The aphids' days are numbered

Look who showed up at the ants' aphid farm!

Ladybugs are such enthusiastic predators of aphids that they are often purchased just for this purpose. I've read that this is unreliable as the ladybugs are apt to fly away when released instead of staying in your garden. If you do want to buy ladybugs, get a native species (check here to see which ladybugs in Ontario are native). Unfortunately, the bug here seems to be the invasive Asian lady beetle (Harmonia axyridis), introduced to control pests, which has an annoying practice of overwintering in peoples' houses! The Asian lady beetle can have many different colours and markings; it is distinguished from native ladybugs by the white markings on and behind the head, which surround a black "M" or "W".

The bright colouring of the ladybug is a warning to other predators that ladybugs secrete a toxin when attacked.