Pomacea canaliculata, commonly known as the golden apple snail or the channeled apple snail, is a species of large freshwater snail with gills and an operculum, an aquatic gastropod mollusc in the family Ampullariidae, the apple snails. South American in origin, this species is considered to be in the top 100 of the "World's Worst Invasive Alien Species". It is also ranked as the 40th worst alien species in Europe and the worst alien species of gastropod in Europe.
Distribution The native distribution of P. canaliculata is basically tropical and subtropical, including Argentina, Bolivia, Paraguay, Uruguay, and Brazil. The southernmost record for the species is Paso de las Piedras reservoir, south of the Buenos Aires province, Argentina.
Non-indigenous distribution This species also occurs in the United States, where the initial introductions were probably from aquarium release, aka "aquarium dumping". The non-indigenous distribution includes: Lake Wawasee in Kosciusko County, Indiana; Langan Park and Three Mile Creek in Mobile, Alabama; a pond bordering the Mobile-Tensaw River Delta in Baldwin County, Alabama; Little Wekiva River, Orlando, Florida; a lake near Jacksonville, Florida; Miramar Reservoir in San Diego County, California; and a pond near Yuma, Arizona. Established populations exist in California and Hawaii. Moving north, the Government of Alberta has labelled channeled apple snails as an invasive species. Alberta's Minister of Environment and Protected Areas Rebecca Schulz, alongside the Alberta Invasive Species Council, is working hard to make Alberta invasive species free, which includes addressing the issue of channeled apple snails. The species has been found in China since 1981. Its initial point of distribution in China was Zhongshan city. The species has been found in Chile since 2009 with a restricted distribution. The species has also been found in the Philippines, Japan, Korea, Taiwan, Vietnam, Cambodia, Laos, Papua New Guinea, parts of Indonesia and Malaysia, Singapore, and Guam. In 1980, the apple snail was introduced to south-east Asia as a food item and aquarium pet. First, it was introduced to Taiwan, then Japan, then Thailand and the Philippines. Instead of catching on, snails were released or escaped and have become a major agricultural pest. Samples taken 3 December 2020 in Mwea Constituency, Kirinyaga County, Kenya were the first in that country, and indeed the first in continental Africa.
Shell description
The shells of these apple snails are globular in shape. Normal coloration typically includes bands of brown, black, and yellowish-tan; color patterns are extremely variable. Albino and gold color variations exist. The size of the shell is up to 150 millimetres (6 in) in length.
Ecology
Habitat
This species lives in freshwater lake, river, pond and swamp habitats and tolerates a wide range of temperatures. In natural settings, they rely on grasses and other emergent vegetation growing along the perimeter of bodies of water to lay their eggs. Where invasive, they can utilize crops such as rice and taro as a substrate for reproduction.
Feeding habits Pomacea canaliculata is extremely polyphagous, feeding on vegetal (primarily macrophytophagous, feeding on floating or submersed higher plants), detrital, and animal matter. Diet may vary with age, with younger smaller individuals feeding on algae and detritus, and older, bigger (15 millimetres (19⁄32 in) and above) individuals later shifting to higher plants. This species negatively impacts rice and taro agriculture worldwide where it has been introduced.
Life cycle
In temperate climates, the egg-laying period of this species extends from early spring to early fall. while in tropical areas reproduction is continuous. The duration of the reproductive period of P. canaliculata decreases with latitude, to a minimum of six months in the southern limit of its natural distribution. Adult females oviposit on emergent vegetation at night, but will also lay their eggs on rocks and manmade surfaces like boats. Once laid, the eggs take approximately two weeks to hatch, during which time the bright pink or orange coloration of the eggs fades. First direct evidence (of all animals), that proteinase inhibitor from eggs of Pomacea canaliculata interacts as trypsin inhibitor with protease of potential predators, has been reported in 2010.
Predators The snail kite, Rostrhamus sociabilis, is a predator of this species in South America. The fire ant, Solenopsis geminata, has also been observed to prey upon this species.
Parasites Approximately 1% of the Pomacea canaliculata on sale on local markets in Dali City, Yunnan, China were found to be infected with pathogenic Angiostrongylus cantonensis in 2009.
Control Crude cyclotide extracts from both Oldenlandia affinis and Viola odorata plants showed molluscicidal activity comparable to the synthetic molluscicide metaldehyde. Because submerging developing eggs below the water reduces hatching success, manipulating the water level in agricultural fields and dammed reservoirs may provide a tool for controlling invasive populations.
Human use
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