louder raspy sound, almost like a zipper being rapidly closed, audible from two to three meters away! The researchers found that the baby bees made these sounds using a sort of built-in drum kit, consisting of a pair of calluses. A triangular one on their heads… and a horseshoe-shaped one around their anus.

The raspy sound is produced by dragging the horseshoe-shaped callus on the baby bee butt along the wall of the brood cell. This seems to act as an alarm to the other larvae nearby, which then kicks off more extended periods of butt-rasping and head-tapping sounds from the whole group. So just who are the babies making these sounds for?

The researchers suggest that the sounds are a response to threats from parasitic wasps. Some wasps use a technique called vibrational sounding to hunt for hidden insect larvae in plant stems. The wasps tap on plant stems and listen for the characteristic echo of a hollow cell containing a baby bee.

Kind of like echolocation, used by bats and dolphins. If they successfully find a brood cell, the wasp will use their ovipositor to lay their own egg inside. An egg that will wake up to a delicious bee larva snack.

Needless to say, this is bad for the bees. But through this raucous drumbeat, the researchers say, the wasps’ vibrational sounding is thrown off, and they can’t pinpoint the brood cell. And thus, the baby bees live to make butt beats another day.

Bees are lovely, but they are also crucial pollinators. So we need to understand them all. From social honeybees to solitary species like these.

And it’s also just something totally new that we have learned about baby bees! We had no idea that the little guys were able to get their Ringo on, but if it keeps the wasps away, more power to ‘em. Maybe you, too, want to learn to play the drums, but you’re having trouble getting in the habit of practicing.

You might want to check out Fabulous! The app was born at Duke University and uses behavior science research to gently support your personal goals. And you can customize it to tell it what those goals are.

So you can use it to help you remember to practice music, or anything else you want to do! The first 100 people who click the link in the description will get a free one-week trial and 25% off a Fabulous subscription, so you can start building your ideal routine. [♪ OUTRO].