Even though theyıve taken up residence in everything from dorm rooms to backpacks, ladybugs have a beneficial purpose in our ecosystem. The massive swarms we see around campus are all of one specific species of ladybugs: the Asian lady beetle.

The Asian lady beetle, which can be anywhere in color from pale yellow-orange to deep orange-red with up to 20 black spots, often congregates in large numbers on buildings around this time of year. This type of beetle is often called the Halloween lady beetle, due to its coloring and high activity this time of year.

During warm weather, Asian lady beetles inhabit maple, walnut, willow, and oak trees, and feed on various aphids, certain animal scales, and a few other insects. Lady bugs in general are excellent predators of aphids on pecans, pine trees, ornamental shrubs, roses, and other plants.

In 1979 and 1980, the USDA released the Asian lady beetle in Louisiana and Mississippi as a biological control over the aphids that were harming pecan trees. Because the Asian lady beetles have done so well at controlling aphids, pecan farmers no longer need to spray insecticides in many areas.

By 1994, the Asian lady beetle had spread to Alabama, Georgia, South Carolina, and Florida. They have now made their way into the Midwest in increasingly large numbers.

Ladybugs feed mainly on aphids. When their supply of aphids becomes exhausted during this time of year they move from the trees and shrubs to buildings for the winter.

Even though the lady beetle is an excellent control for aphids and scales, they can become a nuisance when they gather in very large numbers during the autumn. For several days during autumn they typically cluster on sunny, southwest sides of light-colored rock outcroppings, in the corners of windows, door frames, porches and other spots. St. Olafıs light-colored limestone buildings provide ideal homes for the Asian lady beetle.

Contrary to some reports, ladybugs do not bite or sting. However, they do sometimes pinch exposed skin. They do not carry disease, nor will they reproduce indoors.

The best prevention method is to caulk around windows, doors, siding, utility pipes, and other openings.

If you already have lady beetles inside, do not kill them with insecticides, crush them, or handle them. Doing so may result in orange stains on walls and fabric. When stressed, lady beetles will sometimes secrete a harmless, but staining, orange substance from their leg joints.

Vacuuming is the preferred disposal method. It is recommended that you put a handkerchief between the vacuum hose and the dust collection bag to act as a trap to collect them. They can then be released outside.