The life cycle of a ladybug include four stages: egg, larva, pupa and adult. Female ladybugs can deposit as many as 50 eggs throughout their life cycle; the life cycle depends on species, but can reach up to three years. Eggs hatch after about three to seven days and the larval stage generally lasts two to four weeks. The pupa stage, when the ladybug is dormant inside a cocoon, lasts for about one week. After emerging from the pupa, adult ladybugs feed before hibernating until next spring, when they mate.
Ladybugs have a pair of antennae, three pairs of legs and an exoskeleton to protect their bodies. They are often small and vary in color from bright-red to yellow, depending on species. Ladybugs can have different numbers of spots, an important feature for species identification. When feeling threatened, ladybugs can secrete a foul taste fluid from their legs commonly called "beetle juice."
Ladybugs are beetles of the family Coccinellidae, with about 5,000 species worldwide, 450 of them living in North America. Native species found in Louisiana include the nine-spotted ladybug (Coccinella novemnotata), the ash-gray ladybug (Olla v-nigrum), the small-spotted psyllobora (Psyllobora parvinotata) and several species of the genus Hippodamia and Adalia. The most common introduced species are the seven-spot ladybug (Coccinella septempunctata) and the Asian ladybug (Harmonia axyridis), which was intentionally introduced to Louisiana from the 1960s to 1990s to control agricultural pests in pecans and apples.
Ladybugs are beneficial to humans, and are used to control plant-sucking aphids and other agricultural pests. Some species of ladybugs lay their eggs on colonies of aphids, so they feed on the aphids as soon as they hatch. However, some species, such as Epilachna varivestis, can also attack the plants. Introduced species, such as the Asian ladybug, can become pests when invading homes to hibernate. They can also outnumber and threaten native species, when competing for food.