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What three garden visitors taught me about the surprising science hidden inside a purple coneflower.
One warm summer afternoon, I was watching the purple coneflowers blooming in my flower bed when three familiar visitors caught my attention.
A monarch butterfly landed gracefully on one of the flowers.
A few minutes later, a bumblebee began exploring the centre of another nearby coneflower.
Then, to my surprise, I noticed a Japanese beetle resting quietly on the purple outer petals of a third flower.
At first, nothing seemed unusual.
Summer gardens are full of insects, and coneflowers attract many different visitors.
But the longer I watched, the more curious I became.
The monarch butterfly and the bumblebee spent their time moving across the raised centre of the flower.
The Japanese beetle didn’t.
It remained on the purple outer part of the flower.
That simple observation raised several questions.
Why were the butterfly and the bee interested in the centre?
Why was the beetle somewhere else?
And why did the flower beneath the beetle remain perfectly intact, even though Japanese beetles are well known for damaging many garden plants?
The answers would take me far beyond the three insects themselves.
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Three Visitors, Three Different Messages
Visitor #1 – The Monarch Butterfly
When most people think about monarch butterflies, they immediately think of milkweed.
That association is absolutely correct—but it tells only part of the story.
Milkweed and nectar-producing flowers play very different roles in the monarch’s life.
Did You Know?
🌿 Milkweed = the nursery
Female monarchs lay their eggs on milkweed because their caterpillars can feed only on milkweed leaves.
🌸 Coneflowers = one of the restaurants
Adult monarchs no longer feed on leaves. Instead, they visit nectar-rich flowers, such as purple coneflowers, to obtain the sugars they need for flight, reproduction, and eventually migration.
(Interestingly, milkweed flowers also produce nectar for adult butterflies. The nursery-and-restaurant analogy simply highlights the different roles these plants play in the monarch’s life cycle.)
As I watched the butterfly, it slowly uncoiled its long, straw-like mouthpart—called a proboscis—and inserted it into the centre of the coneflower.
It wasn’t eating the flower—it was drinking nectar.
The butterfly seemed to know exactly where the reward was.
At the time, I assumed it was simply feeding from the middle of the flower.
Later, while reading the scientific literature, I discovered something fascinating.
Researchers found that the two innermost whorls of currently open disc florets produce the greatest nectar rewards, making this part of the flower especially attractive to nectar-feeding insects.
Without realizing it, I had been watching the monarch visit the richest part of the flower.
The monarch clearly benefited from its visit.
Whether the coneflower benefited is more difficult to answer.
As monarchs move among flowers, some pollen may accidentally stick to their bodies and later be transferred to another flower. Although monarchs are not specialized pollen collectors like bumblebees, they can still contribute to pollination.
From my observation alone, however, I could not determine whether that happened.
Rather than forcing this interaction into a single ecological category, I think it is more accurate to acknowledge that the monarch clearly benefited by obtaining nectar, while any benefit to the flower could not be confirmed from my observation.
This reminded me that nature doesn’t always fit neatly into the categories we learn in textbooks.
Sometimes careful observation tells us exactly what happened.
Other times, it tells us what we still don’t know.
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Visitor #2 – The Bumblebee
At first glance, the bumblebee appeared to be doing exactly the same thing as the monarch.
It was also visiting the centre of the coneflower.
It was also feeding.
But appearances can be deceiving.
Although both insects were using the same part of the flower, they were not looking for exactly the same meal.
Like the monarch, the bumblebee drinks nectar because it provides the sugars needed to power flight.
Unlike the monarch, however, it may also collect pollen.
Pollen is much more than the yellow dust we often notice on flowers.
It is rich in proteins, healthy fats, vitamins, minerals and other nutrients that are essential for developing larvae growing back in the colony.
The monarch has no need to transport pollen.
Its future offspring will receive all the nutrients they need from milkweed after the eggs hatch.
The bumblebee, however, must bring those nutrients home.
Its entire body reflects that responsibility.
Unlike the relatively smooth body of a butterfly, a bumblebee is covered with thousands of branched hairs that readily trap pollen grains.
As it moves across the tiny flowers in the centre of the coneflower, pollen can cling to those hairs. The bee then combs the pollen from its body and packs it into specialized structures on its hind legs called pollen baskets, or corbiculae, before carrying it back to the colony.
The butterfly simply has no need for such equipment.
Its long proboscis is perfectly designed for drinking nectar, but it lacks both the structures and the biological need to gather pollen.
That difference beautifully illustrates how anatomy reflects biology.
The monarch invests in the next generation by carefully choosing the right plant on which to lay its eggs.
The bumblebee invests in the next generation by continuously gathering food for developing larvae.
Although they were visiting the same flower, they were solving two completely different biological problems.
The monarch came for an energy-rich drink of nectar to fuel its own activities. The bumblebee came for nectar as well, but it may also have been gathering protein-rich pollen to nourish the next generation. For monarchs, the next generation depends on finding milkweed. For bumblebees, it depends on bringing pollen back to the colony.
Unlike the monarch, the broader relationship between bumblebees and flowering plants is widely recognized as a classic example of mutualism.
The bee gains nectar for energy and pollen to help nourish developing larvae.
As it moves among flowers, it commonly transfers pollen between them, helping the plants reproduce.
Although I could not follow this particular bumblebee to another flower, its pollen-collecting anatomy and behaviour illustrate why bumblebees are among the most effective pollinators.
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A Question Still Waiting for an Answer
By now, I thought I understood what I had observed.
Two insects had visited the same part of the flower for different reasons.
But the third visitor would challenge that understanding.
Unlike the monarch and the bumblebee, the Japanese beetle seemed to be responding to a completely different message.
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Visitor #3 – The Japanese Beetle
The third visitor puzzled me the most.
The Japanese beetle never explored the raised centre of the coneflower. Instead, it remained on one of the purple outer ray florets.
That immediately caught my attention.
The previous summer, Japanese beetles had caused considerable damage throughout my garden. They fed on my roses, raspberry plants, bean plants, grapevine leaves and even my prune tree.
Seeing one on a coneflower, I expected to find the same kind of destruction.
But the flower appeared perfectly intact.
Why?
Research shows that adult Japanese beetles feed on the leaves, flowers and fruits of more than 300 plant species.
So finding one on a flower wasn’t surprising.
What surprised me was what I didn’t see.
There was no obvious feeding damage.
Of course, a single observation cannot tell the whole story.
The beetle may simply have landed moments before I noticed it.
It may have been resting.
It may have been exploring the flower.
Or it may have fed so briefly that no visible damage remained.
If the beetle had begun consuming petals or other flower tissues, the interaction would be classified as herbivory, where one organism benefits by feeding on another.
During my observation, however, I could not confirm that herbivory had actually occurred.
That distinction matters.
One of the lessons I hope readers take away from this article is that science asks us to separate what we observe from what we infer.
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Another Conversation Was Taking Place
While reading about Japanese beetles, I discovered another fascinating form of communication.
Unlike butterflies and bees, Japanese beetles do not rely only on the flower’s signals.
They also respond to chemical messages from both plants and other beetles.
When Japanese beetles begin feeding on a suitable host plant, the damaged plant releases airborne compounds known as plant volatiles.
Other beetles can detect these chemicals and may be attracted to the same plant.
This helps explain why gardeners often see large groups of Japanese beetles feeding together.
Female Japanese beetles also release a sex pheromone that attracts males.
This is a different chemical message from the one released by damaged plants.
In other words, while the coneflower may be communicating with visiting insects through its colour, shape, scent and floral rewards, Japanese beetles may simultaneously be responding to an entirely different chemical conversation taking place around them.
Nature is often carrying on several conversations at once.
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The Hidden Secret
Until then, I had been focusing on the insects.
Then I realized I had overlooked the most interesting part of the story.
The flower itself.
Like many people, I had always thought of a purple coneflower as a single flower surrounded by purple petals.
It isn’t.
What appears to be one flower is actually a flower head made up of hundreds of tiny individual flowers called disc florets.
Each disc floret can produce nectar, pollen and eventually a seed.
The purple structures surrounding the centre are called ray florets.
Rather than producing nectar or pollen, their primary role is to attract visiting insects.
If we could translate that biological signal into words, it might simply be:
“A resource is available here.”
The real reward lies in the tiny disc florets packed together in the centre.
Researchers have also shown that the two innermost whorls of currently open disc florets produce the richest nectar rewards, making them especially attractive to nectar-feeding insects.
Suddenly, everything I had observed made sense.
The monarch butterfly and the bumblebee weren’t feeding from one large flower.
They were visiting hundreds of tiny flowers working together.
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Did You Know?
🌼 A purple coneflower isn’t one flower.
The raised centre is made of hundreds of tiny disc florets.
The purple outer “petals” are ray florets, whose primary role is to advertise the flower to potential visitors.
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One Flower. One Biological Message.
As I reflected on everything I had learned, one idea kept coming back to me.
Nature is constantly presenting information. Every organism perceives that information through its own biology and responds accordingly.
Flowers are one beautiful example of that principle.
They communicate—not with words—but through colour, shape, scent, nectar, pollen and other biological signals.
Together, these signals announce that a potential resource is available.
The remarkable part is that the flower does not change its message depending on the visitor.
Instead, each organism interprets those same signals according to its own biological needs, through its anatomy, sensory system, and life cycle.
That interpretation determines how it responds.
One flower. One biological message. Three insects. Three interpretations. Three responses.
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What Does Each Insect “Hear”?
🦋 Monarch Butterfly
“Fresh nectar is available.”
The monarch responds by drinking nectar to fuel flight, reproduction and, eventually, migration.
Any pollination that occurs is incidental to its search for nectar.
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🐝 Bumblebee
“Nectar and pollen are available.”
The bumblebee drinks nectar for immediate energy and may collect pollen to nourish developing larvae back in the colony.
Its specialized anatomy makes it one of nature’s most effective pollinators.
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🪲 Japanese Beetle
“This may be a place to land, investigate or feed.”
Unlike the butterfly and the bee, the beetle may also be responding to chemical messages from damaged plants or other beetles.
Its response depends on many factors, some of which cannot be determined from a single observation.
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A Summary of Three Biological Interpretations
| Visitor | What does it “hear”? | Response | Ecological Perspective |
|---|---|---|---|
| 🦋 Monarch butterfly | “Fresh nectar is available.” | Drinks nectar for energy. | Nectar-feeding visitor; possible incidental pollen transfer. |
| 🐝 Bumblebee | “Nectar and pollen are available.” | Drinks nectar and may collect pollen for the colony. | A classic example of a generally mutualistic plant–pollinator relationship. |
| 🪲 Japanese beetle | “This may be a place to land, investigate or feed.” | Explores, rests or feeds depending on the circumstances. | Potential herbivore, although feeding was not confirmed during this observation. |
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Final Thoughts
When I first looked at my coneflowers that afternoon, I thought I was simply watching three insects visiting my garden.
Instead, I had witnessed three species perceiving the same flower in three different ways.
The coneflower hadn’t changed.
The information it presented hadn’t changed.
Only the visitors’ interpretations—and their responses—were different.
The monarch found the energy needed for adult life.
The bumblebee found nourishment for itself and, potentially, for the next generation waiting back in the colony.
The Japanese beetle reminded me that nature often raises more questions than answers, and that careful observation is the first step toward understanding.
And perhaps the greatest surprise of all was discovering that the flower itself had been hiding the biggest secret.
What looked like a single flower was actually hundreds of tiny flowers working together, each contributing to an intricate biological system.
Science often begins with careful observation.
Sometimes it answers our questions.
Sometimes it simply helps us ask better ones.
The next time you see a coneflower, take a closer look.
You may not just be watching insects.
You may be witnessing several biological conversations unfolding at the same time.
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Further Reading
For readers interested in exploring this topic further:
Open-access scientific research
- Floral Nectar Production, Nectary Anatomy and Ultrastructure of Echinacea purpurea – explains the structure of coneflowers, nectar production, and the roles of disc and ray florets.
- An Analysis of the Pollinators of Echinacea purpurea – examines the diversity of insects visiting purple coneflowers.
- Chemical Ecology of the Japanese Beetle (Popillia japonica) – reviews host-plant volatiles, sex pheromones, and aggregation behaviour.
Additional resources
- The Xerces Society – Monarch conservation and pollinator-friendly gardening.
- Lady Bird Johnson Wildflower Center – Botanical information on Echinacea purpurea.
- Ontario Ministry of Agriculture, Food and Agribusiness (OMAFRA) – Japanese beetle biology and management.