Small computer reveals how Tahitian snails avoid violent predators
Cindy Gros Mission. An evolutionary biologist from the University of Michigan peers around as she walks through a wooded valley north of Tahiti. Most visitors come to this South Pacific island to enjoy the beaches and clear waters, but BIC is there for another reason. She has found her prey. There are white dots the size of a bean on the sunny leaves. Polynesian snail, A small snail with a big story on the risk and resilience of island species. Researchers are starting to understand how this species survived where many of its parents died, using a small computer the size of a grain of rice.
Over the past several centuries, especially since the 1980s, hundreds of Pacific Island snails have become extinct. They give a phenomenal explanation 40 percent Extinction of all documented animals. Isolated from the outside world, like the other flora and fauna that have evolved on the island Tens of millions of yearsThese species had little protection against the large number of invasive species introduced by humans, intentionally or unintentionally. In many cases, trying to control one invasive species by introducing another invasive species has only increased the confusion.
“What we can say about this family from a conservation status standpoint is very difficult,” says Brenden Holland, a conservation biologist at the University of the Pacific in Hawaii who studies land snails. P. hyalina.. “These strains are poorly adapted to control invasive predators and tend to be a major threat. So over the past 40 years or so, very unusual levels of extinction have occurred. I have been seen. “
However, as cousins no longer exist one by one, P. hyalina, Currently listed as Vulnerable, but suspended. It was not easy. In Tahiti, formidable predators hunt them: the invasive pink wolf snail, YamahitachioAlso known as cannibalistic snails. These snails can grow 4 inch Long and impressive bursts of speed are possible: they can reach while hunting prey 19 mph A short distance away. The pink wolf snail is particularly terribly armed Radula (Appendages like tongues lined with teeth) It can stretch, extraterrestrialStyle beyond this mouth. The teeth themselves are stretched to scrape the meat more efficiently. “It can be devoured [another snail] It takes a little while to just beat the whole or the soft tissues of the snail’s body, ”Bick explains. “It’s a pretty brutal way.”
Native to the southern United States, the pink snail has been introduced to Tahiti, Hawaii, and many other Pacific islands to control another invasive species, the giant African snail. African giants can be up to eight inches long and were deliberately introduced to the region as a potential food source. Arrived in Tahiti in 1967. “It grows fast and people once thought it would be a really useful source of protein,” explains the Netherlands. “It turns out it’s teeming with pathogens and parasites. So people started eating them and started getting sick, then people stopped eating them and [the snails] I went out and started to eat it all. “
The pink wolf snail was introduced in 1970s I expect to eat African snails. Unfortunately, predators also like to eat a lot of other snail seeds. In Hawaii, for example, Holland study Wolf snails show that they prefer to hunt native snails rather than African species.
How Big and his colleagues P. hyalina I managed to survive this greedy predator. They deduced it P. hyalinaThe bright white envelopes of the dark pink wolf snail can help survive even when exposed to greater sunlight than the dark pink wolf snail. A transition zone that has given way to habitat that is sunnier than dense forest soil, such as an open area of trees, can serve as what the team called a “sun shelter.” P. hyalina Able to withstand hours of bright sunshine, pink wolf snails are likely to overheat and therefore avoid the area.
To test this hypothesis, the scientists decided to measure the amount of light received by different species of snails during the day. Every morning for several days in the early morning hours, Bick and his colleague set out in search of snails.
When they found a pink wolf snail, the researchers stuck a small computer to its shell. This was the first field application for the Michigan Micromote (M3), announced in 2014 as the world’s smallest computer. (The engineer from the University of Michigan at the time Even smaller the computer. )
The researchers then took on the difficult task of monitoring the snails throughout the day while computers measured the animals’ exposure to the sun. “If you look back for five seconds, you can lose out on the benefits,” Bick says of the relatively fast brownish wolfsnail. “They blend very well with leaves and soil soils.”
P. hyalina Snails don’t move much during the day, but tracking snails presents another challenge. The researchers were not allowed to adhere directly to the snails because they are a protected species. Therefore, I attached a computer to the sheet where the snail is placed.
Finally, the researchers’ hypothesis was confirmed thanks to this new field test. their treaty, Released in June Communication biology, P. hyalina The sun shelter may have saved because it was exposed to a lot more sunlight than the wolf snail. P. hyalina From his horrible predatory hands, or rather mouth extinction.
“Biologists and environmentalists of this generation are looking for new answers, so this treaty interested me a lot,” said the Netherlands, which was not involved in the study.
Bick believes this treatise shows why humans need to protect forest edge habitats and the solar shelters available to them. P. hyalina Unlike many other island species, this is a fighting chance.
“I think it’s a pretty exciting story,” Bick says. “Most of the time we talk about or about to be extinct, but we never talk about success stories.”
She sees P. hyalinaThe story of resilience as a small piece to solve a bigger puzzle: “Given climate change, globalization and ever-increasing deforestation,” says Bick. “What do we need to survive in this ever-changing environment, this ever-changing world?