Check out this cool moth!
It's a Cinnabar Moth (Tyria jacobaeae) and it's on the outside of my house, right next to the front door. I've seen three others also. Besides being just amazingly beautiful, their larva eat tansy ragwort almost exclusively. Ragwort is an invasive noxious weed here, and also the cause of the vast majority of allergy symptoms. The moth was introduced here specifically to eat the ragwort, although (as with so many of these introductions) it seems not to have worked very well. Paradoxically, ragwort has actually increased in some places where the moth has been introduced. The theory is that the ragwort has flourished because of a perceived lack of need for additional controls. But I wonder if the moth has a way of increasing its natural food supply over time.