Invasive apple snails

This time not a terrestrial but a freshwater topic: apple snails, or the family Ampullariidae.
Joshi et al. have just published a book on the biology and management of invasive species of this group. The book contains 22 chapters, divided into three themes: General aspects of apple snail biology, Country specific reports, and Management and use.

In the second section two chapters deal with Pomacea canaliculata respectively in Argentina and Ecuador.

The Argentinan chapter is written by P.R. Martin et al., the abstract reads “Pomacea canaliculata is in many respects the best known species of apple snails (family Ampullariidae), although the available information is both fragmentary and geographically biased. Most studies in its non-native range have focused on applied aspects in managed or arti cial wetlands in various countries in Southeast Asia. In its natural range the emphasis has been on basic studies of its reproductive biology, ecology and behaviour in populations from small streams at the southernmost extreme of its distribution (Southern Pampas, Argentina). The extreme geographic position and the lotic nature of these populations may have biased some conclusions about the behavioural and ecological traits of P. canaliculata; contemporary evolution and genetic exchange may also have diversi ed these traits in the non-native range. Even though the ecological information from native populations may not be directly applicable elsewhere, it nevertheless remains as a necessary reference to understand the full potential of adaptation and spread of P. canaliculata to new environments around the world. Surprisingly enough, comparative studies of native and non-native populations of Pomacea spp. are almost lacking. This short review focuses on the distribution, thermal biology, aerial respiration, feeding, reproduction, phenotypic plasticity and shell shape of Pomacea canaliculata in its native range in Argentina.

The Ecuadorian chapter is M. Correoso et al.; the abstract is “This article characterises and analyses the presence of the alien invasive species Pomacea canaliculata in Ecuador, a pest present in many countries that has severe impacts on agriculture, human health and the natural environment. For the rst time, a list of the native species of the genus Pomacea in Ecuador is provided, as well as an occurrence map, based on review of existing (but few) bibliographic data, museum collections and recent eld work. There is a lack of information on other mollusc species in Ecuador, but there is the potential for ecological impact of P. canaliculata on the native mollusc fauna, especially other Pomacea species, which may already be in decline. Other biological threats and consequences are considered, highlighting the impacts that the invasion has had in this Andean country. Also, events that have occurred since the detection of the pest are reviewed, in particular, the decisions adopted by the rice agricultural sector in comparison with those reported by other countries facing a similar situation. The epidemiological role of P. canaliculata in Ecuador is analysed following confirmation that P. canaliculata can carry the nematode Angiostrongylus cantonensis, which causes eosinophilic meningitis. Cases of human infection and the possible routes of transmission are discussed, confirming that Ecuador was the first South American country to have cases of the disease. These results are compared with those for the giant African snail (Lissachatina fulica), a mollusc that can also transmit the disease. It is probable that native Pomacea species can also be infected with the nematode. Finally, a wide range of measures and management actions that should be considered, and possibly adopted, by Ecuador are proposed with the goal of controlling this dangerous pest.

Reference:
Joshi, R.C., Cowie, R.H. & Sebastian, L.S., 2017. Biology and management of invasive apple snails. Muõz: Philippine Rice Research Institute, 406 pp. Available at http://tinyurl.com/y8aw4htb

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