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Regional Interests

This Bee Builds Sandcastles at the Beach

While you’re enjoying a day at the beach, female bumblebee-mimic digger bees are hard at work nearby building a different kind of sandcastle. This one’s not for play – it’s part of the nest where their offspring will grow.

TRANSCRIPT

It might seem peculiar, bees living at the beach. But this is their home, and they spend the spring building their perfect beach condos.

At their local watering hole, they’re not actually having a drink. They’re collecting water as a raw material. They slurp it into a pouch in their abdomen called a crop.

They can carry one sixth of their weight in water, hauling it to the side of this cliff in Northern California. Now that’s a view!

Back and forth, back and forth, 80 times a day. They’re building their nests from the cliff’s mix of sand, clay and gravel, spraying water to soften it up. See how she extends her proboscis and uses it like a hose?

Then she digs and digs and digs. They’re digger bees. The females build their nests side by side in what’s called an aggregation.

The males, most of them have died by now, after mating.

The females work peacefully … most of the time. Hey, make your own nest!

Some even make sandcastles, shaping the earth they dig out into a turret. To do that, they pat down the wet gravel with the tip of their abdomen. Scientists think the turrets could help keep out large parasitic insects, like other kinds of bees.

This cratered landscape isn’t unusual. Most of the world’s bee species – 70%! – nest underground.

The nest opening leads to a burrow a couple of inches long. At the bottom, she digs holes called brood cells. She will lay an egg in each one.

But first she needs to stock up on food for her future offspring. This flower is a favorite for nectar.

And check out the pollen on this bee. Wait a minute! That’s not our digger bee. That’s a yellow-faced bumblebee. She’ll sting you if you mess with her. Our bee is a bumblebee mimic. She doesn’t sting. The real bumblebee has a bright-yellow band on the bottom of her abdomen. Our bee has a band higher up. By imitating a stinging bumblebee, she scares predators away.

Back from foraging, our digger packs pollen and nectar into each cell and lays an egg on top. The larva that hatches out will have a ready-made meal.

Then she tears down her turret, bit by bit. She uses it as mortar to seal her nest closed and keep her eggs safe.

After finishing a couple of nests, the bee’s brief, hardworking life comes to an end. The beach will be her final resting place. And next year, the ever-shifting sand will bear witness to her young emerging from their nests.

Hi, it’s Laura here, with a riddle for you. Why does a Mexican jumping bean jump? Watch our episode to find out. And a special thank you to Lawrence Harris, whose generous monthly support on Patreon helps make Deep Look possible. If you want to support us too, there’s a link in the description. Thanks!

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