Photo Caption: A member of the monarch super generation lets its wings fill with fluid after eclosing, or emerging, from its chrysalis. Barring any unforeseen difficulties, it should arrive at its overwintering grounds in Mexico in November. (Photo courtesy of Jill Voegtle)
September 8, 2017
A few week s ago we alluded to the fact that monarch butterflies are having a hard time. Human activities combined with inclement weather in Mexico, where the insects overwinter, has resulted in some pretty severe declines in their overall numbers.
As a result, many people have taken on the task of raising monarch caterpillars and then setting the adults free.
I’ll be honest, at first I didn’t know what to make of this new practice. To me, a healthy animal is most at home in its natural environment. Once humans get involved, there’s always a risk of introducing pathogens foreign to the critters, which they then may pass on to others in the population.
There’s also the potential problem of neglect. What happens when you want to get away for a weekend, or a week, and your little ones need fresh milkweed leaves daily? Sometimes it’s easy to find a willing “babysitter,” but sometimes it’s not.
After considering these pitfalls of monarch raising, I started to take a look at the positives. And you know what? There are many.
For one, monarch caterpillars are just as vulnerable to predators and parasites as other caterpillars. It was long thought that these larvae were basically bulletproof, due to the toxins present in the milkweed sap they ingest daily. But hazards arise even before the caterpillar phase begins. Critters like ants and spiders eat monarch eggs-I’ve seen this myself, on the milkweed in my yard. Then, once the eggs hatch, parasitic wasps and flies can move in, laying eggs on the little cats. From then it’s not long before the larvae get eaten from the inside out.
These perils, combined with a series of bad weather events and continued deforestation in the monarch’s overwintering grounds, have resulted in the butterfly being considered a candidate as a federally endangered species.
Thankfully, monarch caterpillars have lots of fans-heroes, even-that have rallied around the cause. They raise monarchs from eggs to adults, then set them free to face their fate in the wild world.
This time of year is especially important, as it’s the time of the monarch “super generation,” that group that will make the amazing trip from their natal grounds to their overwintering site in the Sierra Madre mountains of Mexico. They don’t pass Go, they don’t collect $200 (yes, that’s an obscure monarch-Monopoly reference). Heck, they don’t even take time or energy to breed prior to starting their journey, which can be as far as 3,000 miles. On wings as thin as paper.
The butterflies of this generation are quite a bit different, physiologically, than their predecessors. For one, the combination of shorter day lengths and cooler temperatures causes the new adults to emerge from their chrysalises in a state of reproductive diapause. Whereas previous generations started breeding within days, the super generation delays this activity until spring.
Super monarchs also have an increased ability to store fat, which is essential not only for their magnificent journey but also to their surviving winter in an area that has very little in the way of food sources.
Although we have yet to see large groups of monarchs heading south (a phenomenon that has become rare as the butterfly’s population has dwindled) the migration nonetheless has begun. Over the next two months the insects will travel as many as 50 miles a day before reaching their destination, the Oyamel fir forests in the mountains west of Mexico City, in November.
Nectar, not just from milkweed, will be essential to a successful flight. It’s the monarch’s jet fuel as they make their way across the plains. Cool temperatures in Mexico this winter will be important too, as such conditions help monarchs conserve the energy they’ll need for the return trip next spring. The Oyamel firs offer shelter, but no food for their winter guests.
Don’t get me wrong, the monarchs that overwinter in Mexico will not make it back to Kane County. They’ll fly a distance, then enact their delayed breeding drive. Those offspring will continue the trek, creating descendants that will move farther along, heading toward the natal grounds of their super generation forebears. In our area, we usually see arrival in June.
Time is short for raising and releasing monarchs this year, but it’s never too soon to start planning for the next. The internet offers some wonderful resources for potential butterfly raisers. A great place to start learning about monarchs, and migration in general, is Annenberg Learner, which hosts a fabulous set of pages called Journey North. Written in easy to understand language, these pages can be accessed at learner.org/jnorth
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
Photo Caption: A female green darner rests in a characteristic pose. The “bullseye” mark at the front of the head is another way to identify this iconic dragonfly species.
The Green Darner
September 1, 2017
I got together with some friends the other night, and after a while the conversation turned to superheroes and, eventually, the movie Green Lantern. Now, I don’t follow sci-fi or comic-book flicks that much, so while my pals debated the merits of the movie’s plot and special effects, and the Green Lantern’s ability to save the universe, or whatever, I let my thoughts drift to another superhero, this one more local in nature: the Green Darner.
The largest of our area’s dragonflies, green darners seem to be everywhere right now. I’ve noticed them in all the places you’d expect to see such insects-along the Fox River, for instance, and circling above the pond at Delnor Woods Park in St. Charles. But I’ve also seen them hovering in parking lots and ball fields, zipping along streets and sidewalks, and even, regrettably, smacked flat on the grill of my car.
Yes indeed, these big guys certainly are everywhere these days, and with good reason. Like other dragonflies, green darners are insectivores-they eat other bugs. And, as you may have noticed, bugs of all types are in abundance right now.
Cruising through the air like a fighter pilot on a mission, albeit with wings the length of popsicle sticks, a hungry green darner will pursue just about any insect that flies. Mosquitoes, thank goodness, are high on the list, but green darners will also go after flies, butterflies, even other dragonflies. In fact, in one much-cited incident, a green darner on the East Coast took down a ruby-throated hummingbird. (But talk about bad timing…for the dragonfly, that is. The attack occurred right in front of a bunch of birdwatchers, who rushed to the aid of the hummingbird and scared the darner away.)
While that story is probably true, many other grandiose tales surrounding darners, and dragonflies in general, are not. Despite everything your grandmother may have told you, dragonflies are neither current nor past associates of the devil. They don’t carry disease and they don’t attack humans. They can’t sting and they don’t bite.
What they can do, though, is amaze you with their antics in flight. They can fly forwards and backwards, and when chasing after a prey item (or another dragonfly impinging on a territory) they can reach speeds of more than 35 miles per hour.
Even more remarkable, they can keep up these performances for weeks on end. Unlike many adult insects, which do not feed and therefore don’t last more than a week or two, an adult green darner can live as long as two or three months.
And while that in itself is impressive, also consider that that same insect may have spent as many as five years as a juvenile, living in water and breathing thru gills. In this stage the young darner, known as a nymph, masters the predatory skills it will retain into adulthood. The only difference is that there are no wings involved and the hunting grounds are underwater.
Green darner nymphs eat their share of mosquito larvae, as well as other aquatic insects. As they grow, they will also take on young crayfish, fish and tadpoles too.
The key to their hunting prowess lies in a secret weapon-a protrusible labium, or lower mouthpart. This jaw-like structure, equipped with two sharp spines, shoots out and nabs whatever hapless prey that comes within range. (Remember the alien in the movie Alien? Remember the body part that would shoot out and grab people? Supposedly that stunning feature was inspired by the lower jaw of a baby dragonfly.)
Green darner nymphs hang out in the muck and mud at the bottom of ponds, marshes and slow-moving streams. To find them you’ll probably need a net, and maybe a little patience.
But if you’d like to catch a glimpse of an adult green darner, all you have to do is keep your eyes open when you’re outside.
As their name suggests, green darners appear green as they zip past. But if you’re lucky enough to find one at rest you’ll notice its long, darning needle-like abdomen is either bluish (if it’s a male) or brownish (if it’s a female).
If you see a bluish one flying in wide circles near a body of water, it’s a male protecting its territory. If you see a brownish one sticking its abdomen into the water, it’s a female laying eggs. And if you happen to see a bluish one and a brownish one hooked together, well, then, rest assured, there will be a sequel to this current generation. Green Darner II will be coming soon to a neighborhood near you.
Pam Erickson Otto watches way more dragonflies than movies. She is also 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, Insect
Photo Caption: This garter snake has an overabundance of melanin, a dark pigment that obscures the individual’s normal markings. The cloudy eyes indicate that the snake is in the midst of a shed cycle. (Photo courtesy of Jill Voegtle.)
Ms. Garter Snake
August 25, 2017
Every time I walk past a particular park district outbuilding, I get a little nostalgic. But not for the farmhouse it once belonged to, nor the era in which it was built.
Nope, my memories are a little more recent. A mere 10 years old in fact. Back then, the structure had a very prominent resident. She was large, and somewhat possessive. She kept careful eye on the place, making sure it didn’t get overrun with rodents, toads, or any other area interlopers.
She was, and remains to this day, the biggest garter snake I’ve ever seen.
She-and I’m fairly confident the snake was female, given its great size of nearly 4 ft. in length and the girth of a big ol’ kielbasa-ruled the roost in the summer months, coiling up by the door and basking in the sun. Her presence was enough to deter not only small creatures but also assorted employees not fond of large snakes.
She met her demise on a sunny February day in 2012. I don’t know the exact sequence of events, as I only witnessed the ending. But I think we can safely assume that Ms. Giant Garter decided to take advantage of the unseasonably warm temperatures-I want to say it was close to 80F that day-and slithered out to soak up some sun.
Probably sluggish from her long winter’s nap, she likely didn’t notice the red-tailed hawk that was cruising the area looking for a meal. When I happened upon the scene, the hawk was flying off with a large, writhing snake trailing from its talons. The bird landed in a nearby tree to enjoy its meal, and I walked away more than a little sad that our friend was gone.
Flash forward 5 1/2 years though and, guess what? We’ve learned that Ms. Garter’s legacy lives on.
One of that snake’s most distinguishing characteristics was an almost complete lack of any sort of markings on her back. Garter snakes of normal coloration will have a prominent yellowish or orangish stripe running down the middle back, or dorsal, surface of the body.
Ms. Garter did not have this distinctive mark. It was something that at the time we attributed to her obviously advanced age. But now given what we found the other day, I’m going to change my opinion.
Our naturalist crew was working on a chunk of land not far from Ms. Garter’s old haunt. And what did they find? A very dark garter snake with no prominent dorsal stripe.
I think Ms. Garter and, now, her progeny, are examples of melanistic garters. Melanism is an overabundance of melanin, a pigment responsible for dark coloration. We’ve written about melanistic squirrels before and how the coloration offers both advantages and disadvantages.
Melanistic individuals of any species will have an enhanced ability to absorb heat. This trait is particularly helpful to reptiles as they require heat from an external source in order to warm their bodies. But being dark carries some disadvantages too, particularly for animals like squirrels that are active in winter. A normally colored gray or fox squirrel can camouflage itself pretty well, even when there’s snow on the ground. But a black squirrel, not so much.
In the snakes’ case, the advantage of being able to warm up quickly may be playing a role in the persistence of melanistic individuals. If they can get moving earlier in the morning, they may achieve more hunting success. And more food consumption can lead to a greater fitness and ability to reproduce.
Even though dark coloration may offer the snakes some benefit, I doubt St. Charles will be overrun with black garter snakes any time soon. But even just one is enough to perpetuate the trait-and the memory of Ms. Garter.
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.Good Natured, Reptile