Nana

Giant East African Snail invasion in the Americas

= = = **Introduction** =

Invasive species are a problem for agriculture in United States. Agriculture is a 171 billion dollar industry in the US and one of the largest concerns is pest cost. However they also disrupt the entire native ecosystem. The invasive species out competes the native species in its niche and may not contribute back the native environment in the same way as the native species. For example, small-snail eating birds specifically have beaks for consuming small native snails.The Adult East African snail is too large for it to be consumed by the birds. = **Organisms involved** =

The Giant East African Snail //Achatina fulica// is a large air-breathing, terrestrial gastropod that can grow between 7 inches and 10 inches in the length and up to 4 inches in height. This organism is listed as one of the world's most invasive invertebrate species. Like most snails, the A.fulica is hermaphroditic, containing both male gonads and female ovaries. They can lay 200 to 400 eggs per clutch and they can mate up to three times a year to yield more than 1200 eggs.

= **Biological Interaction** =

The A. fulica is has a large range of host plants it can consume. It consumes more than 500 species of plants including beans, peas, cucumbers, carrots, onions, potatoes, spinach, broccoli, cabbage, and melons. In the absense of fruits or vegetables the snail will consume: tree bark, stucco paint flakes, and fecal matter. They are a large potential concern to farmers. Although A. fulica is native to Eastern Africa (Kenya, Uganda, etc.) it thrives in any moist tropical climate. Populations are found in Western Africa (Ghana, Nigeria, and Ivory Coast), Hawaii, Southern Florida, the Carribean, and Brazil. The United States Department of Agriculture and the United States Federal Government have ruled A. fulica illegal to import, sell, or purchase in the U.S. This ruling is due the Giant African snail's status as a highly invasive species. This method is fairly successful since the snail cannot travel great distances without deliberate human action (imported as pets or food).

= **Impact/Importance** =

A.fulica is a fast breeder and out completes local snail species.Only two member are need to establish 900 snail in year. They can cause millions of dollars in crop damage by herbivorous predation. The US Federal Government and The US Department of Agriculture have set strict procedural guideline to deal with careful removal of snails. A. fulica not only damages crops by consumption, but decomposition of the snail's body much the soil too neutral for acidic loving crops. Giant Snails can also be vectors for disease. A. fulica a known carrier of the rat parasite, Angiostrongylus cantonensis. They can obtain this parasite by consumption of rat feces. Human can then contract the by eating un-properly cooked snail meat or through contact of mucus membrane fluid. In addtion, attempts to control the invading Hawaiian population of A.fulica with a predatory snail ended with the native snails being driven to near extinct.

=Current Research=

The US department of Agriculture has tracked population of A. fulica. In the cases of A. fulica invasive in Minnesota, Michigan, and Arizona, the snails were successfully exacted from the wild. Both agencies reported that physical removal of adult snails and consistent funding are necessary for preventing colonization of this species. Although the rate of population growth was relatively slow for A. fulica in temperate or desert climates. The main concern being that if the snail were transported to Southern states, their population growth would be unmanageable.

However, a study on "Rapid spread of an invasive snail in South America in Brasil" shows that the A. fulica are exploding in population. The tropical climate of the Amazon and the coastal river habitats are advantagous conditions for A. fulica. From 2002 to 2006 the A.fulica population have more than tripled. They pose a threat to the diversity of the Amazonian farms and ecosystem. The study shows that large scale physical methods and non-mollusk specific pesticides are the only way to control A. fulica and preserve native snail species respectively.

=References=

Silvana C. Thiengo,Fábio André Faraco,Norma C. Salgado,Robert H. Cowie and Monica A. Rapid spread of an invasive snail in South America: the giant African snail,Achatina fulica, in Brasil BIOLOGICAL INVASIONSVolume 9, Number 6, 693-702, DOI: 10.1007/s10530-006-9069-6

Robert C. Venette & Margaret Larson,Mini Risk Assessment Giant African Snail, Achatina fulica Bowdich [Gastropoda: Achatinidae] Department of Entomology, University of Minnesota St. Paul, MN 55108 September 29, 2004

http://www.aphis.usda.gov/plant_health/plant_pest_info/pest_detection/downloads/pra/afulicapra.pdf

http://www.invasivespeciesinfo.gov/animals/africansnail.shtml

Introduced Enemies of the Giant African Snail, Achatina fulica Bowdich, in Hawaii (Pulmonata: Achatinidae) C. J. Davis and G. D. Butler, Jr. STATE DEPARTMENT OF AGRICULTURE, HONOLULU, HAWAII AND UNIVERSITY OF ARIZONA, TUCSON, ARIZONA

[]

Page authored by Nana A Kufuor, student of Dr. Michelle Lum at Loyola Marymount University, Los Angeles.