Wavy-lined Emerald Moth Caterpillar: Master of Disguise
Caterpillars are subject to extreme predation, especially by birds. A single pair of breeding Black-capped Chickadees must find 6,000 to 9,000 caterpillars to rear one clutch of young, according to Doug Tallamy, professor of entomology and wildlife ecology at the University of Delaware. Insects contain more protein than beef and 96% of North American land birds feed them to their young.
It’s thus not surprising that caterpillars have evolved a number of impressive survival strategies, including resembling bird droppings and looking/acting like branches and leaves waving in the breeze. The Wavy-lined Emerald Moth (Synchlora aeratalarva) larva, or caterpillar, uses camouflage as well, but goes about achieving it in a slightly different way; it attaches bits of the plant tissue (often flowers) on which it is feeding onto its back, so that it blends in to its surroundings very effectively. Totally camouflaged, the caterpillar can munch away in relative safety, replacing dead petals with live ones when necessary.
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Male Walkingstick Cerci
Congratulations to Sharon Weizenbaum, Beth Herr and David Ascher for correctly identifying the Mystery Photo as the tip of the abdomen of a Common Walkingstick (Diapheromera femorata), also known as Devil’s Darning Needle, Devil’s/Witch’s Riding Horse, and Prairie Alligator due to its unusual shape. While the Common Walkingstick is a mere 3” long, the largest North American species can grow to 7” and one tropical species may reach 14”.
The Walkingstick lives up to its name – it is easily mistaken for a twig with its slender body and legs. By remaining motionless during the day (or gently swaying in the wind like a leaf or twig would), and feeding on the leaves of various deciduous trees at night it avoids many predators with its physical and behavioral adaptations. The practice of using both camouflage and mimicry is referred to as crypsis.
Both the male and female Walkingstick possess a pair of appendages at the tip of their abdomen known as cerci. The cerci on a female are short and straight, while those on the male are longer and curved. They are sensory organs, but in addition, the male uses his cerci to grasp the female when mating with her (see inset). According to entomologist Dr. Gilbert Waldbauer, the cerci are very effective, allowing the male Walkingstick to clasp the female for many hours (weeks for some species) in order to prevent another male from mating with the female.
This is the time of year you are most likely to notice Walkingsticks, as this is when they are maturing and reproducing. Females drop their eggs to the ground from the canopy and because a portion of the outside (capitulum) of each egg is edible (like the elaiosomes of many spring ephemerals), ants carry the eggs below-ground to their nests and eat the capitulum, leaving the intact eggs to hatch and develop.
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Gray Treefrogs Well Camouflaged
If there is an amphibian that is a master of disguise, it has to be the Gray Treefrog (Hyla versicolor). This remarkable frog is capable of changing its color (gray, green or brown) to match its environment within half an hour, a process called metachrosis. Shades of gray are most common with black blotches on the back while green colors are more prominent during the breeding season and in yearling frogs.
Being a treefrog, it has large, round, sticky toe pads that help it cling to trees and shrubs, where it spends most of its time. Survival is more likely if predators don’t detect you, so Gray Treefrogs have evolved to look a lot like bark.
When the temperature reaches 59° F. the males’ bird-like trilling can be heard coming from foliage next to and hanging over their shallow breeding pools. If you wish to set eyes on a Gray Treefrog, now is the time, as they are calling and a silent Gray Treefrog can be extremely difficult to find!
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Gray Treefrogs Calling
At this time of year, bird-like trills are often heard in wetlands, where male gray treefrogs (Hyla versicolor) are calling to potential mates. The chorus ramps up at night, but the songsters can be hard to find during the day, when they often hide in tree cavities or high up in the canopy. (Their large toe pads produce mucous which allows them to adhere to smooth bark.) The colors of a gray treefrog vary with the colors of its background and environmental factors such as season and humidity, but shades of gray are most common, with black blotches on the back. Variations of brown, green, and pearl-gray colors have been noted, with green being more prominent during the breeding season. Warm, humid weather seems to elicit calls from these well-camouflaged amphibians. To watch and hear a calling gray treefrog, go to http://www.youtube.com/watch?v=2kd5c4p8-0M. (Thanks to Rachael Cohen for photo op.)
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Snowshoe Hares
You’re most likely to see Snowshoe Hares at dawn or dusk, when they are most active. That is, if you can detect them before they detect you. Snowshoe Hares depend upon camouflage as their first line of defense, with seasonal coats to match their environment. They sometimes freeze where they are, making no movement, or take shelter in a protected spot or “form” and sit quietly, with their feet tucked out of sight and their ears pressed tightly against their back, making them all but invisible. If threatened, they can break into a full run leaping up to 12 feet at a time, reaching 30 or more miles per hour thanks to their powerful hind legs. (Photo by Patsy Fortney)
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Woolly Aphids
Woolly aphids are just that – aphids that have special glands that produce wax-like filaments which resemble white wool. When the “wool” is brushed aside, the dark aphid bodies below are apparent. Colonies of woolly aphids often congregate in cottony masses while sucking the sap of a host plant or tree, at which time they are somewhat camouflaged in that they can easily be mistaken for mold or a fungus. When woolly aphids take flight, the wax strands catch the wind and allow them to drift , allowing them to look more like seeds than edible prey.
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Green Lacewing Larvae Use Corpses as Camouflage
Green lacewings are aptly named for the prominent venation of the adults’ wings. Some species in this insect family even have “ears” in the larger veins that allow them to detect the ultrasonic sounds made by hunting bats. Lacewing larvae and adults are both predators of soft-bodied insects such as aphids. Larval lacewings have long, hollow mandibles with which they puncture prey and suck out the liquefied contents, leaving the woolly husks. Some species of lacewing larvae have hairy backs, and camouflage themselves when in the presence of woolly aphids by sticking aphid husks on these hairs. These “trash packets” camouflage the lacewing larvae from predators, including ants that would otherwise attack the larvae if they recognized that they were lacewings and not woolly aphids.
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Woodland Jumping Mouse Succumbs
Usually animals that have been killed don’t last long enough for humans to discover them unless the human disturbs the predator right after it’s killed its prey. This may well have been the case when I came upon this Woodland Jumping Mouse. It is actually fairly unusual to set eyes on a jumping mouse, dead or alive, as they are quite secretive. This remarkable one-ounce rodent has long hind feet and a distinctly long tail, which makes up more than half of its total length of eight to ten inches. Using its hind limbs for propulsion and its tail for balance, the Woodland Jumping Mouse is able to make large leaps of up to eight feet or more to escape danger. (More often it walks around on all fours, or uses short hops for greater speed.) Another survival strategy that jumping mice use is to remain motionless for up to several hours, relying on their coloration and cover for protection. Apparently neither adaptive behavior was effective enough to spare this mouse’s life.
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Abbott’s Sphinx Moth Larva
Abbott’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.)
Killdeer Nesting
This is the time of year when it pays to watch where you walk – there are a number of ground nesting birds, some of which, including killdeer, may choose your lawn or even your garden to build their simple “scrape” nest. Typically killdeer nest on the shoulders of roads, gravel roof tops, fields and gravel parking lots. The nest is very primitive, and there’s actually very little to it — killdeer scrape a slight depression in the ground, to which they often add bits of material, including white objects such as shells and bones. Their pigmented eggs are extremely well camouflaged. The young precocial killdeer chicks are on their feet and feeding themselves as soon as their down feathers dry. (Photo by Sadie Richards)
Long-tailed Weasels Completing Their Spring Molt
Two species of weasels (smaller relatives of mink and otters) are found throughout New England – the long-tailed weasel (pictured) and the short-tailed weasel (also known as an ermine). Both are roughly the same size (somewhere between 9 and 16 inches), with long thin bodies and short legs. Visually telling these two species apart can be challenging unless you get a good look at both the tail and the body, and even then, it can be difficult. A short-tailed weasel’s tail is about 40% of the head and body length, whereas the long-tailed weasel’s tail is more than 45% of the head and body length. In the northeast, in November, both of these carnivores usually start shedding their brown summer coat for a white winter coat, and then molt and start growing in a brown coat again beginning in March. Further south, in Pennsylvania, less than half of the long-tailed weasels turn white, and none do south of the Pennsylvania/Maryland border. (Thanks to Tom Kennedy for photo op.)
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!
Countershading
Countershading is a common color pattern in animals in which the upper side of the animal is darker than the lower side. This color pattern provides camouflage for the animal when viewed from the side, above or below. The counter shading pattern balances the sunlight on the animal’s back and the shadow beneath the animal so as to blend the animal’s side profile with its surroundings. In addition, when viewed from below, a counter-shaded animal with a light belly blends into the light coming from the sky above. When viewed from above, the darker back of a counter-shaded animal blends into the darker ground colors below. Birds (which spend a considerable amount of time in the air) such as this dark-eyed junco, as well as marine animals often exhibit countershading.
Monarch Butterfly Chrysalis
Of the multitude of discoveries that every summer offers us, one of the most magical is that of a Monarch Butterfly chrysalis. While locating a Monarch larva is not all that difficult, especially when they are as prolific as they are this summer, finding a chrysalis doesn’t happen all that often. Most butterfly chrysalises are a rather drab brown, but the Monarch’s is a beautiful green which serves to camouflage it in fields where the caterpillars feed on milkweed and eventually pupate (form a chrysalis). The Monarch caterpillar, when mature, usually seeks a sheltered spot under a leaf or branch where rain will not cause the silk button by which it hangs to disintegrate. The chrysalis in the photograph is attached to a blade of grass which was anchored with silk to another blade of grass in order to make it more secure. No matter how many I’ve seen, each one still takes my breath away.
White-tailed Deer Fawn
White-tailed Deer fawns are close to two months old now, and will retain their spots until their gray winter coat grows in this fall. The dappling of the spots enhances a fawn’s ability to remain camouflaged up until it is large enough and strong enough to outrun most predators. However, it doesn’t hide them from biting insects. During the summer months, when White-tailed Deer, including fawns, have a relatively thin, cool coat of hair, they are very vulnerable to biting insects such as female horse flies and deer flies. These flies make tiny slices with their blade-like mouthparts in their host’s skin in order to have access to their blood. This fawn was being constantly bothered by such flies.
Milkweed Visitors
Milkweed is in full bloom right now, presenting the perfect opportunity for young and old alike to discover the multitude of butterflies, beetles, bees and other insects that are attracted to these magnificent flowers. If you visit a milkweed patch, don’t leave before getting a good whiff of the flowers’ scent – one of the sweetest on earth. How many of the insects you find are carrying milkweed’s yellow pollen “saddlebags” on their feet? You might want to check out my children’s book, MILKWEED VISITORS, which I wrote after spending the better part of one summer photographing the various insects I found visiting a milkweed patch. ( http://basrelief.org/Pages/MV.html )
Question Mark Butterfly
The butterfly known as the Question Mark is in a group of butterflies known as “commas” (a silvery comma can be seen on the underside of their hind wings) or “anglewings” (for their sharply angled wing margins). The Question Mark has a silver dot adjacent to the comma, turning it into a question mark. When its wings are open, the question mark is fairly bright orange and quite noticeable, but when it closes its wings, it transforms into a dead leaf, for the undersides of its wings are dull brown and gray. This Question Mark was drinking sap from a wound in the trunk of a tree. These woodland butterflies prefer rotting fruit, mud, scat, carrion and tree sap over the nectar of flowers.
Delayed Greening of Young Leaves
Many plants practice “delayed greening” of their leaves, including this Red Maple (Acer rubrum). An initial lack of chlorophyll prevents the leaves from photosynthesizing and making food, which means they have little nutritive value, and thus, appeal, to an herbivore. Most plants that delay greening have reddish leaves due to the presence of anthocyanin, a pigment which appears reddish. A majority of herbivorous insects and invertebrates cannot detect colors in the red range of the color spectrum. Young leaves suffer the greatest predation from invertebrate herbivores. Red leaves would be perceived by these leaf eaters as somewhat dark and possibly dead – not a choice food material. It is possible that the red coloration of new leaves allows the plant to make them unappealing to the herbivores that would otherwise eat them.
American Bittern
American Bitterns have returned to New England from their southern wintering grounds, and are announcing their presence with a unique song that Sibley describes as a “deep, gulping, pounding BLOONK-Adoonk” that they repeat over and over. These secret, well-camouflaged marsh birds are almost invisible as they slowly walk through marsh grasses. When they stand still and point their bill skyward, they are easily mistaken for the reeds they inhabit.
Cryptic Coloration
Can you find the brown creeper that’s on the trunk of this black cherry tree? This is cryptic coloration, a form of camouflage in which an animal blends into its environment, at its finest. A forager of insects and spiders tucked away behind and in the crevices of bark, the brown creeper starts its search at the base of a tree, climbing upward and often spiraling around the trunk until it nears the top. It then flies to the base of a nearby tree to begin the process again. As W.M.Tyler wrote in 1948 in Bent’s Life Histories of N.A. Birds, “The brown creeper, as he hitches along the bole of a tree, looks like a fragment of detached bark that is defying the law of gravitation by moving upward over the trunk, and as he flies off to another tree he resembles a little dry leaf blown about by the wind.”
Mourning Cloak Butterflies
With the warm temperatures this week, mourning cloak butterflies have been seen gliding through the leafless woods. Like eastern commas, question marks and red admirals, mourning cloaks overwinter as adults. They resemble dead leaves so much that from a distance the entire insect seems to disappear. Up close you can see the velvety texture of the wing scales, said to resemble the clothing mourners used to wear; hence, their common name. Mourning cloaks live up to ten months — an impressive life span for a butterfly. As they age, the yellow border of their wings fades to an off-white.
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
Naturally Curious with Mary Holland 
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