A [Local] Monster Mash

Here in Vermont you can hardly go outside without seeing signs about buying local.  Local foods are labeled in grocery stores, restaurants proudly display maps of Vermont with pins pointing out where they source their ingredients, and everybody who’s anybody seems to have a CSA share. But for some reason every year around this time even the most devout locavores import their Halloween monsters from far away.  Mummies more at home in Egypt smile out at you from windows, tarantulas usually found in tropical regions crawl all the way into candy bowls in Vermont, and vampires hop planes from Transylvania to lurk on residential porches for a few weeks every October.  Enough!  I say it’s time to put an end to the madness of imported creepies and crawlies, and to get to know a few of our own.  And so, I present to you a Halloween line-up of locally and sustainably sourced (and not-so-scary) monsters:

The Stigmata Mummy-Wasp (Aleiodes stigmator)

Mummified Acronicta Caterpillar with exit-holes of Stigmata Mummy-Wasp, photo by Bryan Pfeiffer

Mummified Acronicta Caterpillar with exit-holes of Stigmata Mummy-Wasp (Photo by Bryan Pfeiffer)

Here’s the good news: the stigmata mummy-wasp didn’t make the monster list for having a painful sting. In fact, these wasps are small and don’t have stingers.  In place of a stinger on their hind end, these wasps sport an ovipositor, which they use to inject their eggs under the skin of an innocent and unsuspecting host caterpillar.  After the eggs hatch the wasp larvae chew a hole in the underside of the caterpillar, causing it to leak fluids that dry and essentially glue the caterpillar to a plant.  Next the larvae mummify the caterpillar by eating the soft innards and lining the empty body with silk.  Inside the hollow caterpillar husk the wasp larvae spin their own cocoons and pupate into adults.  When they emerge from their cocoons they chew their way out, leaving behind the dry husk of a caterpillar that looks like it has been sprayed with buckshot.

Even though this may sound straight out of science fiction, stigmata mummy-wasps are native to Vermont where they generally inhabit wetlands and floodplains.  Though the wasps themselves are small and hard to find, the mummified caterpillars are not.  Their riddled mummies can be found clinging to sticks year round, and if you find one in late fall you might want to watch it closely – you might be lucky enough to spot one of these little monsters emerging.

The Oleander Aphid (Aphis nerii)

Oleander Aphids on a stalk of Swamp Milkweed

Oleander Aphids on a stalk of Swamp Milkweed

There are many types of aphids, but while I was researching for this list one variety stood out: Oleander aphids.  These little orange and black bugs grab onto a stalk of milkweed (or any of several other plant hosts) with specialized sucking mouthparts and drink it dry.  Their story only gets weirder from there.  Oleander aphids develop from unfertilized embryos and all adults are female; males do not occur in nature.  Adult females can be winged or wingless, the former usually showing up when the host plant is overcrowded or dying so that they can fly off to infest a new host.  Both the winged and wingless adults excrete live nymphs instead of eggs, and a colony can grow quickly.  The nymphs develop through five different phases before becoming adults, but nearly all phases look the same and vary only in size.

If an army of jack-o-lantern colored female clones sucking the life out of a plant isn’t Halloween enough for you, I should also point out that oleander aphids have their own mummifying parasitoid wasp.  The aphidiid wasp (Lysiphlebus testaceipes) lays a single egg inside an aphid nymph or adult.  When the egg hatches the wasp larva consumes the aphid from the inside, so that it develops into a brown papery husk of its former self.  Much like stigmata mummy-wasp larvae, the wasp larva then spins a cocoon inside this mummified aphid, pupates, and chews its way out, leaving behind a bloated brown aphid mummy with a hole in it.  When a dense colony of oleander aphids is heavily parasitized, half or more of the aphids in the colony may eventually be only mummified remains while their sisters slurp placidly beside them.  How bewitching.

Horsehair Worms (Paragordius varius)

Resembling an animated, wiry strand of hair, horsehair worms are often spotted writhing in the bottom of woodland streams and pools. As charming as that may sound, their mating behavior is less than romantic.   When a female indicates a willingness to mate, the male releases a cloud of sperm in her general vicinity, and then swiftly dies.  The sperm forms a glob, which finds its way to the appropriate receptacle on the female within the next 24 hours.  A fertilized female goes on  to lay as many as 6 million eggs, and then she too perishes.  As It turns out this is the least offensive part of their life cycle.

Horsehair Worm (on top of leaf) found in a stream in Bristol, VT

The eggs mature, and in 2-3 weeks millions of tiny worm larvae are hunting for hosts in the pool or brook.  They infect many different kinds of aquatic phase insects, including mosquito larvae, and when the infected larva matures into its adult phase, the worm larva comes along for the ride.  Eventually this intermediate host insect is consumed by the host the worm is really looking for: crickets and their relatives.  Once inside this final host the worm begins to absorb nutrients through its skin from the host’s body.  Having no mouth or digestive system of its own, the worm requires an environment where food comes pre-digested.

While growing inside its host, a process that takes 2-3 months, the worm is also practicing mind-control.  An infected cricket will not chirp at all as chirping uses up precious energy and can attract unwanted attention to the worm’s comfortable home. Once the horsehair worm has fully developed inside of its cricket host (reaching lengths of four inches or more), it releases a chemical that drives the host to seek out water.  Meanwhile the worm has carved a hole in its host’s side, and shortly after the host hits the water the worm will emerge in its free swimming adult phase to mate, leaving its injured but still living host behind to begin the cycle again.

From the mummified remains of caterpillars, to the mind games of a parasitic worm, our Vermont backyards boast a roster of Halloween monsters rivaling those of the silver screen.  So this Halloween, when you find yourself telling scary stories with friends, borrow a tale right from your own backyard…and sustainably source your monsters.

Shelby Perry is a second year student in the Field Naturalist Program.  She would like to acknowledge Field Naturalist Graduate, Charley Eiseman, for his help fact-checking sections of this post, and his wonderful book Tracks and Sign of Insects and other Invertebrates: A Guide to North American Species.  

Monarchs Head South Toward an Uncertain Future

MonarchMontage-BryanPfeifferIf I went outside right now, hopped in the car, and started driving, it would take me 45 hours to reach the Monarch Butterfly Biosphere Reserve in Michoacán, Mexico, some 2,823 miles away. Though I badly want to see the groves of sacred firs (Abies religiosa) quivering and dripping with orange and black wings, I’m not leaving today. For now, I am content to have witnessed one of this year’s migrants emerge from its chrysalis. The process was one of biology and of magic.

When I first saw the chrysalis I thought the tiny, metallic gold markings seemed suspiciously intricate for a mere caterpillar’s changing room, and peered at them as if they might instead be explained by sci-fi alien manufacture. It turns out that these spots allow oxygen to reach the developing structures and organs of the enclosed butterfly.

The next morning, in the span of about 15 minutes, this female butterfly inched downward out of her chrysalis, re-distributed fluids from her distended abdomen to unfurling wings, and washed her face in preparation for what was to come. Her autumn journey to the Transvolcanic Mountains of central Mexico— if she can complete it—will take two months. To put this voyage in perspective, it is around seven times the distance traveled by caribou as they migrate from summer habitat to winter haunts. Caribou are billed as the land mammal with the longest migration in North America, whereas the Monarch is a butterfly whose flight has been described as “slow and sailing.”

monarch-1280x920The spring migration of Monarchs to New England is carried out by five different generations, each pushing north at distances more commensurate with their two-to-four-week lifespan and the floating nature of their flight. Monarchs hatched in late summer are among the generation that will live for several months to travel an incredible distance by putting their reproductive tendencies on pause, or rather, on diapause.

Diapause for the Monarch is a sort of flying hibernation that allows the butterfly to extend its lifetime, endure migration, and make it through the winter. Unlike hibernation, however, only specific environmental conditions can induce an organism to enter or exit diapause. In the case of a Monarch, when the days are long enough and the temperatures are just right, the overwintering butterfly shakes herself reproductively awake, mates, and then travels a few hundred miles north to lay her eggs on milkweed before dying.

Sadly, the odds for our particular young Monarch and her progeny are dismal. She faces habitat loss, changing environmental cues, invasive species and car windshields along the many miles of her journey. The population of Monarchs east of the Rockies is estimated to have declined by 90% since its level in 1995.

Nevertheless, government agencies, non-profit organizations, and concerned citizens are mobilizing to try to prevent the migratory Monarch’s extirpation. As with many environmental issues, large-scale actions such as policy change will be crucial. However, because the plight of the Monarch also plays out in our backyards, opportunities to help are close to home. You can plant native milkweeds to benefit individual butterflies. You can join other citizen scientists in supplying data to strengthen and inform the measures we take to protect Monarchs; check out monarchwatch.org.

The first, beautiful moments of a young female Monarch reawakened my awe and concern for this species. Instead of being crushed by the terrible thought that, if Monarchs were to go extinct, this mystical experience might become a mythical one, I am spurred to share the urgency of the situation. Urgency is more powerful when it is underpinned by wonder. And though this combination might seem like a fragile set of wings with which to entrust the fate of a species, I take comfort in the thought of Monarchs fluttering south towards Mexico, unfazed.

Anya Tyson is a first-year Field Naturalist student

Beyond the Jeep Road Sits Coyote — Wilderness in 2015

Southwestern desert

Southwestern desert

By Levi Old

On the first day of a 90-day expedition, our team made camp at the end of a jeep road. The afternoon sun, low in the sky, blanketed the desert’s red and orange rocks. Daylight quickly shifted into dusk. The rocks faded into shapes, and dropped shadows on slick rock in the crescent moonlight. The wind-worn surfaces that stood so vibrant in daytime were gone.

After dinner and a meeting about the next day’s plan, we embraced the opportunity to sleep out in the open. I found a flat boulder, climbed into my sleeping bag, and looked up at the night sky. The 10 students wandered around searching for sleeping spots, chatting with nervous anticipation and preparing their new equipment for a night’s rest.

“I bet this never gets old,” said Ben, 20, from Wyoming.

“Seriously,” agreed Lily from New York, “I’ve never seen stars like this before.”

I peeked over the lip of my sleeping bag and noticed the students gazing at the night sky.

The two college students traveled far from their comfortable existences to attend a three-month wilderness leadership course in the heart of the southwestern desert. Along with my colleague, I was their instructor. Around us, there was a more distinguished instructor— wilderness. Continue reading

Zombie Aspen Leaves

populusleaves-550x410By Bryan Pfeiffer

Rotting and fallen to earth, they might appear dead. But they are not quite dead. They are the undead: zombie aspen leaves.

Find them as you walk the brown autumn paths – yellow leaves with a patch of green tissue radiating from the base of the midrib. Here in Vermont, these are mostly quaking aspen (Populus tremuloides), but I also find the green on big-toothed aspen (P. grandidentata) and, rarely, eastern cottonwood (P. deltoides).

When a friend and I first encountered these some years ago, I collected a few and queried a handful of smart botanists for answers. Many had theories; none had an explanation. It wasn’t until I put a leaf under a dissecting microscope that I found the explanation to be less zombie than something from the film “Alien.” The beast lies within.

populus-caterpillar-moth-550Residing in a tiny pocket of tissue near the base of the green patch is a translucent caterpillar not much more than 2 millimeters in length. It’s feeding in there; I could see the frass (caterpillar poop). With help from Dave Wagner, the renowned entomologist at the University of Connecticut, our critter turns out to be a moth in the family Nepticulidae, probably Ectoedemia argyropeza or most certainly a member of that genus.

“The really cool thing is that the larva secretes an anti-senescent substance that keeps part of the leaf alive – probably a cytokinin,” Dave wrote in an email. Cytokinins are plant hormones that promote cell division. In this case, it seems, the caterpillar keeps part of a leaf alive so that it can keep eating.

This moth is also parthenogenetic; females can produce fertile eggs without help from males, which, as it turns out, are quite rare.

For now, however, the caterpillar will continue to dine in the verdant patch of an otherwise dead leaf. It will pupate for winter. And the tiny adult will emerge to fly in spring. Many species in this genus are black and white with orange scales around the head. But don’t expect to find one. Your best bet for discovering this animal is to watch the trail for patterns in poplar leaves this fall.

And if you’re raking them up, please note that some of those leaves, well, they could be saying, “I’m not dead.”

The Nuclear Option for Dragonflies

By Bryan Pfeiffer


A Common Green Darner (Anax junius) / © Bryan Pfeiffer

On a crisp, sunny day in September, after what was probably a typical summer for a dragonfly (which involves flying around, killing things and having sex beside a pond), a Common Green Darner took off and began to migrate south. As it cruised past the summit of Vermonts Mt. Philo, with Lake Champlain below and the Adirondacks off in the distance, the dragonfly crossed paths with a Merlin.

The Merlin, a falcon that kills in flight, swerved, plucked the dragonfly from the sky with its talons and began to eat on the wing. As the falcon and its prey continued southbound, all that remained in their wake was a single detached dragonfly wing, falling like an autumn leaf toward fields at the base of Mt. Philo.

Eagles, hawks, falcons and Monarch butterflies aren’t the only migrants moving south past mountains this fall. Joining them are dragonflies. Although biologists know plenty about the fall raptor and Monarch migrations, we are only beginning to discover, with some creative chemistry, where these dragonflies go and how migration figures in their conservation.

Fly or Die

Most dragonfly species do not migrate. In fact, most are now dead, having already mated during the summer season, leaving behind eggs or larvae to survive the winter. The killing frost will finish off much of what’s still on the wing. But some survivors will leave.

Wandering Glider (Pantala flavescens) / © Bryan Pfeiffer

Wandering Glider (Pantala flavescens) / © Bryan Pfeiffer

Among the 460 or so dragonfly and damselfly species native to North America, at least five are classic migrants: Common Green Darner (Anax junius), Black Saddlebags (Tramea lacerata), Wandering Glider (Pantala flavescens), Spot-winged Glider (Pantala hymenaea) and Variegated Meadowhawk (Sympetrum corruptum). Each species is on the move this fall.

Dragonflies migrate for the same reasons other animals migrate: to avoid inhospitable conditions, in this case habitats that freeze or become too cold for the dragonflies themselves or their insect prey. Monarchs go to Mexico. Broad-winged Hawks leave for wintering grounds stretching from southern Mexico into South America. Dragonflies head south to who knows where.

Having studied birds for two centuries, biologists know well their breeding and wintering distributions , even to the point of learning the destination of a particular warbler or sparrow after it leaves us in the fall. Ornithologists catch lots of songbirds in nets and place around one leg a tiny silver bracelet embossed with a unique number – an avian social security number – and then release the birds to the winds. A small percentage of them, still sporting their bracelets, are later recaptured while in migration or on wintering grounds thousands of miles away. Better yet, we’re putting small electronic transmitters on large birds, such as Bar-tailed Godwits and American Woodcocks, and tracking their movements real-time with satellites.

On of my tagged Monarchs before heading off toward Mexico.

A tagged Monarchs before heading off toward Mexico.

We can even track the movement of a single butterfly. I myself have placed little stickers, each bearing a unique alpha-numerical code, on the hind wings of more than 1,000 Monarchs here in Vermont and elsewhere in North America, and then set each one free to fly toward Mexico, where many are later encountered by conservationists searching for the buttterflies once they arrive in Mexico. With each recovery, we learn more about Monarchs and how they migrate.

The “Heavy” Hydrogen

Dragonflies aren’t so obliging. For one thing, we’re clueless about where they go. Monarchs concentrate each winter in stands of Oyamel Fir in mountains west of Mexico City. So we know where to find them and how to protect them. Tagging or somehow marking a dragonfly would be like putting a message in a bottle and tossing it out to sea. Actually, I suspect we’d find the bottle before the dragonfly.

Yet it turns out that we need not tag or otherwise mark these migratory dragonflies because they themselves carry clues about where they have been. If the Merlin doesn’t get it first, we can catch any migrating dragonfly, analyze trace elements in its tissue and determine roughly how far it has flown.

Our marker is water, more to the point the two hydrogen atoms in water. Recall from high school chemistry that hydrogen nucleus normally contains a single proton and no neutron. But a tiny fraction of hydrogen atoms around the world carry one proton and one neutron. We call it “heavy hydrogen,” or deuterium. And unlike other such atomic variations among elements (which can be radioactive), deuterium is stable in the environment – a “stable isotope”– and stable in the wing of a dragonfly.


Credit: Migratory Dragonfly Partnership

The amount of deuterium in water varies somewhat predictably in North America. You can map it. The ratio of deuterium to hydrogen in water falling as rain or snow changes on a gradient corresponding roughly with latitude. Water in Alberta, for example, carries a different deuterium-to-hydrogen ratio than water in Alabama.

Because dragonflies grow up as nymphs in water, they incorporate the local deuterium ratio into their tissue. It’s like a dialect or an accent that a dragonfly bears for life – whether as a nymph in water or a free-flying adult in migration. A Common Green Darner on the wing over Mt. Philo or Miami unwittingly carries a particular deuterium ratio, a birth certificate that tells us generally where it grew up. You are what you eat – or drink.

This science isn’t perfect. We can’t pinpoint a dragonfly’s natal waters in the way we know where a banded bird hatched or a tagged Monarch emerged. But stable isotopes are helping us track the range of migrating dragonflies. It’s “better living through chemistry.” After all, we can’t really know a bird or butterfly or a dragonfly – and what it might need in the way of conservation – until we know all the places it lives or wanders.

By the way, you need not be a chemist to help track dragonfly migration. We’re counting dragonflies in the same way we count migrating raptors during hawkwatches each fall. Learn how to do it and report what you find with help from the Migratory Dragonfly Partnership.

And while we’re out there counting, if a Merlin happens to catch a dragonfly first, we can still make a difference … by catching one of those dragonfly wings floating toward Earth.

Bryan Pfeiffer is a writer and field naturalist who specializes in birds and insects. He teaches writing in the University of Vermont’s Field Naturalist and Ecological Planning Programs.

A Prayer for Monarchs


By Rob Rich

The flaring wings or the breezy wisps of aspen and birch are few today. Gone are the flights of spring, but at Mobbs Farm in Jericho autumn is in flight. Apples and acorns plunk down with minimal elegance, but the swirling leaves trade the birds for brightness in the distant wood. And across the rusty meadow, others waft down lightly before winter. This is a day for milkweed, hinting at flurries to come.

They glide with a powdery lift by a pappus – the Greek for “old man” – providing cottony parachutes for each kernel. Soft, green pods once held them moist and tight, but now they are freed as they crack in the crisp, dry wind. The pods tear apart, opening for each white pappus to glisten like eyes in the gaze of the sun. They lift with a grace that seems to laugh at gravity. But failing to plant in the sky, they finally fall. I wantonly tear at some unopened pods, eager to help the silky strands find a resting place on earth.

Continue reading

Petri Dish Pathos


By Matt Cahill

I spent the afternoon sorting a tangle of dead bodies.  Their legs were all snarled in a heap.  I had to pry each little corpse apart, delicately, one at a time.  Down the barrel of my microscope the petri dish was filled with yellow stripes and cellophane wings, stray heads and dispossessed parts.  How lovely, I thought, to see nature up close.

Then in the middle of the pile, underneath the furry abdomen of a bee, a set of small black legs began to wiggle.  These insects had been stewing for two weeks, ever since I had swept them up in my net from the late-summer goldenrod and dumped their squirming bodies into a calm bath of ethanol.  They should have been very much dead.

But the legs kept wiggling.  Pushing the bee aside, a small wasp head emerged, yellow-painted with large black eyes, quivering.  The tiny wasp crawled up on the pile of bodies like a shipwrecked sailor on a sandy shore.  I shook the dish to knock it back under.

“Savage! What gives you the right to kill?” the small wasp yelled when it surfaced again. Continue reading