There are certain issues that need to be talked about, shared, and really drilled into people’s minds. I, however, am getting tired of addressing this issue. Not because it’s not important, but because it’s so important that everyone should know, but they don’t. If everyone knew, I’d be able to spend my time writing blogs about other important topics (of which there are plenty).
But, I digress. We must broach the topic once again. So here we go.
Monarchs need milkweed. This is not new information, nor is it the first time I’ve said it. And, sadly, it won’t be the last. I cannot stress enough how important it is to nurture every part of their life cycle: from egg to egg-producing adult.
I thought this time I would make something a little more photogenic that you can share with your friends to really get the word out.
The relationship between monarchs and milkweed is well-known. Many believe, however, that milkweed is the only plant they need. Adults, when looking for a place to lay eggs, will seek out milkweed but to build up energy for reproduction, they need nectar from other plants. I give a few of the more popular examples above but most any native plant will do.
The most important thing to remember is that monarchs have several generations in one year resulting in a need for nectar-providing plants all season long.
There is a very good reason why monarch caterpillars need milkweed and it has to do with personal safety. The “milk” that runs through the milkweed plant tastes awful…to most… with the exception of a few species (monarchs being one of them).
As the monarch caterpillar digests the leafy goodness that is a milkweed plant, it also takes on those nasty flavours that are well-known in the animal kindgom. As the caterpillar goes through life it will encounter predators at every stage (mostly birds). Due to its bright colours, a bird can learn to identify them with a bad taste and they will move along.
The bad taste that the monarch leaves on a bird’s palate is one that other species have evolved to take advantage of. This is called mimicry and two species come to mind right away: the viceroy and the queen. These two species as adult butterflies look similar to the monarch. The caterpillar of the queen butterfly looks quite similar to that of the monarch caterpillar as well.
Batesian or Müllerian Mimicry?
Before 1991 it was thought that the viceroy was mimicking the monarch for protection because it did not taste bad itself. This would be Batesian Mimicry: where one harmless species copies another harmful species solely for its own benefit. In 1991, however, a study was published that refutes this claim.
Viceroy caterpillars get their bad taste from their food as well: willows, populars, and cottonwoods (all in the Salicaceae family). While monarchs are eating the cardenolides from the milkweed, viceroys are eating salicylic acid. They would (I assume) taste unpleasant in a similar way that monarchs do. *Full disclosure, I’ve never taste tested this theory*. The scientists who published this study had a largely more scientific testing method. Similarly, queens taste just as awful.
This type of mimicry is called Müllerian: where two or more species are harmful but work together to mimic each other. The benefit being that the predator only needs to try one of the mimics to learn that they are dangerous or unpalatable. It is a simple case of strength in numbers.
Back to Monarchs
Swinging this right back around, I’d like to remind you that even though these mimics exist, pesticides do not discriminate. Nor do the wildflowers. Plant milkweed for the monarchs and, while you’re at it, plant a few other nectar-producing beauties. You’ll attract monarchs, yes, but look closely next time: is it a monarch or a viceroy?