|Apertural view of a shell of Pomacea maculata|
informal group Architaenioglossa
Common name of its synonymous name Pomacea insularum is the island applesnail.
The type locality is the Río Paraná, which joins the Río Uruguay just above Buenos Aires, forming the Río de la Plata. The area between the Paraná and the Uruguay is the Argentine province of Entre Ríos, the southern part of which is marshy, with channels connecting the Paraná and the Uruguay.
The initial introductions in the United States were probably from aquarium release, aka "aquarium dumping", in Texas and Florida most likely in the early 1990s, but possibly as late as 2002. Since then, it has rapidly spread from its initial introduced populations in Texas and Florida, and Pomacea maculata has been documented throughout eight southeastern states as of 2013:
- American Canal and Mustang Bayou in Texas,
- in 2006 in Verret Canal in Gretna, Louisiana.
- Spring Hill Lake near Mobile, Alabama;
- Alabaha River in Georgia;
- Lake Munson, Lake Jackson, Lake Brantley, and many other locations in Florida;
- South Carolina
- North Carolina
In Florida, Georgia, and Texas, initially the occurrences of Pomacea maculata were incorrectly identified as Pomacea canaliculata. Subsequent genetic testing confirmed that specimens collected in Florida, Georgia, and Texas were indeed Pomacea maculata.
Byers et al. (2013) predicted potential range of this species in the Southeastern United States. They indicated that the minimum temperature in the coldest months and maximum amount of precipitation in the warmest months are the best predictors.
Pomacea maculata occurs in Latin America where it thrives in some of the Amazonian rivers in Brazil, Venezuela and Peru.
The snail can grow up to 15 centimeters in size. The eyes are just below the antennae. The colour of the shell varies from a pale olive green to a darker green, with dark bands across the shell. The shell is quite thin compared to other family members of the apple snail family. The inside has dark spots (maculata means spotted or stained).
The shells of these applesnails are globular in shape. Normal coloration typically includes bands of brown, black, and yellowish-tan. Color patterns are however extremely variable, and both albino and gold color variations exist.
The size of the shell is up to 150 mm in length.
The color of the visible soft parts is grey-brown with dark spots.
Pomacea maculata commonly colonizes small water bodies, such as roadside ditches and littoral edges of larger water bodies.
Experimentally determined incipient physiological tolerance limits under laboratory conditions for adult and juvenile Pomacea maculata collected in Texas are:
- salinity: from 0.0 ‰ to 6.8-10.2 ‰
- pH: from 3.5-4.0 to 10.0-10.5
- temperature: 15.23 °C - 36.6 °C. It is also possible that the snails have behavioral mechanisms to tolerate low temperatures, such as burrowing, which could not be exhibited in laboratory experiments.
- emersion: from 70 days at 30 °C (<5% relative humidity) to >308 days at 20-25 °C (>75% relative humidity)
This snail lays pink eggs in clutches above the water level. Pomacea maculata egg clutches contain 2000 eggs.
Pomacea maculata voraciously consumes aquatic vegetation. The snail’s extensive consumption of aquatic vegetation and ability to accumulate and transmit algal toxins through the food web heighten concerns about its spread.
The snail eats dead and decaying plant matter and algae.
The limited ecological data on Pomacea maculata in the USA show that the species has considerable impacts, especially on native aquatic vegetation and snail species. In Florida, in particular, Pomacea maculata is much larger and more fecund than the native Pomacea paludosa (that produces 20–30 eggs).
Recent laboratory studies have demonstrated that Pomacea maculata can transfer the neurotoxin linked to Avian Vacuolar Myelinopathy (AVM) to its avian predators. The invasion of Pomacea maculata has possibly affected the endangered snail kite, a specialist predator on the native Pomacea paludosa, which seemingly experienced decreased foraging success and juvenile survival following invasion of Pomacea maculata.
- Hayes K. A., Cowie R. H., Thiengo S. C. & Strong E. E. (2012). "Comparing apples with apples: clarifying the identities of two highly invasive Neotropical Ampullariidae (Caenogastropoda)". Zoological Journal of the Linnean Society 166(4): 723-753. doi:10.1111/j.1096-3642.2012.00867.x.
- Riess, Karlem (March 1946). "Snail Studies in Elementary Biology". The American Biology Teacher (National Association of Biology Teachers) 8 (6): 131–133. JSTOR 4437709.
- Benson A. J. (2008). "Pomacea insularum". USGS Nonindigenous Aquatic Species Database, Gainesville, FL. <[dead link]> Revision Date: 8/14/2007.
- Rawlings T. A., Hayes K. A., Cowie R. H. & Collins T. M. (2007). "The identity, distribution, and impacts on non-native apple snails in the continental United States". BMC Evolutionary Biology 7: 97 doi:10.1186/1471-2148-7-97.
- Byers J. E., McDowell W. G., Dodd S. R., Haynie R. S., Pintor L. M. & Wilde S. B. (2013). "Climate and pH Predict the Potential Range of the Invasive Apple Snail (Pomacea insularum) in the Southeastern United States". PLoS ONE 8(2): e56812. doi:10.1371/journal.pone.0056812.
- Howells, R. G. 2001. History and status of applesnail (Pomacea spp.) introductions in Texas. Texas Parks and Wildlife Department, Management Data Series No. 183.
- D. Shelton, personal communication, Alabama Malacological Research Center. In: Benson, A. J. 2008. Pomacea insularum. USGS Nonindigenous Aquatic Species Database, Gainesville, FL. <[dead link]> Revision Date: 8/14/2007.
- B. Albanese, pers. comm. In: Benson, A. J. 2008. Pomacea insularum. USGS Nonindigenous Aquatic Species Database, Gainesville, FL. <[dead link]> Revision Date: 8/14/2007.
- J. van Dyke, Florida Department of Environmental Protection, personal communication, In: Benson, A. J. 2008. Pomacea insularum. USGS Nonindigenous Aquatic Species Database, Gainesville, FL. <[dead link]> Revision Date: 8/14/2007.
- M. Minno, St. Johns Water Management District., personal communication. In: Benson, A. J. 2008. Pomacea insularum. USGS Nonindigenous Aquatic Species Database, Gainesville, FL. <[dead link]> Revision Date: 8/14/2007.
- D. Denson and L. Connor, personal communication. In: Benson, A. J. 2008. Pomacea insularum. USGS Nonindigenous Aquatic Species Database, Gainesville, FL. <[dead link]> Revision Date: 8/14/2007.
- "Robyn's Snail Species Page". fishpondinfo.com. Retrieved 2009-01-28.
- R. Howells, Texas Parks and Wildlife Department, personal communication. in: Benson, A. J. 2008. Pomacea insularum. USGS Nonindigenous Aquatic Species Database, Gainesville, FL. <[dead link]> Revision Date: 8/14/2007.
- Stijn Ghesquiere. Pomacea (pomacea) insularum, The Apple Snail (Ampullariidae) Website http://www.applesnail.net, accessed 26 October 2008.
|Wikimedia Commons has media related to Pomacea maculata.|
- Pomacea maculata at the National Center for Biotechnology Information
- Pomacea insularum at the National Center for Biotechnology Information
- Non-native applesnails in Florida - with map of distribution of Pomacea insularum in Florida.
- Applesnails of Florida on the UF / IFAS Featured Creatures Web site
- Posch H., Garr A. L. & Reynolds E. (2013). "The presence of an exotic snail, Pomacea maculata, inhibits growth of juvenile Florida apple snails, Pomacea paludosa". Journal of Molluscan Studies 79(4): 383-385. doi:10.1093/mollus/eyt034.