When was the last time you shooed a ladybug (Coccinellidae family), or stomped on its behind? Chances are, never. Most people love ladybugs. With 5,000 species, there are a lot to love. Their colorful domes make them the most recognizable insects in the wild. North Dakota even declared the ladybug the state insect. Yet, no one loves the bug more than farmers do. Ladybugs are hearty eaters, chowing down on aphids (plant lice), mites and other crop-destroying pests. Not all ladybugs are beneficial, however. Many species eat plant themselves. The Mexican bean beetle destroys beans. The squash beetle, eats, you guessed it, squash [source: National Geographic].
Scientists study ladybugs for a variety of reasons, such as trying to figure out why some common species are becoming rare. Other scientists are experimenting with how ladybugs can take the place of pesticides. In Japan, researchers bred ladybugs that don't fly so farmers can use them as a nonchemical biopesticide. It took scientists 30 generations to breed the bugs, which stay on the plant and devour other bugs. The nonflying, bug-eating ladybug has reduced damage to Japan's mustard spinach crop by 90 percent [sources: Hellmann].