Biology

• South American apple snails (Pomacea insularum & P. canaliculata)
  • Members of the freshwater snail family Ampullariidae, known as apple snails. 
  • This family has an impressive track record for becoming invasive. 
  • Channeled Apple Snail (Pomacea canaliculata) has been designated one of the Top 100 Globally Invasive Alien Species by the ISSG.
  • The Island Apple Snail (Pomacea insularum) is difficult to distinguish from P. canaliculata. 
  • Large snails (up to 10cm) with bright pink egg clusters and a shell with 5-6 whorls separated by a deep, indented suture, hence “channeled” apple snail.   
  • Not to be confused with the smaller, beneficial, native snail, the Florida Apple Snail (Pomacea paludosa). 
  • Native to Rio Parana, north of Buenos Aires, Argentina. 
  • Major pest in 18 counties, including the U.S.
  • Voracious herbivore with a wide menu (rice seedlings, taro, duck weed, water hyacinth, algae, azolla, and other succulent leafy plants).  Prefers young, soft plants, but will clip mature, rooted plants at the soil surface. 
  • Will eat eggs and juveniles of other snails and will also eat decomposing organic matter. 
  • Can detect food at a distance using chemical cues. 
  • Densities of over 130 snails/ m2 have been observed in Taro fields in Hawaii and up to 150 snails/ m2 have been reported in the Philippine rice paddies. 
  • Introduced into Texas by 1989, in Florida by the mid-90’s, in Georgia by 2005, and recently discovered in Louisiana, Alabama, and South Carolina. 
  • Potential to spread throughout the entire Southern Coastal Plain in the U.S. from Texas to South Carolina. 
  • Represents a major risk to native wetland and aquatic systems and to agriculture in the Southeast U.S. 
  • Has become a devastating agricultural pest in Southeast Asia, especially of rice.  
  • Destroyed native aquatic vegetation in Thailand leading to serious habitat modification.
  • Greatly reduced Taro production in Hawaii 
  • Competitive interactions with native aquatic fauna, especially native snails.
  • Following its introduction into Florida waterbodies, there is an apparent disappearance of the native apple snail.   
  • Potential for extinction by hybridization of the native Florida Apple Snail. 
  • Intermediate host of important vertebrate parasites, most notably the Rat Lung Worm (Parastrongylus cantonensis). 
  • Amphibious but mostly aquatic 
  • Can bury in the bottom sediments of up to 5 months and survive periods of extreme low water.  
  • Every 12-15 days, females lay bright pink clutches of 25-500 eggs, usually 200-300 eggs.  
  • The eggs hatch in 10-15 days.  
  • Snails can reach maturity 60-85 days after hatching. 
  • One female can produce up to 15,000 offspring per year.