You have seen them, both of them, probably without realizing that they are two completely different kinds of bugs. Not only that, but they aren’t even all that closely related. Monarch Butterflies and Viceroy Butterflies. They look almost exactly alike, and as far as the lay person is concerned, they behave like just about every other butterfly. Yet they are different.
Which is which?
Most of you are probably familiar with the Monarch Butterfly. They are pretty, big, orange and lay their eggs on milkweed. And they are poisonous. Some of you may know of the Viceroy Butterfly, which looks an awful lot like the monarch and mimics the aforementioned monarch to fool would-be predators.
Well, about that whole mimic thing… Turns out it’s not so simple. You see, the viceroy is also toxic[i], and it appears that the viceroy and monarch just might be mimicking each other.[ii] Actually, it’s uncertain which species mimics which, though most seem to think that it is the viceroy that does the mimicking. This is because further south in their range they mimic other butterflies which are also toxic[iii], but I won’t get into them that much because they live in Georgia, Florida, and Mexico[iv], and this blog doesn’t give a rat’s ass about much of what happens in any of those places. This blog is about stuff in New England.
Like I said earlier, despite their similar appearance, they are different. In some ways they are quite different. First there is the well-known fact that monarchs migrate, very unusual for butterflies.[v] However, not all monarchs migrate, as there are no fewer than five generations between the butterflies that migrate north, and those that migrate south.[vi] Viceroys don’t migrate, and neither do monarchs that live in Florida,[vii] but then again, this blog still doesn’t give a rat’s ass about whatever happens in Florida.[viii]Another key difference is the larval and pupa stages. They are absolutely nothing alike. Monarch caterpillars are vividly patterned yellow, black and white and live and feed exclusively on milkweed plants.[ix] The chrysalis of the monarch is initially green, but turns transparent as the butterfly develops.[x] The viceroy caterpillar and chrysalis on the other hand both look like bird crap.[xi] More of that mimicry in action!
But of course, you are looking at adult butterflies in their native habitat, and these two insects do look an awful lot alike. Still, you can tell the difference, and pretty easily – if you know what to look for. The first will be the most obvious: size. The monarch is bigger, they grow to be between 3 and 3/8 inches and 4 and 7/8 inches,[xii] and for those of you visiting the region from outside the USA that would be 86 to 124mm,[xiii] we should so join the rest of the world and go metric, but sadly, I don’t see that changing anytime soon. The viceroy is smaller 2 ½ to 3 and 3/8 inches (or 63 to 86mm[xiv] to all you lovely visitors from overseas) as you can see the largest viceroys are about the same size as the smallest monarchs. So if you happen to find an unusually large viceroy or a very small monarch, there is still one surefire way to tell the two apart. The viceroy has a black band on the rear wings running parallel to the edge of said wings, while the monarch does not.[xv]
So if you see a pretty orange butterfly with black stripes, and you aren’t sure what type it is, well now you know how to tell them apart. Sometime in the future, I plan on writing blog going into more detail about each species, as there is way more interesting stuff about them, especially the monarch.
[v] Author Unknown “Migration and Overwintering” USDA http://fs.fed.us/wildflowers/pollinators/Monarch_Butterfly/migration/index.shtml 15AUG2016
[vi] Author Unknown “Monarch butterfly migration” Wikipedia https://en.wikipedia.org/wiki/Monarch_butterfly_migration 15AUG2016
[vii] Author Unknown “Monarch butterfly migration” Wikipedia https://en.wikipedia.org/wiki/Monarch_butterfly_migration 15AUG2016
[viii] Author Unknown “Monarch butterfly migration” Wikipedia https://en.wikipedia.org/wiki/Monarch_butterfly_migration 15AUG2016
[ix] Author unknown “Create Habitat for Monarchs” Monarch Joint Venture http://www.monarchjointventure.org/get-involved/create-habitat-for-monarchs/ 2015
[xii] Author Unknown “Monarch or Viceroy” Journey North https://www.learner.org/jnorth/tm/monarch/Viceroy1.html 1997-2016
[xiii] Author Unknown “Monarch or Viceroy” Journey North https://www.learner.org/jnorth/tm/monarch/Viceroy1.html 1997-2016
[xiv] Author Unknown “Monarch or Viceroy” Journey North https://www.learner.org/jnorth/tm/monarch/Viceroy1.html 1997-2016
[xv] Author Unknown “Monarch or Viceroy” Journey North https://www.learner.org/jnorth/tm/monarch/Viceroy1.html 1997-2016
Photo Credits: Me