Every Fall, millions of Monarch butterflies migrate south to Central Mexico over the span of 2-3 months to survive the coming winter. However, recent studies show a sharp decline in the population of Monarch butterflies. To help preserve these majestic butterflies and better understand their annual migration paths, the Monarch Butterfly Fund (MBF) initiated the Monarch Butterfly Flight Challenge (MBFC) in search of an innovative, new method to track the Monarchs’ migration.
 
M3 on Monarch
Prototype Michigan Micro Mote (M3) mounted on a Monarch butterfly.
Due to the butterflies’ small size, most digital devices would not work on butterflies like on other migratory animals. Current records of Monarch butterfly migration rely heavily on adhesive paper tags attached to the butterflies’ wings, which researchers would then record identifying information from fallen or chanced upon butterflies at their overwintering destinations in Mexico. As well, chemical analyses (cardenolide fingerprinting and stable isotope analysis) have been important methods for tracking migration by inferring the regional “birthplace” of individual butterflies. However, these methods provide little information about the exact migration paths. A digital solution is much needed.
 
Using the Michigan Micro Mote (M3), the world’s smallest computer to date, our team at the University of Michigan is planning to build a tiny sensor (about 2.0mm x 2.0mm x 4.2mm in size and 20-30 mg in weight) that can be placed on a butterfly without disrupting its life cycle. The sensor accurately logs pressure, light intensity and temperature information from the butterfly’s surroundings, which can be remotely read out once the butterfly arrives at its destination. Paired with accurate weather and environmental information, this data can be used to extrapolate the exact path of the butterfly day-by-day using top-notch machine learning.