JACKI LYDEN, host: In the American Corn Belt this year, the weather has already felt apocalyptic. In the last six months, the Midwest has seen record-breaking floods, devastating twisters, unseasonable cold spells and late heat waves. Add to these forces of nature - this phenomenon.
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LYDEN: Last month, a cloud of insects the size of a tornado swept across flooded fields in Iowa. The eerie vortex shape earned it the name bugnado. The bugnado caught the attention of Dr. Joe Keiper, an entomologist at the Virginia Museum of Natural History. He joins me on the line now. Welcome to the program.
Dr. JOE KEIPER: Good morning, Jacki.
LYDEN: So, looking at this sort of pulsating tornado, these giant rings in the air, what kind of bugs are we talking about?
KEIPER: Well, these are midges, and they're aquatic insects. And it created these beautiful patterns in the air. They were almost surfing on invisible waves of the atmosphere. And it was just not only a very fascinating sight from a scientific standpoint but it was also quite beautiful.
LYDEN: A good experience for them but kind of scary for us. I mean, are these biblical crop-destroying creatures or much more harmless?
KEIPER: Well, fortunately, they really don't do us much harm. They can be a nuisance. You know, you don't want to ride a motorcycle down the road through them with your mouth open. About the only thing that's known about these midges that could really be considered dangerous is when they are in great numbers like this, as the bodies will litter the road, there are reports where the roadway becomes slick just from their presence lying across the roadway that way.
LYDEN: What are they doing? Why are they there?
KEIPER: Well, the midges, when they form these swarms, as a lot of insects do, they're actually in mating mode. The males are essentially nothing more than flying sperm packets. And they will fertilize a female and very shortly afterwards will die and they fall to the ground. And once the female has mated, she's going to find a body of water within which she can drop her eggs. So, that's really what it's all about; it's a huge reproductive situation when you have these bug swarms.
LYDEN: Do they have anything to do with the unusual weather patterns we're seeing in the Midwest this year?
KEIPER: Well, I think it's going to be connected. My understanding is that this area that was flooded was a cornfield at one point. And so the cornfield from the severe floods now is suddenly an aquatic habitat. What makes the situation even more special is that all of this organic matter from the corn plants essentially fertilizes the water and that's perfect bug food. So, really it jazzed up the bug populations to such a high level that I'm predicting that's why we saw the huge numbers that was produced.
LYDEN: The bugnado after-effect.
KEIPER: In a way, that's true.
LYDEN: Dr. Joe Keiper is an entomologist at the Virginia Museum of Natural History. Thank you so much for joining us.
KEIPER: Thank you.
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LYDEN: This is NPR News.
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