The love-hate relationship with some caterpillars can be vexing even for a nature lover

Sue Pike seacoastonline.com Published August 18 2022

I find I have to constantly keep my knee-jerk reactions to certain insects in my garden in check.  I tend to have an us vs them mentality when it comes to insects that I find feeding upon the foliage of plants I hold near and dear to my heart.  I planted a hedgerow a number of years ago that is just starting to flourish.  In it grow a variety of native shrubs-spicebush, elderberry, chokecherry, serviceberry.  The idea is to create safe harbors and food sources for native insects and birds.  Last week two different caterpillars showed up on the serviceberries.  These two caterpillars perfectly illustrate my sometimes conflicted reaction to the insects that eat my plants-a tiger swallowtail caterpillar and some yellow-necked caterpillars (Datana ministra).

Tiger swallowtail caterpillars rest during the day in webby hammocks Sue Pike photo

Tiger swallowtail caterpillars are adorable: medium-sized plump green caterpillars with a swollen thorax (the segment right behind the head, which in this case covers the head) sporting two prominent false eye spots used to scare away would-be predators.  The flying adults are large yellow and black butterflies with the dangling tails, fairly common in this area.  There are two similar tiger swallowtails found in this area.  The range of the Eastern tiger swallowtail (Papilio glaucus) extends further south and the Canadian tiger swallowtail (Papilio canadensis) further north.  To make things more confusing, these two species hybridize in central New England-so this particular caterpillar might be a cross between the two species.  Since it is difficult to distinguish hybrids from Eastern and Canadian tiger swallowtails, I have referred to this caterpillar as a tiger swallowtail-that much I’m sure of. 

Yellow-necked caterpillars are cute in their own way-dark heads, a bright yellow segment just behind the head (hence the name), with sporty brown and yellow stripes running the length of their bodies.  But they lack those engaging cartoon eyes and, more importantly, they are very gregarious-I counted at least 50 on the serviceberry bush.  Groups of ten or more were clumped on the branch tips, actively stripping the serviceberry of its outermost leaves (unlike the low-key solitary tiger swallowtail). Later this summer they will burrow into the ground to overwinter before emerging next spring as small moths.  Instead of the delight I felt upon seeing the tiger swallowtail caterpillar I immediately began planning their demise.    

Yellow-necked caterpillars are not as ‘cute’ as tiger swallowtails and are more obvious defoliators. Large groups can quickly strip branches bare of leaves. Sue Pike photo taken at littleriverphotoworkshop

If you do a search on tiger swallowtail caterpillars you’ll find lots of interesting life-history, nothing about ‘control’ since these are not considered a pest species.  Yellow-necked caterpillars, on the other hand, are considered pests.  They can cause damage to planted fruit and shade trees, but in their natural environment, in a forest for example, they do not significantly damage their host trees.  

The purpose of my hedgerow is to provide food and shelter for native species.  Both the tiger swallowtail and the yellow-necked caterpillars are doing what comes naturally, feeding on the leaves of the trees and shrubs in my hedgerow.  Both of these species provide food for birds, predaceous bugs and parasitic flies. As I considered the fate of my yellow-necked caterpillars I realized that removing them meant removing a food source for others as well as contributing to the decline of a native insect.  I figure that if the yellow-necks feed according to plan they will defoliate just the outer branches of my serviceberry bush.   If I’m lucky some robins (robins evidently love yellow-necked caterpillars) will discover them and provide a little bit of control. But if not, my serviceberry should survive this natural pruning, and hopefully next year will support even more backyard diversity.

Hopefully my serviceberries are healthy enough to withstand these yellow-necked caterpillars! Sue Pike photo

Black bears can have a coat of many colors in Alaska

Sue Pike seacoastonline.com Published August 9, 2022

While working as a naturalist in Southeast Alaska this summer I learned so much about the vastly different flora and fauna found in the temperate rainforest that we were traveling  through.   But even more eye-opening was when I experienced wildlife common to New England in a totally different way.  One species we frequently encountered that I now see in an entirely different way is the black bear.

Brown variation of a black bear foraging on barnacles in Alaska’s Inside Passage Sue Pike photo

When you go to Alaska you expect to see brown bears (the coastal name for grizzly bears), but we saw just as many black bears. Those of us from the East Coast were not too excited by our encounters with black bears.  We were jaded. We all had stories of black bears ripping down our bird feeders or hanging out on our back porches…we were there to see the iconic Alaskan brown bears.   However, with time we began to appreciate just how wild these bears were compared to our suburban black bear neighbors.  In Alaska we watched black bears coming down to the intertidal to eat barnacles and mussels or flip up rocks to catch all the interesting crustaceans that live underneath.  This was a far cry from our bird-feeder plundering backyard bears. 

Black bears (Ursus Americanus)  are found throughout most of North America-from northern Mexico up to the treeline in Canada and Alaska.  Black bears are the smallest of North America’s native bears (black, brown/grizzly and polar), and are the only bear found in the eastern US.   East Coast black bears are usually black, but out west black bears come in a host of colors-anywhere from black to brown to blue/gray to white (the rare and elusive ‘spirit’ or Kermode bear).  In fact black bears have more coat color variation than most North American mammals!  One has to wonder what name black bears would have been given by European settlers if first encountered on the West Coast.

You can tell this isn’t a brown bear (aka grizzly in some parts) by the lack of a shoulder hump and snout shape. Sue Pike photo

The actual reason for these different color phases isn’t known but there are several plausible theories.  The darker black bears are better camouflaged in our deep East Coast woods.  Out west where their habitat includes more big open meadows, lighter colors could provide more camouflage as well as some protection from the more intense solar radiation (like wearing lighter colored clothes in the summer). We saw brown black bears in SE Alaska, a temperate rainforest where thick coniferous forests stretched from the shoreline up to the treeline, one would think the lighter color could be a liability there.   Another interesting idea posits that the brown coat color is a form of mimicry-making black bears look like their larger, more ferocious cousins, the brown/grizzly bears.  The best way to tell a grizzly from a black bear is to look for the grizzly’s telltale shoulder hump.  Black bears can also be distinguished by having a rump higher than the shoulder, a straight face profile with an often lighter muzzle and tall, somewhat prominent ears.

One of the biggest lessons I learned about black bears from my experience in Alaska was just what opportunistic feeders these animals are. Watching them smash barnacles and mussels in the intertidal and then licking them from their paws one minute, contentedly munch on salmonberries the next, then graze on coastal sedges like a deer while waiting for the salmon to run made me realize I don’t really know what they eat in my backyard besides bird food and blueberries.  According to Maine’s Department of Inland Fisheries and Wildlife “Although bears eat meat, their diet is primarily vegetarian, including early greening grasses, clover, and the buds of hardwood trees in the spring, fruits and berries in summer, and beechnuts, acorns, and hazelnuts in the fall. This diet is supplemented with insects, including ants and bees (their larvae, adults, and honey), and occasional mammals and birds. Bears are not considered efficient predators, but they are known to prey on young deer and moose in late spring, and will consume carrion. Bears are intelligent, and adapt rapidly to new food sources, including agricultural crops and food placed to attract other wildlife, such as bird feeders, and untended garbage.”  

We are slowly heading into fall, a time when bears will be bulking up for their winter-long fast.  Females in particular need to put on an enormous amount of fat to support fetal development and milk production.  So, if you haven’t done this already, keep a tight lid on garbage and bring in the bird feeders at night if you have a significant bear population in your area.  Problems between bears and humans are more likely to occur if we allow bears to become too familiar with us. While I knew this already, because we were out in the wilds with bears so much in Alaska this became more real. When walking in the woods with bears (both black and brown) we wanted them to leave when they heard us coming-not view us as a potential source of food. 

Nature News: The Common Loon

published week of August 16th in local Seacoast Media Group newspapers and online 8/20/2021

As a teacher, all summer is a vacation. In theory, because like most teachers I work in some way during the summer, if not a paying job then doing some sort of professional development for the upcoming school year.  So, I take vacations within vacation during the summer-my most recent being a canoe trip down the Richardson Lakes in Maine.  I wasn’t sure what to expect, I was hoping to see moose, but it has been too dry up there-they were staying back in the swamps in the woods since the water level of the lake was 8 feet down.  Instead we spent most of our time in the company of loons.  They regaled us at night with their eerie calls. They accompanied us as we paddled from campsite to campsite, getting so close to the canoe that we were afraid to fish and accidentally catch a loon.  While doing so we learned one of their many common calls-the ‘toot’  (which we had previously thought was a dog barking) and got glimpses into their social and hunting behavior.  

Loon sporting beautiful contrasting breeding plumage including brilliant red eye. sue pike photo

The common loon (Gavia immer) is one of those birds that everyone can identify.  Their breeding plumage is beautiful-black and white checks on their back, a black head with a contrasting black and white vertically-striped neck rings, a bright white belly and piercing red eyes (the bright red eye is probably a visual display since their eyes are brightest during mating season). They have long bodies with feet set in back to help with swimming and huge, dagger-like beaks (one of the many reasons we didn’t want to accidentally catch a loon on our lures).  Loons are members of a family of birds -the loons or divers-that are built for swimming underwater, in fact they only go to land to mate and incubate eggs.  

Loons are built for swimming

According to Cornell Lab’s “All About Birds” in addition to their overall body plan, “Unlike most birds, loons have solid bones that make them less buoyant and better at diving. They can quickly blow air out of their lungs and flatten their feathers to expel air within their plumage, so they can dive quickly and swim fast underwater. Once below the surface, the loon’s heart slows down to conserve oxygen.” Loons have been recorded swimming as fast as 20 miles per hour and can turn on a dime.  They can see well underwater-we watched as loons floating on the surface ducked their heads into the water scanning for the small fish (like yellow perch) that are their primary prey before silently disappearing underwater to catch said fish. 

Loon scanning the depths for fish sue pike photo

The search for young loons and rafting loons

When we picked up our rental canoe we were told that the loons seemed to be rafting up early this year (in preparation for migration to the coast) and that there were no chicks on Upper and Lower Richardson Lakes this year.  We hoped to prove this wrong and find some juvenile loons, but didn’t.  

We did, however, see lots of groups of loons congregating (rafting) on the lake.  While they might be readying for migration, they might also be gathering for a loon social hour.  When we saw groups of loons nearby they were more likely to make short barking calls back and forth (the calls that we originally mistook for dogs) rather than their eerie yodeling calls.  We felt there was a group of 4 loons following our canoe (probably just fanciful imaginings on our part) that would be progressively joined by pairs of loons forming a larger group (we once counted 11 loons) that ‘talked’ and fished for a while and then dispersed. 

Looks to me like social hour for loons sue pike photo

Loons get more social as summer progresses

According to the Cornell Lab, earlier in the summer loons are not social and generally stay just as mated pairs (loons have been observed violently defending their territories against other loons), but as summer progresses they will come together into social gatherings at specific times-these gatherings often include non-territorial birds and unsuccessful breeders with successful breeders joining the groups as summer progresses.  In the fall even larger groups form to fish together before migration.  I wonder whether, because of the absence of chicks, the loons were holding their social gatherings earlier in the season than usual?  I hope that the absence of chicks on the lake wasn’t a pattern for other lakes.  Maine Audubon just held their 2021 Annual Loon Count (a great citizen science opportunity for loon lovers) -the data from that should be ready in a few months.  

This could be a loon in its stressed, aggressive ‘penguin posture’ telling us to go away, or the more social ‘vulture posture’ thought to help amplify their yodeling calls. I’m guessing stressed-since we are near it. sue pike photo

One of the many reasons I love living in the north is our proximity to habitat that supports wildlife like the loon.  Finding loons on a lake is a good indicator that the water is clear and unpolluted, that fish swim in abundance below the surface. The loon is one of those icons of the north-its haunting call reminding us of the wild places on earth-the beautiful places untouched by sprawl and urbanization.  

Nature News: At what point should we give up trying to control the invasives?

published June 24 2021 in The Portsmouth Herald, York Weekly, Fosters’ Daily and other Seacoast Media Group newspapers and online.

I’ve been driving back and forth to Manhattan fairly frequently to visit my aunt and like to spend some of the long drive checking out the vegetation growing in the various rest stops.  There is one pretty little clover-type plant growing in both my super-sandy scrubby field and in most of the roadside rest stops and median strips, bird’s-foot trefoil (Lotus corniculatus), that I decided to investigate further.  This is not the lotus blossom famous for its beauty or, in Greek mythology for its narcotic powers (check out the Lotus Eaters of the Odyssey fame), but rather the name given to the genus of a group of plants in the pea family.  The species name, corniculatus, refers to its common name ‘bird’s-foot’ in reference to the ripened seed pods which curve outwards resembling a bird’s foot, each toe curved like a talon (hence “corniculatus” meaning small horns).  The “trefoil” part of the name, which means ‘three leaves’ is a misnomer, these actually have 5 leaflets, three prominent ones and two hidden beneath.  

Bird’s-foot trefoil are beautiful, aggressive, soil-building, nitrogen-fixing non-natives -sue pike photo

3-foot taproots, fibrous mats of rhizomes–yikes!!

If you take a close look you’ll see that they do have clover-like leaves and flowers that resemble most of our other wild peas.  Sadly, they are non-native, have spread throughout the United States and up into Canada and Alaska and are considered noxious invasives in some states.  A native of Europe and Asia, they were introduced as forage for livestock. With their 3-foot taproots and fibrous mats of rhizomes they can quickly take over an area, smothering other native species.  

Considered edible but all parts are poisonous

I thought, since they are in the pea family, they might be edible. Here’s where it got interesting.  After some intensive googling I found one of my favorite descriptions of its edibility:  “Bird’s-foot Trefoil, Lotus corniculatus, is a member of the Pea Family and has been considered both edible and medicinal but be aware that all parts of this plant are poisonous.” (cargocultcafe.com).  This is one of those plants that contains small amounts of cyanogenic glycosides (cyanide) that are not a huge issue in small amounts (and have been used medicinally in the past)  but can be lethal to humans if enough is consumed.  However, for wildlife it is a different story; bird’s-foot trefoil  is considered a choice food by Canada geese and deer and attracts a variety of pollinators.  

Most of the flowers in my meadow aren’t native anyway….

While I would love to have only native species growing in my yard, I would guess that at least 50% of the plants growing in my field/lawn are non-native.  This is partially because these mowed fields are not a native habitat to this area and so attract and support any non-native open field plant that can get a toe-hold.  I am trying to figure out whether to control this plant to keep it from dominating the field, reducing the overall biodiversity, or to eradicate it completely. Given that we have nutrient-poor sandy soil that many plants don’t like to grow in to begin with, and, as a legume it is a nitrogen-fixer, I’m leaning towards controlling but not eradicating it.   In addition, bird’s-foot trefoil has beautiful clusters of bright yellow pea-like flowers shot through with streaks of red which the bees, wasps and other pollinators seem to love as much as the dandelions, butter-and-eggs toadflax, black-eyed-Susans and daisies that populate the field, which, by the way, are also non-natives. 

Nature News: Where’d the chickens go? The real life story of the foxes and the chickens

published June 19 2021 The Portsmouth Herald, York Weekly, Foster’s Daily and more Seacoast Media Group newspapers and online.

We are seeing lots of evidence of baby animals in our backyard these days. 

A persistent little red squirrel we’ve named Rusty is always coming by to see whether we have any seeds for her young. We figured out she was a female this spring when her eight teats were suddenly impossible to ignore. Baby nuthatches and house sparrows follow their parents through the trees begging for food. We can’t go into the barn until the young phoebes have finally left the nest. And, our neighbors told us about a red fox den just a couple houses down, with beautiful little pups (or kits, both are acceptable names for young foxes) frequently spied rolling around outside their den. 

Red fox pups play outside their den next to neighbors’ house -steve morello photo

I have yet to see the fox, but, unfortunately my chickens have. We had a nice small flock of 11 chickens shrink to an even smaller flock of one lonely bird within two weeks. We don’t know this for a fact, but based upon the piles of feathers that leave a Hansel and Gretel breadcrumb-esque trail up toward the fox den, we have a fairly good idea who the predator is. At least there are some well-fed young foxes out there!

Don’t encourage foxes by leaving out bird food or free-range chickens.

It isn’t a surprise that we have red foxes in the neighborhood. I’ve caught them a couple times with the game camera and have seen their tracks in the snow. I can’t really begrudge them my chickens. I was reading a post by the Maine Department of Inland Fisheries and Wildlife – How to Prevent or Resolve Conflicts with Foxes – and it is fairly obvious that our fox “problem” is our fault. “Research suggests that humans create the conditions for conflict by deliberately or inadvertently providing animals with food and shelter. Preventing or removing access to these attractants is the first essential step to resolving a wildlife problem. This includes eliminating access to shelter, being smart about garbage, planting native plants to attract birds rather than using bird seed, protecting poultry and livestock, and being a responsible pet owner.”  While I love having my chickens free range (chickens are intelligent, curious birds who love exploring their surroundings), I’m not being a responsible poultry owner by letting them free range into a red foxes’ hungry jaws. It never even occurred to me that foxes might love bird feeders as much as bears. 

Our red foxes are probably not native

The red foxes that live in New England are probably not native. There is a huge amount of debate about this in the research community, but what most agree on is that there were subspecies of European red foxes (Vulpes vulpes) in the northern boreal forests of North America prior to European colonization of these parts. We also have a definite native, the gray fox (Urocyon cinereoargenteus), which has a more southern distribution than the red fox, is smaller and more cat-like, and can climb trees. The native North American red fox (now considered a subspecies of the Old World red fox) didn’t do well with the influx of colonists and subsequent habitat disruption, so the gray fox was the one more frequently encountered. Those early colonists liked to fox hunt and didn’t do so well tracking the gray foxes up into the trees, so instead imported red foxes from Europe for recreational fox hunting, and now this red fox has spread throughout the continent. In fact, red foxes are the most widely distributed carnivore in the world and can wreak havoc upon small mammal and bird populations (think about what their introduction to Australia, that lacked this kind of predator all together, must have done to native bird populations!).  

Native or not, red foxes aren’t going anywhere. They can actually be quite beneficial to have in your neighborhood since they do a wonderful job controlling rodent populations (we have a fairly robust rat population – due to all the chickens – so this is great!). 

The Irish word for fox might be the root of the word shenanigans

And, if you think about it, the Old World red foxes  are the type of species expected to do well with a human presence. They are wily animals. Coyotes are one of their main predators around here, so to keep the coyotes at bay, red fox tend to stay close to humans, our presence inadvertently protecting them from coyotes. The Natural Resource Council of Maine has a great post about fox wiliness, with a great fun fact “The Irish word for fox, ‘sionnach’, is believed to be the root of ‘shenanigans,’ to play tricks.”

I have reinforced my chicken pen and acquired some more chickens. I hope to keep these chickens from escaping and getting in harm’s way, but chickens are wily, too. I worry that they’ll figure out how to get out of the somewhat protected chicken run and wander, like the hapless chickens before them, straight back to the hungry local foxes’ jaws.

Nature News: Lambsquarters A Prolific Weed You Can Eat

Published June 12, 2021 The Portsmouth Herald, the York Weekly, Foster’s Daily etc

We recently bought a beautiful load of composted pig and cow manure from a local farm.  I’m still working on building soil in my garden (our native soil is mostly sand–left over from the last glaciers that plowed through this area), so any organic content is great.  Travelling along with the manure was a healthy crop of lambsquarters.  This is a weed that grows almost everywhere–anywhere there are people and soil to grow in.  

Lambsquarters growing in profusion from the composted pig manure -sue pike photo

Lambsquarters are in the beet and spinach family!

Lambsquarters is a member of the goosefoot (Chenopodiaceae) which also includes beets and spinach.   Lambsquarters is not native to North America, but does have an interesting history here.  It is thought to have originated in Europe and Asia and then was spread to Africa, Australia and the Americas by human activity a really, really long time ago. Recent archeological studies have found seeds stored by Native Americans pre-dating the arrival of European colonists(who also most certainly brought lambsquarters with them to the Americas), suggesting that these plants were among the earliest invasive species (perhaps we could call them paleo-invaders along with the humans who brought them) in North America. 

Goose foot-shaped leaves are one distinguishing feature

This fast-growing summer annual typically grows to about three feet tall and, while its leaves can take on a variety of forms depending upon growing conditions, usually has ovate to triangular leaves with toothed or slightly lobed edges with a white coating on the undersides. The scientific name for lambsquarters is “Chenopodium album” which refers to the shape of the leaves. “Chenopodium” comes from the Greek for goose foot – it really does resemble a goose foot. The species name “album” is Latin for white; this refers to that white coating which distinguishes it from other members of this genus.  You can generally guess that a plant has a long history with humans based upon its common names.  

White gritty coating on the underside of this leaf vanishes when you cook it -sue pike photo

One common name for lambsquarters is goosefoot-due to the shape of the leaves.  According to “The Real Food Encyclopedia” (foodprint.org) ““Lamb’s quarters goes by lots of different names, including “white goosefoot,” “pigweed,” “dungweed,” “baconweed” and “wild spinach.” One of its names, “fat hen,” comes from its supposed ability (as a feed) to fatten chickens.” These names speak to its many uses by humans-as a feed for pigs, as a substitute for spinach (it cooks up just like spinach), how great it tastes with bacon.  I love the name “Dungweed”, it  resonates with me and my big pile of pig manure.  

Eat the Weeds!!

There are a couple reasons lambsquarters accompanied humans on our migrations around the world.  It is extremely nutritious-it has even more protein, calcium, phosphorus, iron, vitamin C, and vitamin A then spinach.  Like spinach it is high in oxalic acid–which interferes with absorption of calcium and iron (among other things), so should be eaten in moderation, or blanched.  Blanching leaches out a good amount of the oxalic acid. Before you panic and decide not to eat lambsquarters, be aware that  rhubarb, tea, beer, almonds, chocolate and bananas are also high in oxalic acid.  

The goose-foot shaped leaf is very distinctive -sue pike photo

Lambsquarters has also spread so far because it has all the traits to make it a highly effective weed.  One plant can produce 70,000 seeds.  These seeds are tough, they can survive most digestive tracts (hence all those cute little lambsquarter plants springing out of my manure pile).  While this is a wind-pollinated species, it most often self-pollinates, ensuring a next generation. It also is resistant to many herbicides–which I think is great since herbicides are poisons that we shouldn’t be using in the first place.   I guess the take-home message here is if you want to control it in your garden, eat it before it goes to seed.  Or, alternatively, you can try letting some go to seed and harvesting the seeds-lambsquarters are in the same family as quinoa and amaranth-wouldn’t it be great to produce our own version of superseeds at home in our backyards? We are in the middle of a heat wave, most likely caused by our huge carbon footprints.  This is one small way to reduce our carbon footprint and create a more sustainable future-eat the weeds! 

Nature News: Tracking a predatory stink bug

Anchor stink bug hauling this monarch caterpillar (already dead) around the milkweed plant Sue Pike Photo

Ever since my young cousins in New Jersey sent me photos of monarch butterfly eggs and tiny snow white monarch caterpillars with black heads (they don’t get colorful until later in development), I have been looking for the same on my milkweed plants. Unfortunately, the one and only monarch caterpillar I have found so far was dead, killed by a predatory stink bug. While great for the stink bug, this was, of course, tragic for the monarch caterpillar. We were unhappy as well since we have been encouraging milkweeds and planting all sorts of wildflowers in an attempt to create a safe haven for these beleaguered insects.

Initially, watching this menacing-looking bug drag the hapless carcass of the monarch caterpillar around, I was horrified and wanted to know who the culprit was. Identifying insects can be incredibly difficult. I tried some books and the internet, and I decided it was some sort of stink bug, perhaps an anchor stink bug. According to a “Featured Creatures” bulletin put out by the Florida Department of Agriculture and Consumer Services, the stinkbug “genus is recognized easily by the enlarged long and broadly oval scutellum (located behind the pronotum) … subapical spine on the front femora; and ventral pubescent patches on the males.” I didn’t know what any of that meant, so I resorted to iNaturalist and the awesome folks at bugguide.net for the final identification. My tiny predator did turn out to be an anchor stink bug (Stiretrus anchorago).

The red arrow points to the ‘anchor’ on the stink bug’s back. Not real obvious here. Sue Pike photo

Now that I knew what an anchor bug looked like, I decided to at least learn what one of those seemingly obscure anatomical terms referred to. I call myself a naturalist and, upon finding out what a scutellum was, realized I’m a fairly ill-informed naturalist. All true bugs have a hard plate, called the scutellum, that is usually triangular, on their backs. The anchor bug’s scutellum is unusually large and U-shaped, something like a shield with a black anchor-like pattern on it. Now that I knew what to look for, the scutellum was, indeed, a very prominent and recognizable feature.

While refreshing my memory on insect anatomy, I was reminded of some of the differences between insects that are known as true bugs (some common examples are cicadas, water striders, stinkbugs and spittlebugs) and other insects, like beetles (not true bugs). It can be difficult to identify insects down to their species, but once you know what to look for, you should be able to distinguish a beetle from a true bug fairly easily. Beetles have chewing mouthparts whereas true bugs eat a liquid diet. True bugs have a beak, which they use to suck out the contents of whatever it is they are eating. The anchor bug uses its beak to harpoon its prey and then inject digestive enzymes that first immobilizes the prey and subsequently turn its insides into goo, which they then suck up with those same beaks. If you look carefully at the photo, you can see a tubular structure attaching the anchor bug to the caterpillar — that’s the beak, firmly implanted in the caterpillar. A number of pests (aphids, for example) are true bugs that use their beaks to feed on the fluids inside plants.

The easiest way to know whether you are seeing a true bug or a beetle is the wings on the back. Beetles have hard, leathery forewings that cover up and protect the hind wings. When at rest, the hard forewings meet in the middle of the back forming a line down the middle separating the two wings. These have to be lifted out of the way when the beetle flies. Only the first part of the forewing of a true bug is hardened (hence the scientific name, Hemiptera, which means half wing). At rest, the wings cross over each other so that from above they have a triangular shape. All true bugs also have a scutellum in between the wings, sometimes it is reduced in size and sometimes it is big and obvious, like in the anchor bug.

Anchor bugs live solitary existences, roaming the landscape in search of prey and are considered to be economically beneficial insects. As generalist predators, they are good biological controls of a variety of pest species (though they really aren’t common enough to make a big dent in a pest population). Look for them in your garden or a nearby field, they are strikingly beautiful bugs with their bold patterns of black and red, yellow or white. Now that I know who they are, next time I see one, I will welcome it gladly and not judge it for killing the occasional monarch butterfly, being, as they are, important members of our local backyard ecosystems.

Ice is Magic

published Feb 5, 2020 in the York Weekly, Portsmouth Herald and Foster’s Daily and online at seacoastonline.com

I spent almost the entire first semester last year having my freshmen STEM class run experiments about ice. Every morning, when I walk my dog, we follow a path along the river and observe the ice, marvel at the huge slabs of ice that are carried downstream and stacked like pancakes in some places, crunch our way over the paper-thin ice that coated the hummocks of the floodplain after the last brief thaw, watch dangling orbs of ice form in the waterfall that spills down to feed the river. I, like so many others, am obsessed with ice.

If you think about it, ice formation on a pond or lake is fairly straightforward. As the water gets colder, it gets denser and starts to sink. Liquid water reaches its maximum density at 4 °C (39.2 °F), after that it continues to get colder and freeze solid, but as it freezes, it becomes less dense and floats to the surface and we end up with ice-covered lakes.

Ice slabs pile up in Little River

At first, the ice is paper-thin, fragile sheets that crumble in your hand. As winter’s cold progresses, the ice gets thicker and thicker as more ice is added from the bottom. As long as the pond or lake is deep enough, there should always be at least some liquid water underneath the ice. This is very helpful to the animals that live in the pond or lake. They can survive in the liquid water near the bottom until the spring thaw.

Now, think about a river or stream in which the water is constantly moving. All of that turbulence makes it difficult for a nice sheet of ice to form. On cold winter nights, the surface water of a river cools, crystals of ice form and start to grow. The constant water movement keeps the crystals from growing together into a solid sheet, instead you get a slushy mixture of water and ice called frazil ice. You can see this floating on the top of a river in early winter, or instead of floating on top, because the crystals are so small, they can easily be carried by the turbulence down to the bottom of the river.

Ice slab close-up with river behind it

As temperatures continue to drop, the frazil ice can start to join together at the surface and form round plates of ice with upturned edges (from the plates bumping together). This is called pancake ice. Or, what was more common on my river, ice will start to form along the edges of the river. Ice forms more easily along the edges because there is typically less water movement and the temperature of the shallow water on the edge cools faster. This is called border or shore ice. Border ice will generally enlarge toward the middle of the river until the ice from both sides meet.

Border ice forms along a small stream

Another interesting way a river can freeze is when the frazil ice that is transported to the bottom of the river attaches to the streambed and builds from the bottom up. This is called anchor ice. Anchor ice can grow very rapidly and block the flow of a river or stream causing local flooding. If there is particularly low flow of water along the bottom, an enormous amount of anchor ice can build up. This can be extremely harmful to aquatic life because the anchor ice can physically lift up parts of the streambed and move it downstream, movement akin to the action of a bulldozer, killing small fish and aquatic invertebrates (like dragonfly or caddisfly larvae) that live in the streambed, or freezing fish eggs that were waiting for spring to hatch.

I thought I first fell in love with ice in some dramatic location, perhaps when I crossed Lake Champlain on the ferry one cold winter’s night and watched the prow cut through the ice and listened to it grind against the hull of the boat, or when I was travelling as a National Geographic Grosvenor Teacher Fellow in the Arctic Ocean and witnessed firsthand the ethereal beauty of icebergs and the vast expanses of pack ice in the polar sea. But watching the beautiful, ever-mutable ice along my little river this winter has made me realize that I’ve loved ice since I was a kid watching icicles dangle from the gutters of my house, that no matter where you find it, ice is magic.

In winter’s cold, the subnivean zone is abuzz

Published January 21 2020 The York Weekly, Portsmouth Herald and Foster’s Daily and at seacoastonline.com Titled ‘Nature News’

The subnivean zone lies between the snow and the earth.

This winter has been troublesome; a few weeks ago it was so cold my pipes froze, then it we climbed to unseasonably warm temperatures, then some more snow, and now, very cold again-my pipes continue to freeze. One thing that makes me happy is that we have a nice layer of snow on the ground, insulation that is is vital to the survival of many of the plants and small mammals, even microscopic life forms, that are essential parts of our Northern ecosystem. So, for many, the recent snow was welcome relief from the cold.

While the surface seems empty, underneath, at the interface between ground and snow, a veritable city is rising. Old leaves and branches hold the snow up, creating an open space. The ground also radiates heat, warming the overlying snow, which instead of melting sublimates (when a solid turns into a gas without first becoming a liquid) directly into water vapor. Both of these processes leave a space between the snow and the ground, called the subnivean zone.

The word “subnivean” comes from the Latin for under (sub) the snow (nivean) and is a scientific term referring to the open passageways that form under deep snow.

Six or more inches of snow are all that are needed to trap the earth’s heat and allow a subnivean zone to form. This zone remains humid because of the transformation of snow into moist water vapor and is capped by a layer of ice that acts as an insulating roof. The temperature of the subnivean zone is generally a constant 32 degrees, protecting species that would otherwise freeze.

The most common inhabitants of the subnivean are mice and voles — they make tunnels under the snow connecting sleeping areas and sources of food. Red squirrels also burrow into the subnivean to stash food. Entrance holes to these networks allow carbon dioxide to escape. Carbon dioxide is released when these animals breathe and by the ground itself. Without the entrance holes to serve as ventilation shafts, carbon dioxide could build up to lethal levels.

While the subnivean zone provides protection for mice and voles, it is also the hunting ground for the short-tailed weasel (or ermine), a weasel that, except for its black-tipped tail, turns snowy white in the winter. This small weasel, just the right size to live and hunt in the tunnels under the snow, is a major predator upon small rodents.

All you need is about 6 inches of snow to allow the subnivean space to form

Recent research has unearthed a whole new category of inhabitants of the subnivean zone — microbes that are proving to be important players in the cycling of both nitrogen and carbon dioxide between the earth and the atmosphere. A deep snowpack with an active subnivean zone appears to encourage a healthy microbial population that, through respiration, releases significant amounts of carbon dioxide into the atmosphere. Studies suggest that as much as half of the carbon taken up by plants in the summer is released back into the atmosphere by microbes in winter (Paul Brooks, University of Colorado Boulder). At the same time these microbes, by processing and storing nitrogen, fertilize the soil as the snow melts.

Without a healthy snowpack, without these snowpack microbes, plants don’t do as well come spring. While these microbes may be releasing a lot of carbon into the atmosphere during the winter, they are also necessary for healthy plant growth — plants that will absorb carbon dioxide throughout the growing season.

For all these reasons, it seems to me, a nice deep snow, serving as an insulating blanket on the earth, is a welcome part of our northern winter.

Why do some trees get so tall?

published 12/31/2019 in the York Weekly, Foster’s Daily, the Portsmouth Herald and online on seacoastonline.com

I was just out visiting my son who lives on the coast of Northern California, the land of tall trees, the coast redwoods.  Coast redwoods (these are the state tree of California) are the tallest trees on Earth. I was thinking about our New England tall tree, the white pine (the state tree of Maine), and wondering whether they ever had a chance of growing as tall as the coast redwood.

Navarro River Redwood State Park near Mendocino California

There are a large number of factors that determine how and why a tree grows tall: genetics, environment, age.  The primary reason for a tree to grow as tall as it can is to beat surrounding trees to the sun. White pines and coast redwoods are great at this and will dominate a forest if they can get to the sun first.  White pines typically grow to about 150 feet tall (however pre-colonial white pines have been estimated to reach heights of at least 230 feet) while coast redwoods grow twice as tall-300 feet and taller (the tallest tree in the world is a 379 foot tall coast redwood named Hyperion).  How do they do it?

The two problems that have to be overcome to grow super tall are water and wind.  Coast redwoods tend to occupy sheltered valleys where they are protected from wind.  Like all trees they need to somehow distribute water to all parts of the tree. The long-held dogma of how this is accomplished is that groundwater enters the roots and is pulled upward through the tree by water evaporating from pores in the leaves.  Water is sticky, so as one water molecule evaporates from a pore in a leaf it pulls another water molecule up after it. The taller a tree grows the more difficult it is to get water up to the topmost leaves-gravity becomes a major drag. If those leaves can’t get enough water photosynthesis and growth start to slow.   

However this upward flow of water  isn’t the whole story. It turns out many trees can also absorb water into their leaves and move it downward towards the roots. There has to be water vapor in the atmosphere for this to be a useful adaptation.  Coast redwoods live in the fog belt, their needle-like leaves are almost constantly bathed in fog. Studies by the National Park Service found that some coast redwoods obtain 40% of their water from fog, not their roots!   And, according to a study on coast redwoods published in Functional Ecology (“Pushing the limits to tree height: could foliar water storage compensate for hydraulic constraints in Sequoia sempervirens?” published 2014 by H. Roaki et al) the pinnacle (topmost) leaves of the tallest growing coast redwoods stored water better than trees that didn’t grow as tall. So, tall-growing coast redwoods can take advantage of all that ambient water in the surrounding fog and both store and use it for growth.

Another factor in height is age-it takes time to acquire all of that biomass.  White pines easily live a couple hundred years-the oldest known specimens are over 400 years old.  Coast redwoods, on the other hand, are among the oldest living things on Earth-they can live for more than 2,000 years (the oldest living coast redwood is 2,200 years old).   Hyperion, the tallest tree on Earth, a baby by coast redwood standards at somewhere between 600 and 800 years old has still had a remarkably long life.

Redwood stumps provide nutrients for new growth. Here some sorrel grows at the base of a stump

So, while our East Coast white pines probably couldn’t ever grow as tall as coast redwoods, -conditions and adaptations aren’t quite right-one similarity between these two species is how it feels to walk into a white pine or a coast redwood forest.  There is a cathedral like quality to these forests, they are quiet and dark. The filtered sunlight adds to their majesty, illuminating the mist in much the same way that light falls through the stained glass of a human-made cathedral and illuminates the dust motes floating through the air.   These forests we walk through today are largely young trees. Just imagine the grandeur of a pre-colonial forest, fully mature white pines or coast redwoods reaching towards the stars.