Mer Bleue Conservation Area. There were several of these handsome moth caterpillars on the toadflax plants (also known as butter-and-eggs, Linaria vulgaris). The insects were first released in Ontario in 1962, in order to control toadflax which is considered invasive. Although some reports say that the caterpillars only control a small percentage of the the plants, I definitely have seen a big decrease in the last decade.