What's the big deal about the native Hawaiian tree snails?
Image from Hawaii Forest and Trail
- These snails are not very ambulatory. Some are thought to stay in the same tree (usually Ohia or Kopiko trees) their whole life. Because of this, it was easy for populations to become isolated and change. Because the snails are isolated on island ridges and in lush valleys, they changed and developed into a different species. Each species has its own spiral coloration diverse in patterns, colors, and shapes. The shells are glossy and oblong. Because of the shells' beautiful coloration, the snails are known as jewels of the forests.
- Tree snails give birth to only one or two babies a year.
- Today, many of the species are extinct, and the remaining populations of Hawaiian tree snails have been classified as endangered. On the island of Oahu, all species of the genus Achatinella, also known as the O`ahu tree snails, are federally listed as endangered.
- The snails don't eat their native host plant. The snails are fungus eaters and are especially fond of black sooty mold. By gleaning the leaves of mold they assist in photosynthesis and keep the plants healthy.
- The achatinella and other various species were so beautiful and plentiful that local residents collected them by the thousands in the 1800's.
- Predation has also played a significant role. Once rats made it to the islands, they found the snails to be quite delicious. Even more insidious than rats was the deliberate introduction of the carnivorous snail Euglandia to the islands. Originally brought to the islands and released in 1955 to control the alien African snail, which is an agricultural pest and an intermediate host for cattle liver fluke, it soon found the Hawaiian snails easy prey. In a few years the euglandia made its way from the lowlands up into the native forests and remaining pockets of native snails disappeared. Increased urban construction has crowded out native snails.
Image from www.hawaii.gov/dlnr/Aliens2.html
Image of euglenia snail from www.naturesrepellent.com/images/rosy.jpg
Resource Links
Hawaii forest and trailU.S. Fish and Wildlife Service
