Watching a butterfly emerge from a chrysalis is a rare and captivating experience. That is why hobbyists, classrooms, and families often raise caterpillars to watch the transformation from egg to insect. Many also believe releasing these captive-raised adults aids conservation efforts by rebuilding dwindling wild populations, such as the monarch butterfly.

However, science suggests otherwise.

“A few years ago, there were some studies that showed that captive breeding had detrimental effects on migration,” explained Ryan Norris, an associate professor in the Department of Integrative Biology at the University of Guelph.

A study analyzing the recovery of tagged monarchs found that captive-bred butterflies have lower survival rates and weaker migration success than their wild counterparts.

Traditionally, researchers and citizen scientists track these movements by applying a lightweight adhesive sticker to the underside of the butterfly’s hindwing. Organizations like Monarch Watch use this data to record migration patterns. But indoor rearing disrupts this journey. According to Norris, past studies show that monarchs bred indoors by hobbyists fail to orient themselves properly for the fall migration.

Researchers believe this is because the butterfly’s internal clock is disrupted. In the wild, monarchs adjust their flight angle relative to the sun using a built-in circadian clock in their antennae, which acts as a natural GPS. When raised indoors away from natural sunlight, they cannot calibrate this internal compass, leaving them temporarily disoriented.

To understand the depth of this impact, Norris and his research team are launching a study using a new tool, solar-powered Bluetooth trackers.

“There is a new tag that we’ve been using just since last fall that’s Bluetooth compatible, so it’s picked up by the tag itself when it’s near any Apple device with the blue with its Bluetooth on,” explained Norris.

The thin rectangular trackers weigh 60 milligrams, less than a grain of rice, so they are easily placed on the butterflies. Because a battery would make the device heavier, a small solar panel powers the tracker. While butterflies fly, the tag periodically emits a low-energy Bluetooth signal.

Prompted by previous findings on the negative impacts of captive breeding, Norris designed this experiment to see exactly how indoor rearing alters flight paths.

“We’ll be able to track them all the way to Mexico,” said Norris.

His research started this summer and will continue into the fall to track the monarchs. The Bluetooth trackers allow researchers to map detailed, continuous paths of the butterflies’ migration.

This is a huge advantage over the paper stickers researchers used in the past to track butterflies. There was also a higher chance for reporting the wrong numbers of monarchs when paper stickers were used because the method relied heavily on citizen scientists inputting the data online by reading the unique alphanumeric code off the tiny winged sticker.

The Bluetooth tags offer a more complete picture because they connect to nearby devices.

However, the digital trackers don’t offer a complete picture of the butterfly’s journey.

“We’re capable now of tracking individuals to Mexico, but it doesn’t give us direct information on survival because when we lose a tag, we wonder whether the individual has died or it’s just not near any devices,” said Norris.

When butterflies are tagged with the Bluetooth devices, even the public can access their location through the app Project Monarch. The free app essentially turns everyday smartphones into wildlife tracking stations to follow the migration of monarch butterflies.

By Meg Deak, Local Journalism Initiative Reporter

Original Published on Aug 27, 2026 at 14:59

 

This item reprinted with permission from   Woolwich Observer   Elmira, Ontario

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