There are other birds, lizards, fish, crabs, and rats that will prey on juveniles. Although now widespread in Asia, it is not present in Australia, or in any Pacific islands country other than Papua New Guinea.Įgg and small juveniles are eaten by fire ants and there are birds that specialise in adults. The golden apple snail is on the list of the 100 of the World's Worst Invasive Species compiled by the Global Invasive Species Database, maintained by the IUCN Invasive Species Specialist Group.Ĭountries still free from the golden apple snail should take all practical measures to prevent its introduction and further spread. There are molecular method to separate some species. This applies particularly to Pomacea canaliculata and Pomacea maculata which look very similar. However, the variability of the species make identification difficult, and specimens should be examined by experts. Look for the bright pink egg masses which are characteristic of Pomacea species. And in south China and Taiwan eating the snail raw (a delicacy) has resulted in numerous cases of meningitis, caused by the parasitic nematode, Angiostrongyulus cantonensis, the rat lungworm. Loss of native snails in many places is considered a direct result from apple snail introductions and/or an indirect result from pesticide use to control them. Impacts occur in many Southeast Asian countries where rice is direct seeded (the Philippines, Thailand, Vietnam). For instance, in the Philippines, where the snail occurs over approximately 50% of the area devoted to the crop, losses in yield, replanting, and pesticide use cost many millions of dollars annually. In Thailand, high losses of aquatic vegetation from snail grazing resulted in phosphorus release and concomitant outbreaks of phytoplankton. The snails survive dry times by burying into the mud to hibernate for up to 6 months. Over large distances, spread is helped by the aquarium trade, purposely as a human food, and on planting material, such as setts of taro. Spread occurs by floating in water, and crawling. ![]() The length of the life cycle depends very much on temperature and the occurrence of seasons. The eggs hatch after about 2 weeks, depending on temperature, and the young fall into the water. The snails have gills and a lung.įemale snails lays clutches of pink eggs (about 250 at a time, but this is very variable), above water on parts of plants and on rocks (Photo 4). The body is golden-pinkish or orange-yellow. Tentacles are long and tapering. The snail is a hazard to human health.Īdults have thin shells, 35-60 mm high, which coils to the right (when apex is uppermost and opening is to the right), and varies from yellow brown, greenish-brown to dark brown, often with bands, with a brown horny operculum which closes the opening of the shell (Photo 1&2). Large populations damage natural aquatic vegetation and displace local snail species. ![]() Taro leaves are eaten if they droop into the irrigation water. ![]() Rice seedlings are cut just above the soil surface, and the stems and leaves are eaten. Symptoms & Life CycleĪ freshwater pest of great importance in tropical and sub-tropical wetlands around the world, well adapted to periods of droughts and excessive rainfall. The snail is a generalist, and a large number of crops (rice, kangkong, lotus, taro, and many more) and wild species are hosts. In Papua New Guinea NOT in Australia (intercepted only), nor in Palau (eradicated). Asia, Africa (Egypt, South Africa), North and South America, the Caribbean (Dominican Republic), Europe (Spain), Oceania. ![]() Other Pomacea species are similar, e.g., Pomacea maculata. The name has been given to several Pomacea species, due to confused identification. Eggs of the golden apple snail, Pomacea canaliculata, on a taro petiole (Thailand).
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |