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Do Bugs Burp?

a ladybug sits on a leaf

Do bugs* burp? Kind of, but not really. It all depends on what we mean when we say “burp.” (Also, if you’re wondering about bug farts? We wrote about that too!)

Are We Just Talking About Gas?

If you’re using the word burp to mean that the bug produces gas in the first section of its gut – called the foregut – then the answer is yes. In fact, one of the first parts of the foregut is called the crop. The crop is where a lot of microbial activity takes place when insects eat. In other words, the crop is where lots of tiny organisms in the insect’s foregut start to break down food so that the insect can extract nutrients from it. This process is called microbial fermentation, and it produces a lot of gases, like hydrogen.

But most of that gas is diffused into the insect’s hemolymph (bug blood) and then “exhaled” through the holes in the insect’s body that help it breath. (Those holes are called spiracles, which I mention here because it is a fun word to say.)

However, insects that regurgitate often produce bubbly material. In other words, there are bubbles in their barf. That suggests that some of the air these insects swallow when feeding, or gas produced in their crops, is mixed in with the food that they are eating, fermenting, barfing, and then re-eating.

Are these just chunky burps? You make the call.

Technical Belching

“If you want to be a stickler, it’s important to define what a burp is,” says Aram Mikaelyan, a scientist at NC State University who studies digestion in insects.

One dictionary definition of a burp (or belch) is “to force air from the stomach to come out through the mouth with a noise.”

“This definition would require a burp to be produced by a controlled release of gas from the stomach,” Mikaelyan says. “In humans, a muscle called the diaphragm contracts and relaxes as we breathe in and out. The diaphragm is what pushes out our burps. But insects don’t have body parts that allow them to push gas from their foregut out of their mouths. And this might be why insects cannot – if you’re real technical about it – burp.”

In other words, only animals like us mammals (and maybe birds!) have what it takes to push gas out of our mouths. So enjoy your burps – most animals can’t.

*Note: We know that true bugs are only those insects that belong to the order Hemiptera. That said, it’s not unusual for people to use the term “bug” to refer to any insect, or even any type of arthropod. So, we apologize to the scientists. We just wanted to make sure that people who are curious about bug burps can find their way to this explanation.

This post was originally published in NC State News.