This Partula hyaline snail rested on wild red ginger leaf with an M3 system. (Image Credit: Inhee Lee)
After introducing predatory snails to Tahiti in the 1970s, 56 tree snail species became extinct, but the Partula hyalina remained. University of Michigan scientists and biologists outfitted a P.hyalina with an M3 computer to determine how it survived such an onslaught. These white-shelled snails can withstand more sunlight, allowing them to endure sunlight forest edge habitats. The world’s smallest computer, Michigan Micro Mote (M3), was unveiled in 2014, and this is its first field application.
“The sensing computers are helping us understand how to protect endemic species on islands,” said Cindy Bick, who received a Ph.D. in ecology and evolutionary biology from U-M in 2018. “If we are able to map and protect these habitats through appropriate conservation measures, we can figure out ways to ensure the survival of the species.”
“We were able to get data that nobody had been able to obtain,” said David Blaauw, the Kensall D. Wise Collegiate Professor of Electrical Engineering and Computer Science. “And that’s because we had a tiny computing system that was small enough to stick on a snail.”
Humans brought in the giant African land snail to the Society Islands in Tahiti, where it would cultivate as a food source. However, it turned into a pest. Then, in 1974, the situation worsened. Agricultural scientists introduced the rosy wolf snail, which turned out to prey on 61 native Society Islands tree snail species. Thankfully, five species survived, one of which was the P. hyaline. Known as the “Darwin finches of the snail world,” due to their island-bound diversity, losing a large number of Partula species is a huge setback to biologists studying evolution.
“The endemic tree snails had never encountered a predator like the alien rosy wolf snail before its deliberate introduction. It can climb trees and very quickly drove most of the valley populations to local extinction,” said Diarmaid Ó Foighil, professor of ecology and evolutionary biology and curator of the U-M Museum of Zoology.
In 2015, Ó Foighil and Bick theorized that P. hyalina’s white shell provides an advantage in forest edge habitats due to its light radiation reflection capabilities. To test this hypothesis, they needed to monitor the light exposure levels on the P. hyalina and rosy wolf snails during an ordinary day.
The rosy wolf snail equipped with an M3 system. (Image Credit: Inhee Lee)
At first, they wanted to mount light sensors to the snails but realized such a system with commercially available chips would be too large. Afterward, Bick heard of a 2x5x2 mm system that her institution developed but wondered if it could be modified to detect light. “It was important to understand what the biologists were thinking and what they needed,” said Inhee Lee, an assistant professor of electrical and computer engineering at the University of Pittsburgh.
They needed to come up with a method to measure the light intensity of the snails’ habitats. The team integrated an energy harvester on the M3 system, allowing the battery to recharge via solar cells. Lee concluded that light measurements could be achieved by measuring the battery’s charging speed.
Sensors were directly glued onto the rosy wolf snails. P. hyaline, a protected species, needed an indirect approach. Typically, these snails sleep underneath leaves during the day. The team used magnets to attach M3s on the tops and undersides of leaves where the snails rested. Lee wirelessly downloaded data from every M3 system at the end of each day.
The team discovered that the P. hyalina snail gained ten times more sunlight than the rosy wolf snails. They also suggest that the rosy wolf doesn’t move far enough to where the P. hyalina resides, even in darkness. This is because they wouldn’t be able to escape the sun’s heat.
Ó Foighil stated, “The M3 really opens up the window of what we can do with invertebrate behavioral ecology, and we’re just at the foothills of those possibilities."
Have a story tip? Message me at: http://twitter.com/Cabe_Atwell