Life Cycle
Adult female ladybugs lay eggs, usually on leaves or grasses. Depending on the species, the female may lay anywhere from just a few eggs to 1,000 eggs. The eggs hatch into larvae in about one to two weeks. The larvae feed for one to two weeks, molting as they grow, and then the larvae builds a cocoon, or pupa, in which they change into ladybugs. This process also takes one to three weeks. The adults emerge from the pupa and can live for up to nine months, sometimes hibernating through the winter. Some species of ladybug migrate for the winter.
Feeding
Most ladybugs eat other bugs, such as aphids. The easily recognized seven-spotted ladybug was brought to North America from Europe for just this reason. Some ladybugs do eat plants, however. Ladybugs have voracious appetites.
Habitat
Different species of ladybug are found all over the world. When a non-native species gets introduced to a new country, the new species is considered invasive, and their spread can be prolific. The new species can present a threat to the native species through competing for territory and food.
Defense
Lady bugs are colorful as a defense mechanism. Bright colors in nature often indicate that an insect is poisonous or bad tasting. When a ladybug is stressed, it will produce a foul-smelling liquid to warn off a predator. This liquid not only smells bad, but tastes bad, too. But it has no effect on humans.