To prep the sensors for the snails, Dr. Blaauw’s lab added a tiny energy harvester with solar cells so the sensor could recharge its battery in the sun. They cocooned the system in epoxy to waterproof the sensor, protect it from severe light and cushion it from the rough-and-tumble life of the average snail.
They had one problem. They needed to endow the tiny computers with the power to measure light but keep the system free of large batteries that would flatten a snail. Inhee Lee, now an assistant professor of electrical and computer engineering at the University of Pittsburgh who was then a researcher in Dr. Blaauw’s lab, helped solve the puzzle. Dr. Lee and Dr. Blaauw simply reused the harvester, and measured the speed of its solar charge as a proxy for sunlight.
Using some invasive snails found in a Michigan garden, the researchers first tried and failed to stick the computers to the shells with magnets and Velcro until they figured out how to glue a metal nut to the surface and screw the sensor into the nut. Then the snails and their tiny passengers were ready to weather the simulated elements (buckets of water).
In August 2017, Dr. Bick and Dr. Lee arrived in Tahiti with 55 sensors. They hopped from valley to valley guided by Trevor Coote, an author on the paper and a specialist on these land snails who was based in Tahiti. (Dr. Coote died of Covid-19 in February 2021.)
Each day, the researchers tracked the snails for hours to ensure they did not escape. Occasionally, they got rained on. They did not have a permit to attach computers to the P. hyalina, which is considered endangered, so they stuck cameras directly alongside the snails, on the leaves slept on during the day, essentially tracking how much sunlight the sessile snails received. But the computer-laden rosy wolf snails proved a trickier challenge, as the mollusks were slow-moving but determined to forage (one snail absconded with a sensor for a few days).
The data revealed the sensors on P. hyalina’s habitat received, on average, 10 times as much sunlight as the rosy wolf snails did. That confirmed the researchers’ hypothesis that the bright conditions protected the pale snails from the rosy predators.