In many countries, it is considered good luck if a ladybug (or ladybird) lands on you and then flies away of its own will. In England and Germany, it's thought that the number of spots has a bearing on the luck she will bring. But the best thing that can actually be proven about ladybugs is that they are a gardener's best friend and an aphid's worst enemy.
These cute little critters (scientific name: Coccinellidae) are mostly predatory by nature. They feed upon aphids, mealybugs, scale insects, fly larvae and small caterpillars. They also eat insect eggs and pupae, sometimes cannibalizing those of other lady beetles. There are a few species that are herbivores and can cause problems in gardens, but the most common ladybugs are considered highly beneficial to gardeners and make for one of the ultimate, natural defenses against garden pests.
A surprising bit of trivia is that the average ladybug lives one to two years! So when you buy a container of these lovely red beetles at your local garden supply shop, they'll fly away after they've eaten all your aphids, and live on for several more seasons. To entice them to stick around, here are some great tips.
In Los Angeles, the Natural History Museum has partnered with Cornell University for the Lost Ladybug Project. They even have an illustrated guide to help you identify which kind of ladybugs you have in your neighborhood.
Related Post: Pest Control: Ladybugs 101