Archives For Plant Science & Conservation

Conserving plants is one of the most significant challenges of our time—and a major focus at the Chicago Botanic Garden. From studying soil to banking seeds, from restoring habitats and protecting endangered plant species to developing new ones, Garden scientists are fighting plant extinction, pollution, and climate change through diverse and exciting research.

To most people, the word “pollinator” is synonymous with the word “bee,” but only a fraction of plants are pollinated by bees.

In fact, many different insects and mammals are pollinators—bats, birds, beetles, moths, and more. As part of National Moth Week, we wanted to highlight our work on a very special group of moths: the Sphingidae, or hawkmoths, which pollinate more than 106 plant species in North America alone, and many more around the world.

PHOTO: A newly emerged Hyles lineata hawkmoth.

A newly emerged Hyles lineata hawkmoth

I am a research tech in the Skogen lab. I work with Krissa Skogen, Ph.D., her postdocs Tania Jogesh and Rick Overson, and fellow Garden scientist Jeremie Fant, Ph.D., on a National Science Foundation Dimensions of Biodiversity project entitled, “Landscapes of Linalool: Scent-Mediated Diversification of Flowers and Moths across Western North America.” Our project looks at floral scent and pollination in the evening primrose (Onagraceae) family.

Many species in the evening primrose family are pollinated by the white-lined hawkmoth (Hyles lineata). This pollinator is also an important herbivore! Female moths lay eggs on evening primroses, and their hungry caterpillars feed on the leaves, buds, and flowers. How does scent play a role in attracting hawkmoths? Do moths use it for pollination? Or do they use it to find host plants to lay their eggs? Or maybe both?

PHOTO: Hawkmoth pupae (Hyles lineata).

Hawkmoth pupae (Hyles lineata)

PHOTO: Hyles lineata eggs on an Oenothera harringtonii plant.

Hyles lineata eggs on an Oenothera harringtonii plant

From Dr. Skogen’s prior research, we know that floral scent can vary within and between plant populations. For instance, within the species O. harringtonii, some populations produce a scent compound called linalool while others do not. We think that the plants face a signaling dilemma: How do they use floral scent to invite their pollinators and yet avoid getting eaten? If female moths use linalool to lay eggs, then perhaps, in some populations, the plants benefit from not advertising their scent. To test this idea, we needed to conduct behavioral experiments to understand how Hyles perceive floral scent

This summer, along with Victoria Luizzi, a summer REU student from Amherst College, we looked at which plants female moths prefer to lay their eggs on—plants from populations containing linalool, or plants from populations without linalool. To answer this question, we first went to Colorado (where the plants naturally grow) and got plants from two different populations, one population that we know produces linalool and another we know doesn’t. Meanwhile our collaborator, Rob Raguso at Cornell University, sent us hawkmoth pupae and we patiently waited for them to emerge.

PHOTO: Victoria Luizzi (left) and Andrea Gruver (right) dissect a female moth to count remaining eggs.

Victoria Luizzi (left) and Andrea Gruver (right) dissect a female moth to count remaining eggs.

When the moths emerged they were placed in mating cages. Once mating occurred, females were transferred to a quonset in the evening that contained four plants from the linalool population and four plants from the non-linalool population. The moths were left overnight so the females had plenty of time to choose where they wanted to lay their eggs. The next morning, Victoria counted the eggs on each plant (which was sometimes hundreds!) to see on which plants the females were choosing to lay their eggs. In addition, we dissected each moth to see how many eggs the female did not lay.

PHOTO: Krissa Skogen moves a moth to its new enclosure in her office.

Krissa Skogen moves a moth to its new enclosure in her office

Over the course of the project, 12 females were flown in the quonset. Overall, the moths showed a preference for plants from the population that produces linalool. These data suggest that plants risk inviting foes while advertising to their friends—but we’ll need to collect a lot more data to be certain. Ultimately, both the insects that pollinate flowers as well as the insects that eat them might determine how a flower smells! We hope to continue this study to test our hypothesis further and learn more about how scent influences hawkmoth behavior, and how hawkmoth behavior influences floral scent and other floral traits of the plants they pollinate.


©2016 Chicago Botanic Garden and my.chicagobotanic.org

Most butterflies and moths featured in popular magazines and other media are large, well-known species, such as monarchs and luna moths.

Within scientific communities as well, species descriptions are biased toward larger moths, overlooking the multitude of tiny ones. Despite this tendency to favor larger species, the average moth is actually quite small, though far from nondescript!

PHOTO: Mompha species moth; photo taken in Utah.

Mompha species moth; photo taken in Utah

My research at the Chicago Botanic Garden focuses on an insufficiently studied moth group called Mompha, the largest genus within the family Momphidae. Mompha are tiny moths characterized by 4- to 8-millimeter tufted forewings and distinct color patterns.

PHOTO: Mompha stellella and M. eloisella moths

Specimens up close: Mompha stellella on the left and Mompha eloisella on the right. Both are found in Illinois, typically during the month of August. Photo credit: Terry Harrison

In North America, there are approximately 40 described species, or taxa, of Mompha. In addition to these identified species, a number of undescribed taxa are located throughout the North American West and Southwest. Mompha larvae feed on the reproductive (i.e., flowers, buds, and fruits) and vegetative (i.e., leaves, stems, and roots) structures of members of the Lythraceae, Cistaceae, Rubiaceae, and, most commonly, Onagraceae (evening primroses). In Illinois, Mompha can be collected in your backyard from Oenothera biennis (common evening primrose).

PHOTO: Mompha feeding and caterpillars.

Examples of Mompha bud-feeding and Mompha fruit-feeding caterpillars

Because many Mompha species share the same coloration, the only morphological characteristics—size, shape, and structure of an organism or one of its parts—that accurately differentiate taxa are unique genitalia. Experienced lepidopterists—butterfly and moth researchers or collectors—are able to carefully dissect moths in order to view their genitalia. However, due to the unique skills involved in moth dissection and genitalia identification, few scientists are qualified to identify different Mompha species.

PHOTO: Closeup of Mompha species caterpillar.

Close-up of Mompha species caterpillar

Instead of conducting genitalia dissections, I am sequencing six genes from hundreds of Mompha collected over the span of three years from the Western and Southwestern United States. DNA, like morphological characteristics, can be used to identify and characterize differences between species. To analyze the differences within Mompha DNAI modeled phylogenetic trees.

PHOTO: Tubes of moth DNA samples.

Tubes and tubes of Mompha moth DNA samples

Phylogenetic trees depict evolutionary relationships between species in regard to genetic characteristic; closely related species share similar DNA and are thus placed close together on a phylogenetic tree. These trees will allow me to describe the natural history of Mompha in North America. This means that I will be able to identify new Mompha speciesas well as Mompha host plant preferences, plant structure preferences, emergence times, and geographic isolation.

Check back here in a couple of months to read about the results of my analyses!


Select photos by Donald Hobern (Flickr: Mompha epilobiella) [CC BY 2.0], via Wikimedia Commons, and Rick Overson.
©2016 Chicago Botanic Garden and my.chicagobotanic.org

Gardeners and farmers know that healthy plants need good soil and the right amounts of both water and sunlight. But green roofs are intentionally built with an engineered soil-like substance that more closely resembles a pile of rocks than rich, moist potting soil.

To make matters worse, the tops of buildings are often blindingly sunny and very hot in the summer. So how do plants like grasses and wildflowers survive in this type of harsh environment?

PHOTO: Cactus and allium grown on green roof.

Cactus and other succulents retain water in their tissues. Ornamental onion (Allium) species have underground bulbs that help them get through cold winters and dry summers.

Not all plants will grow on a green roof, even in the temperate Midwest. Most plant species that are successful in the desert-like habitats of green roofs have beneficial adaptations that allow them to absorb and store water and nutrients. Some have succulent leaves with thick waxy coatings to prevent water from evaporating. Others have roots that grow horizontally rather than vertically to maximize the areas from which they absorb water and nutrients. Some use a modified type of photosynthesis to prevent water loss during the hottest and driest part of the day. Still others use bulbs or underground tubers to store nutrients during the long cold winters. Some species may even form partnerships with special fungi in the soil that help their roots with more effective absorption.

While plant species evolved to develop these various adaptations on the ground, such traits serve the individual plants very well in the harsh environment of a green roof. The next time you visit a green roof, you might see a striking diversity of species but you won’t see any wimps. No, these plants are both beautiful and tough. 

PHOTO: Shortgrass prairie plants grown on a rooftop garden at shallow depths.

Even in very shallow soil and full sun, some plants that normally grow in shortgrass prairies are able to grow and reproduce. (This is from some of my research at Loyola University.)

PHOTO: PCSC green roof in summer 2015.

Plants can be both tough and beautiful on green roofs. (This photo is of the Plant Science Center last summer.)

Find more of the best plants for green roofs on our Pinterest board, and see Richard Hawke’s Plant Evaluation Notes for the plants that performed best on our green roof.


Students in the Chicago Botanic Garden and Northwestern University Program in Plant Biology and Conservation were given a challenge: Write a short, clear explanation of a scientific concept that can be easily understood by non-scientists. This post is part of their series.

©2016 Chicago Botanic Garden and my.chicagobotanic.org

Those of us who are Star Wars fans know just how powerful genetic cloning can be. 

Obi-Wan Kenobi’s discovery of a secret clone army illustrated the power of advanced cloning technology. That army of genetically identical clone warriors went on to become the face of the epic Clone Wars. Meanwhile, in a galaxy much closer, plants are also equipped with the ability to copy themselves as a form of reproduction. This form of asexual reproduction is very common in the natural world, and just as powerful to an ecosystem as a clone army is to a galaxy. 

PHOTO: Clone trooper.

This clone may not take over your Garden…

PHOTO: Red Monarda (beebalm).

…but this Monarda might!

Clonality is a form of plant growth that results in genetically identical individuals.

Unlike in sexual reproduction, clonal individuals often spread horizontally below ground via unique root systems. Above ground, these plants appear to be distinct individuals, but beneath the soil surface, they remain connected, as clones of the same original plant.

The Pando, or "Trembling Giant," is a colony of clonal quaking aspens roughly 80,000 years old, in Fish Lake, Utah.

The Pando, or “Trembling Giant,” is a colony of clonal quaking aspens (Populus tremuloides), roughly 80,000 years old, in Fish Lake, Utah. All the trees are a single living organism sharing one massive root system. Photo by By J Zapell via Wikimedia Commons.

From a plant’s perspective, there are many benefits to clonal growth. For example, in an environment with limited pollinators to facilitate sexual reproduction, it might be better to take matters into your own hands and make a copy of your already awesome self. On the other hand, a vulnerability in one clone (for example, to a fatal fungal outbreak) is just as likely to affect all of the other clones, because they share the same genetic makeup. It is important to note that there are ecological downsides to clonality as well. Many invasive species do well in foreign environments because asexual reproduction enables them to reproduce very quickly. Thus, just as we see in Star Wars, clones can either be a powerful asset or a potent enemy.


Abigail WhiteAbbey White is a graduate student working with Andrea Kramer, Ph.D., and Jeremie Fant, Ph.D., developing genetically appropriate seed mixes of vulnerable plant species for restoration.


Students in the Chicago Botanic Garden and Northwestern University Program in Plant Biology and Conservation were given a challenge: Write a short, clear explanation of a scientific concept that can be easily understood by non-scientists. This post is part of their series.

©2016 Chicago Botanic Garden and my.chicagobotanic.org

In the race to save native plants like purple New England aster and fragrant American mountain mint, the Chicago Botanic Garden freezes seeds for future use—but will frozen seeds be able to grow after hundreds of years in storage? Researchers are trying to find out.

Environmental threats such as climate change have caused thousands of plants to become rare or endangered. The tallgrass prairie, which has lost 96 percent of its land to agriculture and other human activities, is one of the earth’s most endangered habitats. By preserving seeds in the Garden’s Dixon National Tallgrass Prairie Seed Bank, researchers are working to ensure that native species don’t disappear in the wild.

Inside the seed vault at the Dixon National Tallgrass Prairie Seed Bank.

Inside the seed vault at the Dixon National Tallgrass Prairie Seed Bank.

In winter 2015–16, two students from the Garden’s graduate program, which is offered in collaboration with Northwestern University, helped with the Seed Bank’s first germination trials. In the trial, a sampling of our oldest seeds was removed from deep freeze—a vault at minus 4 degrees Fahrenheit—and placed in favorable growing conditions to see if they would germinate after 13 years of dormancy.

Alicia Foxx germination trials.

Graduate student Alicia Foxx hard at work counting…

Alicia Foxx germination trials.

…and removing seeds that have germinated on an agar medium.

The results? Species such as New England aster (Symphyotrichum novae-angliae), water speedwell (Veronica comosa), and American mountain mint (Pycnanthemum virginianum) germinated well. Species such as enchanter’s nightshade (Circaea lutetiana) and New Jersey tea (Ceanothus americanus) did not germinate; more research is needed to determine whether these seeds did not germinate because we were unable to figure out how to break their dormancy.

 

Graph showing results: Seed sample sizes for trial were either 24, 60, or 75 seeds, depending on the number of seeds in the collection.

Seed sample sizes for trial were either 24, 60, or 75 seeds, depending on the number of seeds in the collection.

The results show that seed collection is an efficient and cost-effective way to preserve biodiversity for future generations; experts predict that many of our native seed can survive hundreds of years in a seed bank (we’ll repeat the germination test in another ten years). Meanwhile, if you’re interested in joining our team and helping with the critical work of seed collection or banking, contact us

Download/read the full results here: Germinating Native Seeds from the Dixon National Tallgrass Prairie Seed Bank.


©2016 Chicago Botanic Garden and my.chicagobotanic.org