Archives For Jim Steffen

With more than 1,850 known species of moths in the state of Illinois—more than ten times the diversity of butterflies—it is a real adventure sampling the moth species inhabiting the McDonald Woods at the Chicago Botanic Garden.

Using a combination of light and bait traps along with visual searches, I have been investigating the diversity of moth species found in the restored portions of our oak woodland. Moths are removed from the traps and then photographed before being released back to the woodland.

PHOTO: Ctenucha virginica (Virginia Ctenucha) moth.

The metallic scales of Ctenucha virginica (Virginia Ctenucha moth) are striking—even its wings have a metallic sheen.

My interest in moths stems from the fact that many of the species are dependent on one or just a few native plant species for their survival, and as a result, may serve as valuable indicators of the health of our recovering, once-degraded oak woodland. The larval stages—the caterpillars—primarily feed on the roots, stems, and leaves of the plants. Adult moth species are very important pollinators. White-flowered and night-fragrant plant species are often what they seek. There are day-flying moths also, like some of the hawk moths (which are often mistaken for hummingbirds) that are seen visiting a variety of flowers in full daylight. Moths are also a tremendously important part of the food chain. Entomologist Doug Tallamy tabulated the number of caterpillars that were utilized to support one nest of black-capped chickadees and found that they consumed between 6,000 and 9,000 caterpillars, most of which were moth species. Adding even a few native plant species to your yard can benefit a multitude of these valuable invertebrates.

PHOTO: Smerinthus jamaicensis (Twin-spotted sphinx moth).

Smerinthus jamaicensis (Twin-spotted sphinx moth)

PHOTO: Plusia contexta (Connected looper moth).

Plusia contexta (Connected looper moth)

PHOTO: Ponometia erastrioides (Small bird-dropping moth).

Ponometia erastrioides (Small bird-dropping moth)

PHOTO: Plagodis phlogosaria (Straight-lined Plagodis moth).

Plagodis phlogosaria (Straight-lined Plagodis moth)

It is a never-ending surprise to see what new species will show up each time traps are placed.

Some species are so small (usually referred to by lepidopterists as micromoths) that most people would pass them off as gnats or pesky flies. Some micromoths are only 3-4 millimeters long. One in particular I like to refer to as the “Nemo” moth, as in Finding Nemo. I gave this species that name because its colorful pattern reminds me of a clown fish.

PHOTO: A cryptically-colored Noctua pronuba (Large yellow underwing moth).

A cryptically colored Noctua pronuba (Large yellow underwing moth)

At the other end of the spectrum are the moth species that are quite large. The giant silkworm moths, like the luna and Cecropia moths, have a wingspan of more than 140 millimeters. Starting in mid-July and going through September, a group of medium to large moths known as underwing moths starts appearing in the woods. These delta-shaped species are usually very cryptically colored on their forewing and brightly and starkly colored on their hind wing. The cryptic forewing allows them to blend in with the tree trunks they are resting on; the hindwing only becomes visible when they spread their wings to fly. It is thought to be a distraction or scare tactic to foil predators.

Although there is a subtle nuance of shapes, colors, and textures that distinguish many species, there are also those that are in-your-face with shockingly bright colors, metallic ornamentation, stark patterns, and jagged ridges of scales—much like a mountain range on six legs—that never fail to impress me. The looper moths are one good example. Many have stigmas (distinctive white patches and scrolling) on the surface of the wing and spectacular assortments of peaks, crowns, and ridges of scales on the thorax and inner edges of the wings. The scale patterns most likely evolved to break up the silhouette of the moth to make it less visible. One of the hooded owlet moths has a tall patch of scales on its thorax that looks like a witches hat when erect, but it can also be laid down over the moths head to make it look like a broken-off stick.

PHOTO: Leucania pseudargyria (False wainscot moth).

Leucania pseudargyria (False wainscot moth)

In general, there is a new group of species that emerges about every two weeks during the year, with midsummer being the peak for species and abundance. Many moth species have relatively short flight periods and can only be seen at certain times of the year, but some have multiple broods that show up several times during the year. When I show some of these moths to colleagues, they almost always say, “I never knew these things existed.”

Under the cover of darkness, there is a world of beauty and fascination fluttering silently among the trees. It makes me wonder if the full moon doesn’t show up once a month just to shed a little light on the show, just so we don’t miss it completely.


©2016 Chicago Botanic Garden and my.chicagobotanic.org

While working out in the woods this winter, a small lump on the branch of a young elm tree caught my attention. At first I thought it might be a gall, or an injury that had healed-over. On closer inspection, the lump turned out to be a ruby-throated hummingbird nest from last summer. 

Although I see hummingbirds regularly at the Chicago Botanic Garden, I rarely encounter one of their nests. Hummingbirds themselves are amazing, but their nests are truly a marvel of avian architecture. Not much larger in diameter than a quarter, they are just large enough to hold the one to three navy bean-sized eggs of the hummer. For the pint-sized bird to be able to keep the tiny eggs warm during incubation requires that the nest be not much larger than her body. 

PHOTO: Hummingbird nest and quarter (for scale).

Not much larger than a quarter, the ruby-throated hummingbird nest is an engineering marvel.

This is all well and good until the eggs hatch. Growing young hummingbirds can double or triple the amount of room necessary to hold the family. One of the ways the hummingbirds get around this need for flexibility is that they construct the nest of soft plant fibers and then wrap the whole thing with spiderweb silk. This creates an elastic nest that has the ability to expand as the contents of the nest increases. Can you imagine yourself going out and plucking a strand of sticky silk from a spider web with your fingers and then trying to use it to build something out of lightweight fuzzy plant fibers? I imagine you might find yourself wrapped up in a ball like some sort of oversized grotesque moth cocoon. The silk also helps to anchor the nest to the top surface of a horizontal branch.

PHOTO: Spiderweb silk is used by hummingbirds as a nest liner.

Spiderweb silk: the expandable nest liner preferred by hummingbirds.

Keeping the nest just the right size as the need arises helps to keep the growing youngsters warm and secure. In the western states where several species of hummingbirds nest, often at higher elevations, it is not only important to keep the nestlings warm, but also the incubating female, especially at night. Therefore, it is often the case that hummingbirds in these colder situations will locate their nests on a limb with an overhanging branch acting as a sort of roof to help block the nest from the night sky. 

Although this measure helps reduce heat loss, it is often the case that nesting females will go into a state of torpor (reduced physiological activity to lower body temperature) in order to conserve energy on particularly cold nights. This is a principle of physics in which the larger the difference in temperature between objects, the faster the heat flows from the warmer one to the cooler one. Therefore, a hummingbird with a lower body temperature will lose heat more slowly than the one with a warmer body. As I stated earlier, hummingbirds are amazing!

PHOTO: Parmelia sulcata, a common lichen, is used to help disguise the hummingbird's nest.

Parmelia sulcata, a common lichen, is used to help disguise the hummingbird’s nest.

Part of the reason—besides size—I had not noticed the nest earlier is that the birds do a fantastic job of camouflaging it. This also relates to the spiderweb silk. Some or all of the silk used is sticky. Upon completion of nest construction, the birds collect bits of lichen and attach them to the sticky strands on the outside of the nest. Interestingly, the birds seem to always use the same species of lichen, one that goes by the name of Parmelia sulcata

Parmelia sulcata is a light greenish-gray lichen with a leafy (foliose) appearance. One of our more common lichens, it is often seen on the upper branches of trees, and was particularly abundant on the ash trees that died from emerald ash borer. I don’t know if the birds chose this species of lichen in particular or, being common, it is just found most often. It is also interesting that the birds seem to apply the lichens to the nest in an upright position, with the top facing outward, so they look like they could be growing on the nest.

Come birding at the Garden! Take a birding class; join a group, and check your finds against our bird list.

Although this process is fascinating, it is not restricted to hummingbirds. One of the other breeding birds at the Garden utilizes a very similar nest construction technique to hold its three to five small eggs. The blue-gray gnatcatcher, another tiny bird (that somewhat resembles a miniature catbird in appearance and sound), also constructs a nest out of soft plant fibers, including spiderwebs, and applies lichen to the outside of its nest. A nest of this species, a little larger than that of a hummingbird, was found on a branch of one of the locust trees growing in a Garden parking lot.

PHOTO: A female ruby-throated hummingbird (males have the ruby coloring) enjoys a sip of salvia nectar in Circle Garden in summer.

A female ruby-throated hummingbird (males have the ruby coloring) enjoys a sip of salvia nectar in Circle Garden in summer.

PHOTO: A blue-gray gnatcatcher at the Garden; females look similar, but are less blue.

A blue-gray gnatcatcher at the Garden; females look similar, but are less blue.

If you’re lucky, you might find the nest of one of these birds during the nesting season, but if not, keep an eye out for little bumps, lumps, and knobs on bare branches in winter. You might get lucky.

Come #birdthepreserves with the Forest Preserves of Cook County. View our list of upcoming events for free events near you.


©2016 Chicago Botanic Garden and my.chicagobotanic.org

If You Can’t Take the Heat, Stay Out of the Fire

Burning prairies wisely saves animal and invertebrate life, while regenerating the plant landscape.

Jim Steffen —  March 10, 2016 — 2 Comments

This winter has been unpredictable with unusually warm weather one day and biting cold the next. During one of those particularly cold periods in January, I took advantage of the solid ice to work on removing woody invasive plants from one of our isolated wetlands in the McDonald Woods.

We have several such wetlands, but this one is perhaps more interesting than the others, in that it is home to a population of broad-winged skippers (Poanes viator)—an uncommon butterfly that has only been found on six or fewer sites being monitored for butterflies in the Chicago region.

PHOTO: Broad-winged skipper (Poanes viator).

Broad-winged skipper (Poanes viator)

This small brown butterfly is dependent on lake sedge (Carex lacustris) as a larval food plant on our site. It has been found to feed on some other sedge and grass species elsewhere, but here, that is the only plant that its larvae feed on.

In the 26 years I have been managing the 100 acres of the McDonald Woods, this small quarter-acre wetland is the only spot this butterfly can be found. Although there are many patches of lake sedge found throughout the woodland, apparently this butterfly will not leave this small and sunny wetland to venture into the surrounding shade of the oak canopy to take advantage of the other sedge patches.

PHOTO: Lake sedge in winter.

Lake sedge in winter

As I was working among the dormant lake sedge stems—solidly anchored in the thick ice of the wetland—I decided to do a little investigating to see if I could find any clues to the whereabouts of this butterfly in winter. Some butterfly experts think this skipper overwinters as a developing larva, then later pupating before emerging as an adult in early July. However, it seems as though no one is quite sure where exactly the developing larvae would be found.

PHOTO: Broad-winged skipper larva.

Possible Dion skipper larva

As I was working in the wetland, I occasionally plucked a dried-up stem of lake sedge and peeled the leaves back, much as you would peel a banana. Although I did not find a broad-winged skipper larva, I did find the larva of a noctuid moth, what appears to be the larva of a Dion skipper (Euphyes dion), some various fly larvae, a couple tiny adult flies, hundreds of sac spiders (Clubiona maritima), some Linyphiid spiders, Gnaphosid spiders, and a few other spider genera. Although I am well aware that many invertebrates spend their dormant periods hidden away in stems, leaves, and roots of plants, I was amazed to see how much life was present in the dried stems above a solid block of ice.

This revelation got me thinking about my management activities, and in particular, the use of controlled burning. Much like prairies, oak woodlands are dependent on fire to prevent fire-intolerant woody plants from moving in and creating too much shade for the “sun loving” oak trees to reproduce themselves.  

Prairies and oak woodlands evolved primarily as a result of climate, and in particular, rainfall. As you travel eastward from the Rocky Mountains, you first encounter short grass prairie where the rainfall is lowest, then mixed-grass prairie where it is a little wetter, then tall grass prairie where it is still wetter, then oak woodlands and eventually, eastern deciduous forest, dominated primarily by fire-intolerant tree species (like maple and beech), where the rainfall is most abundant.

PHOTO: Euphyes dion by Charles T. and John R. Bryson, Bugwood.org.

Euphyes dion by Charles T. and John R. Bryson, Bugwood.org

These prairies and oak woodlands provided a readily burnable fuel for any fire that got started, whether as a result of intentionally set fires by Native Americans or random lightning strikes. It is not hard to picture the description of early settlers when they wrote about fires that burned for days and covered hundreds of thousands of acres. As the prairie fire approached oak woodlands, they did not go out but continued to burn through the flammable leaf litter and dry herbaceous plants covering the ground of these woodlands.

But historically, these were huge landscapes. Today we are dealing primarily with tiny fragments of the plant communities that once covered thousands—if not millions—of acres. Because the landscape has changed and these remnants are now so small, they no longer experience the landscape-scale fires in which some areas burned while others did not. Back then, when habitats were huge and animal populations were large and widespread, these fires helped to maintain rich and diverse habitats and animal populations for thousands of years. It is always impressive, even after a single fire, to see the abundance of native seedlings emerge from the burned understory and later, the increased flowering of mature plants. But we don’t always consider the unseen other life forms hidden among the dried leaves and stems. Therefore, as managers, it is important that we utilize fire in a thoughtful way to try to restore and maintain all the richness in what remain of these once extensive natural systems.

Getting back to my experience in the winter wetland, there is a tremendous amount of invertebrate life that is present in the dry and burnable plant material in these dormant plant communities. This is particularly important when the entire population of a single species, like the broad-winged skipper, is found in such a restricted space. Plants and animals found in prairies and oak woodlands have evolved adaptations to periodic fires.

PHOTO: The Dixon Prairie in full bloom.

The Dixon Prairie in full bloom

Research has shown that most invertebrates are able to rebound after fire, but as managers, it is important that we make an effort to give these species the best opportunity to flourish on our small remnants. We can best do this by scheduling our burns—not burning the entire patch of any one particular habitat at any one time, especially during extreme weather conditions. And we should always try to leave some remnant vegetation unburned so that populations can regenerate themselves from those individuals that remain. Fire is an extremely important management tool for restoring and maintaining these natural communities, but it must be used wisely.


Photos @ Jim Steffen except where noted.
©2016 Chicago Botanic Garden and my.chicagobotanic.org

One of the most recognized lines from Shakespeare is the following: “Something is rotten in the state of Denmark.” You would have to read Hamlet to get the backstory, but one thing I know as an ecologist, is that we would be in a lot of trouble if there wasn’t a whole lot of rot going on all over the place.

You can probably imagine when walking through our oak woodland, that if things were not constantly rotting, you would be up to your eyeballs in dead leaves, and it would be almost impossible to walk anyway, because of the mass of dead branches and logs lying all over like a bunch of pick-up sticks.

PHOTO: Trichaptum biforme (a hardwood decomposer).

Trichaptum biforme is a hardwood decomposer.

Although there are a tremendous number of organisms that are involved in the rotting process, fungi are the very most important component of this team of decomposers. A tremendous number of species of fungi live in the McDonald Woods at the Chicago Botanic Garden; they can be broken up into two basic categories: those that form symbiotic relationships with living plants (mycorrhizal), and those that decompose organic matter (a.k.a. the rotters).

PHOTO: Another Trichaptum biforme (Violet-toothed polypore).

Another Trichaptum biforme (violet-toothed polypore)

While walking through the woods the other day, I tripped over a downed log and came face-to-face with one member of those decomposers, the bracket fungi. These familiar fungi, also known as shelf fungi, have a characteristic growth form. Most do not produce a stalk (stipe) that supports their cap. Instead, whether on a standing tree or on a log lying on the ground, the cap is attached directly to the wood and projects out horizontally like a shelf or awning.

Gravity causes tropism (the turning or bending in plants and fungi toward or away from an external stimuli), which causes the shelves to orient horizontally out from the wood. This is interesting to observe, especially when a standing dead tree that has shelf fungi falls to the ground, and the new fungi orient in a different direction after the tree falls. (This is one way that you can discover if a tree was dead before it fell to the ground.)

PHOTO: The beautiful layers of Trametes versicolor, or turkey tail fungus.

The beautiful layers of Trametes versicolor, or turkey tail fungus

Just like most of the “mushrooms” we find growing on the ground, these shelf fungi are the fruiting bodies of an organism that we seldom see. The actual organism is a spiderweb-like structure that is either sprawled out within the soil or, in the case of the decomposers, spread throughout the dead plant material.

What is important about these decomposer fungi is that they are able to breakdown cellulose and lignin—the building blocks of plants, and two materials that are unable to be decomposed by almost any other organism. Therefore, without the help of these fungi, we would be swimming in a sea of dead plant material, and all those nutrients and minerals would be locked up—unavailable for other plants to use.

Many of the shelf fungi differ from other fungi, not only because of their growth form, but also because they are usually very woody or leathery in nature. ( I can imagine that people mistake some of these fungi for a deformity in the tree when they feel them and realize that they are as hard as a rock. This is not true of all shelf fungi; some are soft and squishy and quite fragile.)

Some common shelf fungi are the artist’s conk (Ganoderma applanatum), the horse hoof fungi (Fomes fomentarius), the turkey tail fungi (Trametes versicolor), and the sulphur polypore (Laetiporus sulphureus).

PHOTO: Ganoderma species fungus.

Ganoderma species fungus

PHOTO: Sulphur polypore, or chicken-of-the-woods fungus (Laetiporus sulphureus).

Sulphur polypore, or chicken of the woods fungus (Laetiporus sulphureus)

The type of decomposition that takes place is referred to as either white rot or brown rot. In white rot, the fungi breaks down the lignin and leaves the cellulose behind. Wood that is being decomposed by white rot fungi turns off white and stringy. In brown rot, the fungi decompose the cellulose and leave the lignin behind. Brown rot fungi turn the wood reddish-brown and crumbly. In combination, the two types of decomposers reduce even large tree trunks to their component nutrients and minerals and make them available to the environment for living plants to use.

PHOTO: Stereum ostrea, or false turkey tail fungus.

Stereum ostrea, or false turkey tail fungus

Although some of the shelf fungi are interesting and quite attractive, like the turkey tail and violet tooth fungi (Trichaptum biforme), it is not a good sign to see them growing on your favorite shade tree. Some of these shelf fungi can be found on living trees where disease or damage has caused the decomposition process to begin, and may not portend a bright future for the tree. You might also see some of the fungi sprouting from structural elements of your home if the wood is unprotected and exposed to excess moisture—another sign of trouble.

Some of the shelf fungi are very prolific and can occur in the hundreds on a single log, or they might be one giant shelf that can be more than a few feet across and weight 50 to 100 pounds or more. One of these large examples can be seen in our Wonderland Express exhibition.

PHOTO: Shelf fungus on display in Wonderland Express.

Shelf fungus on display in Wonderland Express

PHOTO: Ganoderma lucidum fungus.

Ganoderma lucidum

It should also be noted that these shelf fungi have some aspect to them that are of interest other than their role in decomposition: while most species are woody and unpalatable, the chicken of the woods (Laetiporus sulfureus), is considered one of the best fungi for eating. There are also several species of shelf fungi thought to have medicinal properties, including the attractive Ganoderma lucidum (known as reishi in herbal medicine).

So next time you are out hiking in one of our local forest preserves, consider the “shelf life” around you, and what the woods—and life—would be like without them.

Find out more about the natural world at the Garden and in your backyard: learn about Lepidoptera, bats, and grubs.


©2015 Chicago Botanic Garden and my.chicagobotanic.org

I am sure that most of you know what I am referring to when I say “leap year.” Although this is not a leap year, I am suggesting that we unofficially call 2015 “Lep Year”—“lep” being short for Lepidoptera (from the Latin “scaly wing”), the order of insects that includes butterflies and moths. It has probably been a decade or more since I have seen the diversity and abundance of butterflies and moths that I have seen this past spring and summer.

PHOTO: Euchaetes egle (Milkweed tussock moth).

These voracious Euchaetes egle caterpillars were shredding some of the common milkweed plants near the prairie at the Garden this summer.

Lately, the butterflies have gotten the lion’s share of PR. In particular, the monarch butterfly is on nearly everyone’s radar, due to its precarious situation with dwindling wintering grounds and lack of larval food plants—the milkweeds. However, if you compare the two groups, butterflies and moths, the numbers of moth species outnumber the butterflies by more than ten to one in North America! In fact, there is a moth species that is also dependent on milkweeds—the milkweed tussock moth (Euchaetes egle). The caterpillars of this species are black and orange (a similar color combination to the monarch), and they usually occur in large numbers when you find them. The black-and-orange coloration signals to predators not to eat these fuzzy little fur balls.

The main difference between butterflies and moths is that the moths, in general, tend to be rather drab colored and active at night while the butterflies are mostly colorful and active during the day. These are generalities since you can find very colorful moths, rather drab butterflies, and a number of day-flying moths. There are also structural differences most easily seen in their antennae. While butterflies have narrow antennae with club-shaped structures at the end, the moths can have either thread-like antennae that end in a point in females or fern-like antennae in males. The fern-like antennae of the males are used to detect the chemicals, called pheromones, released by the females when they are ready to mate. Some moths can follow these chemical trails for miles.

Sixty percent or more of the diet of some nestling songbirds comes from caterpillars, and these are most certainly moth caterpillars.

Moths are not only extremely diverse in shape and pattern, they also have a wonderful variety of common names that people have come up with to label them. There are sphinx moths or hawk moths, daggers and darts, army worms and prominents, sallows and quakers, owlets and loopers, and marvels and bird-dropping moths. The names go on and on, some attempting to describe the adults and others the larvae.

PHOTO: Cecropia moth caterpillar (Hyalophora cecropia).

This brightly ornamented Cecropia moth caterpillar (Hyalophora cecropia) will turn into North America’s largest native moth.

It is hard to say which stage of the moth life cycle is more impressive. Although the adult moths are so varied in their shape, size, and patterns, the caterpillars are no less amazing. Take for example the strikingly beautiful brown hooded owlet moth caterpillar.

PHOTO: Brown hooded owlet caterpillar (Cucullia convexipennis).

The brown hooded owlet caterpillar (Cucullia convexipennis) is a stunning specimen to find outside my office.

It would be difficult to find a more attractive critter anywhere, and here it was, right outside my office. Equally impressive are the huge silkworm caterpillars. The Cecropia moth caterpillar (Hyalophora cecropia) is almost shocking, not only because of its massive size, but also because of the large orange-and-yellow spiky beads covered in black spots along its back and the smaller turquoise-spiked beads ornamenting its sides.

And who could talk about moth caterpillars without mentioning the infamous woolly bear? These orange and black-banded caterpillars are often consulted to see what the winter will be like. Unfortunately, the banding on the caterpillar has nothing to do with the weather, but at least it has gotten it a lot of attention. The woolly bear eventually turns into the bright orange Isabella tiger moth (Pyrrharctia isabella).

PHOTO: Woolly bear caterpillar (Pyrrharctia isabella).

Who hasn’t been tempted to touch the woolly bear caterpillar (Pyrrharctia isabella)? Photo by By Micha L. Rieser via Wikimedia Commons

PHOTO: Isabella tiger moth (Pyrrharctia isabella).

The Isabella tiger moth retains its orange-and-black caterpillar coloring. Photo by Andy Reago & Chrissy McClarren via Wikimedia Commons

The high diversity and nocturnal behavior of moths make it not unlikely that you might find a moth or caterpillar you haven’t seen before. The other day, while trimming my rambunctious Virginia creeper vine on the side of my house, I spotted an interesting caterpillar that I had never seen before. As a woodland ecologist I have experience with a lot of caterpillars, so it is always interesting when something new comes along. As it turns out, the caterpillar was the larval stage of an Abbott’s sphinx moth (Sphecodina abbottii). Although this was a new find for me, I still have not seen the adult moth.

Every morning when I come into work, I check the wall outside our building under the light to see if any new moths have shown up during the night. Some of the moths I have spotted this summer are the Crocus geometer, Colona moth, Ironweed borer, large maple spanworm, Ambiguous moth, green owlet, and one of the microlepidoptera, the morning-glory plume moth.

PHOTO: Colona moth (Haploa colona).

Colona moth (Haploa colona)

PHOTO: Crocus geometer (Xanthotype urticaria).

Crocus geometer (Xanthotype urticaria)

PHOTO: Green owlet (Leuconycta diphteroides).

Green owlet (Leuconycta diphteroides)

PHOTO: Morning glory plume (Emmelina monodactyla).

Morning glory plume (Emmelina monodactyla)

PHOTO: Ironweed borer (Papaipema cerussata).

Ironweed borer (Papaipema cerussata)

Most moths do not live for very long as adults. Ironically, some of the largest moth species live the shortest lives. I had the opportunity to see a new species of one of these megamoths for the first time this summer when my wife brought home an Imperial moth (Eacles imperialis) that she found clinging to the window of the school where she works. The very large moths in the family Saturniidae (silkworms and royal moths) emerge either from the soil, in the case of the Imperial moth, or from one of the familiar large cocoons you can find attached to a twig, like those of the Cecropia or Promethea moths. Since these moths do not have functional mouth parts, they are unable to feed, so they live off their stored body fat while searching for mates until they die, usually within seven to ten days.

PHOTO: Imperial moth (Eacles imperialis).

This Imperial moth (Eacles imperialis), had a 5-to-6-inch wingspan, and a body as big as my thumb!


Interested in finding out more? Visit the Moth Photographers Group at mothphotographersgroup.msstate.edu or BugGuide at bugguide.net.

Another new species for me was the painted lichen moth. While removing Japanese beetles from my hazelnut shrubs, I spotted what looked like a large firefly. As it turned out, it was not a firefly at all, but rather a moth that mimics one. Since fireflies are toxic to most predators, the moth gets a benefit from looking like the firefly. Another neat trick they employ is a maneuver known as frass flicking. They are able to expel their excrement nearly a foot away from their body. This is important because some predatory wasps locate their prey by homing in on the scent of their droppings.

There are a number of moths—or more accurately, moth larva—that are pests for gardeners. Almost all vegetable growers have run into cutworms at one time or another. Cutworms were given this name because of their habit of cutting off seedling plants in the garden. There are a number of cutworm species native to this country, but all develop into moths later in their life cycle.

PHOTO: Parasitized sphinx moth caterpillar.

The white structures on this parasitized sphinx moth caterpillar are the cocoons of the braconid wasps.

Another familiar larva is the tobacco or tomato hornworm (Manduca sexta). These are the large green larvae of one of our native sphinx or hawk moths. The Carolina sphinx larva is often found on tomatoes. Although they will rapidly chow down on tomato plant leaves, I generally leave them alone until they have had their fill and work their way down into the soil where they pupate to spend the winter. (I find that they rarely put much of a dent in the productivity of my tomato plants.) If you should happen to dig up one of their pupae when turning over the garden soil, they are a dark, shiny brown, pointed at one end, and have what looks like a teapot handle on the side that houses a long, curved proboscis. If you pick them up, you might be startled by the fact that they often times will swivel around at the middle—probably a predator avoidance behavior. Tobacco hornworm and sphinx moth caterpillars commonly fall prey to braconid wasps, which parasitize them. Leaving these parasitized caterpillars in the tomato garden can be an effective method of pest control.

PHOTO: Female gypsy moth (Lymantria dispar).

Female gypsy moth (Lymantria dispar)

A more serious pest species is the introduce gypsy moth. These moths occur in huge numbers and are capable of completely defoliating adult oak trees over large areas. A few years ago, we avoided an invasion of gypsy moths at the Garden when hundreds of thousands of these moths, in Turnbull Woods forest preserve across Green Bay Road in Glencoe, succumbed to a cool, rainy spring.

Join me and take advantage of this Lep Year—check out the yard lights, hedgerows, and flower beds, and see how many moths, caterpillars, and cocoons you can find!


Photos ©2015 Jim Steffen unless otherwise noted.

©2015 Chicago Botanic Garden and my.chicagobotanic.org