Time-to-event data of four freshwater snail species predation by a prawn and a crayfish
Description
Time-to-event data of four freshwater snail species - Thiara scabra, Tarebia granifera, Melanoides tuberculata and haita acuta - predation by a Macrobrachium rosenbergii prawn and a Cherax quadricarinatus crayfish. Predation was on five snails from each species. Snails were of the same size grade, as were the predators. The animals were fed during the experiment to ensure that predation was due to choice and not starvation. The data includes the predator species (Mr for M. rosenbergii, Cq for C. quadricarinatus) and ID, predator body mass in g, the container code, the snail species and ID and time until snail predation in hours. "Cont" is short for control tank, which did not have any predator, and had only snails to account for background mortality.
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Steps to reproduce
The prey for the food-choice experiments comprised snails collected from fishponds in Emek HaMa’ayanot, Northern Israel, namely, from the Tirat Zvi farm (N 32.400784, E 35.530227), the Ein HaNaziv farm (N 32.471151, E 35.507449), and a drainage trench near Kibbutz Shlukhot (N 32.476060, E 35.486404), based on mapping from a previous study (Moscovitz et al., 2024). A uniform shell width of 4-6 mm at the snail widest point in the shell was determined by using a set of sieves, one with holes of 6 mm and the second of 4 mm, thus snails which were trapped between them after rigorous washing were used for the experiment, as previously described (Savaya-Alkalay et al., 2018; Savaya et al., 2020). Two mirroring food-choice experiments were conducted, one with M. rosenbergii prawns as the predator and the other with C. quadricarinatus crayfish, using 30 medium-sized (±15–20 g) naïve female decapods of each species, as previously described (Savaya et al., 2020; Shaked et al., 2024). Each predator was presented with five snails of each species of size grade of 4-6 mm (a total of 20 snails per predator). Predation on snails was monitored for 1 week. Before the crayfish experiment, each individual was checked for its moult stage using X-ray-assisted measurement of its gastroliths to avoid using crayfish at a far-advanced moult stage, which can alter feeding behaviour (Shaked et al., 2024). Each decapod was held in a covered 130-L experimental tank with an independent internal water filtration-aeration system, under a 12:12 light/dark photoperiod and at 27°C ± 1°C. The decapods were fed dry pellets ad libitum. On the first day of the experiment, they were given an additional feed (frozen bloodworms, artemia, cyclops) about half an hour before the snails were introduced into the tank. The feeding regimen was intended to ensure that predation was due to preference and not to starvation. For each predator species, the experiment was conducted in six rounds, each comprising five experimental tanks and one control tank (snails alone, no predator). This resulted in 30 experimental tanks and 6 control tanks per experiment, for a total of 72 tanks across the two experiments. Snails were checked for vitality three times a day during the first three days of the prawn experiment, and and once a day on the remaining four days. In the crayfish experiment, on the first day, the tanks were examined every 3 h for 12 h (e.g., at 9:00, 12:00, 15:00, 18:00, and 21:00) to pinpoint crayfish preferences. On the following days, the tanks were examined as planned. A snail was considered alive if its operculum was in place, and dead if the shell was empty or in pieces, or if there was no shell at all.
Institutions
- Ben-Gurion University of the NegevSouthern District, Beersheba