Effects of food availability on reproductive output, offspring quality and reproductive efficiency in the apple snail Pomacea canaliculata

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.

Abundance and body size of the moonsnail <i>Laguncula pulchella</i> in the Misuji River estuary, Seto Inland Sea, Japan: comparison with a population in northern Japan

“…Prey availability generally governs the somatic weight of predators (Tamburi & Martín 2011). The density of Ruditapes philippinarum at Site F was eight times greater than that at Site H. Thus, Site H had lower prey availability, which would affect the growth and somatic weight of L. pulchella.…”

Neuston: A relevant trophic resource for apple snails?

“…The growth of the snails with an unlimited renewal of neuston was similar to those in the 100-75% level of trophic availability, whereas those with limited renewal grew at rates that were similar to the trophic availability levels of 75-50%. If the relative trophic availability remains constant at these high levels during the summer and the temperature is around 25 • C, the apple snails would be able to reach maturity in 100 days (Tamburi and Martín, 2009) and their fecundity would not be significantly affected (Tamburi and Martín, 2011).…”

Effect of Food Availability on Morphometric and Somatic Indices of the Apple SnailPomacea canaliculata(Caenogastropoda, Ampullariidae)

“…The large investment in CaCO 3 to build egg shells (Cazzaniga, 1990) and to provide the embryos with storage for initial shell growth (Turner & McCabe, 1990) leads to the prediction that females should develop thinner shells than males, as previously observed by Cazzaniga (1990). Intersexual differences in shell thickness should increase with food availability due to the higher reproductive output in better fed females (Tamburi & Martín, 2011).…”