Latex lovers

So the title of this post is a little misleading I have to admit.  I wouldn’t say these insects particularly love latex, but the words tolerate and sequester come to mind.  With the alternatives being avoid, succumb to, die from…not the most pleasant options.

In the title, I’m referring to the common milkweed plant Asclepias syriaca and its associated herbivores. What a group they are!

Photo courtesy of Folks Butterfly Farm

Milkweed is particularly known for its chemical defenses against herbivory, producing latex and cardenolides for protection.  Usually, these compounds are toxic to insect herbivores.  But, as always in the insect world, there are exceptions.  A handful of insects are specialists on milkweed, feeding on one or a few species because they have evolved a mechanism to overcome the plant defense.  For a full list of specialist herbivores, see here.  The most common milkweed associated insects I see around here include monarch butterflies, the common milkweed beetle, and the small milkweed bug.  But I haven’t been looking very closely.

Photo courtesy of Rhode Island Bugs

Notice the striking color of the beetle, bug, and butterfly.  Their bright coloration is known as aposematic coloration, or warning coloring.  They’re telling predators, “I’m not very good to eat.”  Monarchs, in particular, sequester the toxic cardenolides as caterpillars and butterflies.  The result?  Birds spew their last meal.

The thing I’d like to introduce is the amazing monarch migration across North America.  These butterflies overwinter in lower latitudes as adults, congregating in Monterey, California and Michoacán, Mexico.  Given that we just had (hopefully the last) snow in Ithaca, maybe I should go to Mexico too!

Photo courtesy of Wanderlust Images

For more about this awesome migration and ways to tag and get involved, see here.

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