Ladybugs, also called lady beetles or ladybird beetles, are a very beneficial group of insects widely used for biological pest control. The natural enemy of many garden pests and most famous for their control of aphids, ladybugs will also consume large numbers of whitefly, mealybugs, scales, mites and many other soft bodied insects as well as bollworm, broccoli worm, cabbage moth and tomato hornworm. Ladybugs will consume anywhere from 1,000-5,000 aphids in it's lifetime, including larval and adult stages. There are about 400 different types of ladybugs in the Coccinellidae family in North America and about 4,000 species worldwide — the most common beneficial species in North America is the Convergent Lady Beetle [Hippodamia convergens]. Aphid warrior, bringer of money or good fortune, and favored insect of the Virgin Mary, people have shown a fondness for ladybugs for hundreds of years.
Ladybug adults are small (usually less than 1/4" long), oval-shaped winged insects. These shiny insects are usually red with black spots or black with red spots on the wing covers — the number of spots identifies the type of ladybug. As ladybugs age, the color of the spots fade. Like many brightly-colored insects and animals, ladybugs are distasteful to predators, and birds are the major predator of the ladybug. Ladybugs will play dead when threatened, and when disturbed may force blood out through their joints and other weak areas in their exoskeleton, an adaptation called "reflex bleeding". Their blood contains toxic alkaloids, and has a distinct odor. Possibly because of these chemicals, people in pre-Industrial Europe used ladybugs as a cure for measles and colic, not to mention mashing them and stuffing in cavities to cure toothaches.
Adult females usually lay their clusters of eggs in the vicinity of aphid, scale, or mealybug colonies. The alligator-like larvae are spiny and black with bright spots. After feeding on insect prey for several weeks, the larva pupates on leaves. Adults tend to move on once pests get scarce, while the larvae remain and search for more prey. Depending on the species, ladybugs spawn at least one generation per year and various stages can often be found during the summer months. Adults of some species overwinter by hibernating in large groups often under leaf litter and other debris.
One common complaint of gardeners about using ladybugs for pest control is that once released, they fly off to the neighbor's house while aphids have their way with your garden. This is because the ladybug is a migratorial beetle, and shortly after molting into an adult, the ladybug has the urge to migrate upland. Though a portion may fly off initially and more once your aphids have been consumed, there are a few things that you can do to get your ladybugs to stay.
- Always release ladybugs in the evening because they will not fly at night and are less active when it's cooler.
- Spray a 1:1 solution of water & clear soda pop on the ladybugs just prior to release. The sugar will cause the ladybugs' wings to stick together for a few days, preventing them from flying away. During this time the females should start laying eggs in your garden, and because ladybugs are territorial, those that hatch in your garden will call it home.
- The spots on a ladybug's wings are symmetrical, though a ladybug can have an "odd" spot which actually spans both wings
- A ladybug may fly 100 miles in search of food
- Ladybugs hibernate under leaves during the winter
- A ladybug can have anywhere from 0 to 24 spots
- A ladybug sheds four times during its lifetime