High Fecundity, Rapid Development and Selfing Ability in Three Species of Viviparous Land Snails Phaedusinae (Gastropoda: Stylommatophora: Clausiliidae) from East Asia Author Sulikowska-Drozd, Anna Department of Invertebrate Zoology and Hydrobiology, Faculty of Biology and Environmental Protection, University of Lodz, Author Hirano, Takahiro Center for Northeast Asian Studies, Tohoku University, 41 Kawauchi, Aoba, Sendai, Miyagi 980 - 0862, Japan Author Wu, Shu-Ping Department of Earth and Life Science, University of Taipei, No. 1, Ai-Guo West Road, Taipei, 10048 Taiwan Author Páll-Gergely, Barna Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Herman Ottó street 15, Budapest, H- 1022, Hungary text Zoological Studies 2018 2018-08-02 57 38 1 11 journal article 10.6620/ZS.2018.57-38 1810-522X PMC6517763 31966278 13316188 Tauphaedusa sheridani ( Fig. 1 ) The F0 individuals ( n = 8) placed in the culture were on average 16.55 mm high (SD = 0.72) and consisted of 9.9 whorls (SD = 0.3). They released offspring repeatedly during the experiment (total 741 neonates). During a year, they produced 115 to 195 neonates per pair of snails (mean 164.5, SD = 34.4, n = 4). During a week, the pairs delivered 3.5-4.8 neonates on average (median 4.7, n = 4). On delivery, the neonates had shells 2.00- 2.73 mm high (mean 2.3 mm , SD = 0.15, n = 31) with 2.5 whorls ( Fig. 1B ). Time needed for shell growth ranged between 88 and 113 days ( n = 10). The first reproduction of F1 generation was recorded 160 days after birth. The fecundity of the F1 generation was recorded for 18 snails kept in pairs. During a year, they produced between 109 and 226 neonates per pair of snails (mean 166, SD = 36.8, n = 9). During a week, an average of 3-6.5 neonates were delivered per pair of snails (median 5, n = 9). Also, virgin T. sheridani were capable of reproduction (100% out of 8 individuals). They started releasing neonates seven month after birth and continued until the end of the experiment. During a year, between 65 and 90 neonates were released per virgin snail (mean 77.4, SD = 9.1, n = 8) and during a week, between 1 and 6 (median 2, n = 8). Tauphaedusa sheridani , kept under high humidity, contained 4 to 9 eggs and embryos in the reproductive tract (mean 6.8, SD = 1.37, n = 15) ( Fig. 1D, E ). The majority of the retained offspring (49%) were at the first stage of development (without shelled embryo). Embryos advanced in development (stage IV) were found in low numbers in every adult (range 1-4, mean 2.2, SD = 0.8, n = 15). The embryos’ stage IV shell height varied from 1.48 to 2.47 mm (mean 2.02 mm , SD = 0.25, n = 33) and number of whorls from 1.5 to 3 (mean 2.25, SD = 0.5, n = 33). No adult T. sheridani died during the 60- day exposure to drought. In snails dissected immediately after the experiment, the mean number of eggs and embryos was 5.4 (SD = 1.4, range 3-9, n = 27). The majority of embryos (80%) were advanced in development (stage IV). The shell height of embryos varied from 1.4 to 2.4 mm (mean 2.10 mm , SD = 0.20, n = 113) and number of whorls from 2.0 to 3.0 (mean 2.5, SD = 0.22, n = 113).