Viceroy (aka Not a Monarch)
Most of the time when you see a slightly large orange butterfly with black "veins" in NJ, you're seeing a Monarch . But not all the time. Every once in a while you could be seeing a Viceroy (this this guy). While they look quite similar, there is an excellent field mark to tell the difference. There's a dark line that parallels the back wing; see the circled blue in the 2nd picture. Though both the Viceroy and the Monarch look similar and can be found nectaring on flowers, their lives also have important differences. As you've probably heard by now Monarch caterpillars eat poisonous milkweed plants and become poisonous themselves as a result. Something similar happens with Viceroys, but as caterpillars they eat trees in the willow family , absorb salicylic acid from the trees, and become somewhat poisonous themselves. This is why their relationship with Monarch is now considered to be Mullerian mimicry , where both species benefit from looking like one another. ...