Scientists Are Putting Tiny Transmitters on Monarch Butterflies—Here’s What They’re Discovering

Imagine trying to follow a butterfly.

Not for a few minutes through a garden, but for miles—as it crosses neighborhoods, farmland, highways and eventually entire states.

For generations, scientists studying monarch migration have faced an obvious problem: butterflies are small, fast and remarkably easy to lose.

Traditional tagging has helped researchers piece together their incredible journeys. A tiny numbered tag placed on a monarch’s wing can tell scientists where a butterfly started and, if someone happens to find it again, where it ended up.

But everything that happened in between?

Much of that journey remained a mystery.

Now, researchers are testing technology that sounds almost impossible: tiny solar-powered transmitters light enough to travel on the back of a monarch butterfly.

And this fall, some of those digitally tagged monarchs are taking flight right here in Iowa.

Meet the Tiny BlūMorpho Tag

The technology is called the BlūMorpho, an ultra-lightweight transmitter developed by Cellular Tracking Technologies as part of a larger effort to track insects that were once simply too small for this kind of technology.

The transmitter weighs only about 0.06 grams—roughly the weight of a grain of rice.

Instead of relying on a conventional battery, the tiny device uses solar power. BlūMorpho tags can communicate using Bluetooth technology, allowing compatible devices to detect a tagged butterfly when it comes within range.

That changes the possibilities for monarch butterfly tracking.

Traditional tags depend heavily on a butterfly eventually being recaptured or recovered. Digital tracking can potentially give researchers additional detections along the way, providing glimpses of what happens between release and destination.

Suddenly, some of the blank spaces on the monarch’s migration map can begin to fill in.

Learn more about the BlūMorpho tracking technology from Cellular Tracking Technologies:
https://celltracktech.com/pages/blumorpho

Iowa Monarchs Are Helping Test the Technology

This isn’t something scientists are merely proposing for the future.

It’s happening now.

In July 2026, Monarch Research collaborated with Iowa State University researcher Dr. John Pleasants to attach BlūMorpho tags to Iowa-raised monarchs released at two locations in Linn County.

Eleven tagged monarchs were released at the Monarch Research Station on July 14, followed by another 14 at Noelridge Park in Cedar Rapids on July 15.

Before release, researchers recorded information about each butterfly, including its weight, wing length, sex and overall condition. The tiny transmitter was then carefully attached to the monarch’s thorax.

And the butterflies flew away.

Only this time, researchers had a new way to look for them.

One Monarch Traveled Roughly 50 Miles

Early results showed something fascinating: individual monarchs didn’t all behave the same way.

According to Monarch Research, roughly half of the tagged summer butterflies remained around the Cedar Rapids and Marion area. Some stayed remarkably close to where they had been released.

Others traveled much farther.

One monarch traveled roughly 50 miles northeast, at one point reaching Dubuque.

Another, identified as MR-001, provided researchers with an intriguing look at how a monarch can move through a developed landscape.

After being released near Highway 100, MR-001 moved into a neighborhood near Marion High School before eventually reaching Gardner Golf Course.

Then it stayed.

The golf course contains established prairie habitat with diverse vegetation, including milkweed. MR-001 remained there for weeks.

One butterfly can’t prove why it chose a particular location. But movements like these give researchers questions they can investigate as more monarchs are tracked.

Do monarchs linger longer in certain habitats?

How do they move between small gardens and larger prairie areas?

Which patches of habitat become important stopping points?

And how much ground can one butterfly actually cover in a day?

Those are surprisingly difficult questions to answer when your research subject can simply fly over the horizon.

Read more about the Iowa BlūMorpho study from Monarch Research:
https://monarchresearch.org/news-and-events/monarch-research-launches-blumorpho-tagging-study

Now Comes the Really Big Test: Migration

Tracking summer monarchs around Iowa is one thing.

Following a migrating monarch heading south is something entirely different.

This September, researchers with the Iowa Monarch Conservation Consortium are using BlūMorpho-tagged monarchs as part of migration research as thousands of monarchs move through Iowa on their journey south.

The technology is also being tested elsewhere across North America.

During the broader 2025–2026 Project Monarch Collaboration, hundreds of BlūMorpho transmitters were deployed on migrating monarchs. Some radio-tagged monarchs from the 2025 fall migration were later detected in Mexico.

And researchers are still pushing the technology further.

In September 2026, monarchs carrying digital trackers were also released in the Pacific Northwest. One butterfly released in Portland traveled more than 125 miles in just four days.

Think about the scale of that for a moment.

A creature weighing less than a paperclip can travel hundreds—and ultimately thousands—of miles across a continent.

Now we’re beginning to develop technology small enough to travel along with it.

But How Does a Monarch Know Where to Go?

Tracking tells scientists where a monarch travels.

That raises another remarkable question:

How does the butterfly know which direction to fly in the first place?

Monarchs don’t simply follow the butterfly ahead of them to Mexico. The generation making the long fall migration has never made the journey before.

Yet monarchs possess an extraordinary natural navigation system involving the sun, polarized light and an internal biological clock that helps them maintain the correct direction as the sun moves across the sky.

We’ve explored that remarkable ability before in The Butterfly GPS: How Do Butterflies Navigate Without Maps?

Read it here:
https://thebutterflyconnection.com/the-butterfly-gps-how-do-butterflies-navigate-without-maps/

Together, these two sides of the story are fascinating.

Scientists are developing better technology to figure out where monarchs go, while the butterflies themselves already possess the biological technology needed to know how to get there.

Your Phone Can Become Part of the Experiment

Perhaps the most unusual part of this tracking technology isn’t attached to the butterfly at all.

It’s probably sitting in your hand.

Members of the public can download the Project Monarch Science app, enable Bluetooth and location services, and help search for tagged butterflies.

When a compatible device detects a tag, that encounter can add another piece of information to the butterfly’s journey.

In other words, ordinary people carrying smartphones can become part of a continent-wide butterfly tracking network.

That’s especially relevant in Iowa this fall. The Iowa Monarch Conservation Consortium is encouraging the public not only to help detect tagged monarchs but also to report monarch roosts—the temporary clusters that form when migrating monarchs gather to rest.

Learn how Iowans can participate through the Iowa Monarch Conservation Consortium:
https://www.cals.iastate.edu/news/2026/iowa-landowners-asked-help-track-monarch-migration-fall

Why Scientists Want to Know Where Monarchs Go

We already know a remarkable amount about monarch butterflies.

We know eastern monarchs undertake an extraordinary multigenerational annual migration between Mexico and much of the United States and Canada.

We know their caterpillars depend on milkweed.

We know adults depend on nectar-producing plants.

And decades of traditional tagging have revealed incredible long-distance movements.

But knowing monarchs need habitat isn’t quite the same as watching how an individual monarch actually uses the landscape.

Does it spend several hours in a backyard pollinator garden?

Does it travel across miles of agricultural land before stopping?

Does a small patch of restored prairie become an important refueling station?

Where does it rest overnight?

Which routes does it choose on its way south?

Those details matter.

The more scientists understand about how monarchs actually move through real landscapes, the more information conservationists have when deciding where habitat restoration and protection may be most useful.

From Migration Science to the Monarch in Your Hand

All this technology is helping scientists study monarchs on an enormous scale—following them across landscapes and, potentially, across a continent.

But some of the most extraordinary things about a monarch can be seen without tracking it anywhere.

Look closely at its wings and you’ll find thousands upon thousands of microscopic scales. The heavy black veins create the stained-glass pattern we instantly recognize. Males and females even carry subtle visible differences.

It’s one reason butterflies have fascinated scientists, collectors and artists for centuries.

At The Butterfly Connection, that intersection of nature, science and art is exactly what inspires what we do. Our real butterfly displays and butterfly-wing jewelry allow these intricate structures and patterns to be appreciated up close.

Explore The Butterfly Connection’s real butterfly collection:
https://thebutterflyconnection.com/

And if the monarch itself is what caught your attention, you can also find real monarch butterfly wing jewelry in our collection:

https://thebutterflyconnection.com/real-butterfly-wing-jewelry

From a Sticker to a Signal

There’s something beautifully fitting about using cutting-edge technology to study an animal whose migration remains one of nature’s great mysteries.

For decades, researchers have relied on simple tags, dedicated volunteers and the hope that a tagged butterfly might eventually be found again.

Those methods remain enormously valuable.

But now researchers have another tool.

A solar-powered transmitter weighing about as much as a grain of rice.

A network of smartphones and receivers.

Scientists and citizen researchers watching for signals.

And somewhere over an Iowa field this fall, a monarch carrying one of those tiny transmitters may already be heading south.

For centuries, we’ve watched monarchs disappear over the horizon.

Now, for the first time, we’re getting better at following them.