Tuesday, July 22, 2014

Wonderful Webs

Beams from flashlights and smartphones bobbed around the Cable Community Centre, poking into all the nooks and crannies, scanning window frames and exploring under the eaves. Dusk had fallen quickly while we listened to Larry Weber—author of “Spiders of the North Woods,” retired middle school teacher, and ultra-enthusiastic naturalist from northern Minnesota—show slides of local spiders. Now we were looking for the real things – not just photos.

Shouts of “Oh wow!” “What’s this?” “Good find!” and “Everyone should get a good look at this one!” cut through the evening air. Larry spotlighted a particularly messy corner. There, a completely unorganized jumble of threads glistened. “Cobweb spider,” he stated, pointing to the tiny dot of a creature sitting in the mess. “You probably know some humans who keep their homes really tidy,” he explained with a twinkle in his voice, “and some that don’t.” These spiders don’t.

You can often find cobweb weavers in dark corners inside and outside buildings. They have plump, round abdomens, and usually hang upside down in their web--waiting for prey. During the day, they may hide, so the best time to see them is after dusk. Earlier that afternoon we found several empty cobwebs in the bark crevices of a huge white pine, when Larry led us on a spider hunt at the Museum’s Wayside Wandering Natural Play Area.

It was a day just packed full of spiders. The crown jewel of our afternoon spider hunt was a giant yellow crab spider, so named because of the way it holds its large front legs. In early summer, Larry finds crab spiders on daisies, he said, and they are white. By later in the summer, when the coreopsis, goldenrod, and other yellow flowers dominate, he finds mostly yellow crab spiders. They are the same spider, just with the amazing ability to change color slightly to match the flower in which they hide.

Crab spiders can make silk - and Larry demonstrated that by dangling a smaller crab spider by its dragline - but they don’t spin webs. Why bother when you can hide in a flower and just wait for a pollinator to come to you?

However, a beautiful web can endear even the most dedicated arachnophobe to spiders for at least a moment. According to Larry, the perfect web is on a two dimensional plane, with not a single thread broken, and completely covered with dew. Those webs, with the radiating spokes, spiraling threads, and beautiful symmetry, are the creations of orb weaver spiders.

Each evening (or morning, depending on the species) the orb weaver will spin a new web, and a few hours later, it is gone again. What happens to it?

If the spider is successful, insects fly into the sticky, elastic threads of the spiral and get caught while struggling. The spider can rush forward and throw out sheets of swathing silk to subdue the insect. If the catch is large, the spider may wait patiently until the insect has exhausted itself in the struggle. Then the spider injects venom through its fangs to further subdue the insect, follows that with a dose of digestive juices, and finally slurps up an insect smoothie into its sucking stomach.

After all that, the web is usually pretty torn up. Indeed, many spiders will eat their web each day. The silk proteins are then recycled for use in their next web.

Larry’s perfect web--with no threads broken--is an unsuccessful web with a hungry spider.

But we don’t need perfection to enjoy spider webs covered with dew. Mid-summer is when the spiderlings are hatching and growing, and many tiny webs may cover your lawn each morning. The funnel-shaped sheet webs you see in the grass are made by funnel weavers. If you watch closely, you may notice that the webs increase in size each week as the little spiderlings grow up.

Funnel webs aren’t sticky, but they allow the spider, lying in wait at the base of the funnel-shaped retreat, to feel the vibrations of a passing insect, run out, and grab it. Funnel weavers aren’t fans of cold weather, and they scurry indoors on cool nights. You may wake to find one trapped in the smooth porcelain jail of your bathtub or sink. They are harmless, and easily moved back outside with a cup and piece of paper.

If you have bushes in your yard, you probably have “bowl and doily” webs made by the sheet web weavers, too. The web consists of a horizontal platform with many anchoring threads in a delicate maze above. The spider waits below the platform, and may pull its catch right through the bottom of the web.

Late July is the perfect time to spend some time admiring the delicate artistry of our eight-legged, two-body-parted friends. Their wonderful webs catch mosquitoes, moths, and other pesky insects, while adding breathtaking beauty to our early morning walk.

To find out even more amazing facts about spiders and their webs, you can check out Larry Weber’s book, “Spiders of the North Woods,” and visit the Museum’s current exhibit: Nature’s Superheroes—Adventures with Adaptations.

For over 45 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! The current exhibit, “Nature’s Superheroes—Adventures with Adaptations,” opens in May 2014 and will remain open until March 2015.

Find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Discover us on Facebook, or at our blogspot, http://cablemuseumnaturalconnections.blogspot.com.


Hooked on the River

It didn’t take long to pack their Duluth packs. Six of the seven boys had been on a canoe trip with me before; the newbie was a younger brother. Sleeping bags, sleeping pads, head lamps, and mess kits from the National Park Service went into the garbage bag-lined packs with their clothes, toothbrushes, and extra shoes. Within half an hour, the seven boys, two leaders, and two volunteer drivers were on our way to the Namekagon River landing just below the Hayward dam.

Many hands make light work. Unloading the Canoes on Wheels boats (a Friends of the St. Croix Headwaters program that lends canoes to educational programs for free) at the landing went quickly. I’m often impressed with these local kids – they jump right in to help and don’t complain. Just before launching the canoes, we slathered on sunscreen and fueled up with gorp (aka trail mix). “Two hands,” I reminded them as I poured the peanuts, raisins, and M&Ms from the bag. To drop an M&M is a major fail.

Soon we’re all floating. Two great blue herons rose like dinosaurs from the reedy shallows just around the first bends. Kingfishers swooped overhead, and cedar waxwings gave their high, thin, whistles from the shrubs on shore. The boys probably didn’t notice the bird songs, though, as they focused on navigating through quick water and around rocks. One canoe got distracted by some fishing line tangled in the alders, and the boys managed to free quite a bit before moving on. They’ve been told how dangerous lost line can be to wildlife, and a use for the line was already swimming in their heads.

A light drizzle gave way to tentative sunshine as we landed at our first night’s campsite. After we gathered around the picnic table, David, an intern with the Park and my co-leader, asked “Does anyone know where the closest National Park is?” “Right here!” several boys replied. In 2012, when I first ran a trip like this, none of the kids realized that we live so close to a Park.

Many local residents drive by the brown NPS arrowhead signs every day, and never stop to realize that they live right next to a National Park. The Namekagon River is a tributary of the St. Croix, and therefore is part of the St. Croix National Scenic Riverway, a unit of the National Park Service (NPS).

Both the Cable Natural History Museum and the Park Service want to get kids on the river. So, the Park and the Museum have developed a marvelous partnership in the past few years. I provide the trip guiding experience, camp food, and participants, and the Park provides camping gear, a second adult to come along, a Park Ranger for an evening program, and logistical support. This year, funding was provided through the St. Croix River Association, which was awarded an America’s Best Idea grant from the National Park Foundation. As I tell our Park partners, just like lichens, we couldn’t do it without each other.

The boys are the ones that really benefit, though. We covered our miles quickly on the first day, and recurrent drizzle dampened their enthusiasm for swimming. So what could they do around the campsite? Before too long, one kid was making a fish hook by filing down the metal end of bungee cord found near the fire ring, another was whittling a fishing pole from a stick, and a third was untangling the fishing line found earlier.

Not a single boy pulled out an electronic device, or even mentioned wanting one. Two Frisbees (one of mine and one found in the weeds on the river) were sailing among the tents. A few other boys were practicing intently with David’s kendama, an extremely addictive wooden skill toy that originated in Japan.

No one was bored. Everyone was safe. I sat back and let them be boys in the woods.

Soon the fishing pole was outfitted with a wooden bobber, baited with a raisin, and ready for testing. The whole troupe followed Gavin down to the landing, and watched as he swung the hook and line into the current. Evening light reflected off the trees, and bugs skittered along the surface. The onlookers soon dispersed, but Gavin stood quietly – our most talkative boy sliding easily into the fisherman’s meditation.

After several minutes without any nibbles, Gavin decided to try the other canoe landing – a backwater area filled with water lilies and muck. As he waded in wearing sandals, I heard him mutter to himself “I hope I get a leech on my foot so I can use it for bait.”

I’m not sure when Gavin took a break, but at some point we all drifted back around the picnic table to watch the kendama practice. Then, out of the blue, Gavin exclaimed, “I’ve got a leech!” with not a hint of disgust or fear in his voice. Nearby, Grant, who had whittled the fishing pole, replied “Sweet! Now we have bait!” with the same untainted joy.

The boys never caught a fish with their make-shift pole and leech bait, but I know they caught even more of the spirit of the Riverway: adventure, resourcefulness, stewardship, and beauty. In the next two days we paddled rapids, cooked over a campfire started with flint and steel, learned about the Voyageur history of the river, picked other people’s trash out of a fire grate, admired bald eagles and osprey soaring above, and paddled 15 miles in a morning.

Around the campfire I asked the kids what they wanted in a trip next year. “More fishing!” exclaimed one. “Can we go longer?” suggested another. Obviously, we’re all hooked on the Namekagon River.

For over 45 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! The current exhibit, “Nature’s Superheroes—Adventures with Adaptations,” opens in May 2014 and will remain open until March 2015.


Find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Discover us on Facebook, or at our blogspot, http://cablemuseumnaturalconnections.blogspot.com.

Firefly Fireworks

Fireworks exploded over the lake as I brushed my teeth. On these warm, midsummer nights, darkness takes forever to fall, and both the late-June fireworks and my bedtime were delayed longer than ideal. Now in a sleepy haze, I shut my windows and turned on the fan, hoping to muffle their crackles and pops enough to fall asleep.

As I lay there with the lights off, though, a different sort of light glowed through my window. And then another, and another; blinking on and off among the treetops. Without my glasses on, they appeared as fuzzy balls of light, but I knew those patterns...I recognized those fairy-like glimmers from deep in the childhood core of my memories -- fireflies!

For several minutes, I smiled at the fireflies through half-closed eyes. A few females had chosen my window screen for their stationary perch, and were now trapped inside the glass. Outside, males swooped and blinked among the trees, using their special patterns to entice the ladies to respond.

Fireflies use bioluminescence to attract mates, lure prey, and warn predators of their toxic taste. Sometimes they blink once, twice, five times in a row and then go dark. Other times they swoop through the air, leaving a streak of light imprinted on your vision. Each species has a special pattern of dashes and dots; their own Morse code for “Hey Baby, you light up my world.”

And there are femme fatales among them. Female fireflies in the Photuris genus will hide in the grass while mimicking the mating flashes of other firefly species. Males of the other species come seeking a lover’s tryst, only to discover that what the femme fatale really wants is them as a meal. Other less daring fireflies just drink nectar, or eat nothing at all during their short adult lives.

Firefly light is not just known for what it draws in; it is also amazing for what it doesn’t give off: heat. Nearly 100% of the energy released by the chemical reaction is emitted as light. Compare this to an incandescent light bulb, which releases 90% of its energy as heat, or even a fluorescent bulb, which releases 10% of its energy as heat. The firefly comes out way ahead.

How do they do it? Specialized cells in the fireflies’ abdomens contain a chemical called luciferin and make an enzyme called luciferase. The luciferase speeds up a reaction in which luciferin combines with oxygen and gives off light – cold light – in the process. Scientists think that the precise on-off switch is controlled either by nerve cells or by the oxygen supply from the abdominal trachea.

Because the reaction happens in the presence of magnesium ions and ATP (adenosine triphosphate, the molecule that biologists call the “energy currency of life”) luciferase can be used in forensics and medicine to detect the presence of magnesium or ATP. Abnormal levels of ATP may indicate cells are diseased due to cancer or muscular dystrophy. The same chemicals can help us detect bacterial life causing food spoilage. The fireflies’ molecules have even been built into spacecraft to detect life in outer space.

Sadly, fireflies – incredible beetles – are on the decline all over the country, and all over the world. Many people have noticed. “There just aren’t as many as when I was a kid,” is a common phrase. As with most creatures these days, habitat loss, pollution, and human encroachment seem to be at fault. Luckily, there are some simple ways you can help.

Fireflies need marshy areas with rotting wood and forest litter to complete their life cycle. A few days after the stationary female and flying male hone in on each other’s titillating twinkles, the female lays her fertilized eggs just below the soil surface. Once the larvae hatch, they feed on other larvae, snails, and slugs found in moist habitats. Remarkably, the larvae glow, which is a form of warning coloration just like the monarch butterfly’s orange wings. Warning of what? The larvae contain a toxin similar to one found in the skin of poisonous toads.

Here’s where you come in: the larvae need protected places to hatch and overwinter, either underground or under the bark of trees. You can help provide this habitat by planting trees and leaving fallen logs and leaf litter in the back corners of your yard, especially in late summer and fall. Leaving some soggy areas or even creating a water feature or rain garden can improve the habitat even further.

When you cultivate a backyard habitat that will attract wildlife, it becomes even more important to keep pesticide and herbicide use to an absolute minimum. Many chemicals end up killing non-target organisms, and your perfect lawn may be the reason you don’t see as many fireflies as you used to. Let your lawn, or at least the edge, get a little shaggy, too. Fireflies need tall grass for cover during the day.

Finally, you can turn off your exterior lights and draw your blinds at night so that your light pollution doesn’t disrupt fireflies’ special messaging systems. Plus, with the artificial lights off, you’ll be all set to watch with wonder as these natural fireworks quietly light up the night.

For over 45 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! The current exhibit, “Nature’s Superheroes—Adventures with Adaptations,” opens in May 2014 and will remain open until March 2015.

Find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Discover us on Facebook, or at our blogspot, http://cablemuseumnaturalconnections.blogspot.com.


Sex in the Garden (aka pollination)

“Maybe you should write about pollen,” suggested a neighbor as she brushed yellow dust off of her pants. Remembering the film of gold on my car, the cheery lemon color of my dust rag after wiping off the windowsills, and my co-workers’ recent sneezing fits, I agreed. “That sounds like a great idea!”

Pollen is an amazing substance that has an essential place in nature, but it can also mean a mess of dust and allergies in the summer.

First and foremost, pollen is one half of the equation in plant sex. At a recent pollinator garden workshop at the Cable Natural History Museum, natural landscaper Sarah Boles held up the delightful botanical book “Sex in the Garden,” by Angela Overy. “That’s what it’s all about, really,” commented Sarah matter-of-factly. And it’s true—that yellow dust floating through the air is basically sex on the breeze.

A tiny grain of pollen is a surprisingly complex unit that contains the male genes of the plant. A protective coating keeps the pollen dormant until it is safe inside a female of its own species. Inside the pollen grain, proteins, amino acids, fats, and sometimes carbohydrates, lie in wait to fuel the growth of the pollen tube. The pollen tube grows from where the pollen lands on the stigma, down through the pistil to the ovules, and allows the male gametes to fertilize the ovule (egg). In some species, a single cell can grow into 12-inch long pollen tube! In this case, because of the shape of the flower, size does matter.

Some plants can pollinate themselves, but most plants must cross-pollinate with another individual in order to produce viable seeds. Wind can do it sometimes, but that’s also where the insects, and our Pollinator Garden, come in. Flower nectar is like Kool-Aid, and pollen is more like mixed nuts. These tasty bribes entice bees, butterflies, beetles, flies, and hummingbirds to help transfer pollen from flower to flower while they are vying for a snack.

Because plants must have pollen left over from feeding the masses in order to fertilize their ovules, they make a lot of those pesky little particles. Wind pollinated trees especially must make a lot of pollen in order to ensure that some grains get where they need to go. This is the reason my car, my house, and the inside of my nose are all currently dusted with pollen.

Pine trees have male and female cones instead of flowers, and for a few weeks now, the small, papery, male cones have been releasing light, fluffy clouds of “golden smoke.” But inhale away! Pine pollen comes with a whole host of health claims such as “increasing libido” and “skin rejuvenation.” If you don’t want to scrape it off your windshield, you can buy an 8 oz. bottle online for just $69.99.  

Some plants, like orchids, have low numbers of sticky pollen grains instead. Their flowers are specialized, and often only attract one type of pollinator. If one bee is visiting one type of flower, it is pretty easy for the pollen grains to get an accurate transport service. This saves the plant energy on pollen production, and saves our sinuses, too.

Common milkweed, another plant, preferred by many nectarivores and pollinators, has a specialized pollen relay system, and therefore is easy on the nose. Milkweed pollen is shaped like saddlebags, with two pollen grains connected by a black line. The whole thing snaps onto a visiting insect’s leg to catch a ride! Then the pollinium falls off into another milkweed flower. Sometimes the flower gets a bit aggressive, and accidentally lassoes the insect it was trying to hire as a courier.

Goldenrod is a bit less aggressive. While it produces plenty of pollen, the grains are big and sticky; good for hitching rides on bees, bad at making you sneeze. The real culprit for late summer allergies is another wind pollinated plant – ragweed. A single plant, with its inconspicuous spike of green flowers, can produce about a billion pollen grains per season. These tiny spiked balls, shaped disturbingly like medieval weapons, float freely on the breeze and into your nose, causing about half of all cases of allergic rhinitis in North America.

Because of its irritating, wind-blown habits, ragweed is definitely not a member of our freshly planted Pollinator Garden. But many other native flowers are. Our hope is that by providing a wide variety of nectar and pollen producing plants, with ample caterpillar host plants as well, our little garden will offset a tiny bit of the native habitat that’s been plowed under or paved over. Habitat loss is the biggest challenge facing most critters these days, but we can all help in our own back yards.

Sometimes, though, good intentions can end up with dire consequences. Large nurseries (including those that supply big box stores) must use fungicides and pesticides to keep their plants looking healthy. One class of those insecticides, called neonicotinoids, has been found to leave residues in the pollen and nectar of treated plants. Those residues can be directly lethal, or just weaken an insect so that something else can kill it. You can help by purchasing plants from a trusted source, and asking informed questions about their growing process.

Pollen may be a dusty, sneezy, annoying part of summer, but it is also a player in the beautiful (and necessary) game of plant reproduction. By cultivating your own pollinator-friendly plot with pesticide-free plants, you can help increase the summer fun of sex in the garden!

Want more resources? The Xerces Society and the Pollinator Partnership have great websites: www.xerces.org, and pollinator.org. You can also watch our garden grow by following us on Facebook!

For over 45 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! The current exhibit, “Nature’s Superheroes—Adventures with Adaptations,” opens in May 2014 and will remain open until March 2015.


Find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Discover us on Facebook, or at our blogspot, http://cablemuseumnaturalconnections.blogspot.com.

Master Naturalists


Last week, ten students, two instructors, and a dozen natural resource professionals wove together the story of Wisconsin’s natural history. The students all finished the course as certified “Wisconsin Master Naturalist Volunteers.” This new program is based on a successful Minnesota Master Naturalist program and is similar to the Master Gardener program. It provides 40 hours of coursework in natural history, interpretation, and conservation stewardship, and then requires 40 hours of volunteer service per year.

The students learned that the basic plot of our Wisconsin story is universal:  the landscape we see today is a result of geologic history, current climate, and recent disturbance. Endless variety in these three criteria results in the existence of every ecosystem from rainforests to deserts, and everything in between.

Our Northern Wisconsin story began 3 billion years ago, at an outcrop of very old rock near the town of Mellen. Professor Tom Fitz of Northland College guided the new geologists in making observations. Bands of different colors and crystal sizes gave the rock a striking striped appearance. “This is a very pleasant rock,” Tom chuckled at his own joke, “and geologists call it gneiss.”

Then Tom delved into interpretation--using information about the rock to imagine a sequence of events that could have created it. By looking at the minerals contained within the light and dark color bands, scientists can tell that this rock started out as many layers of different types of volcanic rocks. Those layers were buried deep within the earth, smashed and metamorphosed under heat and pressure, and then revealed at the surface by ages of erosion. Veins that cut across this gneiss have been dated to 2.7 billion years ago, so we know that this gneiss is even older. These rocks form the heart of the continent.

Racing forward in time--but traveling just a few miles down the road--we came to a mass of rock formed 1.1 billion years ago while the continent was trying to split itself apart along a fault that bisects Lake Superior. As the continent spread, the crust thinned, and magma welled up in huge shield volcanoes. During one such explosion, hot granitic magma rushed up from below, splintering chunks of black rock out of the volcano’s walls. Those chunks fell back into the pale magma, and it cooled underground into a formation that looks like chocolate chip cookie dough. Once again, erosion revealed it to us.

Luckily, the rift stopped spreading, and the North American continent didn’t rip apart. Millions of years passed while rocks formed and eroded. Glaciers came and went, eroding and depositing a mish-mash of sediments. When the ice melted most recently (about 10,000 years ago) it left behind the landscape much as we see it today. The ski trails around Cable, the huge pile of gravel known as Mount Telemark, the clay plain near Ashland, even the swath of sandy soil that extends southwest from the Bayfield Peninsula, are all the legacy of the glaciers.

And that legacy matters. Any ecosystem is composed of both biotic (living) and abiotic (non-living) components. The geology, plus our current climate (with plenty of moisture and seasonal temperature variation) provides the substrate for our local communities (both natural and human) to grow.

As the week flew by, we packed our days full of conversations with natural resource professionals. All of those scientists added events, plot twists, relationships, and layers of complexity to our Wisconsin story.

Up on the Moquah Barrens north of Ino, WI, we stood on hundreds of feet of sand washed out of the glaciers by rivers of melt. The dry soils, and the history of fire, logging, farming, and management, all resulted in a patchwork of oak scrub and pine savannah. Those habitats, in turn, attract certain birds. As the mid-morning sun burned the mosquitoes away, we extracted a clay-colored sparrow, Eastern towhee, and brown thrasher out of the mist net. While retired biologist Jim Bryce banded the birds, he commented on their close relationship to this dry, brushy habitat.

After Jim taught us the proper way to handle the tiny songbirds, we took turns holding and releasing the day’s catch.

Later, Matt Bushman, a botanist for the USFS, gave us a botanical tour of burned areas within the barrens. As we walked from thick brush to more open grassland, the effects of fire, selective logging, and targeted brushing drove home the importance of recent disturbance in shaping a landscape.

Finally, Tom Doolittle, wildlife biologist on the Chequamegon-Nicolet National Forest, integrated wildlife management into our story. The geology of the sand plain and the plant communities it supported had once attracted great flocks of dancing sharp-tailed grouse each spring. Now humans are trying to mimic historic disturbance patterns to help the dwindling population of sharp-tails recover.

We ended the week exhausted, but with a good understanding of how the landscape we see today is a result of geologic history, current climate, and recent disturbance.

Although the newly certified Master Naturalist Volunteers have a solid base of knowledge, they will be adding details and depth to this story of Wisconsin’s natural history for many years to come. Find out more about this program at wimasternaturalist.org.

For over 45 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! The current exhibit, “Nature’s Superheroes—Adventures with Adaptations,” opens in May 2014 and will remain open until March 2015.


Find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Discover us on Facebook, or at our blogspot, http://cablemuseumnaturalconnections.blogspot.com.

Dragonflies!

Blue skies and a fresh breeze put a spring in my step as I gathered tools – hoe, rake, shovel – from the shed at the Cable Community Garden. My garden would be fully planted by the end of the afternoon, and I was looking forward to the satisfaction of working the soil, tossing rocks, and nurturing new life.

It was hot, though, in my long pants, long sleeves, and hat. The bugs have been bad at the garden (and everywhere else in northern Wisconsin!), and it’s hard to carefully place seeds in a row AND slap mosquitoes at the same time.

Then, as I carried a flat of squash plants to the gate, I looked up. A cloud of dragonflies was darting everywhere with amazing speed and agility. For as far up and as far out as I could see, their tiny silhouettes filled the sky. And then it dawned on me, I hadn’t slapped a single mosquito since I got out of my car!

For weeks now, people have been asking me “When are the dragonflies coming?” “Soon,” I’d answer, or “I’ve seen a few by the lake.” As beautiful as dragonflies are for their own sake, these queries were really about the mosquitoes. Deep snow, a late winter, and a quick spring (once it came) have somehow conspired to bring the little bloodsuckers out in terrible numbers. People yearn for the dragonflies to eat the mosquitoes.

Dragonflies are exquisitely adapted aerial predators. Each of a dragonfly's four wings operates independently, powered by its own set of muscles, resulting in fantastic maneuverability. Dragonflies can fly backward and forward, straight up and straight down, hover, accelerate to full speed in a split second and make hairpin turns. Small antennae seem to have little function except to measure air speed in flight – which can reach 30 mph.

Dragonflies have adapted to see faster, too. Together, a dragonfly's eyes and brain can detect movements separated by only 1/300th of a second! Dragonflies also possess an almost super–human capacity for selective attention. They can focus on a single mosquito in a swarm, track the moving target and adjust their path to intercept the prey with a 95% success rate. Appropriately, the word "dragon" comes from an ancient Greek word that means "sharp-sighted one".

Three pairs of legs attach to a dragonfly’s slanted thorax. This tilts the legs forward, and creates a spiny basket used to catch prey on the wing. Small insects can be scooped into the mouth without pause, but larger prey are taken to a perch. There, the dragonfly can masticate the insects with the serrated teeth on their mandibles. These teeth give dragonflies their scientific family name – Odonata – from the Greek word for “toothed one.”

While dragonflies can eat their own weight in food every 30 minutes, they aren’t actually reliable mosquito control. Dragonflies complete just one generation each summer, while mosquitoes breed multiple times. In addition, eating mosquitoes is like you trying to make popcorn into a satisfying dinner. Dragonflies prefer bigger prey – even other dragonflies – when it is available.

Even so, the dragonflies really seemed to make a dent in the mosquito population in the garden. So why did they take so long to arrive?

Many dragonfly species synchronize their transition from nymph to adult, which results in a “mass emergence.” By all metamorphosing at about the same time, dragonflies can ensure that males and females will mature at the same time and find mate. The cloud of dragonflies will also overwhelm predators, and ensure that at least some survive.

Different species are on different schedules, though. While we see dragonflies from spring to early fall, we are actually seeing a series of different species. Most adult dragonflies live only a few weeks, although some can live up to a year.

The “spring species” of dragonflies that zoomed over my head spent last summer as aquatic larvae growing into their final stage before metamorphosis. Then they stopped growing, and overwintered as almost-adults, ready to emerge when the water warmed enough.

Now they are fierce aerial predators, patrolling the skies with agility and grace. As I happily tend my garden without long sleeves or bug spray, I don’t think it’s too much to call them my angels of mercy. Do you?

For over 45 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! The current exhibit, “Nature’s Superheroes—Adventures with Adaptations,” opens in May 2014 and will remain open until March 2015.


Find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Discover us on Facebook, or at our blogspot, http://cablemuseumnaturalconnections.blogspot.com

Saturday, June 14, 2014

Field Trip!

“Did anyone read the banner on the front of the Museum as you came in?” I asked a room full of fidgety second graders. “Super insects?” offered one kid. Not quite. “Nature’s amphibians?”  piped up another student. From their confused looks I quickly realized that A) These second graders are not yet practiced at speed reading while walking, and B) They were probably much too excited at getting off the bus to start their field trip to remember anything they might have read outside! I can’t say I blame them.

“It says Nature’s Superheroes,” I exclaim with a dramatic sweep of my arm, “That’s what you’ll be learning about today.”

“Underneath that title it says something else, too. It says ‘Adventures with…..’ and then there’s a big science word that you might know. It starts with an A, and it means: something an animal has or does that helps it survive in its habitat.” After a little guessing, with kids’ tongues getting twisted, I wrote the word “adaptations” on the marker board. I could see looks of recognition on their faces.

Then we talked about some animal adaptations. Butterflies’ ability to change shape, spiders and their webs, bats with their excellent hearing, gray tree frogs’ ability to become almost invisible, dung beetles strength to roll dung balls, peregrine falcons’ diving speed, and dragonflies amazing flight capabilities—all of those skills help the animals survive, so they are adaptations. Finally we made the connection—all of those animal adaptations are also super powers shared with our favorite comic book heroes.
 
“So today, when we talk about the super powers of these animals, what are we talking about?” I asked the group. “Adaptations!” came the reply. (Success!)

“Great! Now you get to meet our seven Nature’s Superheroes.” As students volunteered, I fitted each one with a colorful superhero cape depicting one of the seven animals, and a prop to represent their super power/adaptation.

The peregrine falcon held up a sign that said “Speed Limit 242 mph” to show how fast they can dive. The spider got to carry a butterfly net as a web. Super-cool aviator glasses made the dragonfly kid look ready to fly. I tied big bat ears onto the head of another volunteer. And finally, the kid who waved his hand wildly because he wanted Super Strength donned the purple dung beetle cape, looking sheepish. His eyes brightened, though, when I gave him barbell made out of beach balls and a foam pool noodle to show off is strength.

After a round of applause and a round of parental photo opps, we split into three groups for the rest of the field trip.

One group went with Joe Brady, our indomitable volunteer, into the exhibit hall. They stopped at the entrance and donned colorful capes, then got the “Museum Behavior” talk before entering through tall glass doors. They came out of the exhibit chattering excitedly about flying in the green screen studio, climbing on the spider web, watching the world’s fastest flower explode, seeing a peregrine falcon dive, finding the elusive gray tree frog, and listening to bats.

A second group stayed in the classroom with Katie Connolly, our Naturalist/Curator who is in charge of all the animals at the Museum, both dead and alive. Those kids were allowed to touch and hold our two live snakes – a western hognose snake named Digger, and a Great Plains rat snake named Emory. Snakes have both Super Senses (smelling with their tongue) and Super Invisibility (excellent camouflage.)

Finally, I herded the third group into the Outdoor Classroom, where we acted out the monarch butterflies’ Super Transformation from caterpillar to butterfly. You may think that Clark Kent’s change into Superman was impressive, but he doesn’t hold a candle to the amazing metamorphosis that goes on inside a chrysalis. According to the Nature’s Superheroes comic book (published with the exhibit) “A whirlwind of activity takes place inside the chrysalis. The caterpillar’s body dissolves. Out of this ‘soup,’ new body parts and organs assemble in a Super Transformation.” All of that, in just 10 days!

Amazing as they are, butterflies need our help. Kids spotted a couple monarchs floating above the lilac bushes, but overall their numbers are dangerously low. Each student planted flower seeds to add to the butterflies’ food supply.

Then, with the leaders’ watches perfectly synchronized, the three groups switched stations so they could each experience all the fun. 

This whirlwind of activities has been taking place for three weeks, as hundreds of students visit the Museum on their spring field trips. We gather them all back into the classroom at the end, and I ask the simple question: “Which was your favorite superhero and why?” The answers I get tell me that the kids learned some impressive facts about Wisconsin animals, understood the importance of planting their flower seeds, developed an emotional connection with nature—and had fun!

(You can experience the fun, too, even if you’re an adult, by visiting our “Nature’s Superheroes” exhibit or attending one of our many public programs. See photos of the exhibit at the Cable Natural History Museum Facebook page.)

For over 45 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! The current exhibit, “Nature’s Superheroes—Adventures with Adaptations,” opens in May 2014 and will remain open until March 2015.

Find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Discover us on Facebook, or at our blogspot, http://cablemuseumnaturalconnections.blogspot.com