Photo Caption: Up, up and away! These recent spider hatchlings, which are of the species Argiope aurantia, commonly known as garden spiders or banana spiders, are preparing to disperse through a method known as ballooning. (Photo courtesy of Cathy and Steve Martens)
June 23, 2017
Balloons. Can you think of anything more festive? Colorful balls of, usually, latex, floating through the air, leaving oohs and aahs in their wakes. And then all the destruction…Balloons set free to float in the sky can end up killing wildlife with their strings and the fact that some, especially white and pink ones, look like food once they’re deflated and on the ground, or in a body of water.
Actually, let’s leave that topic for another. Instead, this week we’re going to celebrate the joy of ballooning. And don’t think I’m full of hot air!
Ballooning is the term used when baby spiders – known as spiderlings – hatch from their egg case and find an almost immediate need to disperse.
Think about it. A hundred or so spiderlings in one small space, all hungry and needing to feed. Unless they hatch next to a mating cloud of gnats, or feed on each other, they’re all going to starve if they stay in one place. So out of necessity, they go ballooning.
I’m not exactly sure how the term originated; in fact another word to describe the phenomenon is kiting. But I would imagine that seeing teensy spiders floating through the air, with “strings” attached, probably had something to do with it.
Those strings though aren’t ordinary lengths of twine. They’re spider silk, an amazingly strong material for its thickness and weight. We’re all familiar with it, having seen webs around our houses, yards and parks. But little did we know that these protein fibers have the strength, per unit of measurement, of steel.
Spiders have the ability to create different types of silk, depending on use. Some types of silk are made for producing webs, some encase egg sacs, and still others are used for wrapping up fresh prey. Then there are the draglines, which are used for navigation, web building…and ballooning.
I remember a few years back sitting in the Signature Room, the restaurant on the 95th floor of the John Hancock building. I was lucky enough to sit by the window. But while my dining companions were oohing and aahing over the Chicago skyline. Big deal. Meanwhile, I was watching a large cluster of spiders holding their own in the wind, which was considerable, while mending their webs, capturing prey and doing other such spiderly chores…95 stories, or more than 1,000 feet in the air!
At the time I wondered how the heck the spiders got up that high. One thousand feet is nearly 1/5th of a mile. That’s quite a hike for a creature barely an inch in length, including the legs.
That’s where the magic of ballooning comes in. Spiderlings-even older spiders, from time to time-use this method of transportation to leave one area and arrive at another.
Ah, but there’s a hitch.
Rather than dictating their destination by controlling their silk, spiders are at the mercy of the winds. On a still day they may move a few yards. But when the winds pick up, spiders can move hundreds of miles. That’s how spiders ended up way up on the Hancock building, as well as remote destinations like islands in the middle of nowhere.
The key to a long-distance moving adventure lies in that marvelous silk. While it is inclined to stay straight in calm winds, it contorts and forms a parachute-or balloon-of sorts when the winds pick up.
I don’t know if you’ve noticed, but we are in the midst of ballooning season. I’ve seen random web fibers all over the place, likely the production of young spiderlings taking off to find their fate.
The next time you’re struck in the face by a length of spider silk, don’t panic. Think of the little spider that made it, and how s/he has embarked on a wild and potentially perilous journey, a balloon ride for one, with no waiting. Up, up and away!
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, Insect, Spiders
Photo Caption: Stoneflies, even the common species, are increasingly hard to find these days. This juvenile, also called a nymph, was found underneath a rock in Ferson Creek at LeRoy Oakes Forest Preserve in St. Charles.
June 16, 2017
(Ed. Note: This column is the last of a three-part series on the Fox River’s famous, or perhaps infamous, ‘River bugs.’)
It may seem, at first glance, that our Fox River bugs are a pretty homogenous bunch.
I mean, really, how different could they be? Head, thorax, abdomen…two antennae, six legs, wings… Glanced from the windows of passing cars, or even up close and personal on a windshield or radiator grill, these often-plentiful insects all appear to share a certain sameness.
But talk to a naturalist, fisherman or anyone else passionate about streams and aquatic ecosystems, and you’ll quickly learn that the various groups of River bugs are as diverse as ecological niches they occupy.
The Trichoptera, or caddisflies, are notable for their fanciful larval cases, their hairy little wings, and their tendency to form dense mating swarms that weirdly coincide with river town street festivals.
The Ephemeroptera, or mayflies, are famous for their short adult lives and, in some circles, their gorgeous colors, lacy wings and long, flowing “tails.”
And then we have the Plecoptera, or stoneflies. When outdoor enthusiasts speak of these River bugs-and we do, a lot-the conversation takes on a completely different tone. Voices hush, and faces take on a look of awed reverence. For stoneflies are the Holy Grail of all River bug-dom.
Like caddis and mayflies, stonefly juveniles, or nymphs, are aquatic. But unlike their underwater neighbors, most of which are tolerant of small amounts of impurities, stoneflies are exceedingly persnickety about their environment. They need cool, well-oxygenated water with a rocky, unsilted substrate-habitat that’s hard to find in developed areas. As a consequence, stoneflies are at the present time a rarity here in the TriCities.
So you can imagine my surprise when, just the other day, our St. Charles Park District nature camp kids discovered a stonefly nymph in Ferson Creek at the LeRoy Oakes Forest Preserve.
Talk about a reason to celebrate. Miss Pam was jubilant indeed! I tried, futilely, to contain my glee as we examined the inch-long creature that we kept, briefly, in a white collection cup.
With more than 650 species in nine families in North America alone (3,400 species worldwide) I wasn’t about to hazard a guess as to which group this individual belongs. But all the classic stonefly hallmarks were there. Two tails, or cerci, two claws on each foot, and two sets of wing pads, along with branched, filamentous gills poking out from beneath the thorax.
Later on, looking at the pictures we’d taken streamside, I thumbed through a few references and was quickly reminded of how aquatic entomologists, to me anyway, seem slightly masochistic. So many species, so many tiny parts…
Paging through options I decided that, if I had to make a guess, the Ferson Creek stonefly may be a member of the Perlidae, a family also known as the common or summer stoneflies. Since I savor my sanity, that’s how far that i.d. will go. And even at that it’s still a guess, a very tenuous one at that.
Regardless of identity, this little guy without a doubt belongs to a group of insects whose roots date back to the Permian period, some 250 million years ago. Primitive in appearance (that is, no showy swag like wing scales or hairs) stoneflies are strong climbers but weak fliers. Populations are localized and tend to remain that way for eons.
While you won’t see stoneflies forming dense mating clusters the way various other River bugs do, these species have developed rituals that, I dare say, are even cooler: They drum.
Now, we’re not talking Buddy Rich or John Bonham-style percussion here. Stonefly drumming is a subtle thing; it has to be. Even giant stoneflies, the largest North American species, measure a scant 40 millimeters, or about an inch and a half, at maturity. If you’re not a stonefly, you’ll need special equipment to hear the sound. But it’s drumming nonetheless, a behavior that, as one scientist puts it, “improves the efficiency of mate-finding in an otherwise silent, drab, relatively sedentary insect.”
Male stoneflies are the ones that begin the performance, tapping their abdomens against a surface, such as a log, in a species-specific pattern. Female stoneflies then indicate their interest by drumming back in a simplified response pattern.
If all goes well, mating occurs, females deposit their eggs and the cycle begins again.
Fingers crossed, there will be lots of drumming along Ferson Creek this year. Stoneflies a few years back were awarded the dubious distinction of “highly imperiled” by aquatic entomologists R. Edward DeWalt, Colin Favret and Donald W. Webb of the Illinois Natural History Survey’s Center for Biodiversity. Decades of habitat modifications, including dams, drain tiles, stream channelization and development have made things tough for Illinois’ plecopterans.
Interestingly, the stretch of Ferson where the nature campers found their stonefly is just downstream from a recent dam removal. Water now tumbles over boulders that had once impeded the creek’s flow, creating a rush of clear, cool, well-oxygenated water.
I remember making a similar stonefly discovery in the Fox River at Glenwood Park Forest Preserve, shortly after the south Batavia dam had been removed. This location, where aquatic species diversity has measurably improved, is also a favorite hangout of another species once considered imperiled-the bald eagle.
Stoneflies may not be as iconic as our nation’s symbol, but they’re no less important members of our Fox River watershed. With continued attention to habitat improvement, including dam modifications and stream re-meandering, there could come a day when stoneflies lose their Holy Grail status.
Wouldn’t it be great if they were just another River bug?
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, Insect
Photo Caption: An Ephemeridae mayfly rests next to its freshly cast skin. Mayflies are the only insects that experience a subimago, or sub adult, life stage in which they are winged and capable of flight but not fully mature.
June 9, 2017
(Ed. Note: This column is the second in a three-part series on the Fox River’s famous, or perhaps infamous, ‘River Bugs.’)
For many folks, the daily routine is more like a mad dash from start to finish. Wake up, make the coffee, eat breakfast, get dressed, then hit the ground running – off to the office, the grocery store, the gym; phone calls, meetings, housework, errands, appointments. It’s a wonder how we get everything done, huh?
Well, if you think you’ve got it rough, consider the life of the mayfly.
In one short, 24-hour burst (or 48 or 72 hours, depending on species and fat stores) mayflies need to emerge from the underwater habitat where they spent their youth, shed their exoskeleton, fly a short distance, avoid predators, shed again, join a mating swarm, fly some more, avoid more predators, find a mate and create the next generation.
No time for wine and candlelight, no sirree. Mating occurs on the fly, literally, and then females head back down to the water to deposit their eggs, either by flying just above the surface or by dipping their abdomen into the water here and there until the supply is exhausted.
It’s a jam-packed agenda, for sure, with one very noticeable item missing. At no time during their adult phase do mayflies have to stop and feed. In fact, they couldn’t even if they wanted to. Having done all their eating as aquatic nymphs, adult mayflies lack functional mouthparts.
And so it is that, even under the best conditions, the final item on the mayfly’s to-do list is short and sweet: Die.
So famously fleeting is this insect’s adult life that its entire order, Ephemeroptera, reflects its brevity.
Can you say ephemeral?
I suppose it’s our nature to focus on this one brief part of the mayfly lifecycle. After all, the majority of our own lifespans is spent in adulthood. But for mayflies, as is the case for most insects, it’s the juvenile, or nymph, stage that lasts the longest.
In our area, mayflies spend one to two years in this phase, living at the bottom of well-oxygenated streams and feeding on plant material or other small organisms. Again, as is true for other insects, the nymphs progress through several immature stages known as instars.
Although there is considerable variation between the different kinds of mayflies (611 species in 59 genera and 21 families in North America alone) all share some common traits. They have three, or sometimes two, caudal filaments-“tails”-protruding from their hind end. They breathe through gills located along either side of the abdomen. And because they are relatively intolerant of pollution, they make excellent indicators of water quality.
In short, mayfly nymphs are pretty darn cool. But what really distinguishes this insect from all others is what happens next.
When the time comes to leave the water, mayflies don’t just molt one last time and fly away. Nope, not these guys. They are the only insect order with a sub-adult, or subimago, life stage into their maturation process.
As fly fishermen, many of whom are wonderful aquatic entomologists, will tell you, the subimagos, or duns, have wings and can fly, but they are not yet fully mature adults. Only after a period of anywhere from hours to days (but typically overnight) does the insect molt one more time-wings and all-to emerge as an imago, or adult (spinner in fly fisher-speak).
Like the caddisflies we explored last week, mayflies undergo what’s called synchronized hatching. All the mayfly nymphs of a particular species develop at about the same rate and emerge at about the same time. Mass emerging means mass mating, and an assurance that the cycle will perpetuate year after year.
Any day now we’ll be experiencing one of these synchronized emergences. In years past, right around July 1 at Pottawatomie Park in St. Charles we’ve seen a hatch of a species I believe belongs to the Ephemeridae. This family, also known as the burrowing mayflies, have nymphs with legs that are adapted for digging in sand and silt-something that’s present in abundance along that particular stretch of the Fox River.
As adult mayflies go, these individuals are large, over an inch in length, not including their two long, trailing tails. Unlike the caddisflies and other insects that emerge from the Fox River and make a small splat on your windshield, these River Bugs make the sort of splatter that requires washer fluid and several swipes with the wipers.
Although most humans (fly fisherpersons excepted) may not be too excited about the mayfly hatch, our local fauna probably are tickled pink – especially insect-eating birds such as swallows, swifts and purple martins. Look for them to be out in force too this soon too, snapping up the bounty that all too quickly will be gone.
Next Week: The Stoneflies
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, Insect