Euglandina rosea
Partula tree snails and the Euglandina threat
Partula snails Partula conservation Euglandina

Euglandina rosea

Since their first introduction to tropical islands in the 1800s the giant African land snails Lissachatina fulica (=Achatina fulica) and Achatina immaculata have been regarded as serious agricultural pests. These two species, originating from East Africa and Madagascar, have now been introduced to at least 27 countries, largely accidentally. Extremely high densities of these species occurred on several Pacific islands in the 1940-50s. The effects of the population explosions prompted much interest in methods of control, including hand collection, chemical and biological control. The latter has been the most widely used option. This included a variety of taxa from flatworms to reptiles, including predatory snails.

Research into molluscan predators of Achatina started in the 1940s and predatory snails started being introduced to islands in 1950 with the East African Gonaxis kibwezensis was released on Agiguan in the Marianas Islands as a test project. A survey of Agiguan in 1952 showed that the population was increasing slowly, having little effect on A. fulica. Despite the poor results of this initial project introductions of G. kibwezensis were made to 11 other islands during the 1950s. In 1957 the larger species Macrogonaxis quadrilateralis was released on Oahu and Maui (Hawaii) and later to many other islands. In 1955 the carnivorous snail Euglandina rosea was collected in Florida and released on the Hawaiian islands. 616 snails were released on Oahu island, in 1958 12,000 were moved from Oahu and transferred to other islands in the Pacific. These initial introductions were undertaken without thorough trials being completed. Although there have been some claims that this species controls Achatina there is no good evidence for this.

Other introductions have taken place:

The results of these introductions have been variable: some failed, others established but remained rare and in some places rapid expansion occurred. The established introductions did not cause the expected declines in Achatina populations and in several cases Euglandina introductions have been blamed for the rapid extinction of many native molluscs (especially in Hawaii and French Polynesia). Two families of snail have been particularly badly hit: the Partulidae and Achatinellidae. In the Partulidae sine 1978 Euglandina has been directly responsible for the complete extinction of 52 species, a further 11 survive only in captivity and another 35 are at serious risk of extinction. In the Achatinellidae the introductions in the 1950s have led to 27 complete extinctions, 27 species extinct in the wild and 22 on the edge of extinction. Many other species have probably been lost without being noticed.

In order to find ways of controlling the threat Euglandina poses to many snail faunas the ecology of the predator has been studied by several research groups, although additional studies are needed:

  • Justin Gerlach 1992-4 - ecology of Euglandina and a comparison of its impacts in Seychelles, Mauritius, Reunion, New Caledonia and French Polynesia.
  • Clifford, K.T., Gross, L., Johnson, K., Martin, K.J., Shaheen, N., Harrington, M.A. - Slime-trail tracking in the predatory snail, Euglandina rosea.
  • Cook A 1983. - Feeding by the carnivorous snail Euglandina rosea Férussac. J. Mollus. Stud. Suppl. 12A: 32–35.
  • Cook A 1985a. - Functional aspects of trail following by the carnivorous snail, Euglandina rosea. Malacologia 26: 173–181.
  • Cook A 1985b. - The organisation of feeding in the carnivorous snail Euglandina rosea. Malacologia 26: 183–189.
  • Cook A 1989. - Factors affecting prey choice and feeding technique in the carnivorous snail Euglandina rosea Férussac. J. Mollus. Stud. 55: 469–477.
  • Coote T, Clarke D, Hickman CS, Murray J, & Pearce-Kelly P 2004. - Experimental release of endemic Partula species, extinct in the wild, into a protected area of natural habitat on Moorea. Pac. Sci. 58: 429–434.
  • Cowie RH 2001. - Can snails ever be effective and safe biocontrol agents? Int. J. Pest. Man. 47: 23–40.
  • Davis EC, Perez KE, & Bennett DJ 2004. - Euglandina rosea (Férussac, 1821) is found on the ground and in trees in Florida. The Nautilus 118: 127–128.
  • Davis-Berg, E.C. - The predatory snail Euglandina rosea successfully follows mucous trails of both native and non-native prey snails.
  • Gerlach J 1999. - The ecology of western Indian Ocean carnivorous land snails. Phelsuma 7: 14–24.
  • Gerlach J 2001. - Predator, prey and pathogen interactions in introduced snail populations. Anim. Conser. 4: 203–209.
  • Griffiths, O., A. Cook & S.M. Wells. 1993. - The diet of the introduced carnivorous snail Euglandina rosea in Mauritius and its implications for threatened island gastropod faunas. Journ. Zool. 2129(1): 79-89
  • Holland, B.S., T. Chock, A. Lee & S. Sugiura. 2012 - Tracking Behavior in the Snail Euglandina rosea: First Evidence of Preference for Endemic vs. Biocontrol Target Pest Species in Hawaii. Amer. Malacol. Bull. 30(1): 153-157.
  • Kinzie RA 1992. - Predation by the introduced carnivorous snail Euglandina rosea (Férussac) on endemic aquatic lymnaeid snails in Hawaii. Biol. Cons. 60: 149–155.
  • Meyer III, W.M. and R.H. Cowie - Distribution, movement, and microhabitat use of the introduced predatory snail Euglandina rosea in Hawaii: implications for management.
  • Meyer WM & Cowie RH 2010. - Feeding preferences of two predatory snails introduced to Hawaii and their conservation implications.
  • Shaheen, N., K. Patel, M. Moore & M.A. Harrington. 2005. - A predatory snail distinguishes between conspecific and heterospecific snails and trails based on chemical cues in slime.Anim. Behav. 70: 1067-1077
  • Sugiura, S., B.S. Holland & R.H. Cowie. 2011. - Predatory behaviour of newly hatched Euglandina rosea. J. Moll. Stud. 77

    More details of Euglandina biology can be found on the Jacksonville shells Euglandina page

    Compiled by Justin Gerlach: contact

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