If you’ve got an infestation of red beetles with black spots, they’re probably not ladybugs, but their close relative the Asian lady beetle. Although ladybugs and Asian lady beetles look similar, and belong to the same insect family, they behave very differently.
Ladybugs are highly beneficial, harmless insects that eat garden pests, such as aphids. They don’t bite, they never congregate in large numbers, and when it gets cold, they rarely seek shelter inside homes. On the other hand, Asian lady beetles tend to gather in large groups around warm, reflective surfaces, such as windows, and they will attempt to enter your home for shelter in winter. They also bite, and leave yellow, foul-smelling residue wherever they gather.