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Pest Management Priducts Division of CSPA
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As soon as the weather warms in the spring, the multi-colored Asian lady beetles begin emerging from their winter quarters. They will continue to do this until they have all departed for the season. After they leave, they will look for food, mate and the females will begin laying eggs on foliage. A short time later both males and females will die.
Lady beetles go through four stages of life over an average of 20 days. They start as eggs, change to a larva, pupa and an adult with wings. Eggs are laid on host plants where the larvae can feed on aphids and other arthropods. Beetles are known to eat about 300 aphids before they are adults! Multicolored Asian lady beetles like many plants such as: evergreens, apple and maple trees, alfalfa, wheat, cotton, tobacco, and small grains. Larvae molt four times before becoming a pupa. These beetles can produce up to five generations in areas with extended periods of warm weather. Adult beetles can live as long as 2 to 3 years.
Asian lady beetles follow their instinctive behavior and fly to sunny, exposed surfaces when preparing to hibernate through the winter. The time of beetle flight varies but is usually from mid-September through October (depending on weather). Light colored buildings and walls in full sun appear to attract the most beetles.
Habits
Asian lady beetles, like other accidental invaders, are "outdoor" insects that can be a severe household nuisance during late fall and winter. Wooded residential and industrial areas are especially prone to problems. They do not feed or reproduce indoors; they cannot attack the house structure, furniture, or fabrics. They cannot sting or carry diseases. Lady beetles do not feed on people though they infrequently pinch exposed skin. Lady beetles may leave a slimy smear and they have a distinct odor when squashed. From the exteriors of buildings they crawl under siding and roofing and into cracks and gaps in foundations and around windows, doors and other openings. They may continue to move into the living areas of homes or they may spend the winter inside the attic or wall voids. Mild, sunny winter days can wake these dormant insects. They become active and move into the home's living quarters. Once spring arrives, the remaining lady beetles wake up and attempt to move outdoors. Not all succeed and many are trapped indoors. Multicolored Asian lady beetles do not reproduce indoors.