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Ask Dr. Universe Entomology
University Communications Network > Ask Dr. Universe > Academic Subjects > Biology > Entomology

What makes fireflies light up at night? – Asher, 7, Maryland

Dear Asher,

When I was a kitten, there were tons of fireflies in my grandparents’ yard. My litter mates and I loved to gently catch them and let them go.

I talked with my friend Richard Zack about how and why fireflies light up. He’s an insect scientist at Washington State University.

Those glowing insects are a kind of beetle. But we call them fireflies or lightning bugs. Their glow is a form of bioluminescence. That’s when a chemical reaction inside a living thing makes it light up.

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What are butterfly cocoons made of? — Anabelle, 8, Massachusetts

Dear Anabelle,

When I was a kit, I looked a lot like the adult cat I would become—even though I was smaller and fluffier. But wiggly caterpillars don’t look like butterflies at all.

I talked about this with my friend Allan Felsot. He’s an insect scientist at Washington State University.

He told me cocoons are mostly silk. But they’re usually made by moths. A butterfly “cocoon” isn’t really a cocoon at all. It’s called a chrysalis.

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Why do all insects have six legs? – Charlie, 10, Ohio

Dear Charlie,

There are about 40 kinds of cats out there—like me. There’s only one kind of human on Earth now. But there are more than a million kinds of insects. That’s just the insect species we know about.

Every single one of those insects has six legs.

I talked about why that is with my friend Allan Felsot. He’s an insect scientist at Washington State University.

He told me there must be some evolutionary reason insects have six legs—like better stability when walking.

“In biology, every ‘why’ question has the same answer,” Felsot said. “Things are the way they are because of adaptations that have allowed organisms to live longer.”

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Why do crickets make sound? – Carola, 7, Virginia

Dear Carola,

Have you ever read the book “The Very Quiet Cricket?” It’s about a young cricket who can’t chirp until he grows up.

My friend Rich Zack reminded me of that book when we talked about your question. He’s an insect scientist at Washington State University.

He told me only adult male crickets make sound. Sometimes they chirp to defend their territories. It’s how they tell other male crickets to stay away.

But the main reason they chirp is to find a mate. Cricket chirps are mating songs. That song will be different for different kinds of crickets—and the song changes when the female cricket shows up.

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Do insects have blood in their bodies? – Raman, 7, Washington

Dear Raman,

You probably don’t look like an insect. You don’t have feelers or wings. You keep your skeleton inside your body instead of on the outside. But what about blood? Do insects have blood like yours?

I talked about this with my friend Richard Zack. He’s an entomologist at Washington State University.

“Insects have hemolymph,” he said. “It’s very similar to blood.”

Zack told me hemolymph moves differently through the body, and it doesn’t do everything blood does.

Humans and other mammals have closed circulatory systems. That means their blood travels in blood vessels. A heart pumps the blood all over the … » More …

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Do ants hibernate in the winter? – Garrett, 10, Illinois

Dear Garrett,

When most people think about hibernation, they picture bears snoozing away the cold winter in their dens. You’re right that other animals do that, too.

I talked about your question with my friend Laurel Hansen. She’s an entomology professor at Washington State University. Her specialty is carpenter ants.

“We think most ants in our temperate climate will have diapausing larvae and what I would call overwintering adults,” Hansen said.

Diapausing and overwintering are like hibernating but not quite the same. There are a few things to know about ants to understand what these terms mean.

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How many beetles are there in the world? – Tu, 12, Utah

Dear Tu,

If beetles seem to be everywhere, that’s because they are. Some beetles stand out because they’re colorful. Think about jewel beetles and ladybugs. Others play useful and weird roles in the ecosystem—like the poop-rolling dung beetle. Their ancestors probably even ate dinosaur poop.

Nobody knows exactly how many beetles there are, but scientists have some ideas. I talked about it with my friend Joel Gardner. He’s the collection manager for the insect museum at Washington State University.

When scientists find a new species, they describe what it looks like. They give it a name. They publish that information so other people know about it. That’s called describing a species. Scientists describe new insect species all the time.

Gardner told me scientists have described about 400,000 species of beetles so far. There are many more beetles we don’t know about yet. Altogether, there are probably between 1 million and 2 million beetle species.

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When was the first bee made? – Henry, 7, Illinois

Dear Henry,

It’s easy to love bees. They’re furry and buzzy. Along with other insects, birds and bats, they pollinate about one-third of the plants we eat.

I talked about how long bees have been buzzing around Earth with my friend Silas Bossert. He’s an evolutionary biologist in the Department of Entomology at Washington State University.

“The oldest bee fossil that is really without doubt a bee is between 65 and 70 million years old,” Bossert said.

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How does honey last forever? Gillian, 7, Illinois

Dear Gillian,

Archaeologists exploring ancient Egyptian tombs sometimes find honey. It’s thousands of years old, but you could still safely spread it on your toast!

I talked to my friend Brandon Hopkins, professor in the WSU department of entomology, about why honey lasts so long. He told me honey is one of the only foods that never spoils.

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Dr. Universe: Do spiders sleep? - Peter, 10, South Dakota

Dear Peter,

At the end of the day, you probably curl up in a cozy bed for a little shut eye. Unlike you, most spiders have eight eyes, and they never shut any of them. They don’t even have eyelids!

I talked about spider sleep with my friend Richard Zack, an entomologist and professor in WSU’s College of Agricultural, Human, and Natural Resource Sciences. He also runs the biggest insect museum in the state of Washington at WSU. He told me that spiders and insects do rest. They nestle into a safe spot and enter a “stupor,” which means they’re very still.

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Dr. Universe: What are bees’ wings made of? -Natalia, 13, Kennewick, WA

Dear Natalia, Bee wings may be small, but they are really strong. I learned all about bee wings from my friend Melanie Kirby, a honey bee researcher at Washington State University. Kirby said you can think about bee wings as if they were a kite. If you make a kite out of thin tissue, it might rip. But if you make it out of a strong plastic film it will be stronger. Bee wings are made of a material called chitin (KITE-IN) and it’s a lot like keratin, the material that makes up your fingernails. Chitin is what makes up the wings on each side of the bee’s body. Read More ...

Dear Dr. Universe: Why do flowers smell so nice? – Miles, 5

Flowers not only smell nice to humans, but also to many insects and birds who help the flowers do a really important job. Let’s imagine that you are a bee or a butterfly. You don’t have a nose on your face, but instead use your two antennae to smell things. As you fly around, you catch a whiff of chemicals floating in the air. Down below, you see a field of daisies. The flowers are releasing some chemicals, which are the building blocks of a smell. Read More ...

Dear Dr. Universe: I would like to find out how ants are so strong. How is it possible that they can carry weight that is heavier than themselves? –Anita, 11

Dear Anita,

Ants are pretty good little weightlifters. My friend Rich Zack, a scientist at Washington State University who studies insects, knows a lot about ants. One kind of ant that he has studied can carry up to 20 times its own weight.

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What is the smallest insect on Earth? -Laurenz, 8, Molino, Philippines 

Dear Laurenz,

When I saw your question, I set out to explore with my bug net and a magnifying glass. I was searching all around for tiny insects when I ran into my friend Laura Lavine, a Washington State University scientist who studies bugs.

She said there are nearly a million different kinds of insects on Earth. The smallest of all the known ones are called fairyflies.

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Why do bees make hexagons in their hives? Why not any other shape? -Aditya, 10, New Delhi, India

Dear Aditya,

When bees make hexagons in their hives, the six-sided shapes fit together perfectly. In fact, we’ve actually never seen bees make any other shape. That’s what I found out when I visited my friend Sue Cobey, a bee researcher at Washington State University.

Cobey showed me some honeycombs where the female bees live and work. Hexagons are useful shapes. They can hold the queen bee’s eggs and store the pollen and honey the worker bees bring to the hive.

When you think about it, making circles wouldn’t work too well. It would leave gaps in the honeycomb. The worker bees could use triangles or squares for storage. Those wouldn’t leave gaps. But the hexagon is the strongest, most useful shape.

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I saw a caterpillar and a butterfly in the neighbor's yard. So my question is, what exactly happens inside the little sack they're in while they transform into a butterfly and HOW exactly do they do it?  -Eston

Dear Eston,

Springtime sets the stage for one of the greatest transformations in the natural world.

“It’s the construction of a butterfly or moth from caterpillar soup,” said my friend David James, an entomologist at Washington State University. James studies the science behind metamorphosis, or how a creature transforms.

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