Common Name: Ladybug, Lady or Ladybird Beetle
Scientific Name: Various
Since lady is defined as “a woman of good family, social position, breeding, etc.,” this may refer to the fact that most species of this beetle family are highly beneficial insects; only 3 of 475 United States species are not beneficial. Some species have a habit of overwintering in structures and are therefore nuisance pests. Ladybugs are found worldwide with about 475 species occurring in the United States and Canada.
Adults about 1/32-3/8″ (0.8-10 mm) long; shape distinctive, broadly oval to nearly round, strongly convex dorsally, nearly flat ventrally. Color red, orange, yellow, brown, or shiny black, usually with various markings including white spots; often bright yellow, red, or orange with black markings or black with yellow, orange, or red markings. Head partly to completely concealed from above. Antenna short to usually very short, 8-11 segmented, with weak club of 3-6 segments. Tarsi apparently 3-3-3, actually 4-4-4 (3rd segment minute). Larvae look like tiny flat alligators, often with numerous spines and/or wartlike structures; color usually blackish, some with red, orange, or yellow spots or bands; some species secrete a white waxy material which makes them resemble mealybugs.
(1) Tortoise beetles (Chrysomelidae) with tarsi appearing 4-4-4, actually 5-5-5 with minute 4th segment.
(2) Handsome fungus beetles (Endomychidae) have base of pronotum with 2 lengthwise grooves and usually black with red or orange.
(3) Marsh beetles (Helodidae) with antenna threadlike or saw toothed and tarsi 5-5-5 with 4th segment lobed beneath.
(4) Shining mold beetles (Phalacridae) with antennal club distinct, 3-segmented, tarsi apparently 4-4-4 (actually 5-5-5), and brown or black with no markings.
(5) Other similarly shaped beetles (order Coleoptera) with a distinct antennal club and/or tarsi different.
1. Asian lady beetle, Harmonia axyridis (Pallas). Adults typically with pronotum black with wide ivory lateral/side margins and basal median mark yielding dark M-shaped patter, elytra mustard yellow to dark reddish orange, each usually with several black spots but spots sometimes indistinct or absent; length about 1/4-3/8: (6-10 mm); found throughout the United States and parts of Canada.
2. Convergent lady beetle, Hippodamia convergens Guerin-Meneville. Adults with head, pronotum, and legs black, pronotum with a whitish margin and centrally with 2 convergent whitish lines, elytra red, each with 6 black marks with anterior 3 smaller than posterior 3 but varying to elytral spots almost absent; length about 1/8-1/4″ (4.2-7.3 mm); found throughout the United States and southern western Canada.
3. Nine spotted lady beetle, Coccinella novemnotata Herbst. Adult with head black with pale band between eyes, pronotum black with pale yellowish front and side margins, elytra orange to reddish yellow each with 4 black spots but varying to elytral sports almost absent, scutellum (triangular piece between elytral bases) black and black extending into elytra; length about 3/16-1/4: (4.7-7.0 mm); found throughout the United States except for costal North Caroline southward to west Florida peninsula and from southern Louisiana west through central Texas to southwestern New Mexico, and in southern Canada but extending far northward in western Canada.
4. Spotted lady beetle, Coleomegilla maculata (DeGeer). Adults elongate, somewhat flattened; color red or yellowish orange, head with black margins, pronotum with 2 black spots, and 6 or 7 black spots on each elytron, length about 1/8-3/8″ (4-8 mm); found from Ontario through Florida, west to Minnesota and Texas, and west along the Mexican border through southern California.
5. Twicestabbed lady beetle, Chilocorus stigma (say). Adults black except pronotal front and side margins, spot on each elytron, and abdomen red or yellow; length about 1/8-3/16″ (3.75-5 mm); found east of the Rocky Mountains and adjacent southern Canada.
6. Two spotted lady beetle, Adalia bipunctata (Linnaeus). Adults typically with pronotum black with wide ivory lateral/side margins and basal median mark yielding dark M-shaped pattern, elytra orange, each with a median black spot; length about 1/8-3/16″ (3.5-5.2 ,,); found from Labrador, Canada, to Alabama, west through Alaska and California.
The overwintering adults emerge from hibernation and the orange eggs are laid on end in single or multiple groups of 12 on plants infested by aphids (plantlice), mealybugs, scale insects, etc. Larvae pass through 4 molts. Mature larvae attach to leaves by the tip of their abdomens and pupate without forming a cocoon.
Larvae and adults are predaceous on aphids, mealybugs, mites, scale insects, other soft-bodied insects, and their eggs, making them very beneficial insects. A few species are leaf feeders and are important plant pests, for example, the Mexican been beetle, Epilachna varivestis Mulsant. In the autumn, adults seek protected places in which to overwinter. These may include under leaves, rocks, and landscape timbers, but also inhabited structures.
Unfortunately, the release and use of lady beetles for biological control by organic gardeners, the USDA (especially the Asian lady beetle for control of aphids on pecan trees and fruit crops), and others has greatly increased the incidence of their entering structures to overwinter by artificially increasing their numbers.
Because lady beetles are beneficial and are not of any health or structural importance, no direct control is recommended. Use of preventative physical barriers aimed at adults before they congregate and attempt to enter structures and educating the consumer are the best solution. Physical barriers involve exclusion. Although total exclusion is probably not possible, all vents (roof, overhang, weep holes, etc.) should be screened with at least 16-mesh screening. Caulk (silicone based is recommended) around cable entrances, windows, doors, overhang, facia boards, etc. Installation of remotely close chimney caps (spring-loaded with a cable running through the flue pipe and a lock-catch in the fireplace) may be advisable. These steps should be taken in June or July.
No attempt should be made to kill these beetles in wall voids at any time because dead insect bodies attract dermestid beetles (larder beetles, carpet beetles, etc.). Dermestid larvae wander and readily enter the living space, causing numerous complaints. Instead, wait until summer when all live overwintering adults are out of the wall voids. Then follow the outside control measures given above. However, temporary relief is possible by using a vacuum to remove the beetles, and sealing their entryways into the living space. Temporary but immediate indoor relief can be achieved by vacuuming.
To prevent the entry of more adults, seal the possible routes of entry with paintable silicone caulk and/or expandable foam. Entry points include around window pulleys (seal with tape or steel wool), window frames, door frames, baseboards, etc. For electrical outlets and switch boxes and heating duct and return-air vents, remove the cover plate, seal, and replace. For light fixtures and ceiling fans, remove the fixture to its base plate, seal, and replace. Most species can be harvested with insect light traps (ILTs) from problem areas such as attics and false-ceiling voids.