Among calyptraeid gastropods, males become females as they get older, and egg capsules containing developing embryos are maintained beneath the mother's shell until the encapsulated embryos hatch. Crepipatella dilatata is an interesting biological model considering that is an estuarine species and thus periodically exposed to elevated environment-physiological pressures. Presently, there is not much information about the reproductive biology and brooding parameters of this gastropod. This paper describes field and laboratory observations monitoring sex changes, brooding frequencies, sizes of brooding females, egg mass characteristics, and embryonic hatching conditions. Our findings indicate that C. dilatata is a direct-developing protandric hermaphrodite, changing from male to female when individuals were between 18 and 20 mm in shell length. At our study site in Quempillen estuary, females were found to be brooding almost continuously throughout the year, having an average maximum of 85% of simultaneous brooding, with a short rest from April through June. No relationship was found between the number of capsules per egg mass and the size of the brooding female. However, capsule size and the number of embryos and nurse eggs were strongly related to female size. The offspring hatched with an average shell length > 1 mm. About 25% of the hatched capsules were found to contain both metamorphosed (juveniles) and non-metamorphosed (veliger) individuals. The sizes of the latter were < 1000 mu m. The length of hatching juveniles was inversely related to the number of individuals per capsule, which seems related to differences in the availability of nurse eggs per embryo. Although fecundity per reproductive event of this species is relatively low (maximum approx. 800 offspring per egg mass) compared with those of calyptraeid species showing mixed development, the overall reproductive potential of C. dilatata seems to be high considering that females can reproduce up to 5 times per year, protecting their encapsulated embryos from physical stresses until well-developed juveniles are released into the population, avoiding a dangerous pelagic period prior to metamorphosis.
Knowledge of reproductive biology is crucial to improving in situ and ex situ breeding programmes for felids. We reviewed the available literature (223 publications) on the reproductive biology of all 38 felid species. We found that 78% of the publications (173) were focused on either or both the oestrous cycles (84) or ejaculate traits (92) of felids. Literature was biased towards the domestic cat Felis catus (31), the cheetah Acinonyx jubatus (27), and the panthera lineage (66). There was a paucity of literature on the caracal lineage (7), the bay cat lineage (3), members of the domestic cat lineage other than the domestic cat (11), and several species of the ocelot lineage. The mean duration of oestrus varies little between the different lineages and species (mean 5.2 days, range 1–10 days, nE = 2265). However, the duration of interoestrus varies greatly in most species (e.g. 1–118 days in the domestic cat). Gestation length also varies significantly between species, but is similar within each lineage and related to adult body size. Non‐pregnant luteal phases appear to persist for half the duration of pregnant luteal phases (48%, 21–71 days, nE = 256; c.f. previous reports of one‐third the duration of pregnant luteal phases). Sperm motility (sperm motility index), sperm viability, and acrosome intactness are high in the fresh ejaculates of most felid species [69% (26–90%, nE = 2104), 69% (49–87%, nE = 443), and 84% (21–100%, nE = 1763), respectively]. Teratospermia is highly prevalent within Felidae, but is particularly problematic for the puma and lynx lineages [ejaculates with 76% (63–94%) and 79% (63–98%) abnormal sperm, respectively]. Teratospermia appears to be linked to low genetic diversity. The maintenance and enhancement of genetic diversity through the use of assisted reproductive technologies should be a long‐term goal for felid conservation management. A short‐term management goal should be to improve the success of assisted reproductive technologies in felids by minimising captivity‐related stress, which can adversely affect fertility and ovarian activity.
Different aspects of reproductive biology of S. plagiostomus were studied in this work from February 2014 to January 2015. Fishes were collected from Sheringal valley right from Kumrat thal valley to Chukyatan Dir Upper. Fecundity and Gonado-somatic index was studied using gravimetric to infer about breeding season and reproductive potential. The mean value of absolute fecundity recorded was 14670.39 while mean value of relative fecundity was noted as 34.78. The mean value recorded for conditioned factor was 0.912 g/cm(3). Relationship of fecundity with body length, body weight, ovary weight and the interrelationship of body length and body weight was established statistically using Linear Regression. The values of determination coefficient (R-2) at P 0.05). The study provides basic information about the reproductive potential and behavior of S. plagiostomus which will be handy towards its culture.