Lady beetles, often called Ladybugs or coccinellids, are the most commonly known of all beneficial insects. In Europe these beetles are called "ladybirds." Both adults and larvae feed on many different soft-bodied insects with aphids being their main food source.
Adult lady beetles are domed shaped, oval or convex, often shiny with short legs and antennae. Wing covers are dark, reddish-orange to pale yellow, with or without black spots or irregular marks. Some are solid black or black with a red spot. The head is concealed from above. They have three distinct tarsi (feet), and range from 1/16 to 3/8 inch long. Larvae are elongate, somewhat flattened, and covered with minute tubercles or spines. Most larvae have large, sickle-shaped mandibles (jaws) and resemble tiny, six-legged alligators blue-black with orange spots. Tiny, yellow, oval eggs are laid upright in clusters of 10 to 50 on undersides of leaves.
The length of the life cycle varies depending upon temperature, humidity, and food supply. Usually the life cycle from egg to adult requires about three to four weeks, or up to six weeks during cooler spring months. In the spring, overwintering adults find food, then lay from fifty to three hundred eggs in her lifetime (tiny, light -yellow eggs are deposited in clusters of 10 to 50 each) in aphid colonies. Eggs hatch in three to five days, and larvae feed on aphids or other insects for two to three weeks, then pupate. Adults emerge in seven to ten days. There |
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may be five to six generations per year. In the autumn, adults hibernate, sometimes in large numbers, in plant refuse and crevices.
Lady beetles, both adults and larvae, are known primarily as predators of aphids (plant lice), but they prey also on many other pests such as soft-scale insects, mealybugs, spider mites and eggs of the Colorado Potato Beetle and European Corn Borer. A few feed on plant and pollen mildews. One larva will eat about 400 medium-size aphids during its development to the pupal stage. An adult will eat about 300 medium-size aphids before it lays eggs. About three to ten aphids are eaten for each egg the beetle lays. More than 5,000 aphids may be eaten by a single adult in its lifetime. The lady beetle's huge appetite and reproductive capacity often allow it to rapidly clean out its prey.
During the autumn, lady beetles crawl to overwintering sites where a few to several hundred will gather in an aggregation. The aggregation site may be located at the base of a tree, along a fence row, under a fallen tree, or under a rock. Beetles are always found under leaves which protect them from cold winter temperatures.
Sometimes beetles become a nuisance by their presence when congregating in and around homes. Some congregate in large numbers on the sunny side of the house. Caulk and seal spaces and gaps to prevent them from coming inside.
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