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Campus & Community

S.O.S. - Save our snails: The Hawaiian tree snail and the Kamehameha butterfly are close to extinction, but all hope is not lost

Two snails sit on a banana leaf
Snail species Amastra spirazona.
Photo by Lilly Thomey

Saving endangered snails and butterflies in Hawaii requires raising them in the safety of a lab, releasing them into carefully crafted environments where they can thrive without getting eaten by predators and then surveying them using tiny field cameras, explained biologists in the Snail Extinction Prevention Program and Pulelehua Project.

Despite biologists’ best efforts, the coordinator of the SEPP said they sadly lost the last remaining snail of the species Achatinella apexfulva. His name was George.

“George was … the last descendant of a handful that were found in the Ewa Forest Reserve [near Pearl City] about 30 years ago,” said David Sischo, the coordinator of the SEPP and the Pulelehua Project. He said George and other snails were brought to the University of Hawaii. He explained, “Prior to those founding individuals being discovered, the species were thought to be extinct. These were the last known individuals.

“A pathogen or parasite that came through the lab caused mortality in all the individuals except for George. He was the last known individual and passed away in 2019 on New Year’s Day.” Sischo said the cause of death was likely old age.

When an endangered species is down to one individual, as was the case with Achatinella apexfulva, the species is functionally extinct because they have no one to breed with. However, there is still a chance for their genes to live on. George was planned to be bred with a snail from a closely-related species, Achatinella concavospira. Unfortunately, Sischo said the breeding never came to pass.

“It was unlikely to work anyways,” said Sischo. “It was kind of a last-ditch, Hail Mary effort. ... By the time we received approval to make that happen, he passed away. He may have been too old to reproduce anyway. We don’t really know.”
Because all Achatinella species are considered endangered under the Endangered Species Act, he said any actions involving captive breeding must be approved by the Hawaii Department of Land and Natural Resources Division of Forest and Wildlife, which oversees the protection efforts.

“The Hawaiian Islands had about 750 distinct species of snails that existed nowhere else in the world,” he explained. “About half our snail species have been lost already, and about 100 species are likely to go extinct soon without prevention.” Hawaii’s delicate ecosystem has been hard hit since European contact, and the Hawaii Invertebrate Program officials say it is working to reverse this.

Sischo describes SEPP as a shield against extinction. Its lab on Oahu is a captive-rearing facility housing close to 40 species of snails, he said, all of whom are extinct in the wild. The endangered snails were gathered to the SEPP lab in order to grow and breed them safely away from predators and other threats.

Major threats to the snails include invasive predators the snails never evolved a defense against, such as rosy wolf snails, rats and Jackson’s chameleons, Sischo explained. All three species find the slow-moving, colorful snails to be a tasty and easy-to-get treat.

At the program’s small lab complex on Oahu, there are a few trailers and gardens where several dwindling species of native invertebrates are carefully maintained. In the hopes of one day repopulating the Hawaiian Islands, Sischo said the snails are watched after in small but stable breeding populations.

On both Oahu and Maui, captive-bred snails are released into special patches of land that have been searched inch by inch to remove predators, Sischo explained. They also have a predator-proof fence erected around them. The released snails, from that point, will only face the threats naturally found on Hawaii, such as heavy rain or competing with other native snails for food. Under these circumstances, the snails can thrive like they once did, Sischo said.

These patches of land, called exclosures, require maintenance, which is one of the duties of SEPP intern, Lilly Thomey. She said she lives in Halawa and began working for SEPP through Kupu and Americorps. She also works to restore native habitats and survey the habitats snails were once recorded living.

“A favorite story of mine is when I first camped in the northern Koolau mountain range for an overnight snail survey,” Thomey shared. “My co-workers and I spent the day working in a snail exclosure, performing upkeep duties and then set aside time to watch the sunset over the Waianae mountains with the silhouette of Kauai in the background. Once it was sufficiently dark, we piled on some layers, turned on our headlamps and went back to the exclosure to perform a night-time snail count.

“While looking high and low for Achatinella lila and Achatinella sowerbyana, a moonbow lit up the landscape, casting shadows across Poamoho Summit and Kaneohe Bay. We paused our survey and a solid 10 minutes of our time was dedicated to absorbing as much as we could of the scenery. I felt so fortunate to be in that place with the snails in those conditions.” says, “A moonbow is a rare natural atmospheric phenomenon that occurs when the moon’s light is reflected and refracted off water droplets in the air. Moonbows are much fainter than rainbows made by the sun and often appear to be white. This is due to the smaller amount of light reflected from the surface of the moon.”

According to Thomey, if Hawaii lost all of its snails, the ecological consequences would be dire. Native plants that co-evolved with native snails need the snails to survive.

Without the native plants, she said Hawaiian landscapes would lose their nutrients.“Working with these Hawaiian land snail species is an uphill battle, but being able to release snails back in the wild or see a population bounce back in the lab makes all the effort, time and brain muscle power worth it,” Thomey said.

Two brown and white lined snails on the underside of some leaves.
Snail species Partulina splendida.
Photo by Lilly Thomey

For some snails, their natural defenses against predators make it difficult for SEPP to even get them to the lab in the first place, Thomey explained. She said her favorite species, Laminella sanguinea, are found on the Waianae mountain range on Oahu.

“A behavior of theirs is to cover themselves in debris, such as dirt and snail feces, so they can hide their deep, red-colored shell. Though this cryptic adaptation was once meant to deter native bird predators, this camouflage makes it hard for us to find them in the wild when we need to [move them] or evacuate populations,” Thomey explained.

Jana Maravi, who lives in the Punchbowl area near downtown Honolulu, is also a Kupu intern placed with HIP by Americorps, but she works on the Pulelehua Project. Maravi said pulelehua means butterfly and is used to refer to the Kamehameha butterfly called Vanessa tameamea. This butterfly is a rare and endangered Hawaiian insect and one of only two endemic species of butterfly in Hawaii, Maravi explained.

The Kamehameha butterfly is threatened by predators, but at the Pulelehua Project, Maravi said they’re still trying to figure out what predators these would be. Right now, all they know is that something is eating their butterflies. Caterpillars carefully raised in the HIP labs are released only to disappear, she said.

“My job is to put out cameras in the field and systematically deploy these caterpillars.”

She said she has a background with scientific camera work, which is how she ended up with the Pulelehua Project. “We have these little field cameras that run on constant video 24/7 out in the field. Every other day, we take a big battery down with us and swap out the battery and the memory cards.

“These tiny cameras can focus … on the caterpillars, as opposed to other field cameras that normally focus on deer. They’re special for our invertebrate project. We just sort of attach them to different branches, and the caterpillars feed on maki, a native plant here. They hang out on the leaves in front of the camera, and we can see what predators come and take them.”

In addition to releasing and monitoring the caterpillars, which Maravi readily described as “adorable” with their fat green bodies and tiny nubby legs, she said the Pulelehua Project also plants native plants and eliminates invasive species.

“There’s a lot of introduced butterflies and insects [in Hawaii]. So, it’s really cool to be able to work with something there’s only two [species] of,” Maravi said. “It’s really unique here. It’ll be great to see them naturally in the area we’re working in again one day.”