These articles are written to apply to the northeastern
corner of Illinois. Problems and timing may not apply outside of this
area. |
Ladybugs Again Returning to Houses
October 4, 2001
Once again, the multicolored Asian lady beetle is very visible around
homes and buildings. On a nice sunny fall day, they can be observed flying
around yards and parks and converging on walls of buildings, especially
on south or west walls. Unfortunately, they often make their way into
the building to spend the winter.
Multicolored Asian lady beetles are relatively new to Illinois and the
upper midwest. These insects range from 1/4 to 3/8 inch long, and usually
have orange wing covers with 19 black spots. However, as the name implies,
shades of color can vary and spot numbers range from none to 19. In all
cases, the area behind the head has a pair of white oval markings that
form a black M-shaped pattern. This can distinguish this species from
other lady beetles.
The multicolored Asian lady beetle species migrates to cliffs in its
native Asia to overwinter in cracks and crevices. Not finding any cliffs
here, the insect goes to buildings instead. This is why they are common
in and around homes as cool weather returns with fall.
Lady beetles will not reproduce indoors and do not feed indoors. They
are only indoors for shelter to overwinter, and will find their way back
outdoors in spring. They will feed on aphids and other insect pests on
plants.
Restrict entry into homes by caulking or using weather-stripping to seal
cracks and crevices. If needed, remove by hand or vacuuming when found
indoors. Spraying insecticides indoors is not suggested. Multicolored Asian lady beetles may bite, but do not injure humans. If
crushed or handled roughly, they may leave a stain on fabrics, carpet,
or drapes. In addition, dust produced from the accumulation of dead multicolored
Asian lady beetles in wall voids may trigger allergies or asthma in people.
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