Asian lady beetles are common throughout most of the United States and parts of Canada. The scientific name is Harmonia axyridis (Pallas). This is one of a very large family of beetles known as Coccinellidae. Many people call these beetles “ladybugs.”
Multicolored Asian lady beetles are about 7 mm long. As the name indicates, they occur in a wide spectrum of colors ranging from yellow to orange to red and have a varying number of spots. The variability of appearance in the adults can mislead people to think they are different species. A characteristic that assists in their identification is an “M” shaped marked located behind the head.
There are about 5,000 species of ladybug beetles worldwide, so depending on the species and habitat, there is a large variation in this insect’s life cycle. For example, some lady beetles are predators, while others are plant feeders. However, all ladybug beetles undergo complete metamorphosis – four distinct life stages – the egg, larval, pupal and adult. The duration of the ladybug beetle’s life cycle from egg to adult varies, but ranges from about 1-2 months.
A female ladybug beetle lays eggs in clusters on the underside of a plant leaf or twig. Generally, the female will choose a plant that is infested with their prey – aphids or scales. Eggs are laid during the spring and early summer. One fertile ladybug beetle can produce up to 1,000 eggs, and eggs hatch in about five days. Larvae have been described as looking like very tiny alligators. If predators, the larvae feed upon their prey insects and may often consume some of the un-hatched eggs if prey is scarce. The larvae go through four instars, molting and becoming larger at each instar stage. The larval stage takes about 1-2 weeks to complete. This is the insect’s resting stage when it goes through the transformation into an adult. Depending on the species and the environmental conditions, the pupal stage lasts about 3-12 days. Eggs are deposited by females on the underside of plant leaves. The larvae emerge and will search for insects on the plant to prey upon. They eventually will pupate into adults. The time from egg to adult varies with environment and resource availability but typically is 15 to 25 days.