Dormancy and Arousal Cycles in Freshwater Snails

Animals from our laboratory-cultured Rosedal strain (N = 6–14 per group) were separated into groups with equal numbers of adult males and females (4–5 months old). Active (control) animals were kept in aquaria at 26–28 °C (aquarium tap water was changed three times a week) and fed ad libitum with a diet consisting of fresh lettuce, dried P. canaliculata eggs, and carp food pellets (Shulet Peishe, Argentina). Culture conditions have been previously described (e.g., [21 (link)]). Two experimentally induced dormant (hypometabolic) states were set: (I) animals kept out of water in plastic containers for 7 days (short-term estivation), and (II) animals kept in an aquarium at 10–12 °C for 7 days (short-term hibernation). Half of the animals from each experimental set were immersed in water at 25–28 °C for 30 min, during which they resumed activity (the “arousal” groups). Thus, animals comprised five groups: (1) control (active), (2) estivation (est), (3) arousal-est, (4) hibernation (hib), and (5) arousal-hib. Our laboratory has previously characterized the experimental inductions of activity–dormancy–arousal cycles [11 (link),12 (link),13 (link),21 (link)].