These tiny trackers were designed to be light enough for a butterfly
Researchers track animal movements through tags on their limbs, wings, and shells, but how do you track a creature that weighs less than a gram? To build a device tiny and light enough for a monarch butterfly, designers had to make the smallest wildlife tracking device on the planet. A tiny transmitter for butterflies designed by the New Jersey-based Cellular Tracking Technologies (CTT) is called…
Researchers are using miniature trackers to monitor the movements of butterflies, which weigh less than a gram. Cellular Tracking Technologies (CTT) in New Jersey created the BlūMorpho, the world's smallest wildlife tracking device. Weighing just like a grain of rice, the device is three-and-a-half centimeters long. It operates without a battery, instead using a miniature solar panel to power its functions.
CTT's vice president of global market development, David La Puma, explained that their primary focus is on birds, so weight saving is a top priority. The development and manufacture of the BlūMorpho required a significant investment due to the extreme constraint of keeping the device as lightweight as possible for butterflies. The tracker is equipped with an antenna that runs down the body of the model and transmits data to fixed receiver stations.
The device was first used in spring 2025 when 30 butterflies were released from Ontario, Canada, to track their migration south as part of Project Monarch. Over 400 butterflies were tagged and tracked last fall, and the goal is to tag more than 2,000 butterflies after tagging over the winter.
The researchers hope that understanding the butterflies' migratory patterns could be beneficial, especially as their population declines due to threats like climate change and habitat loss. They are also using the trackers to determine if the butterflies have a better chance of survival if they migrate earlier in the year. The Vermont Center for Ecostudies is placing the trackers on the butterflies after slowing them down with a fridge for about 20 minutes. The device is then glued to the butterfly's thorax with nontoxic eyelash glue.
The findings reveal that butterflies take various migratory paths across a broad geographic area. They have been able to observe how fast they fly, how far they travel, and how long their sustained flight lasts. The trackers also reveal the approximate location where the butterflies stop to find nectar and refuel, which could be small pollinator gardens or near threats like roadways and pesticides.
Conservation scientist Desirée Narango stated that seeing how important small patches of habitat are for the butterflies' migratory journeys has been eye-opening. The researchers are now considering using these transmitters on dragonflies or bumblebees as well.
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