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Wasps Keeping Watch: Some tiny stingers could help gaurd our groceries

Did you start today right with a healthy breakfast?

If you’re like a lot of kids, cereal is a favorite breakfast food. Which cereal do you like most? Corn flakes? What about Cheerios or Rice Krispies?

Well, you’re not the only one who likes eating cereal. And you won’t believe what else does: insects!

In fact, Agricultural Research Service (ARS) scientists say hungry insects destroy billions of dollars of cereal grains each year!

And it’s not just farmers’ fields and grain warehouses that bugs invade. They can get into people’s houses, too. Have you ever come across a little bug when reaching into the cupboard for a box of crackers or some cereal? Scientists at ARS’s Grain Marketing and Production Research Center in Kansas are trying to find ways to keep insects from nibbling on our grain.

Bugs can sneak into the huge canisters and sacks in which grains are stored. They can also crawl into bags of flour in grocery stores. Some even chew through tough plastic packaging. Right now, most store owners and grain-storage managers have to spray smelly chemicals to get rid of hungry bug pests. ARS scientist Paul Flinn and Matthew Grieshop, a former Kansas State University graduate student, wanted to find a safer way to beat those bugs. Their strategy? Fight “bad guy” insects with “good guy” ones.

The "good guy" is a speck-sized wasp that attacks the yucky, gooey bug eggs that can spoil a box of cereal. The name of the wasp is Trichogramma deion, and it's about 1/2 millimeter in length.

The pests that Flinn and Grieshop were trying to zap are called "Indianmeal moths." They’re a problem because the adult female moths will lay their eggs near spilled flour or cereal and sometimes right on boxes of cereal! Eeeewwww!

Sure sounds gross, but the mother moth does this because a small amount of flour dust, or a crevice in a box of cereal, is a safe hiding place where her eggs won't be disturbed. And there’ll be plenty of food for the larvae that hatch!

For their experiments, the scientists hid some moth eggs in a lab that was set up to look like a grocery store. It had shelves and lots of cereal boxes. When released, the helpful wasps knew just where to go. After finding the eggs, the wasps laid their own eggs inside the moth's! Then, in just about 10 days, tiny new wasps emerged from the dead moth eggs to look for more eggs to attack. Another wasp the scientists tested, called Habrobracon, finished the job by attacking larvae that hatched from surviving eggs.

Don’t worry about the wasps hurting you. As Flinn says, “These minuscule wasps won’t harm humans, and they won’t eat cereal." Trichogramma wasps are only interested in moth eggs; Habrobracon only target the larvae as both a home and meal for its own maggot-like brood.

So, the next time you see a wasp buzzing around, remember: That little insect could have an important job someday. And in the meantime, it’s helping to pollinate the flowers and trees.

--By Erin Peabody, formerly Agricultural Research Service, Information Staff


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