Archives For Ecology & Wildlife

The Chicago Botanic Garden is actively maintaining, restoring, and recreating four natural areas at the Garden: woodlands at McDonald Woods and the Brown Nature Reserve, the Dixon Prairie, the Skokie River Corridor, and the 60-acre Garden Lakes. These activities teach restoration ecologists a great deal about habitat management, which can be applied in other regions.

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 or BugGuide at

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

Echoes of a Silent Night

Senior ecologist Jim Steffen describes his close encounters with curious and beautiful bats.

Jim Steffen —  October 29, 2014 — 2 Comments

A few years ago, in early spring, I was traveling through McDonald Woods at the Chicago Botanic Garden, searching for some of the flat-bodied crab spiders (Philodromus) that typically spend the winter in communal groupings under the loose bark of dead trees. Upon reaching a small stand of dead American elm trees, I began to lift the loose remaining bark away from one of the trees to see if any spiders were present.

As I gently pulled the bark away from the trunk, a tiny black hand reached up over the top edge of the bark. It quickly became obvious that there were more than spiders under this bark!

Although I was a little startled to have this hand slowly reach out in front of my face, I immediately realized that this piece of loose bark was the day roost of a silver-haired bat. The silver-haired bat is a medium-sized bat that is a dark chocolate brown or black with white hairs scattered among the dark hairs on its back. I gently released the bark so as not to disturb the napping bat any more than I already had. This is just one example of why it is important to maintain at least some dead standing trees in our woodland communities.

PHOTO: Silver-haired bat.

A silver-haired bat curls up tightly on a tree in McDonald woods. Photo by Jim Steffen

Even though bats are fairly common mammals in our area, since they are almost totally nocturnal, we don’t get to see them all that often—especially at close range, when we would be able to admire their delicate form and attractive appearance. Bats are in the order Chiroptera, roughly translated as “hand wing,” and are the only mammals that are actually capable of true flight (unlike flying squirrels—which we also have at the Garden). 

You might be familiar with another group of small mammals known as shrews. Shrews are mouse-like animals that are actually carnivores that feed heavily on invertebrate populations. Although bats may have varied diets around the world, here they are primarily insect eaters, much like shrews with wings.

When I was in college studying mammology, we used to go out at night and look for streetlights where there were large numbers of moths and other flying insects attracted to the lights. We would then take out our car keys and jangle them around to make high-pitched sounds with the keys clinking together. These high-pitched sounds would simulate the high-pitched sounds produced by the echolocation sounds produced by hunting bats to locate their prey. (Unless we are equipped with special listening devices, we are not able to hear the sound of bat echolocation.) Often times, many of the moths would begin flying erratically, or drop out of the air as though they had been struck with a stupefying charm from Harry Potter’s wand. These moths have evolved defensive tactics to help them avoid being eaten by bats by flying in erratic patterns or closing their wings and dropping if they heard the sounds of an approaching bat. 

PHOTO: Eastern Red Bat

An eastern red bat (Lasiurus borealis) clings to black landscape fabric at the back of one of the buildings here at the Garden. Photo by Jim Steffen

Many years later, while removing invasive garlic mustard from our oak woodland a few summers ago, I came upon an oak tree with a broken branch. All of the leaves on the branch had turned a bright reddish-brown that stood out against the backdrop of all the other green foliage. On closer examination of the branch, I spotted a female eastern red bat hanging upside down, in typical bat fashion, with its single offspring clinging to it. I don’t know if the bat was aware of it, but this dead branch provided the perfect camouflage for her rich color.

This made me think about how these mammals perceive the world. Do bats have color vision, and was this red bat able to tell that the dead branch would be such a good match for its own color? Most nocturnal animals tend not to have color vision, since color does them little good in the dark. Most bats are various shades of brown, black, or gray. (It is a different story for birds that are mostly active during the day and use bright colors as a means of attracting mates or advertising territories.)

PHOTO: Lasiurus cinereus (hoary bat).

Hoary bat (Lasiurus cinereus by Daniel Neal [CC-BY-2.0], via Wikimedia Commons

We have five species of bats that are likely to be seen at the Garden. Some of them are summer residents, like the little brown, big brown, and eastern red bat, while others are mostly migratory species, like the silver-haired and hoary bats that show up during their spring and fall migrations. Years ago, in the late fall, while using fine nets at night to capture owls for attaching U.S. Fish and Wildlife Service bird bands, I often caught many of the large, hoary bats migrating south for the winter. These large bats have an attractive frosted appearance with a mix of white and reddish hairs all over their bodies.

While I was studying birds in the tropical rain forest of Central America, I often encountered small colonies of bats hanging at eye-level, under the broad leaves of Heliconia plants. I think these wide, tent-like leaves were chosen mostly for the protection they gave the bats from the torrential downpours that occurred every day. However, the bats we find here are either solitary animals, like the red, silver-haired, and hoary bats that live solitary lives in the woodlands and forests, or they are colony-forming bats, like the little and big brown bats, that search out attics, barns, or large hollow trees where they gather in groups to raise their young.

Some of the bat species also search out caves or old mine shafts during the wintertime, where the subterranean habitat provides moist, stable conditions with above-freezing temperatures suitable for hibernation. It is possible to construct bat houses that, if placed in the proper locations, can attract and support colony-forming bats during the summer.

We have several of these bat house installed on buildings around the Garden. This summer, one of those houses contained half a dozen bats—probably little browns. It is best to place bat houses in full sunlight, since the bats have high body metabolisms and prefer very warm conditions for roosting during the summer. Think you’d like to build a bat house? Construction details can be found at the Bat Conservation International website at

PHOTO: Flying squirrel.

Another local flier, this very tame flying squirrel enjoyed a snack of walnut with his photo op. Photo by Jim Steffen

Bats are more than curious and beautiful creatures; they are also tremendously important components of a healthy environment. They are extremely important control agents of insect populations. Many of the insect species they eat are harmful crop pests, like army cutworm, or irritating or disease-carrying species like mosquitoes. Some bats can consume more than 1,000 mosquitoes in a single night! Bats are in trouble now for many reasons—not the least of which are climate change, exotic diseases like white-nose syndrome, and habitat loss.

Although bats are seldom seen and often have scary, erroneous wives-tales associated with them, we should be working hard to correct the problems that might lead to a truly silent night.

©2014 Chicago Botanic Garden and

Damselflies 101

Carol Freeman —  September 6, 2014 — 4 Comments

The Chicago Botanic Garden is a great place to find damselflies. You can find them in every location here, and different locations will often yield different species.

PHOTO: Rare form of male Eastern Forktail damselfly.

This is the rare form of the male eastern forktail damselfly. You can see what looks like an exclamation point on its back, similar to the fragile forktail damselfly. ©Carol Freeman

For example, you might find stream bluets along the river and orange bluets hanging out on the lily pads. Most species measure about an inch in length and can be easily overlooked, but when you take time to slow down and search for these tiny gems, you will be rewarded with finding some of nature’s most beautiful hunters. Indeed, these tiny insects are fierce hunters—but don’t worry, as they neither bite nor sting humans. Their preferred food choice is other, smaller insects (including mosquitoes).

The main differences between dragonflies and damselflies are their size and wing positions. Damselflies, in general, are smaller, and hold their wings over their abdomens. Dragonflies tend to be larger, with a heavier body, and hold their wings out to the side.

The most common species around here is the eastern forktail damselfly. Identifying them can be tricky, as they come in several different varieties! The males and females look very different from each other, and the females change color as they age.

PHOTO: Male Eastern Forktail damselfly.

This is the most common coloring for the adult male eastern forktail damselfly (Ischnura verticalis). Note the blue on the end of the abdomen. ©Carol Freeman

PHOTO: Immature female Eastern Forktail damselfly.

This is a young female eastern forktail damselfly (Ischnura verticalis). She will turn a light, powdery blue as she ages. ©Carol Freeman

PHOTO: Female Eastern Forktail damselfly.

This is the most common coloring of the adult female eastern forktail damselfly (Ischnura verticalis). ©Carol Freeman


PHOTO: Male Fragile Forktail damselfly.

This is an adult male fragile forktail (Ischnura posita) — similar to the rare form of the eastern forktail. Keep your eyes open for this one, as they often fly near the eastern forktails. ©Carol Freeman

I like to get out early in the morning. The light is low, there is often dew, and the insects move a bit more slowly until they warm up. One of my favorite places in the Garden to photograph damselflies is in the Dixon Prairie. They like to hang out on the grasses there. Walking slowly on the path next to the plants, you will see what look like tiny flying sticks. Damselflies will often congregate in one area and, if disturbed, sometimes land just a short distance away. I like to use my 105mm or 200mm macro lenses to photograph these beauties. They will fly until the first really hard frost. There are dozens of species native to this area—all of them beautiful and fierce hunters. 

PHOTO: An adult female Eastern Forktail damselfly eating another insect.

Here is an adult female eastern forktail damselfly with her catch of the day. ©Carol Freeman

©2014 Chicago Botanic Garden and

One of our favorite insects at the Chicago Botanic Garden is the praying mantis. So we were very excited to obtain an egg case earlier this spring. We decided to keep it indoors so we could watch it hatch, and then release the newly hatched insects into the Garden.

PHOTO: Preying mantid egg case on a twig.

About 100 praying mantises emerged from this ootheca and were released into the Grunsfeld Children’s Growing Garden.

A praying mantis egg case is called an ootheca (pronouned oh-uhTHEE-kuh). The plural is oothecae (oh-uh-THEE-see). The ootheca was produced by a female praying mantis last fall. She laid her eggs in this foam of protein that hardened around a stick and protected the eggs through the winter. The eggs usually hatch in mid-June to early July. The half-inch-long immature praying mantis nymphs resemble the adult, but they do not have wings. 

PHOTO: Hundreds of baby mantids pour out of an egg case.

Colorless praying mantis nymphs emerge from the ootheca all at one time. During their first hour, they darken in color to blend in with their surroundings.

After our praying mantises hatched inside an insect cage, I discovered that a bed of false sunflower plants (Heliopsis helianthoides) in the Grunsfeld Children’s Growing Garden was infested with red aphids. I released the praying mantises, and the hungry babies immediately began to feed.

PHOTO: Mantis nymphs on the head of a Rudbeckia flower covered with aphids.

At first, the praying mantis babies seemed a little bewildered by their new surroundings, but they quickly acclimated.

PHOTO: Mantis nymph on a flower stem eyes aphids—a tasty meal.

This mantis held very still as it eyed its prey.

PHOTO: A row of mantis nymphs on a leaf face a stem covered with red aphids.

These four little mantises lined up and stared at the aphids that would certainly become lunch soon.

It wasn’t exactly aphid carnage—much to the disappointment of our eighth grade Camp CBG helper, Joshua, who assisted me with the release—but the young predators did appear to enjoy their first meal.  

PHOTO: Preying mantis on liatris bloom in August.

By the end of August, some of our little friends will be as big as this praying mantis (and just as hungry)!

It may surprise you to know that although it looked like a bad infestation, aphids are not really a big problem for the plants. When they are very abundant, it does not take long for natural predators like praying mantises and ladybugs to find them and move in for a feast. Predatory insects will take care of the problem if you are patient and let nature take its course. If aphids show up in your garden and they bother you, we recommend hosing them off with water rather than using an insecticide, because chances are pretty good that there are beneficial insects on your plants, too. Hosing with a strong jet of water will knock off all the bugs and kill most of the aphids, but it won’t be as devastating to the mantises or other beneficial insects as poison.

We have placed praying mantis oothecae in the Regenstein Fruit & Vegetable Garden and Elizabeth Hubert Malott Japanese Garden, as well as in the Children’s Growing Garden, to ensure that there will be a population of our favorite insect for you to find. Many of them will survive on aphids and other insects they capture and devour on our flowers, and they will grow up over the summer. The next time you visit, stop by and see if you can find them helping our plants remain healthy and less bothered by pests.

©2014 Chicago Botanic Garden and

Monarch butterflies have left their overwintering sites in Mexico and are heading back toward the Midwest, including the Chicago area.

Unfortunately, far fewer monarchs will be making the northward flight this year and the chance to see large numbers of these beautiful butterflies in your garden or flying across a prairie is becoming less certain.

Explore pollinators at World Environment Day, June 7.

Join us Friday, June 6, for the Make Way for Monarchs research symposium.

PHOTO: Asclepias tuberosa, a native milkweed species, in bloom.

Butterfly weed (Asclepias tuberosa) is one of many native milkweed species that provide food for monarch butterfly caterpillars and a nectar source for flower visitors such as bees and butterflies.

In the 1990s, hundreds of millions of monarchs made the journey each fall from the northern plains of the United States and Canada to forested sites north of Mexico City. In western North America, more than a million monarchs made a shorter flight to tree groves on California’s coast. However, monarch numbers have been declining for more than a decade, and this year scientists documented record low numbers. We have seen more than a 90 percent decline.

Why is this occurring? We don’t know for sure, although there are several factors that are likely contributing. Habitat loss due to urban development and large-scale agriculture are key concerns. Farms now cover vast areas and many grow genetically modified crops that allow herbicide applications to be used on and around the crop, including in areas where milkweed—the one plant that monarch caterpillars need—used to grow. These “Roundup ready” crops have been identified as a major cause of milkweed loss throughout the Midwest. Additionally, millions of acres of farms and urban land are treated with toxic insecticides. The loss of forest habitat in Mexico and the decline of monarch groves in California may also be playing a role. In the West, severe drought is likely contributing to reduced monarch populations. These threats are compounded by climate change.

We do not have to sit and watch these declines continue.

We can provide these butterflies (and other wildlife) with high-quality, insecticide-free habitats. This is not something that needs to be restricted to a distant wilderness. Indeed, it is a cause in which everyone can take part. Homeowners and farmers can plant milkweed to support monarch caterpillars, and native flowers to provide nectar for adult butterflies, and work to limit the impact of insecticides. Land managers can ensure that milkweed stands are adequately protected.

Sign up for “The Monarch Butterfly: How You Can Help Save This Iconic Species,” Saturday, June 7, at 1 p.m.

PHOTO: A native milkweed pod burst open in winter, distributing seeds.

The Milkweed Seed Finder gives you quick access to regionally appropriate seed sources, with options to search by milkweed species and by state.

The Xerces Society’s Project Milkweed has been working with native wildflower seed nurseries, the USDA Natural Resources Conservation Service (NRCS), and community partners to produce huge volumes of milkweed seed that are being used to restore monarch habitat. In just three years, this work has led to the production of 35 million milkweed seeds! As a result of this effort, milkweed seed is rapidly becoming more available in many regions of the country. To make it easier for people to find seed sources, we’ve launched the Milkweed Seed Finder, a comprehensive directory of milkweed seed vendors across the country.

In addition, the Xerces Society’s work with farmers and the NRCS has led to the creation of tens of thousands of acres of wildflower habitat that includes milkweed, across much of the monarch’s breeding range.

Aldo Leopold wrote in A Sand County Almanac, “One of the penalties of an ecological education is that one lives alone in a world of wounds.” For the sake of the monarch—and so many other species—it is time to heal as many wounds as possible.

©2014 Chicago Botanic Garden and