Page Banner

United States Department of Agriculture

Agricultural Research Service

Related Topics


Bug Gut Analysis: What's Eating You?

Ever wonder what spiders and bugs eat?

There's an easy way to find out: mash them up and see what's inside.

It's called a bug gut analysis. Scientists use it to keep pest populations under control. A pest is an insect that bothers other plants or animals. If there are too many of them, they can cause a lot of problems.

James Hagler and Steven Naranjo are entomologists (en-toe-MALL-o-jists) with the Agricultural Research Service (ARS). An entomologist is a scientist who studies bugs. Hagler and Naranjo work with insects that eat cotton, like whiteflies.

Whiteflies like cotton a lot, but this is a big problem because they are pests. They can make a cotton plant sick by sucking up the sap in its veins or by giving it a virus. Or they can cover the plant with a liquid called "honeydew," which is sticky and gross. Plus it's expensive to clean.

Ten years ago, there were lots of whiteflies in Arizona. The cotton farmers wanted to get rid of them. But how? One way is to find natural predators. A predator is an animal that eats other animals. But what kind of animal eats whiteflies? The farmers wanted to know. Scientists wanted to know, too.

Sometimes, being an entomologist is like being a detective. Hagler and Naranjo went to the cotton fields and collected insects and spiders to look for clues.

The entomologists crushed the specimens they had collected and put them on a special plate. Then they looked at what was inside their specimens' guts. Everything an insect (or spider) eats is in its guts. If it has eaten a whitefly recently, there will still be bits of whitefly in there. So the scientists added antibodies (AN-tee-BOD-eez). An antibody is a kind of protein.

These antibodies are like special magnets: they only stick to bits of protein from the whiteflies. If they bind together, there will be a color change. That means the bug is a whitefly predator.

By looking at insect guts, the scientists identified 18 whitefly predators. The cotton farmers were very happy.

What happens next? When scientists identify a predator, farmers can use it to keep their farms safe. The predators will eat the whiteflies, and the cotton will be healthier.

Scientists can use this method for all sorts of insect pests--not just whiteflies. This way, farmers can protect their crops without using lots of chemicals. It's cheaper for the farmers and healthier for everybody--except the pests, of course!


Bug Gut Analysis: Dr. Watts Saves the Day

A poem

One day in the fields of his old cotton farm,

Farmer Hillman came running to raise the alarm.

"There are pests in the cotton! A million! There's lots!"

"Don't worry," his son said. "Let's call Dr. Watts."

Dr. Watts took one look at the cotton and smiled.

"We can fix this," he said to the farmer and child.

"These insects like eating your cotton," he said.

"Let's find predators who will eat them instead."

So they made a collection of all they could find,

Every wasp, mite, and beetle – and bugs of that kind.

"To the lab!" Dr. Watts cried. "Let's look for a mite

(Or a wasp or a beetle) to help in our fight."

In the lab he took all of the insects and squished

Them and left them to sit on a strange kind of dish.

"This step is the first," he told Hillman. "Now wait.

In the bug guts are proteins. They'll stick to the plate."

"Step two," he said, tossing the bugs in a bin,

"Is to add a protein to this plate. If within

All these guts there are pests, then the protein will stick,

And we'll know they are there. Isn't that a neat trick?"

Then he added an enzyme (this part was step three)

Which could only attach to the antibody

Of the pest in the fields. If it stuck, then they'd know

That the bug on the plate was a cotton pest foe.

To see if it stuck, Dr. Watts did step four,

And he added one thing to the protein-gut gore:

A catalyst (something that causes a change).

So they looked at the plate and they saw something strange.

A color reaction! It was a success!

The insect could help them get rid of the pests!

They bought all the bugs that the test had revealed,

Putting them on the plants in the old cotton field.

All the pest-eating bugs saved the cotton, thanks to

Dr. Watts, who knew Science. And now you know, too.


By Laura McGinnis,Agricultural Research Service, Information Staff

Back bug gut's start page | Sci4Kids home

Sci4Kids: Bridging the gap between science, agriculture, and you.

ARS: Solving agricultural problems with science.


Last Modified: 8/12/2016
Footer Content Back to Top of Page