Well, if you don’t have many Monarch Butterflies, maybe you’ll settle for Monarch mimics. Here you see a Viceroy Butterfly (Limenitis archippus) that visited us last week. It’s a mimic of the Monarch (Danaus plexippus) that also protects itself by signaling its toxicity. Both have colors and patterns that are virtually identical.
The Viceroy is smaller than the Monarch, but that may not be obvious when the two are not seen together. However, there is one small, but easily-observable, difference. As you’ll see if you compare the circled areas of this Viceroy with those on the archive image of a Monarch shown below it, only the Viceroy has a thin band across its hind wings.
The mimic is well-named. A “viceroy” in diplomatic circles is a replacement ruler that is exercising authority on behalf of a sovereign (e.g., monarch). The Viceroy Butterfly is known as a “Müllerian mimic” (named after scientist Fritz Müller) because it’s one of two or more toxic (or otherwise dangerous) species that mimic each other’s warnings of toxicity (or danger) to predators.
There also are “Batesian mimics” (named after scientist Henry Walter Bates), which are harmless species that mimic warning signals of harmful species. Before extensive research, the Viceroy Butterfly was thought to be a Batesian mimic, and some reports wrongly describe it as such. (Primary image taken in Brooklin, Maine, on September 8, 2023.)