"The Convergent Lady Beetle (Hippodamia convergens), so named for the convergent white marks on its pronotum (just behind the head) occurs naturally in Ontario. Nonetheless, huge numbers of Convergent Lady Beetles are imported from California and sold by supermarkets and garden centres for use as attractive little weapons against aphids and other pests. This practice seems justified by studies that have shown Convergent Lady Beetle adults to eat almost 60 aphids per day, consuming up to 500 aphids before laying the first of up to 2,500 eggs that hatch into voracious larvae that look like little alligators, each with the potential to consume another 25 aphids or so per day. That all adds up to a lot of dead aphids, but doesn't necessarily add up to aphid control for the purchasers of imported beetles. Those big bags of Convergent Lady Beetles you can buy here in Ontario were collected in the western United States, where well-fed, fat-laden, adult beetles can be harvested by the millions when they head up into the mountains to spend the "off season" in huge hibernating masses. Unfortunately, beetles harvested from these vast aggregations rarely stay put when they are released into a Canadian garden, and probably are of little or no benefit as aphid control agents."
