Photo Caption: Do you see monarchs mating? Look again! These two butterflies are viceroys, distinguished from monarchs by the dark line across the hindwing. Look for this species in moist areas where willows grow.
September 22, 2017
A couple of weeks ago we took a look at the current darling of the butterfly world, the monarch, Danaus plexippus. It is in the midst of some trials and tribulations, but also has legions of supporters helping it stage a comeback.
This week, though, I’d like to introduce you to another very similar, yet distantly related cousin to the monarch, the viceroy, Limenitis archippus. Often mistaken for one another, the two actually lead very different lives.
The monarch, as we’ve learned, incorporates migration into its fascinating life cycle. Right now the so-called super generation is preparing to make a migration of thousands of miles to the mountainous fir forests outside Mexico City. Meanwhile, the viceroys are preparing to hunker down and ride out our Midwest winter.
Now, even if we have the mild winter the forecasters are predicting, don’t expect to see viceroys fluttering by. Their overwintering strategy is to hatch from an egg, grow a wee little bit as a larva, then snuggle up inside a willow leaf and enter the stage of insect hibernation known as diapause. They’ll remain in that state until the daylight periods start to lengthen and temperatures start to warm, usually in late April or May.
So even though that’s a really cool strategy that’s interesting in its own right, there’s even more amazingness to the viceroy’s life story. Their likeness to monarchs is more than just coincidence. It’s part of a survival strategy known as mimicry.
Open any entomology book dating back to the 1970s or before and you’ll read that viceroys are the safer-to-consume of the two species because they lack the cardiac glycosides, or toxic heart chemicals, that many monarch acquire by eating milkweed. The books describe how the two types of butterflies exhibit Batesian mimicry, the phenomenon whereby one nontoxic species evolves to look like another toxic species in order to avoid predation.
But-and it always seems like there’s a but when it comes to nature-the story isn’t quite that simple. As it turns out, viceroys aren’t that tasty after all. More recent studies have shown that the species can be just as unpalatable, and potentially dangerous to consume, as monarchs.
Viceroy caterpillars’ main food supply is willow leaves, and willow is a plant that is rich in aspirin-like compounds. As we know, a little aspirin can be a good thing, but too much causes lots of problems. So, really, viceroys are potentially as problematic to predators as monarchs are.
Instead of Batesian mimicry, monarchs and viceroys are examples of Mullerian mimicry. Without getting too complicated, the definition of this form of imitation describes two toxic species mimicking each other, thus enjoying double the protection from predators.
To complicate things just a little bit further, some milkweed plants don’t produce toxins, so the caterpillars that feed on them aren’t toxic at all. They retain this non-toxicity into adulthood.
I’ve not actually witnessed any type of wildlife predator going after a monarch or a viceroy, but have seen a fair share of monarchs with bird bill-shaped chunks missing from their wings. And I also, many years ago, watched my baby brother eat a dead monarch I’d pinned as part of an insect collection. Was it the orange color that attracted him to the butterfly? Was it scientific research? The world may never know. But, for the record, he’s pushing 49 and seems just fine.
(For the curious, Batesian mimicry is named for the 19th century British naturalist Henry Walter Bates. Mullerian mimicry is named for Johann Friedrich Theodor “Fritz” Muller, a German naturalist of the same time period. Both men spent considerable time in Brazil, and formed their theories while watching butterflies.)
Pam Erickson Otto is the manager of nature programs and interpretive services at the Hickory Knolls Discovery Center, a facility of the St. Charles Park District. She can be reached at 630-513-4346 or firstname.lastname@example.org.Butterfly, Good Natured, Insect
The critters picked their favorite books to share with the kids tonight! What a fun program with cookies, stories and animals to pet.
Photo Caption: Talk about a tough nut to crack! Lacking sharp rodent incisors, humans usually need to resort to hammers or other such tools to open and enjoy the sweet taste of the shagbark hickory nut.
Shagbark Hickory Nuts
September 15, 2017
I’ll admit it. I’m a cookie-dough freak. Even though I know full well that baked cookies taste really good, I just can’t resist digging into the bowl with a spare spoon and letting a gooey glob, gritty with sugar, slide down my gullet. If the dough happens to contain chocolate chips, look out; the oven’s optional when those babies are around.
Squirrels, I suspect, are the same way. Only instead of cookie dough, their downfall is nuts.
Walk in the woods these days and it’s easy to find evidence of the furry critters’ foraging-especially underneath shagbark hickory trees. Shagbark hickory nuts, it seems, are the chocolate chip cookie dough of our local woods.
It appears that 2017 is a big year for hickory nuts, and already it’s difficult to find one that’s not been nibbled. The thing is, the nuts aren’t quite “done” yet. They still need a few more weeks on the tree.
Over time the bitter green husk, which tastes a little like a really bitter green apple, tinged with hot peppers, will darken, harden and split. Inside lies the shell that protects the nut’s ultimate prize: a protein-rich, fat-laden nutmeat.
I’m not much of a connoisseur (clearly! I eat raw dough and sample green nuts, for heaven’s sake) and I can’t speak for squirrels’ taste buds, but to me a hickory nut is among the finest flavors our woods have to offer. It’s reminiscent of pecan, which makes sense as both trees belong to the genus Carya.
But the hickory nut seems more buttery-probably because of its high fat content. According to one source, 1 oz. of hickory nuts contains 186 calories, 152 of which come from fat. If my math is right, that translates to a fat content of more than 80%. It’s cholesterol free, but still…
With our pampered suburban lifestyles, we tend to recoil at such a high number (raw chocolate-chip cookie dough, with nuts, has 46% fat). But for squirrels, and other woodland creatures that have to work hard for every calorie they consume, finding a nut-laden shagbark hickory is like hitting all five lottery numbers, plus the Powerball. It’s literally fat city; a few thousand of these babies, stashed away in tree cavities, crevices and underground, means survival will be a lot simpler this winter.
But wait, there’s a catch. When it comes to survival, there’s always a catch.
If every delicious, nutritious shagbark hickory nut was eaten, there’d be no baby hickories sprouting next spring. And really, flavor and nutrients aside, the next generation is really all a mature hickory tree is about.
And so the nut comes packaged in one of the toughest shells around. You’ve heard of the phrase, “a tough nut to crack?” I have a feeling whoever coined the term may have been referring to hickory nuts.
Humans usually have to resort to hammers to open a hickory nut. Squirrels and other rodents have it a little easier, provided their incisors are in good shape, but they still need to invest considerable effort into opening each shell. It’s a given that some nuts will go uneaten, thus ensuring at least a few new hickories coming up next year.
As summer transitions into fall, I’ll probably snack on a hickory nut or two, unless the squirrels beat me to them. If that’s the case, though, I suppose won’t be too upset. There’s always cookie dough.
Pam Erickson Otto is the manager of nature programs and interpretive services at the Hickory Knolls Discovery Center, a facility of the St. Charles Park District. She can be reached at 630-513-4346 or email@example.com.Good Natured, Plant