But is what we think is a Monarch always a Monarch?
The word Viceroy is derived from the French 'Roi' meaning King (Anglicized as Roy), and Vice ... like the Vice President. So Viceroy means Vice King. The word was used for the Ruler of Colonial India where the Viceroy was given all of the powers of the Monarch in England (Queen Victoria for most of the time and the best known Viceroy was her cousin Lord Mountbatten). The Viceroy had real Imperial power unlike the symbolic power of our Governor General who is often described as 'Vice Regal' but never as Viceroy and has no power.
What does this have to do with Butterflies? Well if the Monarch is King of the Butterflies, then what more appropriate name for a butterfly that is almost the same but a wee bit smaller --- than Vice King or Viceroy.
Monarch caterpillars feed exclusively on Milkweed. The Milkweed sap contains a chemical the disrupts the functioning of cardiac sodium pump in animals. This discourages grazing animals who get violently ill after ingesting the milkweed. Insects are also affected by this chemical, but a few like the Monarch Caterpillar and the Red Milkweed Beetle are not only unaffected by the poison but store it in the tissue unmetabolyzed. This protects the caterpillar from predation and the protection is also passed on to the different metamorphic stages including the adult butterfly.
The Viceroy mimics the Monarch and thus inherits the predator protection by virtue of it's similar appearance. Mimicry where one of the mimics is poisonous or has some other defense and the other is harmless is called Batesiam mimicry. Some Viceroys feed on poplar and are harmless but some feed on willow and have the very bitter and unpleasant salicylic acid from the willow in their tissue. These Viceroys are equally unpalatable to predators. Mimicry where both mimics are unpalatable to predators is called Mulleriam mimicry. The Monarch/Viceroy therefore exhibits both Batesian and Mullerian mimicry depending on the food source of the individual.
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| Viceroy Butterfly (Presqu'ile Provincial Park) |
Look at the photograph of a Viceroy Butterfly above. I had initially classified that as a Monarch, until learning more about mimics when I realized that it is not a Monarch but a Viceroy.
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| Monarch Butterfly (Presqu'ile Provincial Park) |
The second picture is the Monarch.
The Monarch does not have the additional black stripe on the hind wing. This is something that I learned while volunteering at the Presqu'ile Park Nature Centre. There is a Monarch display at the Nature Centre where caterpillars are caught and placed on Milkweed kept in a glass case. The Monarch goes through the metamorphosis and the visitors can see the various stages. Every morning there are are some adult butterflies in the display which are released by the first kids to show up. Last week there was a single butterfly and, as I discussed the 'Monarch' with the early visitors, the naturalist who was present said 'no, that's a Viceroy' leading to the discussion that triggered this post.
When examining the cocoons at the top of the display, most were green (Monarchs) but one recently vacated one was grey and more slender (Viceroy). There was also some non-milkweed plant matter for the Viceroy caterpillar to feed on. So I learn something new at the Nature Centre every time I volunteer.
Sometimes I almost want to believe the saying that 'ignorance is bliss'. If you don't know then you don't worry. Previously I could easily identify every 'Monarch like' butterfly as a Monarch, now I have to get a good view with the hind wing is exposed. If the wing is folded (as it often is) then the category (based on my current level of expertise) must be 'unidentified'.
So don't be too hasty to identify a Monarch, like me, you could very well be wrong.
See my website www.photobirding.net for details on these birds.
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