Aug 02, 2016
Singing Snails – Jewels Of The Jungle
At one time in Hawaiian history, it is said that if you shook any tree in the forest, a rainbow of brightly colored tree snails would rain down upon you. Exhibiting beautiful shells, Pupu Kani Oe, "the shell that sounds long." or kahuli, as Hawaii’s tree snails are known, have long been described as the “jewels of the jungle” so mentioned in countess traditional chants, songs, and poems. Early naturalists in their exploration of the islands were so enchanted by the beauty of Hawaiian terrestrial snails and their mysterious radiation, that it strongly influenced their impressions and beliefs about evolution and island biogeography. Enamored by the beauty of the shells, collectors from around the world contributed to the decimation of the snail population by collecting thousands and thousands of the tiny mollusks. Kāhuli tree snails are endemic, unique to Hawai‘i, and now found only on the island of O‘ahu. Just imagine, you are walking through the tropical rainforest and you hear a faint song carried on the wind. Where might it be coming from you ask, the ferns, the trees, the grass? As you move along the trail, the sound seems to fade, while you can’t help but notice the array of different snails, serenely munching away on the forest foliage. Some are a brilliant yellow stripped with chocolate brown, some are ivory white with cascading blue and tan swirls, yet others are shaded of peach-tinted white with pink or purple stripping. Hawaiian folklore records that the sweet song is the sound the snails singing as they slide up and down the trunks of the trees. Doubters and disbelievers say tiny crickets living deep in the vegetation of the forest floor more likely produce the sound. Species Radiation
Hawaii’s terrestrial snails at one time accounted for a significant portion of the forest fauna. Aside from cultural significance, aesthetic appeal, and their integral role in elucidating theories of island biogeography and evolution, tree snails once made up a significant portion of the forest canopy terrestrial fauna. Isolated in lush valleys and on high mountain ridges, the Hawaiian terrestrial tree snail population exploded in a diverse array of colors, shapes and sizes. Born live, emerging from the parents shell as “miniature” adults, baby snails are ready to graze the nutritious spores and fungi that cover the forest tree leaves. In a symbiotic relationship, the snails do not eat the leaves, but rather the harmful fungi that feed upon them. Greater than 750 species of terrestrial snails once inhabited the Hawaiian Island chain. Scientists sadly report that more than 90 percent of snail diversity in the islands has been lost, representing a stunning and senseless example of one of the worst species losses in the entire world. You may ask why are Hawaii’s snails slipping away to oblivion? There are a lot of areas to place the blame. Manmade air pollution, acid rain, volcanic organic gases (VOG) which originates from Pele’s activity on the Big Island and blankets the other islands when carried on the prevailing winds, and extensive habitat destruction from introduced ungulates including goats, pigs and deer have degraded vast amounts of forest vegetation and fragmented snail populations. In a sad act of poor stewardship of the land, the predatory rosy wolf snail, rats and carnivorous Jackson’s chameleons, introduced to the islands, all feast on Hawaii’s native snails. It’s no wonder snails are dying faster than they can reproduce. Tree Snail Population Recovery
Today, when terrestrial tree snails are found in the forest, it helps scientists define areas less impacted by habitat destruction and the activities of introduced species. The mere presence of snails is a sign of recovery and hope. Several species of tree snails have proved beneficial in increasing nutrient cycling of the forest floor, other species of terrestrial snails benefit host plants by munching on algae and fungus that grow on plant stems and leaves.