They’re just “ladybugs” (sort of) and if they’re trying to move into your home, know that while it might be annoying, they are “mostly” not harmful.
The sudden migration of the coccinellids into our homes signals that the beetles need to a place to hibernate for the winter. They like light colors. And apparently, once a few get in through the cracks and crevices of our homes, they emit a pheromone to communicate to the others they’ve found a good campsite.
If we have a light colored house or some space around our doors or windows, the Asian lady beetle will find you. It happens when we have a warm day after some colder days. The beetles are seeking warmth and shelter. A little winter home.
Aren’t they a lot cuter when they’re outside?
The aphid-eating beetle called the Harmonia axyridis, and most commonly known as the harlequin, multicolored Asian, or simply Asian ladybeetle, will bite and does stink.
This species is widely considered to be one of the world’s most invasive insects, partly due to their tendency to overwinter indoors and the unpleasant odorand stain left by their bodily fluid when frightened or squashed, as well as their tendency to bite humans.
According to an entomology paper from Oklahoma State University, “Ladybug Invasion: Coping with Multi-colored Asian Lady Beetle,” the best way to keep the Asian Lady Beetles outside is to seal up cracks in and the spaces around your doors and windows to keep them out.
Beetles are most active on warm, sunny days following periods of cool weather and are attracted to illuminated surfaces, especially the southwestern walls of buildings. Beetles will find refuge in cracks, crevices, and other voids that often lead to spaces behind siding, soffits, and inside attics. Most beetles will remain in these areas until the weather warms in late winter or early spring, at which time ALB will begin to wander and seek escape routes to the outdoors. Inevitably, many of these beetles end up finding their way into homes and other buildings, bringing ALB in close contact with people … It is also important to point out that unlike termites, ALB does not consume wood and so causes no structural damage. Unlike fleas, roaches, and fruit flies, ALB does not reproduce inside buildings—it is only hiding from the weather. However, ALB is a nuisance pest because it can accumulate indoors in large numbers and when disturbed, produces an unpleasant, acrid odor and yellowish fluid that can stain curtains and clothing. http://entoplp.okstate.edu/pddl/pddl/2009/PA8-4.pdf/
The best way to prevent beetles and other insects from getting indoors is to seal all cracks and crevices in outer walls with mortar or a similar compound. Caulk should be used to seal openings around windows and doors. As a bonus, this will help reduce your heating bills. Also, be sure to repair all holes and tears in window screens. The outward appearance of a structure may also influence its likelihood of being invaded and, therefore, could be manipulated to reduce the number of beetles entering a building. There is some debate about exterior color as it relates to attractiveness to ALB, but light-colored buildings tend to be more attractive to these beetles than darker buildings. Contrasting light-dark colors, such as light trim on a dark base color, may also attract ALB. http://entoplp.okstate.edu/pddl/pddl/2009/PA8-4.pdf/