Anyone with milkweed in their yard can help monarch butterflies just by mowing their lawn at the right time.

When apart from the bug it mimics, the normally tasty viceroy butterfly turns sour. The discovery made biologists rethink old theories about animal mimicry.

Many butteflies use their wings to mimic other species to protect themselves from predators. Now, a new study shows how just one gene is key to their color.