Animals and Plants of the Finger Lakes

Goddess of the Moon: The Life History of the Luna Moth

We can thank Linnaeus for the name of the luna moth, Actias luna, an apt epithet for this, perhaps the most beautiful of our nocturnal insects.

It seems likely that Linnaeus recalled the Roman moon goddess Luna in 1758 because of the moth’s distinctive hindwing spots – translucent discs with a dark crescent edge, like the moon when it’s nearly full. Perhaps he also realized that the entire moth is a living avatar of the moon – at rest by day, on the move by night, exquisitely pale, subtle yet spectacular.

Luna moths are among the largest moth species in North America, with a wingspan of 3 to 4 inches. They are common in deciduous forests from Saskatchewan to Texas, and from Nova Scotia to Florida. Scientists believe that populations of luna moths throughout their range have adapted to prefer particular local hardwood trees as host plants, including birch, hickory, beech, willow, and cherry.

The larvae have five molt stages, or instars, culminating in the formation of a pupa encased in a papery cocoon and wrapped in leaves. After about three weeks, their metamorphosis now complete, adult luna moths cut their way out using serrated spurs near the base of the front edge of their wings. They typically emerge in the morning, leaving time to spread and dry their wings before their first night of flight.

Adult luna moths do not eat at all, and therefore have only vestigial mouthparts and no digestive system. Their sole purpose in life is to reproduce. They have only about a week to do so before they die.

The females emit a sex pheromone, which the males can detect even at a great distance with their broad, feathery antennae. They usually mate after midnight. The females begin laying eggs by the following night, continuing for several nights more. The eggs hatch after another week, and the cycle begins anew.

In the northern parts of their range, including our Finger Lakes region, luna moths typically breed once per year in June. In the south, luna moths breed up to three times a year. For the year’s last generation, the shorter duration of sunlight late in the season causes the pupa to enter diapause, a state of suspended development. Late-forming pupae fall to the ground in autumn with the leaves that encase them, and then spend the winter waiting in the leaf litter on the ground until the longer days of spring signal that it’s time to emerge.

Luna moths, especially large larvae and adults, are high-value targets for insectivores. Therefore, luna moths have evolved remarkable adaptations to foil predators. The caterpillars are light green, matching the color of the leaves they feed on. But when they sense a predator about to strike, the caterpillars abandon attempts at concealment. Instead, they rear up their heads, possibly to confuse the predator, sometimes making a clicking sound with their mandibles, followed by regurgitation of foul-tasting liquid.

Luna moths likewise rely on visual camouflage as adults. Their green wings blend right in among any cluster of broad leaves. Furthermore, the forewings have reddish-brown leading edges that branch to teardrop-shaped spots, looking just like twigs with little emergent buds. Therefore, people rarely find luna moths in their natural habitats, instead encountering them most often near buildings illuminated by artificial lights at night.

Most amazingly, adult luna moths have even evolved acoustic camouflage to evade capture by echolocating bats. The key is the long twisting tails on the moths’ hindwings. In 2015, biologists at Boise State University recorded that bats captured 81 percent of luna moths whose tails were removed, but only 35 percent of those whose tails were intact – in the latter case, commonly directing their attacks at the moths’ tails instead of their bodies. Then in 2016, experts in applied physics and neuroscience at the University of Washington and Johns Hopkins University determined that the tails not only shift the location of the echoes, but because of their twists, also scatter the reflected sounds in all directions.

Thus the luna moth embodies not only the full moon in its pale majesty, but also the new moon in its obscurity and unrevealed potential. Hidden among the green leaves, unseen on the forest floor, undetected even by close-range sonar calibrated through eons of evolution, the moth eludes the senses even as it fires the imagination. And just as the ancients saw divinity in the new moon advancing to fullness and waning again, so too can we marvel at the moth’s life history, from egg to caterpillar to pupa to adult and repeating in a never-ending cycle, miraculous in all its phases.

This story by Mark Chao first appeared in our newsletter, The Land Steward, as part of the Closer Look series about plants and animals of the Finger Lakes region.

Animals and Plants of the Finger Lakes

Ol’ Greenie Back-eye: The Eastern Newt

The three weird sisters in Macbeth stirred eye of newt and toe of frog, wool of bat and tongue of dog, along with a number of other eclectic ingredients, into their cauldron.

Although there’s some speculation that “eye of newt” might have been an herbalist’s term for mustard seed or daisy, it’s quite likely that the witches were in fact using small amphibians to give extra oomph to their spirit-conjuring potion. Following are a few reasons why you, too, might want to consider using the eastern newt (Notophthalmus viridescens) in your own enchanted homebrew this summer.

Second of all, newts are, like adder’s fork or blind-worm’s sting, wonderfully poisonous. There’s probably nothing special about their eyes, but their eggs and skins are saturated with a powerful neurotoxin called tetrodotoxin. It dissuades fish, though apparently not frogs and turtles, and it’s the same substance found in the flesh of fugu, the deadly pufferfish prized by Japanese gourmands. According to urban legend, hallucinations can be induced by licking amphibians, but licking a newt is likely to land you in the hospital, or worse. (The newts of the West Coast are even more poisonous than those of the Finger Lakes. In one infamous case, an entire Oregon camping party died when a rough-skinned newt fell into their coffee pot.) Tetrodotoxin won’t pass through intact skin, though it can irritate eyes and mucous membranes. Ironically, we’re far more toxic to newts than they are to us: the oils, salts, and chemicals that coat human hands soak right into their permeable skins.

Finally, they’re even more spectacular shapeshifters than our other local amphibians. A newt starts life as a dull-colored, translucent, minnow-like larva that feeds on even smaller aquatic crustaceans and insect larvae. Its almost invisible, twig-like legs are dwarfed by feathery gills growing like squirrel ears from the tops of its neck.

After two to five months, the larva metamorphoses into the terrestrial juvenile form known as the eft. (Linguistic note: “eft” is an ancient form of the word “newt.” Through changes in spelling and pronunciation, mistakes in copying texts, and shifts in language patterns, “a newt” became the standard way to refer to certain members of the family Salamandridae, whereas “an eft” became a rare dialect form. Like the creatures themselves, one word slowly transformed into another over time.) The gills of the larva disappear and lungs develop; the rudderlike tail shrinks; the legs grow much more substantial, and eyelids grow over the eyes. Its body floods with tetrodotoxins, a fact that it advertises by changing its color to an uncanny red-orange that stands out like a neon sign against the dark forest floor. The larva had the furtiveness of a tiny prey item, but the eft moves with the doggedness of an animatronic toy. Like other animals with prominently advertised chemical defenses such as skunks, efts don’t need to move quickly or hide from predators. They look good enough to eat – I’ve always thought that they resemble Japanese gummy candy – but they’re ten times more poisonous in this stage, so please resist putting them in your mouth.

The eft’s noxiousness is so well respected by predators that several other species have evolved reddish coloration in order to piggyback on its success: the red salamander (Pseudotriton ruber), the northern redback salamander (Plethodon cinereus), and the spring salamander (Gyrinophilus porphyriticus).

After several years, the eft grows up. Skin that was dry and vermillion becomes slimy and dull olive-green; the rudder-like tail regrows and the adult re-enters the water, though it keeps its lungs for the rest of its life. Most of the poison ebbs from its body and it will rely mostly on camouflage for protection. Its wild teenaged years may be over, but it retains tiny red spots on its back that are a sign to the local fish that it still contains enough tetrodotoxin to make a charm of powerful trouble: like a hell-broth, boil and bubble.

This story by Jacqueline Stuhmiller first appeared in our newsletter, The Land Steward, as part of the Closer Look series about plants and animals of the Finger Lakes region.

Animals and Plants of the Finger Lakes

River Otters: Neither Fish Nor Flesh

Izaak Walton’s treatise, The Compleat Angler (1653), is a meditation on the practice and poetry of sport fishing. Walton has little affection for river otters, which he believes must be exterminated because they take the fish that sportsmen want to keep for themselves.

Yet, he explains, their predatory nature can also be handily exploited by human fishermen. Otters captured as pups can be trained to bring back fish or to drive them into waiting nets. Otter fishing is surprisingly ancient and widespread: Marco Polo reported seeing Chinese fishermen using trained otters, and the practice is known to have existed on every continent where river otters are found.

Our local otter species – which European settlers were still using as a fishing companion as late as the nineteenth century – is the North American river otter (Lontra canadensis). It inhabits the same inland wetlands as beavers and muskrats. These three brown furbearers might at first glance be confused with each other, but they are from very different families. Beavers and muskrats are rotund, frumpy rodents, whereas the river otter is a mustelid, a fierce and sleek carnivore related to weasels and fishers. His flat head, which is topped by tiny ears, big eyes, and a wide nose, do not merely help him catch fish in murky water but also give him the cutest face in the Finger Lakes. The word otter is related to the Greek word hydra, or water-serpent. He does indeed look a bit like a furred eel or a small seal: as Izaak Walton says, he seems to be neither fish nor flesh. On land, his lithe, liquid leap-bounds are unmistakable, even from a distance. He slides on mud or snow whenever he can to save energy, leaving fluid tracks behind. And in the water, he is pure mermaid.

However, the long, streamlined shape that makes the otter such an agile aquatic hunter is also a serious liability. The large surface-to-volume ratio of his body plan loses heat very quickly in cold water, a particular problem because otters do not hibernate and must feed themselves constantly. Massive marine carnivores such as whales are protected by thick layers of blubber. But the otter is small and must remain supple in order to loop and harrow after fish; he cannot accumulate fat that might slow him down or render him too buoyant.

In place of fat, he has a luxurious, oily pelt. His underfur is almost unimaginably dense and velvety, and is further protected and insulated by long, hollow guard hairs. Under an electron microscope, individual hairs look a bit like the segmented stems of Christmas cactus; the fins that project from each hair interlock when the fur is mussed. Through a variety of adorable grooming behaviors, the otter knits his fur into a glossy wetsuit that keeps his skin perfectly dry.

For all the river otter’s resilience, he is also quite delicate and quickly disappears from polluted wetlands. As an apex predator, otters were never as numerous as other furbearers, and overhunting decimated their numbers. By the early 1990s, they were gone from western New York and rare in the rest of the state. There is, of course, little interest in reintroducing extirpated predators that might pose threats to humans, such as cougars and wolves. However, almost everyone agreed that the charismatic otter deserved to return. (Otters, it should be said, are shy but can be fierce: do not approach them.) Thus the New York River Otter Project was formed, a joint effort involving the NYS DEC, veterinarians from Cornell, numerous non-profit organizations, trappers, wildlife rehabilitators, and a group of enthusiastic citizens led by Dennis Money. Over several years, otters were trapped in the Adirondacks and released into the Finger Lakes and Genesee River. Now, twenty years later, the otters seem to have recovered and the project has set the standard for river otter reintroductions in both the U. S. and worldwide. It is a task made more urgent by the fact that most river otter species are in steep decline. Otters have assisted humans for thousands of years; it is now time for us to return the favor.

This story by Jacqueline Stuhmiller first appeared in our newsletter, The Land Steward, as part of the Closer Look series about plants and animals of the Finger Lakes region.

Animals and Plants of the Finger Lakes

The Surprisingly Common Bobcat

Each year, the New York State Department of Environmental Conservation (DEC) receives many reports from people who think they have seen cougars or lynxes, both animals that are considered extinct in New York state.

Sometimes these mysterious animals turn out to be nothing more than house cats, fishers, or even dogs. If it really is a large wild cat, it’s almost certainly a bobcat (Lynx rufus).  A recent rash of local media coverage — the animals have been spotted in Canandaigua and Lansing — might lead you to think that bobcats are rare in this area, or that they are recent arrivals.  Although sightings of this secretive and solitary animal may be newsworthy, the animals themselves are fairly common.  Unless you live in the middle of a city, chances are very good that a bobcat lives somewhere nearby.

The bobcat is a stocky animal about the size of a cocker spaniel and weighing twenty to thirty pounds. Its species name, rufus, is Latin for “red,” and in forested areas bobcats tend to be reddish-brown above, white below.  (In drier climates, and in the winter, their coats are more grayish.)  The bobcat’s fur is marked with black spots and bars, patterns that render it almost invisible on the sun-dappled forest floor. From a distance, the most obvious difference between the bobcat and a gigantic domestic cat is the former’s very short (“bobbed”) black-tipped tail.  If you are fortunate enough to see the animal up close, you will notice a ruff of facial hair and large ears topped with black tufts that may act as antennae.  Hind legs that are longer than the front legs give the bobcat more power when jumping, as well as a bobbing gait.

Historically, the bobcat was present in all lower forty-eight states, but its population was dramatically reduced in the intensely cultivated midwest and the heavily populated eastern seaboard.  However, it seems to have made a remarkable comeback in recent years: currently, it is found in every state except Delaware. Despite the pressures of development and widespread hunting and trapping, most populations seem to be stable or increasing, and possibly even spreading.

This success story is attributable to several quirks of bobcat biology, as well as a few serendipitous events caused by human activity.  The bobcat is a density-dependent breeder: the fewer cats there are, and the more food there is, the more litters will be born.  Thirty-nine states, including New York, allow a bobcat harvest, but thanks to the animal’s reproductive habits, these harvests don’t seem to have put a dent in the population.  Furthermore, the bobcat’s solitary nature means that populations are not as susceptible to communicable diseases as are social animals like the raccoon.

Unlike the lynx, which prefers the snowshoe hare, the bobcat will prey on everything from voles to small livestock.  Bobcats are nothing if not enterprising: in the Adirondacks, a large part of the cat’s winter diet is made up of deer, including full-grown bucks that can be five or more times its size.

Bobcats are also successful because they are habitat generalists.  They can live just about anywhere —from swamps to forests, desert to “urban edge”–– as long as there is sufficient cover for them to stalk their prey and raise their young.  As Nathan Roberts, at the Cornell Department of Natural Resources, puts it: “All they need is a bush to hide behind, and a rabbit, and that’s bobcat habitat.”  Over the last century, the abandonment of farms in upstate New York has created a patchwork of forest and farmland that is perfect for this little predator.

Interestingly, although humans have often made life hard for the bobcat, they may also have contributed to its success.  Cougars compete with bobcats and may even kill them where their territories overlap, so the extirpation of the larger cat in the northeast may have benefited the smaller.  Farming and logging in northeastern forests destroyed lynx habitat but created ideal conditions for the bobcat.  Global climate change may turn out to be the greatest boon of all for the feline.  Bobcats, unlike lynxes, are not suited to deep snow.  If milder winters with less snow are in our future, it is likely that the bobcat will expand further north and into higher elevations, at the expense of its shyer and less adaptable northern cousin.

This story by Jacqueline Stuhmiller first appeared in our newsletter, The Land Steward, as part of the Closer Look series about plants and animals of the Finger Lakes region.

Animals and Plants of the Finger Lakes

Our American Mink

Several members of the family Mustelidae are native to New York State:  fisher, marten, two kinds of weasels, river otter, and American mink (Neovison vison).

These animals differ in size but otherwise look quite similar to each other, with long, narrow bodies; tiny, rounded ears; dense fur; and well-developed anal glands.  All of our native mustelids are cute, but the mink, with its curious, alert face and shiny, button-like brown eyes, looks especially like a toy.  Don’t be fooled, though: it punches far above its weight of a mere one to three pounds.

The long, narrow body of the mink allows it to hunt successfully in many different environments.  It prefers to be in or near water, and slips as easily as an eel after fish, frogs, crustaceans, and muskrats.  It can wiggle into burrows to catch rodents — it has occasionally been tamed and used to hunt rats — or shimmy down holes to grab snakes.  Its bounding, rolling gait is comical, but it is fast enough to catch rabbits and birds.  Amazingly, it does not seem to be handicapped by its tiny head and jaws and doesn’t hesitate to attack animals several times its own size.

Because mink sometimes wreak havoc in henhouses, destroying entire flocks at once, people assume that they kill for pleasure.  This behavior is not completely understood, but probably has more to do with physics than hedonism.  The same body shape that makes the mink such an agile, adaptable predator also has a high surface-area-to-volume ratio that leaves the animal extremely vulnerable to heat loss.  In order to stay alive, it must eat a third of its own body weight every day, and since it is a solitary animal, it must find food on its own.  The problem is compounded when the temperature drops, because the mink does not migrate, hibernate, enter torpor, or stockpile a significant amount of food in winter.  Perhaps because it must remain light and sleek in order to hunt effectively, it doesn’t store much body fat, either.  In order to gain a little more food security, it may kill more than it can eat at one time and cache the rest under the ice and snow.  The mink that kills all of the chickens in a coop and leaves the carcasses lying around is probably only following its instinct to kill whatever, and whenever, it can – after all, in the wild, animals do not live in large densities inside small spaces that have no escape routes.

The mink is of course synonymous with its thick, glossy, dark brown fur (domesticated mink, which are larger and less hardy than wild mink, have been bred for many different coat colors).  Hundreds of thousands of mink pelts were exported to Europe between the seventeenth and nineteenth centuries; when the price was not high enough to justify the transport costs, the pelts were simply burned at the trading posts.  Its cousin, the sea mink, was driven to extinction by this merciless overexploitation, but the tough little American mink somehow managed to ride out the era of the fur trade.  In fact, the animal still apparently occupies the same range that it did before Europeans arrived in North America, endemic to most of the U. S. (with the exception of the arid southwest corner of the country) and almost all of Canada.  Today, the most serious threats to the mink come from the destruction of wetlands and water pollution.  Because of its position at the top of the food chain and its extreme sensitivity to toxins, the mink is a bioindicator for aquatic environments.  A study is currently underway to measure how PCBs in the Hudson River are affecting the species.

The story of the mink has taken an ironic twist.  When mink fur became extremely fashionable in the early and mid-twentieth century, fur farms stocked with American mink were established in many areas of Europe.  Over time, animals escaped (or were deliberately released by animal activists) and established themselves in the wild.  The American mink is now a serious pest in Europe, where it is contributing to the precipitous decline of native species.  One of the hardest hit is the European mink, which is now critically endangered.

This story by Jacqueline Stuhmiller first appeared in our newsletter, The Land Steward, as part of the Closer Look series about plants and animals of the Finger Lakes region.