Giant African Snail

Achatina (Lissachatina) fulica Bowdich

Giant African Snail

Giant African Snail

Legal Status: Unwanted Organism - MPI
Status in New Zealand: Not in New Zealand
Organism: Insects, worms and other land invertebrates

Giant African Snail Information Sheet

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Name: Achatina (Lissachatina) fulica Bowdich
Taxonomic Position: Animalia: Mollusca: Gastropoda: Stylommatophora: Achatinidae
Common Names: Giant African Snail

This snail is not established in New Zealand and would pose a threat to agriculture, the environment and human health if it became established. It is considered to be one of the most damaging land snails in the world.

The snail can also act as a vector of human disease such as eosinophilic meningitis which is caused by the rat lungworm parasite, Angiostrongylus cantonensis. The parasite is passed to humans through eating raw or improperly cooked snails or freshwater prawns. It is advisable to wash hands after handling the snail.

Biology

Achatina fulica is a tropical snail, but can survive cold conditions, even snow, by hibernating. Snails are hermaphroditic, and after a single mating can produce a number of batches of fertile eggs over a period of months. A. fulica lays eggs in batches of 100 to 400 with up to 1200 being laid in a year. Eggs are spherical in shape (4.5-5.5 mm in diameter) and are yellow to cream in colour. These hatch after about 8-21 days at a minimum temperature of 15°C.

A.fulica is distinctive in appearance and, when compared with New Zealand snails, is readily identified by its large size and relatively long, narrow conical shell. Reaching a length of up to 200 mm the shell is more commonly in the size range 50 to 100 mm. The colour can be variable but is most commonly light brown, with alternating brown and cream bands on young snails and the upper whorls of larger specimens. While the adult has an average life of five to six years it may live as long as nine years. It will readily enter a state of hibernation and can survive for months in this state.

Hosts

The normal food of Achatina fulica consists of decayed vegetation and animal matter, lichens algae and fungi. However, it is likely that the potential of the snail as a pest may only become apparent when it is established in a new environment such as New Zealand. It has a voracious appetite and has been recorded as attacking over 500 different kinds of plants including a large number of ornamentals, most species of vegetables, legumes, pumpkins and melons although it has a preference for brassicas, lettuce, potato, onions, sunflowers and Eucalyptus. A. fulica has been recorded on the bark of relatively large trees such as citrus.

Distribution

Originally a native of Eastern Africa it is now present in most of the Pacific & Indian Ocean Islands including Guam, French Polynesia, New Caledonia, Papua New Guinea, Samoa, Timor, Vanuatu, Philippines, Indonesia, India, Sri Lanka, Malaysia, China, Taiwan, Brazil, Caribbean, Mauritius, Réunion, Seychelles and parts of western Africa.

Biosecurity Risk to New Zealand

As A. fulica is not established in New Zealand the main biosecurity risk lies in the introduction of the snail attached to plant material, crates, containers, machinery or motor vehicles. It can hide out of general sight and eggs may be introduced in soil. Snails can be active at 10°C when provided with sufficient moisture. Snails in hibernation, that have drawn deep into their shell, can lose 60 percent of their weight and consequently can be mistaken for dead specimens, and carried by travellers as shell-collector specimens. Interceptions are also made at the airport as travellers bring in the delicacy to cook to satisfy expatriates with a meal from home!

Containers and cargo from high-risk giant African snail (GAS) infested countries are inspected on arrival.

If you find this beast phone: 0800 809 966

Page last updated: 18 March 2013