We Can Now Track Individual Monarch Butterflies. It's a Revelation.
For the first time, scientists are tracking the migration of monarch butterflies across much of North America, actively monitoring individual insects on journeys from as far away as Ontario all the way to their overwintering colonies in central Mexico.
This long-sought achievement could provide crucial insights into the poorly understood life cycles of hundreds of species of butterflies, bees and other flying insects at a time when many are in steep decline.
The breakthrough is the result of a tiny solar-powered radio tag that weighs just 60 milligrams and sells for $200. Researchers have tagged more than 400 monarchs this year and are now following their journeys on a cellphone app created by the New Jersey-based company that makes the tags, Cellular Tracking Technologies.
Most monarchs weigh 500 to 600 milligrams, so each tag-bearing migrator making the transcontinental journey is, by weight, equivalent to a half-raisin carrying three uncooked grains of rice.
https://www.nytimes.com/2025/11/17/science/monarch-butterfly-migration-tracking-sensor.html