Taxonomic name: Euglandina rosea (Ferussac, 1818)
Synonyms:
Common names: cannibal snail (English), escargot carnivore de Floride (French), euglandine (French), Rosige Wolfsschnecke (German), rosy wolf snail (English)
Organism type: mollusc Native to the southeastern United States, the predatory snail Euglandina rosea was introduced to islands in the Pacific and Indian Oceans from the1950s onwards as a biological control agent for another alien species, the giant African snail (Achatina fulica). However, it is neither host specific nor an effective control for Achatina fulica. In French Polynesia, the fast moving Euglandina roseal rapidly eliminated local endemic species. One group threatened by Euglandina rosea is the Partulid tree snails, which evolved separately from each other in isolated valleys and exhibit a variety of unique characteristics. Many Partulid tree snails have been lost already and today the survivors exist in zoos and in the world’s first wildlife reserves for snails. This invasion by a biological control agent has caused a significant loss of biodiversity. Description
Adult shell tall and slender, height up to about 6cm, width to about 2cm. Shell colour pinkish. Occurs in:
natural forests, planted forests, ruderal/disturbed, scrub/shrublands, urban areas Habitat description
Euglandina rosea is not entirely ground-dwelling; it is frequently seen in trees and will also go under water in search of its prey. General impacts
The land snail faunas of the islands of the tropical Pacific are being homogenized. Once, Pacific islands harbored immense numbers of species, most of them unique to the region, and the great majority endemic to single islands or archipelagos (Cowie 1996, 1997a, in Cowie and Cook 2001). They are being replaced by a small number of tropical tramp snail and slug species that are becoming increasingly widespread (Cowie 1998a, R.H. Cowie, unpub., in Cowie and Cook 2001). One most prominent case of the negative influence of introduced species is that of the carnivorous land snail Euglandina rosea which caused the extinctions of Partula (endemic tree snails) in French Polynesia as well as the marked decline of endemic land snail faunas of Hawaii and Mauritius (Murry et al. 1988; Clarke et al. 1984; Hadfield 1986, Murray et al. 1988, Griffiths et al. 1993, Wells 1995, in Satoshi 2003). The best documented cases are those of the achatinelline tree snails, which are endemic to the Hawaiian Islands (Hadfield 1986, Hadfield et al. 1993), and the previously mentioned partulid tree snails, which are widely distributed on most of the high islands (not atolls) of the tropical Pacific, except for the Hawaiian Islands (Murray et al. 1989, Cowie 1992, Hopper and Smith 1992, in Cowie and Cook 2001). These species seem especially vulnerable to unnaturally heightened levels of predation probably because of their extremely slow rate of reproduction (Cowie 1992; Hadfield et al. 1993, in Cowie and Cook 2001).
The earliest introductions of E. rosea in the Pacific were to Papua New Guinea. Following these introductions officials at the Hawaii Department of Agriculture argued that E. rosea would control numbers of the giant African land snail (Achatina fulica) (another invasive species) (Nishida and Napompeth 1975, in Cowie 2000). However, there is no rigorous scientific evidence that E. rosea controls A. fulica (Christensen 1984, in Cowie 2000) and E. rosea is a failed biocontrol agent that choses instead to prey on native snail species. As a consequence the World Conservation Union (IUCN) has formally condemned the deliberate introduction of E. rosea and other carnivorous snails. Most governments and other authorities appear to be aware of the potential threat posed to native fauna by E. rosea, however, under pressure to do something about A. fulica, they may misguidedly consider the introduction of E. rosea (and other species such as the flatworm Platydemus manokwari).
E. rosea was found experimentally to be able to serve as both an intermediate and a paratenic host of Angiostrongylus cantonensis. Geographical range
Native range: southeastern USA, especially Florida.
Known introduced range: Hawai‘i, Kiribati, French Polynesia, American Samoa, New Caledonia, Vanuatu, Solomon Islands, Palau, Guam, Northern Mariana Islands, Papua New Guinea, Japan, Hong Kong, Taiwan, N. Borneo, Madagascar, Seychelles, Mauritius, Réunion, India, Andaman Islands, Sri Lanka, Bahamas, Bermuda. Local dispersal methods
Agriculture (local): Deliberate spread by agricultural officials as a biological control agent.
Natural dispersal (local): Probably once established, natural spread is the main means of spread.
Natural dispersal (local): E. rosea was reported to spread across the island of Moorea at the rate of about 1.2 km per year (Clarke Murray and Johnson 1984). Nutrition
A predator of other snails. It appears to prefer smaller individuals, which it swallows whole, but will attack large snails by entering through the shell aperture. It finds its prey by following their slime trails. Reproduction
Cross-fertilising hermaphrodite. Lays eggs.
This species has been nominated as among 100 of the "World's Worst" invaders Reviewed by: Major update under progress
Dr. Robert H. Cowie, Center for Conservation Research and Training, University of Hawaii, Honolulu, Hawaii, USA.
Compiled by: Dr. Robert H. Cowie, Center for Conservation Research and Training, University of Hawaii, Honolulu, Hawaii, USA & IUCN/SSC Invasive Species Specialist Group (ISSG).
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Last Modified: Monday, 17 July 2006
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