"The ladybug is one of the few insects which enjoys popularity around the world, and for good reason. These pretty insects are credited with many virtues. Ladybugs have long been considered a symbol of good luck and fortune. Because of their ability to eat an enormous supply of aphids, ladybugs were believed to be sent from heaven to save crops. In some cultures, the sight of a ladybug indicates a bountiful harvest, a harbinger of good weather or a good luck omen."

http://www.birdsforever.com/ladybugs.html