Life cycle of the apple snail Pomacea canaliculata (Caenogastropoda: Ampullariidae) inhabiting Japanese paddy fields

Abstract

The life cycle of the apple snail Pomacea canaliculata was monitored over 2-and 1-year periods in Nara (cold district) and Kumamoto (warm district), respectively. The life cycles were similar in both districts: most hatchlings appeared after August, and although some had grown to Ն20 mm by autumn, the majority of juveniles remained Ͻ20 mm. The survival rate over winter was very low (Ͻ1%) in Nara, and moderately low (9%) in Kumamoto. After winter, survivors grew rapidly with low mortality, reproduced actively in summer, and most died during the following winter. The survival rate during mid-term drying (drying of fields for about 2 weeks in summer) in Nara was high (ca. 90%) in both years. In Nara, snail density after winter decreased to 1/43 of that in Kumamoto, but survivors in Nara grew larger and laid more eggs. Due to these effects, egg density in July, and also snail density in September, in Nara recovered to ca. 1/3 of that in Kumamoto.

Insights from an Integrated View of the Biology of Apple Snails (Caenogastropoda: Ampullariidae)

“…Similar responses are noted with snails from northern Argentina (Yoshida et al, 2014). Pomacea canaliculata may not have successfully colonized these temperate areas without some ability to adapt to cold conditions (Ito, 2002;Yoshida et al, 2009), and juveniles of P. canaliculata are more tolerant to both cold and desiccation than those of P. maculata (Yoshida et al, 2014). (Unfortunately, the specimens identified by Yoshida et al (2014) as P. maculata are almost certainly a much more narrowly distributed species, which would lead to considerably different interpretations of their data; Hayes, unpublished.).…”

“…A one-to two-year life span, similar to that observed in laboratory populations reared at 25°C (Estebenet & Cazzaniga, 1993;, may be expected in warmer, subtropical and tropical areas where winter temperatures are not low enough for the snails to become inactive. In their introduced range of more temperate southern Japan, high winter mortality means that the proportion of snails that survive two summers is low (Yoshida et al, 2009). However, a water temperature of 18°C seems to be adequate to trigger reproductive activity in overwintering P. canaliculata (Albrecht et al, 1999), and reproductive activity still proceeds if temperature is lowered from 25°C to 18°C (Albrecht et al, 2005).…”

“…Although snails show dif-ferences in size at hatching, maturity and maximum size, often in response to different densities (Tanaka et al, 1999;Yoshida et al, 2009Yoshida et al, , 2013, such differences disappeared in snails reared under homogeneous laboratory conditions, indicating a strong environmental influence; slightly higher mortality, growth and oviposition rates in laboratory snails from unstable and unproductive habitats were attributable to genetic differences among source populations . The high environmental tolerance of P. canaliculata and its successful establishment in new environments may be associated with this high level of ecophenotypic plasticity .…”

“…Population density and per capita food availability are probably important (Tanaka et al, 1999;Yoshida et al, 2009Yoshida et al, , 2013. For P. canaliculata, the relationship of food availability with size, age at maturity and reproductive performance differ between males and females Estoy et al, 2002a, b;Tamburi & Martín, 2009a.…”

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

“…results) although under the experimental conditions of this study P. canaliculata behaves as a semelparous species . Paddy field populations in temperate Japan are also semelparous (Yoshida et al 2009), but in this case it is mostly due to the high winter mortalities which prevent most individuals from attaining a second reproductive period.…”