Adriana Avelina Ruíz Márquez delicately attaches a miniature transmitter to the thorax of a monarch butterfly using fake eyelash glue. Weighing just half a gram, the butterfly effortlessly carries the 60-milligram device, complete with a tiny solar panel. Once the operation is done with precision using a toothpick and a Q-Tip, Ruíz Márquez releases the butterfly, watching it flap its wings and take flight.
This innovative tracking device, a first in Mexico for tagging monarchs before their migration north to the U.S. and southern Canada, is expected to unveil secrets about the insects’ behavior and migration patterns. By utilizing smartphones, the device aims to shed light on the mysteries surrounding the monarch butterflies’ route, activities upon arrival, and departure.
The El Rosario butterfly sanctuary, located in Michoacán state about 180 kilometers west of Mexico City, hosts a significant portion of North America’s east of the Rocky Mountains monarch population during winter. As part of the Monarch Butterfly Biosphere Reserve, this sanctuary is vital for the species’ survival, covering approximately 135 square kilometers across Michoacán and the State of Mexico.
Teams from the federal Commission for National Natural Protected Areas and World Wildlife Fund (WWF) Mexico have tagged a total of 160 monarchs across the reserve, with 40 in El Rosario, using the new transmitters. This effort aims to provide detailed insights into the initial stage of the butterflies’ northern migration, according to biologist Eduardo Rendón Salinas from WWF Mexico.
The tracking of monarchs between colonies, previously only theorized, can now be observed with the help of these transmitters. The super generation of monarchs, spanning up to 5,000 kilometers on their journey north over three to four generations, is a unique phenomenon. The monarch butterfly’s annual two-way migration, from the Prairies to the Maritimes and down through the U.S. Northeast and Midwest, is a marvel of nature.
The microchipped transmitters emit signals detectable by nearby iPhones, enabling crowd-sourced tracking of the butterflies’ trajectory. By using Bluetooth and location services, the Project Monarch app or a handheld receiver can trace the butterflies’ path with unprecedented spatial detail. This technology surpasses previous tagging methods, providing a deeper understanding of the monarchs’ movements during migration.
As the transmitters were successfully used in a continent-wide monarch tracking project involving over 20 groups, they have proven to be a valuable tool for monitoring butterfly populations. By October, around 400 monarchs had been tagged, tracked from Canada to Cuba, and monitored entering Mexico’s Monarch Butterfly Biosphere Reserve in November.
The El Rosario sanctuary, protected by the community, becomes a haven for the butterflies between November and March. The monarchs form massive clusters on oyamel branches, with local patrols ensuring the area’s conservation. The community’s dedication to safeguarding the sanctuary and promoting sustainable tourism reflects their commitment to preserving this natural wonder.