Conchological variation in Pomacea canaliculata and other South American Ampullariidae (Caenogastropoda, Architaenioglossa).

Universidad Nacional del Sur, Departamento de Biología, Bioquímica y Farmacia, San Juan 670, 8000 Bahía Blanca, Argentina.
Biocell: official journal of the Sociedades Latinoamericanas de Microscopía Electronica ... et. al (Impact Factor: 0.58). 09/2006; 30(2):329-35.
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    ABSTRACT: Phenotypic plasticity in life history traits favors the establishment of invaders and may magnify their ecological impacts. Pomacea canaliculata, the only freshwater snail listed among the 100 worst invaders worldwide, is able to complete its life cycle within a wide range of conditions, a capacity attributed to its life history plasticity. Using snails from their native range in Argentina we investigated the changes in fecundity, egg mass traits, offspring quality, and efficiency of food conversion into eggs in response to different levels of food availability throughout different life stages. Pre-maturity mortality was not affected by chronic reductions of up to 80% in food availability. Females fed ad libitum demonstrated no significant reproductive output differences when mated with males raised at different food availability levels. For females, the number and total weight of eggs and the size of egg masses decreased at high levels of food deprivation. Their efficiency of conversion into eggs of the food ingested during the reproductive period increased with deprivation, as did the survival time of their offspring. In contrast, the egg mass laying rate and the individual egg weight did not differ under different food availability regimes. Reductions in food availability have been suggested as a control method but our results indicate that fecundity would be lessened only at deprivation levels higher than 50% and would be partially compensated by an increase in hatchling survival. KeywordsWetlands–Paddy fields–Plasticity–Life history–Maternal effects–Efficiencies
    Biological Invasions 01/2011; 13(10):2351-2360. · 2.51 Impact Factor
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    ABSTRACT: The aim of this study was to test the hypothesis that positive rheotaxis and anti-detachment behaviors contribute to the persistence of Pomacea canaliculata in lotic environments. This invasive apple snail is commonly considered a lentic dweller. In a first series of trials in a laboratory flume, current velocity was gradually increased until snails’ detachment. Detachment velocity was highly variable, with some snails able to withstand strong currents during short periods. Sexually undifferentiated snails were the most resistant to detachment; most of the snails that resisted high velocities were facing flow before detachment. In a second series of trials, snails’ net displacement was estimated at three fixed velocities (0, 0.15, and 0.30 m s-1). Current velocity did not influence mean net displacement, which was not different from zero. Marked snails were released in a stream and recaptured 24 h later estimating their net displacement. Most recovered snails dispersed a short distance from the release point and crawled through sites with very low current velocities. A small proportion of snails drifted downstream, indicating the existence of different dispersal mechanisms. Snails were able to resist current velocities that are among the highest recorded in streams in the Pampas region. P. canaliculata did not show a positive rheotactic response; in flowing water, snails crawl more often upstream, but at a slower pace than downstream. At the population level, a slow upstream spread seems possible in plain’s streams, probably being enough to compensate drift, but not to colonize headwaters. Irrigation systems are feasible pathways for the spread of this species in invaded regions.
    Aquatic Ecology. 01/2012; 46(1-46):129-142.
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    ABSTRACT: During the summer of 2009, apple snails (Mollusca: Ampullariidae) of the genus Pomacea were found to have established a self-sustaining population for the first time in Europe (Ebro Delta, Catalonia, Spain). This group is known for its genetic diversity and at least two distinct species are represented in a clade typified by Pomacea canaliculata. Various citations refer to egg size and color, and clutch size, in addition to shell morphology, for distinction between species. However, due to overlapping characters and phenotypic plasticity, genetic analyses are becoming more widely used methods for this group. Herein, we present a method for DNA extraction to identify species with sufficient precision from empty shells recovered from the field. This technique may be of use more widely for analyses of shells archived in museum collections for phylogenetic and taxonomic studies.
    Molluscan Research 01/2013; 33(1). · 0.62 Impact Factor


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