Lady beetles, often called ladybugs or ladybirds, are some of the most commonly known beneficial insects. In fact, the Convergent Lady Beetle is the official state insect of Ohio! Both adults and larvae feed on soft-bodied insects like aphids. There are many species of lady beetles found in Ohio, but the most common ones are listed in the tables below. It is important to remember that when identifying a lady beetle, the number or shape of the spots may vary slightly between individuals of the same species. Be sure to also focus on the patterning of the area just behind the head (the pronotum), as this is typically more consistent within a species.
Common Lady Beetles of Ohio: Native Species
|Convergent Lady Beetle
© Scott Peden
|Spotted (or Pink) Lady Beetle
© Jon Rapp
|Parenthesis Lady Beetle
© Tom Murray
|Polished Lady Beetle
© Peter Cristofono
Common Lady Beetles of Ohio: Exotic Species
|Multicolored Asian Lady Beetle
© Cheryl Moorehead
|Seven-spotted Lady Beetle
© Rich Kelly
|Fourteen-spotted Lady Beetle
© Tom Murray
|Variegated Lady Beetle
© Tom Murray
Adult lady beetles are dome-shaped, circular or oval, and shiny with short legs and antennae. Wing covers are dark, reddish-orange to pale yellow, with or without black spots or irregular marks, while others are solid black or black with red spots. The head is concealed from above and they range in size 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, black, six-legged alligators with orange spots. Small, yellow, football-shaped eggs are laid upright in clusters of 10 to 50 on undersides of leaves.
Life Cycle and Habits
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 50 to 300 eggs in her lifetime, typically 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 may be five to six generations per year. In the autumn, adults hibernate, sometimes in large numbers, in plant refuse or crevices.
Lady beetles, both adults and larvae, are known primarily as predators of aphids, 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 species even 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 wipe out its prey.
During the autumn, lady beetles crawl to overwintering sites. Some species aggregate to overwinter. For these, a few to several hundred will gather to protect themselves from cold winter temperatures. The aggregation site may be located at the base of a tree, along a fence row, under a fallen tree, under a rock, or in your house!
Sometimes lady beetles become a nuisance when congregating in and around homes. This is especially true for the exotic Multicolored Asian Lady Beetle, Harmonia axyridis (for more information, see OSU Extension's fact sheet specifically about this species). They tend to congregate in large numbers on the sunny side of the house. Caulk and seal spaces and gaps to prevent them from coming inside. Physically remove lady beetles found indoors. Since lady beetles are beneficial and are not harmful to humans, insecticide treatment is not suggested.
If prey is plentiful, the lady beetles will stay, lay eggs and become effective aphid predators, especially in greenhouses. However, in some cases, most of the beetles will leave the area regardless of the availability of food. There are several companies that have lady beetles for biological control available for purchase, but you can encourage locally occurring populations by providing flowering plant resources and overwintering sites.
For more information, contact: Dr. Mary Gardiner, Department of Entomology, The Ohio State University OARDC, Wooster, OH 44691, firstname.lastname@example.org
This fact sheet is a revision of the fact sheet, "Lady Beetles," originally written by William F. Lyon.