Ladybug Facts, Identification and Control
Scientific Order: Coleoptera (all Beetles)
Scientific Family: Coccinellidae
The convergent lady beetle (hippodamia convergens)
The seven-spotted ladybug (coccinella septempunctata)
The multicolored asian lady beetle (Harmonia axyridis)
Size: Varies based on specific species, but generally range from 1 to 10 millimeters. The most common ladybug, the convergent lady beetle (hippodamia convergens), usually measures 4 to 7 mm. The seven-spotted ladybug (coccinella septempunctata), also common, measure around 6.5-7.8 mm. The multicolored asian lady beetle (Harmonia axyridis), which is often considered a pest in New York, also measures around 7 mm long.
Color: The ladybug’s scientific name, “coccinellidae,” is derived from the Latin “coccineus,” which means scarlet. Ladybugs are famous for the vibrant red or orange color of their wing sheaths. Different species of ladybug species range in color from red or reddish-orange to light tan or even yellow.
Ladybugs are generally considered beneficial because they primarily prey on other, more destructive pests, including aphids, scale insects, mealybugs, spider mites, and other crop- or property-destroying pests. Ladybugs can be so helpful that they are even sold to farmers, who use them as a natural means of protecting crops from pests that would feed on them.
Some ladybug species, including the Mexican bean beetle and the squash beetle, feed on plants and are considered destructive pests.
Ladybugs usually remain outside during warm months, but throughout fall, they seek long-term shelter where they can keep warm during winter.
Ladybugs are considered a nuisance when they congregate around and inside homes in large numbers. Multicolored asian lady beetles, in particular, are known for flocking to vulnerable homes in huge groups.
When threatened, ladybugs can bite and also discharge a yellow chemical to dissuade predators. This substance smells bad and can occasionally stain walls, floors, and other surfaces.
Skin irritations or minor allergic reactions to the chemical have also been reported, particularly after encounters with the multicolored asian lady beetle. Ladybugs may also automatically secrete their defensive substance when crushed.
Like most beetles, ladybugs reproduce sexually. During mating season, ladybugs secrete pheromones which attract prospective partners.
After fertilization, female ladybugs may wait several months before laying eggs. They typically use this time to find a good place to lay these eggs, where food and shelter is prevalent.
Ladybugs go through four life cycle stages: egg, larvae, pupae, and adult. The size and appearance of ladybug eggs and larvae differ from species to species, but eggs are usually quite small and spindle-shaped. A single female ladybug can lay hundreds of eggs at once. These eggs hatch in 3 to 10 days.
Different species of ladybugs have different lifespans, but most ladybugs naturally live for about a year after reaching adulthood. Ladybugs that feed on aphids grow faster but age faster than ladybugs that feed on scale insects.
Along with their distinctive coloration, most ladybugs have black dots on their wing sheaths. The number, size, and arrangement of dots varies from species to species--there are two-spotted, seven-spotted, and nine-spotted species, for example. Some ladybugs may have as many as 19 black dots, while some may have none at all.
Contrary to popular belief, multicolored asian lady beetles might also look red and can also have black dots. The best way to differentiate between the multicolored asian lady beetle and other lady bugs is to look for the asian lady beetle’s unique ‘M’-shaped marking on the top of its wing sheath, near its head.
Most ladybugs have white markings on this mostly black section of their wing sheath, but the asian lady beetles’ are shaped differently and tend to be larger.
Despite their name, ladybugs are actually considered beetles. They have all the defining characteristics of all species in the beetle family, including the elytra wing covers.
Signs of Infestation
Because ladybugs aren’t considered pests, you’ll probably only notice their presence if you actually see them. In the winter, ladybugs may enter a home in large numbers. Check damp, dark areas of your home such as a basement, crawl space, attic, or closet.
If you have a particularly bad infestation, check for yellow staining on floors or walls, particularly in corners.
Ladybugs tend to be attracted to light-colored homes and homes that receive afternoon sun exposure. You’ll probably also see more ladybugs in fall and spring if you live near wooded areas or open fields.
As ladybugs congregate, they’ll give off pheromones to let other ladybugs know they’ve found an attractive place to wait out the winter. This pheromone attracts other ladybugs, and only grows more attractive as more ladybugs show up. The pheromone also lingers, so that ladybugs will be able to find their way back to their wintering place year after year.
Treatment and Prevention
Ladybugs attract each other by secreting pheromones. These pheromones grow stronger and more attractive the more ladybugs are grouped together in close proximity. Find areas of your home where large concentrations of ladybug congregate. Vacuum them up frequently, and immediately empty out your vacuum’s bag.
Ladybugs enter a home through small cracks and crevices. It’s a good homeowner’s practice to inspect your home for vulnerabilities in late summer or early fall. Look for cracks in the walls, floors, or foundation; make sure windows and doors are seated and sealed properly; replace damaged screens, seal around utility lines, etc.
Keep particularly vulnerable areas such as attics, basements, or crawl spaces clear of debris and clean them regularly.
If you vacuum up a ladybug congregation, thoroughly clean that area afterward and look for the way the ladybugs got in. If there was a large concentration in your home, chances are the method of entry is nearby.
Discoverlife.org Ladybug identification guide
Penn State College of Agricultural Science Department of Entomology Multicolored Asian Lady Beetle Ladybug fact sheet
University of California Agriculture and Natural Resources Statewide Integrated Pest Management Program Pest Management Gallary entry on convergent lady beetle