Dru Taylor, age 12, of Bartlesville, Oklahoma, for her question:

Are ladybugs really useful in gardens?

These pretty little insects are useful in gardens, fields and orchards. Modern gardeners buy them by the quart, in place of harmful chemical insecticides. Ladybugs are nature's insecticides and they do their work with no damage to the environment. They are carnivorous and their menus include at least 20 insects that prey upon our crops and gardens. Many species devour aphids that ruin the roses. Others favor scale insects of various types.

Some years ago, the citrus groves of California were attacked by the cottony cushion scale insect, who sneaked into the country from Australia. The mortal enemy of the pest is a certain ladybug beetle, also from Australia. These were imported and released in the scale infested orchards. In a few years, they brought the situation under control. It's nice to know that we have 350 native ladybug species, all eager to defend our greenery from various insect pests.