This beetle is indigenous to North America, and has been tried as a bio-control agent for ragweed in places like Russia, where ragweed is a serious invasive. It doesn't seem to be as effective as hoped. However, one wonders whether our ragweed population would not be much higher if these beetles were not working away to control the plants! This beetle, by the way, is not on a ragweed, but on beggarticks (Bidens) which was growing near some ragweed.