Ladybugs are commonly yellow, orange, or scarlet with small black spots on their wing covers, with black legs, head and antennae. A very large number of species are mostly or entirely black, gray, or brown and may be difficult for non-entomologists to recognize as Ladybugs.
Ladybugs are small insects, ranging from 0.04 to 0.4 inches.
Ladybugs are typically predators of Hemiptera such as aphids and scale insects, though members of the subfamily Epilachninae are herbivores, and can be very destructive agricultural pests, though conspecific larvae and eggs are also important resources, particularly when alternative prey are scarce.
Most Lady bugs overwinter as adults, aggregating on the south sides of large objects such as trees or houses during the winter months, and dispersing in response to increasing day length in the spring. With the Asian Lady Beetle, Harmonia axyridis, eggs hatch in 3-4 days from clutches numbering from a few to several dozen. Depending on resource availability, the larvae pass through four instars over 10–14 days, after which pupation occurs. After a teneral period of several days, the adults become reproductively active and are able to reproduce again, although they may become reproductively quiescent if eclosing late in the season.
Most Ladybugs are beneficial to gardeners in general. As in many insects, ladybugs in temperate regions enter diapause during the winter, so they often are among the first insects to appear in the spring. Some species gather into groups and move to higher land, such as a mountain, to enter diapause. Predatory ladybugs are usually found on plants where aphids or scale insects are, and they lay their eggs near their prey, to increase the likelihood the larvae will find the prey easily.
Ladybugs are generally considered useful insects as many species feed on aphids or scale insects, which are pests in gardens, agricultural fields, orchards, and similar places. The Mall of America, for instance, releases thousands of ladybugs into its indoor park as a natural means of pest control for its gardens. Some people consider seeing them or having them land on one's body to be a sign of good luck to come, and that killing them presages bad luck. A few species are pests in North America and Europe.