Archives For Nature in View

Dragonflies capture summer

Carol Freeman —  September 13, 2018 — 1 Comment

Summer won’t be over for a while in my book—not as long as there are dragonflies around. I think I’ve seen more dragonflies this year at the Chicago Botanic Garden than I have in the past ten years combined. The quick, strong fliers seem to be everywhere. 

Female Eastern Pondhawk

Eastern pondhawk dragonfly, female. Most dragonflies have very different-looking males and females. This one was in the Native Plant Garden. Photo ©Carol Freeman.

Some of the dragonflies migrate south toward the Gulf Coast through September and maybe beyond. With the help of citizen observers, scientists are studying the migration patterns of this fascinating insect, which has a near 360-degree field of vision that helps it avoid predators.

The most abundant dragonfly I’ve seen this year is the Eastern pondhawk, with blue dasher dragonflies coming in a close second. I’m also seeing quite a few damselflies, which are generally smaller and more thin-bodied than dragonflies and tend to hold their wings above their bodies. (See my blogpost Damselflies 101 for more information.)

Female Blue Dasher Dragonfly

Blue dasher dragonfly, female. She looks very different from her male counterpart. Photo ©Carol Freeman.

Male Blue Dasher

Blue dasher dragonfly, male. Hanging out on the waterlilies. Photo ©Carol Freeman.

Dragonflies and damselflies, both in the order Odonata, can spend several years as aquatic nymphs before they emerge into the beautiful winged insects we see on land, which is why you will often see them around water. They are fierce hunters in both stages. They don’t bite or sting humans, though.

Green Darner

The common green darner dragonfly is one of the first dragonflies to emerge in the spring, and one of the species that can be found migrating in huge swarms in the fall. Photo ©Carol Freeman.

Dragonflies can be found here from March through the first hard freeze in the fall. Right now, you might even be lucky to find yourself in the middle of a migrating swarm of green darners, black saddlebags, or wandering gliders as they head south. About 90 different odonates can be found in the Chicago area. Each one is a delight to behold.

Eastern Amberwing

Eastern amberwing dragonfly, male. This is one of the smallest dragonflies in our area, at just more than 1 inch long. Photo ©Carol Freeman.

Widow Skimmer

Widow skimmer dragonfly, male. This is one of the larger, flashier dragonflies, and it is easy to identify. Photo ©Carol Freeman.

Eastern Forktail Damselfly

Eastern forktail damselfly, female. This is the most common damselfly in our area, and it can be found in the Dixon Prairie. Photo ©Carol Freeman.

Dragonflies are territorial and will often chase off other dragonflies, only to return to their favorite perch. A favorite place to find them at the Garden is around the waterlilies and lotus blossoms, but you can spot them throughout the 385-acre grounds. Drop by and keep an eye out for the dragonflies near the late-summer blooms. 

Skimming Bluet Damselfly

Skimming bluet damselfly, female. This is a small, delicate damselfly found in the Dixon Prairie.
Photo ©Carol Freeman.

Slender Bluet Damselflies

Slender bluet damselflies, getting ready to lay some eggs. I found this pair along the shoreline next to parking lot 5.
Photo ©Carol Freeman.

©2018 Chicago Botanic Garden and my.chicagobotanic.org

At Butterflies & Blooms on Monday, I saw something I had never seen before in my five years as a butterfly wrangler at the Chicago Botanic Garden. I noticed that a leopard lacewing’s right wings were bright orange, just like any other male of the species, but the left wings were beige—only females have beige wings. This lacewing was half male and half female, or a gynandromorphic butterfly.

Underside of the gynandromorphic leopard lacewing

Underside of the gynandromorphic leopard lacewing

Topside of the gynandromorphic leopard lacewing

Topside of the gynandromorphic leopard lacewing

That morning, when I had discovered the male-female lacewing, butterfly visitors had been waiting for me to release butterflies from the pupae chamber. So I packed up the lacewing, with all of the other newborns. I then released each of the two dozen butterflies that had hatched that morning, saving our special discovery for last. I got everyone’s attention and announced, “This is extremely rare! As a butterfly wrangler, I have released many thousands of butterflies, but this is the one and only butterfly that is literally half male and half female!” The visitors were fascinated by the lacewing, which sat on the tip of my finger. Then it took flight and was free in the blink of an eye. Luckily, one of our volunteers snapped some beautiful photos.

Later, it occurred to me that this specimen could actually be a valuable contribution to science, and if nothing else, something that everyone should get a chance to see. I tried to find and capture it so an expert could take a closer look. A full day went by without anyone seeing it. I was afraid we had missed an opportunity to contribute something special to the scientific community, but our luck was about to change. 

On Wednesday morning, I was chatting with a young butterfly enthusiast about the gynandromorphic lacewing. I asked him if he could keep an eye out and possibly help me find it. He said, “Oh, you mean like this one?” He turned and pointed to the rare creature, which was sunbathing just behind his head. I couldn’t believe it. I offered to name the butterfly after him, but he modestly declined. I’m still trying to reach out to experts. Meanwhile, after that, I brought the special butterfly back into the pupae chamber, where it has been on display to visitors. I have been feeding it by hand, using a piece of foam dipped in fruit juice and Gatorade, which the butterfly seems to love.

Here is a little information about gynandromorphism. Gynandromorphs are very rare, but can be found in birds, fish, crustaceans, and butterflies, among other organisms. Usually, gynandromorphs have an uneven mixture of male and female features, but our special butterfly has an even rarer form of gynandromorphism because the male and female traits are bilateral, meaning they are split perfectly down the center of the body. How rare are we talking? In a 1980s study, only five out of 30,000 butterflies displayed gynandromorphism.

So how does gynandromorphism occur? There are several possibilities having to do with mishaps that occur during early cell division. Butterflies have a W and a Z chromosome for female and male, respectively. Sometimes, the W and Z chromosomes get stuck together during cell division, resulting in a mixture of male and female traits. In another scenario, the embryo is “double fertilized,” resulting in both female and male nuclei throughout the organism. The causes include bacterial or viral infections, ultraviolet radiation, and other environmental factors that can alter an organism’s DNA during division and growth.

In any case, it’s cool to have a butterfly with such a rare deformation that is still fully able to exist as a healthy adult, sipping nectar and basking in the adoration and fascination of its fans. We have not yet named this butterfly, so please leave some suggestions. The typical lifespan of an adult butterfly is about two weeks, so drop by Butterflies & Blooms and say hello to our newest celebrity.


©2018 Chicago Botanic Garden and my.chicagobotanic.org

Bees in the Big City

Andrea Gruver —  August 15, 2018 — 3 Comments

The plants you see from your train seat on the Metra Union Pacific North line may help conservation scientists learn about how urban areas impact native bees.

Although most people think of honeybees when they think about bees, there are more than 4,000 native bee species in the United States and 500 species in Illinois alone. Like their honeybee counterparts, native bees are undergoing global declines, making them an important conservation concern. With the growth of urban areas, native bees may be faced with new challenges, yet we don’t know the extent that urban areas impact native bees.

My research at the Chicago Botanic Garden is investigating how urban areas may affect native bees in Chicago. Chicago is an ideal city to study the impact of urbanization on native bees because the intensity of urbanization slowly wanes from the urban core of the city out into the surrounding suburbs.

Megachilid (leaf cutter) bee

My research is focused on native bee species in Illinois like these Megachilid(leaf cutter) bees.

Megachilid (leaf cutter) bee

Part of that research is about bringing public awareness to the other native bees we have around Chicago.

To explore native bee communities along this urbanization gradient, I have a series of eight sites along Chicago’s Union Pacific North Metra (UP-N) railway. I chose the sites along the rail line because they followed a perfect gradient from very urban to very suburban. I was also drawn to them because most of the vegetation around the sites is unmanaged and composed of similar species.

All of the sites vary in the levels of green space and impervious surface (concrete/buildings) surrounding the sites. Sites near downtown are surrounded by nearly 70 percent impervious surface, while sites near the Chicago Botanic Garden are surrounded by just 15 percent impervious surface.

[Click here to view video on YouTube.]

Studying bees in this area along the Metra line allows us to ask a variety of questions about native bees. For instance: Are there fewer bees in highly urban areas? Are there different bees in natural areas compared to urban areas? Do the bees in highly urban areas have different traits than those in natural areas?

Pollinator Collection Near the Metra with Andrea

Andrea and an intern collect bees along the Metra line.

This summer, a few interns at the Garden and I have been gathering and sampling bees at each of my eight field sites. To catch the bees, we use two methods. First, we set out fluorescent colored bowls with soapy water that attract and capture the bees. Secondly, we use a butterfly net to capture bees at the site throughout the day. When we are finished sampling, the bees are taken back to the lab at the Garden’s Daniel F. and Ada L. Rice Plant Conservation Science Center and pinned for future study.

In addition to collecting the bees, we also record all of the flowering plants and count how many flowers are blooming at the sites.

Although our days are currently filled with fieldwork and pinning, in the fall we will spend almost all of our time in the lab identifying the bees down to the genus or species level. When we have all of the bees identified, we can then start analyzing the data for my master’s thesis and answer some of the questions we have put forth. We suspect we will see a higher abundance and diversity of bees in sites located in more natural areas with more flowering plants.

My research will help us understand how urban areas are shaping native bee communities and help us determine what landscape features promote native bee diversity in urban environments, some of which can be implemented in urban restoration projects. We also hope that this work will illuminate the amazing diversity of native bees we have here in Chicago.


©2018 Chicago Botanic Garden and my.chicagobotanic.org

One day at Butterflies & Blooms, I noticed a crepuscular, cosmopolitan imago puddling in order to prepare for an upcoming lek. What did I just say?

The vocabulary surrounding Lepidoptera can be very specific—and not so easy to understand. Let’s break it down, and go over some of my favorite butterfly and moth terminology (and learn some of the amazing things these insects do). Then, see if you can decode the sentence above. 

Painted Lady (Vanesa cardui)

The very cosmopolitan painted lady (Vanesa cardui)

Cosmopolitan—In this case, a cosmopolitan is not a mixed drink or a well-traveled individual—although this term is related to being in many geographic locations. “Cosmopolitan” describes a butterfly species that is found worldwide. The painted lady is considered cosmopolitan; it is found on every continent except Australia and Antarctica.

Crepuscular—Crepuscular species tend to be most active at dawn and dusk. At Butterflies & Blooms, we have a few species that prefer to fly around during the early morning and late afternoon, when the sunlight is less intense. Species such as the giant owl, as well as other butterflies in the genus Caligo are considered crepuscular based on this behavior pattern.

Diapause—Here in the Midwest, many people wonder how butterflies survive the winter. The answer is diapause. Chrysalids can feel and respond to the temperature outside of their protective exoskeletons. If they notice a few cold nights, they will react by going into a dormant phase called diapause. When this happens, they cease development, and the shell of the chrysalis will turn brown and harden; this is how they survive the overwintering. Many pupae are green in order to blend in with the surrounding foliage, so it makes sense that they would turn brown in the winter to blend in with the dead, brown foliage. When the warmth and light of spring return, they become green again and complete their metamorphosis into adult butterflies.

PHOTO: Danaus chrysippus chrysalids

One of these Danaus chrysippus chrysalids is not like the others. Did it begin to enter diapause during shipment? Or did this African queen butterfly begin its pupation in an area without typical greenery? We are still learning ourselves.

Eclosion—Here at Butterflies & Blooms, we normally refer to our butterflies as “emerging” or even “hatching” from their pupal state. The correct scientific term for this is actually “eclosion.” If you want to impress (or possibly annoy) your friends, tell them that when chrysalids complete their diapause, they resume metamorphosis, and eclose into adult imagos! 

Frugiverous—Butterflies such as the ever popular blue morpho, giant owl, and the great orange deadleaf are frugiverous; they come from habitats where there aren’t many wildflowers available, so they turn to feeding solely on fruit instead. This is why we have trays of fermented fruit in the exhibit.

PHOTO: monarch butterfly on fruit tray.

A selection of watermelon, banana, grapefruit, and orange slices are an attractive source of food to frugiverous butterflies like this monarch.

Generalist vs. Specialist—Some butterflies are successful because they “specialize” in certain plant families. This means that their success is somewhat tied to the success or failure of the particular plant they evolved to rely on. This is the case for monarch butterflies. Monarchs have evolved to rely on plants in the milkweed (Asclepias) family as both a nectar source and host plant on which to lay eggs. Although there are many different types of milkweed, this is still considered a niche. On one hand, this can be a benefit, because the monarch can capitalize on the unique benefits that come from plants in the milkweed family. On the other hand, if milkweed declines, monarchs don’t have any alternative plant families to use as hosts.

Generalists, such as the painted lady, can use a wide variety of plants families to lay eggs on, such as carrots, mints, and nettles. This ensures that they will always be able to find suitable host plants. Humans are also generalists, as we are able to use a wide variety of food sources and habitats.

Imago—While we simply refer to our butterflies as “adults,” the true term for the final stage of butterfly development is “imago.” The life stages of a butterfly are egg, caterpillar (larvae), chrysalis (pupae), and adult (imago). Interestingly, the term “imago” also refers to a human individual’s idealized image of himself or herself. What’s your personal imago?

Lekking—This is a very interesting term, because until the blue morpho was discovered, lekking was not thought to be a behavior found in butterflies. Lekking is a type of mating ritual in which all the males form a group and compete, showing off their most admirable features. The males with the right stuff will be the ones who get to mate and pass on their genes. With blue morphos, only the most colorful males will get this privilege. I once witnessed a group of blue morphos “lekking” at Butterflies & Blooms. A group of about ten males were hypnotically circling around a single female. I couldn’t believe my eyes!

Polymorphism—Some of our butterfly species display polymorphism, including the mocker swallowtail and the postman. This means that within the species, the wings can have numerous pattern variations. This can make their identification tricky. The postman butterfly (Heliconius melpomene) is intensely studied by Lepidopterists because its patterning is more variable than any other butterfly species on earth. Here at Butterflies & Blooms, we have observed at least four distinct patterns from this one species of butterfly. Some have a white “skirt” along the bottom of their hind wings, some have a red spot on each forewing, and yet others have a pair of red spots on each wing.

Heliconius melpomene aglaope

Heliconius melpomene aglaope

Heliconius melpomene melpomene

Heliconius melpomene melpomene

Heliconius melpomene amaryllis

Heliconius melpomene amaryllis

Puddling—Puddling is the tendency of butterflies to sit in wet soil or stone and extract the minerals from the ground. Apparently, puddling is somewhat exclusive to male butterflies, because they need these minerals for sperm production. This is also why the butterflies (especially males) land on visitors. They drink our sweat to obtain these precious salts, sometimes absorbing them directly through a t-shirt!

Blue-spotted Charaxes (Charaxes cithaeron)

A blue-spotted charaxes (Charaxes cithaeron) puddles in gravel after a brief rain shower

Sexual Dimorphism—Butterflies tend to have different color and sizes based on whether they are male or female. This phenomenon is known as sexual dimorphism. Because female butterflies lay eggs, they tend to be a bit larger than the males. The males tend to have richer coloration and/or bolder patterns. Just like birds and fish, females will tend to choose the males with the boldest colors, as this indicates healthy genes.

Male leopard lacewing (Cethosia cyane)

Male leopard lacewing (Cethosia cyane)

Female leopard lacewing (Cethosia cyane)

Female leopard lacewing (Cethosia cyane)

These are just a handful of terms I like to use when talking about our amazing collection of butterflies. Expect to be quizzed on them during your next visit to Butterflies & Blooms!


Postman comparison images by Notafly (self-made Own photograph.Studio.Nikon.) [CC BY-SA 3.0 or GFDL], via Wikimedia Commons

Flame-bordered charaxes (Charaxes protoclea) and blue-spotted charaxes (Charaxes cithaeron) ©Patty Dodson

©2018 Chicago Botanic Garden and my.chicagobotanic.org

If you happened to walk around the Heritage Garden in late June, the unusual blue color of the Moroccan mountain eryngo (pronounced eh-RING-go), Eryngium variifolium, probably caught your eye, and its peculiar perfume tickled your nose. It was also swarming with flying insects.

The odor was not lovely and sweet. I would describe it as similar to musty, molding fruit—not unpleasant, but certainly not a fragrance you would wear. It only lasted a few days, during which time it hosted an amazing number and variety of insects. I attempted to photograph and identify as many of them as I could. This was a lot harder than I expected, because the insects were in constant motion and most of them were small. I didn’t always capture the key features needed to identify them at the species level. In spite of this, you’ll see that that the variety was astounding. Let me introduce you to what I found at the Chicago Botanic Garden recently.

1. Carpenter bee

PHOTO: a carpenter bee perched on a eryngo flower.

Carpenter bees are often confused with bumblebees because of similar size and coloring. The carpenter bee has a black abdomen and a black spot on the back of its thorax (middle section). That’s how to tell the difference.

2. Mason bee

PHOTO: a mason bee on an eryngo flower head.

Mason bees are in the Megachile family. The are also known as leaf-cutter bees.

PHOTO: a megachile bee is covered in pollen.

This mason bee has filled the “pollen baskets” on its hind legs with pollen from the eryngo, and they are now swollen and bright yellow. Pollen is also sticking to the hairs on its thorax and underside. It is a good pollinator!

Carpenter bees and Mason bees are native to our region. Honeybees are not native to the United States. I saw honeybees in the Heritage Garden, but they were not interested in this flower. Honeybees tend to go for sweeter-smelling flowers.

3. Red admiral butterfly

PHOTO: a Red Admiral butterfly is perched on a eryngo flowerhead.

The red admiral, with its characteristic red stripe across the middle of the upper wings, is  common in our area.

4. Azure butterfly

PHOTO: the azure butterfly's wings are smaller than that flower head it is perched upon.

This tiny gray-blue butterfly is an azure. Some azures are the same blue color as the eryngo flower.

A monarch butterfly also flew overhead while I was taking pictures, but it didn’t stop by. Again, the scent of this flower isn’t attractive to all pollinators. 

5. Squash vine borer (moth)

The squash vine borer larva can be a nuisance in a vegetable garden, but it is a beautiful and beneficial pollinator as an adult moth. Sometimes we have to resist the urge to judge our fellow creature as being good or bad. 

PHOTO: Picture of the moth perched on an eryngo flower head.

The squash vine borer was the flashiest visitor I saw on the flowers.

6.  Syrphid flies (hoverflies or flower flies)

When we think of flies, we tend to think of those annoying houseflies or other pests, but there are other kinds of flies. The Syrphidae family, also known as hoverflies or flower flies, feed on pollen and therefore serve as important pollinators for many plants. I found three species of syrphid flies on the eryngo.

PHOTO: flower fly hovers next to the flower head.

Flower flies resemble bees because of their yellow and black striped pattern, but this little insect bears the large eyes and short antennae that are characteristics of a fly.

PHOTO: flower fly on a leaf.

This syrphid is very small, only about a a quarter of an inch long. It looks a lot like the first, but it had a rounder abdomen. The pointed end is an ovipositor, so after inspection, I believe this is the female and the other may be male, so I counted them together.

7. Another kind of syrphid fly

PHOTO: syrphid fly on a eryngo flower

This syrphid fly is a little bigger and fuzzier than the previous one. It could easily be mistaken for a bee.

8. Mystery fly, possibly another syrphid

PHOTO: small black fly on a eryngo flower.

I was having a difficult time getting good picture of some of these small insects, and as a result, I didn’t get enough details to identify this half-inch-long fly with white triangles on the back of its abdomen.

9. Green bottle fly

Houseflies fall into the family of flies known scientifically as Calliphoridae, also called the blowfly family, and they were also represented on our eryngo plant.

PHOTO: green bottle fly seen from the back.

One view of this green bottle fly (genus Phormica) shows its iridescent green body.

PHOTO: Green bottle fly from the front.

The same green bottle fly can bee seen with its proboscis sipping nectar from the flower in this image.

10. Cluster fly

PHOTO: cluster fly on a flower.

This is the only image I got of another blowfly species, a cluster fly (genus Pollenia).

11. Tiger fly (I think)

Tiger flies prey on carpenter bees, which were feeding on the eryngo flowers, so seeing this predator around the eryngo makes sense.

PHOTO: a fly of some kind is perched on a leaf, partially hidden by the stem of the plant.

I could not get a good picture of this one, because it was hiding in the shadows under the flowers. The wing pattern suggests some kind of tiger fly. Its secretive behavior is also a clue to its identity.

12. Vespid wasp

The wasps I observed were far too busy collecting nectar and pollen to notice me. I had no concerns about being stung.

PHOTO: wasp perched on a eryngo flower.

Vespid wasps are a large family of wasps that include paper wasps—those insects that make the big paper nests. These insects live in colonies and they do sting when they feel threatened.

13. Black garden ant

I watched a few ants appear very determined as they walked up the stems of the eryngo, dipped their heads into the flower centers, and went back down the stem as swiftly as they arrived.

PHOTO: Ant on an eryngo.

The ants must have a colony living in the ground under the Eryngo.

14. Damselfly 

Where there are a lot of flying insects, there are going to be some predators. There were damselflies hovering over the blossoms, feeding on the flies, not the flower. 

PHOTO: bronze and blue damselfly perched on an Eryngo flower.

Damselflies are difficult to identify without getting a really good closeup of their abdomens and markings—and my picture wasn’t good enough. I believe this is some kind of spreadwing.

15. Assassin bug

Assassin bugs fall into the category of insects known as “true bugs.” I saw few assassin bugs lurking around the eryngo flowers.

PHOTO: an assassin bug hangs out at the bottom of the flower, probably about to catch another insect.

Assassin bugs and their kin have piercing mouth parts that penetrate their prey and suck the juices out. This guy wasn’t there to feed on nectar or pollen.

16. A spider web

Like the damselfly and assassin bug, this spider is hanging out somewhere under the flowers to prey on the flies, bees, and other insects that happen into its web.

PHOTO: Spider web that was underneath the flowers.

Spiders tend to set their traps and hide. I never saw the spider that made this tangle-web but I suspect it was well fed.

In total, I found two kinds of bees, two butterflies, one moth, six flies, one wasp, one ant, one damselfly, one assassin bug, and one spider—sixteen different bugs on this one bright, smelly plant!

The take-away from my experience is that scent is a really successful strategy for attracting pollinators. Like the titan arum, the Moroccan mountain eryngo produced a super potent blast of odor for a brief period time and then moved on to the next phase in its life cycle, which suggests that it requires a lot of a plant’s energy reserves, and may not be sustainable for a long time. This strategy works well  as long as the timing of the bloom coincides with the pollinators’ need to feed and ability to get to the flowers. 

I find this phenomenon fascinating. If you share my passion for plants and their relationships with insects, check out Budburst at budburst.org and find out how you can help scientists who need your observations to contribute data to their research. 


©2018 Chicago Botanic Garden and my.chicagobotanic.org