Effects of temperature on fertility in hybrid hermaphroditic Argopecten scallops

Abstract

Temperature is a critical factor affecting the growth, development and reproduction of aquatic organisms. The interspecific F1 hybrids between hermaphroditic bay scallops (Argopecten irradians) and Peruvian scallops (Argopecten purpuratus) exhibited significant heterosis in yield, but sterility in most hybrids hindered large scale interspecific hybridization and speciation. We first explored the physiological effect of temperature on the fertility of hybrid hermaphroditic Argopecten scallops with F1 hybrids treated at 6 different temperatures (18 °C, 20 °C, 22 °C, 24 °C, 26 °C, and 28 °C). The results showed that the final mortality rates from 18 °C to 22 °C were significantly lower than those from 24 °C to 28 °C. With the decrease of the temperature, the size, gonadal index, ATP content, and expression of most genes related to fertility regulation gradually decreased in F1 hybrids treated at 22 °C, 20 °C and 18 °C, and the apoptosis rate of oocytes gradually increased, but the activity of SOD (superoxide dismutase) and CAT (catalase) first increased and then decreased. The fertility of hybrids treated at 22 °C, 20 °C and 18 °C gradually decreased with the decrease of the temperature. According to gene expression, temperature may regulate the fertility of Argopecten F1 hybrids by affecting apoptosis, meiosis, ATP production and damage repair to inhibit the genesis and maturation of germ cells. Our findings suggest that temperature can affect the hybrid fertility of hermaphroditic Argopecten scallops and provide the basis for further research on the mechanism of temperature on sterility.