Ladybugs are, of course, not really bugs. They're actually beetles, belonging to the order (coleoptera) and the family Coccinellidae. There are about 500 species of ladybugs native to North America, but in recent years the scene has been dominated by an exotic species, the Mutlicolored Asian Lady Bug, Harmonia axyridis.
These plucky little invaders have caused quite a stir!

After failed attempts to establish them over a period of 70 years, they suddenly and unexepectely appeared on the east coast. In the 90s they rapidly spread across much of the USA, colonizing many of the same places where attempts to establish them had failed! They crowded out native species and in some places they are the only ladybugs to be found. It is feared that this could lead to the extinction of some species. They aren't well adapted to the cold, so they seek warm, protected places to overwinter. Finding such a place, they send out pherenomes which attract others, thus some midwesterners have awoke to the sight of thousands of Multicolored Asian Lady Beetles in their houses. When disturbed they exude a yellow liquid which causes stains and has an unpleasant lingering odor. Though the orange, 19 spotted variety shown here is quite common, there are other varieties sporting different colors and numbers of spots. Despite their diverse apppearance, Multicolored Asian Lady Bugs are all the same species so if you see an orange 19 spotted ladybug mating with a yellow 2 spotted partner you can't assume that their efforts are being wasted!