Often called "ladybugs" or "ladybird beetles", lady beetles (Coccinellidae) are the most familiar insect predator to most people. Although dozens of species occur in Colorado, they are all typically a round-oval shape. Most are also brightly colored and often spotted.
Females periodically lay masses of orange-yellow eggs. The eggs are quite distinctive, although they somewhat resemble those produced by elm leaf beetle. Eggs are usually laid near colonies of insects (aphids, scales, etc.) which will later be fed on by the larvae.
During the summer eggs hatch in about five days. The immature or larval stages look very different from the more familiar adults and often are overlooked or misidentified. Lady beetle larvae are elongated, usually dark colored and flecked with orange or yellow. They can crawl rapidly over plants, searching for food.
Adult and larval lady beetles feed on large numbers of small soft-bodied insects such as aphids. Lady beetles also eat eggs of many insects. Pollen, nectar and honeydew are other common foods.
One group of very small black lady beetles, aptly dubbed the "spider mite destroyers" (Stethorus) are also very important in controlling spider mites. Another unusual group are Coccidophilus spp. which are important predators of scales. Larvae of some lady beetles, e.g., those which specialize on aphids within leaf curls or feed on mealybugs, produce waxy threads which cover their body.
Lady beetles reproduce rapidly during the summer and can complete a generation in less than four weeks under favorable conditions. As a result, they often overtake a pest outbreak, controlling many potential insect problems.
Unfortunately, lady beetles tend to be 'fair weather' insects that are slow to arrive in the spring and often leave the plants by late summer. (A few kinds along the Front Range even 'head for the hills', spending the cool seasons at high elevations, protected under the snow.) As a result, late season 'blooms of aphids sometimes occur, as they continue to feed and escape their natural enemies.
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