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Moths

Caterpillars Molting

6-25-14 caterpillar molting 044A caterpillar is the larval stage of a moth or butterfly. It is the only stage that has chewing mouthparts, and therefore a caterpillar spends most of its waking hours eating. This consumption of food results in massive growth, making its skin/exoskeleton very tight. When this happens, a hormone called ecdysone is produced, prompting the caterpillar to molt, losing its old exoskeleton (to left of caterpillar in photo) under which is a new and larger exoskeleton. After the molt, while the new exoskeleton is still soft, the caterpillar swallows a lot of air, which expands its body. Then, when the exoskeleton hardens, it lets the air out and has room for growth. Caterpillars molt four or five times as they grow. Each different caterpillar stage is called an instar. (Photo: Forest Tent Caterpillar)

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Fern Balls

fern ball 216At this time of year, many new sterile fern fronds have “fern balls” at their tips – something has taken the last few inches of the tip of the frond and stitched it together into a ball-shaped shelter bound with silk. If you open one of these balls, you may find frass – droppings from the immature insect that was dwelling within the ball while consuming the terminal leaflets of the fern. Sometimes, but not always, you’ll find the larva responsible for the frass. Many species of ferns, as well as other plants, are host to many species of larvae, and many of these larvae are immature moths. Pictured is Christmas Fern, Polystichum acrostichoides, which is likely the host of the larva of Herpetograma sphingealis, the Serpentine Webworm Moth, or its close relative, H. aeglealis. Larvae live in these shelters for about a month before pupating and emerging as small, brown moths.

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Rosy Maple Moths Emerging

6-9-14 rosy maple moth 161This is the time of year when moths rule the nights. Many moths in the silkmoth family, Saturniidae, emerge in June, including giant silkmoths such as Luna Moths and Cecropia Moths. A smaller member of this family also appears at this time of year. While the 1 to 2-inch Rosy Maple Moth (Dryocampa rubicunda) wingspan doesn’t come close to many of the giant silkmoths’ 5 to 6-inch wingspan, its pink and white or yellow coloring is stunning. Adults emerge mid-May through mid-July in the late afternoon, and they mate in the late evening. Females begin laying eggs at dusk the next day in groups of 10-30 on leaves of the host plants (Red, Sugar and Silver Maples, as well as Box-elder and some oak trees). The eggs hatch in about 2 weeks and the larvae are referred to as Green-striped Mapleworms. They occasionally do considerable damage to their host trees when their population soars. In New England there is only one brood per summer, with the larvae pupating and overwintering underground.

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Showy Orchis Flowering

6-4-14 showy orchis 267A walk in deciduous woodlands at this time of year could result in the sighting of several species of orchids, one of which, Showy Orchis (Galearis spectabili), has a stalk of several flowers which typically bear lavender hoods (one variant is white). Potential pollinators, most of which are long-tongued bumblebees, butterflies, moths and bees, land on a white petal below the hood which acts as a “landing pad.” The insect next heads for the tip of the nectar-filled spur located at the back of the flower. In getting there it brushes against, and often picks up, packets of pollen (pollinia) before moving on to the next blossom, where cross-pollination ideally takes place. (Thanks to Ginny Barlow for photo op.)

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Promethea Moth Cocoon

4-22-14  promethea cocoon 478When a Promethea Moth caterpillar, one of our giant silk moths, is ready to pupate at the end of the summer, it strengthens the stem, or petiole, of a leaf on its host plant with silk and then attaches the silk to a nearby branch, assuring that the leaf will remain attached to the tree. (Imagine having the instinctive foresight in your youth that this caterpillar had!) The caterpillar then curls the leaf around itself and spins its cocoon inside the curled leaf. The cocoon dangles from the host plant throughout the winter and in early summer the moth emerges. Now is the perfect time for finding a Promethea Moth cocoon, as last year’s leaves are gone on most trees, and this year’s buds have yet to open. Look for a tree or shrub that has just one dead leaf hanging from one of its branches. (Cecropia caterpillars favor black cherry, poplar, ash, maple, oak and willows trees among others.)

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Cecropia Moths Pupating

11-11-13 cecropia cocoon dissected  056Our largest North American native moth, the Cecropia Moth, Hyalophora cecropia, spends the winter as a pupa inside a cleverly-crafted 3” – 4”-long shelter, or cocoon, which it creates and attaches lengthwise to a branch while still in its larval stage. The Cecropia caterpillar, with the silk glands located near its mouthparts, spins not one, but two silk cases, one inside the other. In between the two cases, it spins many loose strands of very soft silk, presumably to enhance the insulating properties of the cocoon. Inside the inner case, the caterpillar splits its skin and transforms into a pupa. Come spring, an adult moth will emerge from the pupal case and exit the cocoon through one end which was intentionally spun more loosely, allowing the moth to crawl out the somewhat flexible tip. (Note: dissected cocoon was not viable.)

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Bruce Spanworms Emerging & Mating

11-7-13 winter moth IMG_4880I try not to repeat post topics, but in the past two days the sudden emergence of inch-long, tan moths in the woods has been so dramatic that I couldn’t not mention them. These ghost-like, light tan moths are referred to by entomologists as Bruce Spanworm moths, Operophtera bruceata, named after an entomologist by the name of Mr. Bruce. They are often called Winter Moths, due to the fact that they are one of the latest moths to be seen flying, as well as Hunter Moths, as they share the woods with hunters at this time of year. From October to December Bruce Spanworm moths emerge, mate and lay eggs. While this timing is unusual, it makes sense when you think about it — many birds, their primary predators, have left for their wintering grounds. All the moths you see in the air are males — females are wingless and cannot fly. The females crawl up the trunk or branch of a tree and send out pheromones to attract winged males. After mating, the female lays eggs which hatch in the spring, and the larvae feed on a wide variety of deciduous leaves, favoring Trembling Aspens, Sugar Maples, American Beeches and willows. Periodic outbreaks of these caterpillars can result in heavy defoliation.

NB: “This is easily confused with Operophtera brumata – Winter Moth, which is an introduced species from Europe and an abundant pest in the Northeast. Also easily confused with Autumnal Moth (Epirrita autumnata).” Kent McFarland


Witch Hazel Flowering and Dispersing Last Year’s Seeds

10-11-13  witch hazel flower and fruits 055Witch Hazel (Hamamelis virginiana) is nature’s final fanfare of the fall. As colorful fall foliage disappears, the yellow strap-like petals of Witch Hazel’s fragrant flowers brighten denuded woods. These flowers are pollinated by moths that are still active this late in the season, and develop into small, hard capsules that remain dormant throughout the winter. During the following summer, these capsules develop to the point where they expel two shiny black seeds 10 to 20 feet away from the tree. The seeds take another year to germinate, making the length of time from flowering to germination approximately two years. (In photo, the yellowish-tan capsules were formed this summer, and the one brown, year-old capsule has opened and dispersed its seeds.)

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Apple Scat

10-4-13 woolly bear scat 028At this time of year it’s not unusual to find the scat of various mammals consisting mostly of apple. Red Foxes, White-tailed Deer, Cottontail Rabbits, Porcupines and Black Bears, in particular, are all avid consumers of this appetizing fruit. Birds, including Purple Finches, Cedar Waxwings and Northern Mockingbirds, also include apples in their diets . While many insects drink the juice of apples, it’s not that often you see an insect like this Woolly Bear caterpillar (the larval stage of the Isabella Tiger Moth) consuming a sizable chunk of a McIntosh apple and leaving behind tell-tale scat. (Discovery by Sadie Richards)

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Abbott’s Sphinx Moth Larva

7-26-13  Abbott's Sphinx Moth larva 066Abbott’s Sphinx Moth larvae feed on grape and Virginia creeper leaves during the night. During the day they tend to rest on the woody vines of the plants they are eating, and because they are well camouflaged, they remain hidden from most humans’ eyes. Both as larvae and adults, these moths are well equipped for survival. Older larvae have two color forms, one resembling unripe green grapes (in photo), and the other is brown and looks much like a branch. In their last stage, or instar, both forms have a rear eyespot which looks like a human eye, right down to the white reflection spot in it, which scares off potential predators. If the caterpillar is pinched or prodded, it squeaks and tries to bite the attacker. The adult moths, which emerge next summer after pupating all winter, also defend themselves with both color and behavior. They are brown with yellow bands on their underwings, which make them look something like a bumblebee, and when they fly, they create a buzzing noise. (Thanks to Heidi, Tom and Simmy Wetmore for photo op.)


Moth Eyes and Biomimicry

7-1-13 luna eyes 020Because moths need to use every little bit of light available in order to see in the dark, their eyes are highly non-reflective. (This is also helpful in decreasing the chances of predators spotting them.) Scientists, through biomimicry, have come up with a number of technological advances, including the development of a film that can be applied to solar cells which helps keep sunlight from being reflected off of them before the light can be utilized. Man-made materials based on the structure of moth eyes could someday reduce the radiation dosages received by patients getting x-rayed, while improving the resolution of the resulting images. Research on recreating the pattern found on moths’ eyes onto plastic could lead to reflection and glare-free display screens for televisions, cell phones, computer monitors, eyeglasses, speedometers and more.


A Great Christmas Present!

If you’re looking for a present for someone that will be used year round, year after year, Naturally Curious may just fit the bill.  A relative, a friend, your child’s school teacher – it’s the gift that keeps on giving to both young and old!

One reader wrote, “This is a unique book as far as I know. I have several naturalists’ books covering Vermont and the Northeast, and have seen nothing of this breadth, covered to this depth. So much interesting information about birds, amphibians, mammals, insects, plants. This would be useful to those in the mid-Atlantic, New York, and even wider geographic regions. The author gives a month-by-month look at what’s going on in the natural world, and so much of the information would simply be moved forward or back a month in other regions, but would still be relevant because of the wide overlap of species. Very readable. Couldn’t put it down. I consider myself pretty knowledgeable about the natural world, but there was much that was new to me in this book. I would have loved to have this to use as a text when I was teaching. Suitable for a wide range of ages.”

In a recent email to me a parent wrote, “Naturally Curious is our five year old’s unqualified f-a-v-o-r-I-t-e  book. He spends hours regularly returning to it to study it’s vivid pictures and have us read to him about all the different creatures. It is a ‘must have’ for any family with children living in New England…or for anyone that simply shares a love of the outdoors.”

I am a firm believer in fostering a love of nature in young children – the younger the better — but I admit that when I wrote Naturally Curious, I was writing it with adults in mind. It delights me no end to know that children don’t even need a grown-up middleman to enjoy it!


Bruce Spanworm Moths Flying

If you’ve walked in New England woods recently, chances are great that you’ve noticed light tan moths with a one-inch wing span flitting about — an odd sight for this late in the year. These are male Bruce Spanworm Moths (Operophtera bruceata), also called Winter Moths, as the adults are active from October to December. They belong to the Geometer family of moths, the second largest family of moths in North America, which includes many agricultural and forest pests. The males are seeking wingless, and therefore flightless, females to mate with. Eggs are laid in the fall, hatch in the spring, the larvae pupate in the summer, and emerge as adult moths in the fall. Bruce Spanworm larvae periodically defoliate hardwood trees, preferring the buds and leaves of sugar maple, American beech and trembling aspen trees.


Woolly Bears on the Move

Although it’s fun to try to predict the severity of the coming winter by the amount of brown on a woolly bear caterpillar (the more brown = the milder the coming winter, according to folklore), the coloration of any given woolly bear caterpillar has more to do with its diet and age than the coming weather.  The more a Woolly Bear eats, the more frequently it molts, and each time it molts a portion of the black hairs (setae) is replaced by brown ones.  A Woolly Bear can molt up to six times — the best fed and oldest woolly bears, which have molted the most number of times, have the widest brown bands. (After overwintering as caterpillars, Woolly Bears pupate and emerge as small, brown moths called Isabella Tiger Moths, Pyrrharctia isabella.)


Yellow-shouldered Slug Moth

You could hardly be blamed for not recognizing that this bright yellow-green, half-inch-long, oval creature is the larval stage of a moth!  Possessing suction cups rather than prolegs, the Yellow-shouldered Slug (Lithacodes fasciola) glides, rather than crawls, over the leaf it is consuming.  Perhaps this is why these caterpillars show a preference for smooth-leaved trees and shrubs such as basswood, beech, cherry, maple and oak (although this particular individual was found on a witch-hazel leaf).  The Yellow-shouldered Slug pupates inside a cocoon all winter, and in the spring a small, brown moth emerges.


Spined Soldier Bug

The Spined Soldier Bug is a predatory stink bug which preys on a variety of other insects (over 90 species), especially the larvae of butterflies, moths and beetles. It is one insect that farmers actually welcome, as it preys heavily on the larvae of the European corn borer, Mexican bean beetle, cabbage looper, Colorado potato beetle, flea beetles and many other crop pests. The adult Spined Soldier Bug has a prominent spine on each “shoulder.” It also has piercing-sucking mouthparts which it uses to impale prey and suck out their internal juices. The photograph shows a Spined Soldier Bug dining on the innards of a monarch caterpillar.


Tobacco Hornworms & Brachonid Wasps

Tobacco Hornworms, Manduca sexta (often found feeding on tomato plants and confused with Tomato Hornworms, Manduca quinquemaculata) are often the target of a species of Brachonid wasp that parasitizes beetle, moth, fly and sawfly larvae. The adult wasp lays her eggs inside the hornworm with her long ovipositor. The eggs hatch and the wasp larvae feed on the caterpillar. Eventually the wasp larvae emerge and form white pupa cases on the skin of the dying hornworm larva, inside of which they transform into winged adults. Braconid wasps are extremely good at locating hornworms, even when there are very few to find. Because they parasitize hornworm, cabbage worm, aphid and gypsy moth larvae, Braconid wasps are considered important biological control agents. If you want to discourage Tobacco Hornworms in your tomato patch, allow the wasps to complete their metamorphosis – this accomplishes both the demise of the hornworm, as well as an increased population of Braconid wasps.


Common Milkweed Pollination

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The structure of the Common Milkweed (Asclepias syriaca ) flower is such that its pollen, produced in two saddlebag-like sacs with a black appendage joining them, snaps onto an insect’s leg when the two come in contact with each other. To assure that the chances of this are high, the pollen sacs (pollinia) hang inside a slit that is located between each of the five cups, or hoods, that contain nectar. An insect lands on the slippery flower, attracted by both the scent and availability of nectar, and inadvertently one or more of its six legs slips down between the hoods into a slit, where the pollinia automatically attach to the leg. The insect withdraws the leg upon leaving to find more milkweed nectar, and the attached pollinia eventually falls off onto another milkweed flower, pollinating it. Unfortunately, about 5% of milkweed flowers visited trap insects because they cannot extract their legs from the slit. It is not uncommon to see an insect dangling from a Common Milkweed flower – during a 30 minute visit to a milkweed patch recently I released 2 flies, 3 skippers (butterflies) and one honeybee that were caught, but hadn’t yet perished.


Hummingbird Clearwing Moth

Of all the insects I’ve found in milkweed patches over the years, the Hummingbird Clearwing is one of my favorites. It is a species of sphinx moth, named for its habit of hovering at flowers while it gathers nectar with its proboscis in a manner similar to that of hummingbirds. In fact, they are often mistaken for hummingbirds. The transparent wings, light brown thorax and dark chestnut abdomen are the field marks to look for. A diurnal moth, the Hummingbird Clearwing can often be found during the day in milkweed patches.


Luna Moths

Yesterday’s post was, as you quickly guessed, an eyespot from the forewing of a Luna Moth, Actias luna, one of North America’s giant silkworm moths. With a wingspan up to 4 ½,” it is one of our largest moths. Markings that resemble eyes are found not only on moths, but also on butterflies, birds, fish and reptiles. When they occur on butterflies and moths, eyespots are usually on the wings and are thought to scare off potential predators as well as to direct attacks away from vital body parts. After emerging from their cocoons, Luna Moths live for only about a week, during which time their sole mission is to mate. Like many other ephemeral insects, Luna Moths have no mouthparts and thus, do not eat as adults. (The phenomenal number of Luna Moths this summer may, in part, be due to the mild winter we had, which allowed more pupae to survive.)


Cecropia Moth

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Who would ever associate a lime green caterpillar with colored knobs with a large, brown moth? Thanks to someone’s keen observation, we know that these are both stages of one and the same insect — a Cecropia Moth. It is North America’s largest native moth — individuals with a wing span of over six inches have been documented. Cecropia Moths are emerging from their 3-inch cocoons this month, as are other giant silk moths, including the Luna Moth and Prometheus Moth.
NOTICE: I will be away for the next week in northern Maine, trying to photograph the largest member of the deer family. Blogs will resume on Monday, June 11.


Noctuid Moth Larva

The striped caterpillar that is crawling along the surface of fresh snow is the larval stage of a noctuid or owlet moth (species unknown).  Noctuids are dull-colored, medium-sized, nocturnal moths that are attracted to lights in the summer. They usually possess a well-developed proboscis (mouthpart) for sucking nectar.  You may be familiar with the common garden pests, cutworms, which are also noctuid larvae.  How this larva survives freezing temperatures I do not know, but I have seen several dozen at a time crawling around on top of the snow.  Note:   Jean Harrison, a fellow nature lover, just identified this larva as  Noctua pronuba, a winter cutworm also known as the greater yellow underwing (moth), a recent immigrant from Europe.


Staghorn Sumac Seed Heads and Their Inhabitants

If you pull apart a red, fuzzy seed head of Staghorn Sumac (Rhus typhina) this time of year, you will find, in addition  to a multitude of seeds, a profusion of scat in the shape of miniscule round, grey balls.  If you’re lucky, you’ll find the larval insect that produced this scat.  Chances are, according to Charley Eisman, author of Tracks and Sign of Insects, that many of the resident insects are in the Gelechioidea family of moths.  The larvae of these moths are consumers of Staghorn Sumac seeds, and judging from the amount of scat usually present, they spend a considerable amount of time inhabiting the seed heads.  It’s likely that Black-capped Chickadees and other birds you see gleaning sumac fruit are actually there  for the larvae as much as the seeds.

 

 


Naturally Curious wins National Outdoor Book Award

I am delighted to be able to tell you that this morning I learned that NATURALLY CURIOUS won the Nature Guidebook category of the 2011 National Outdoor Book Awards.  I’m honored and humbled by this recognition.   http://www.noba-web.org/books11.htm


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