Gender-role adaptation depending on trade-offs between growth and reproduction in the simultaneously hermaphroditic freshwater snail, Physa acuta

Abstract

The size advantage model was applied to predict the behavioural gender- role in simultaneous hermaphrodites. The results from our previous study indicated that small snails of the species Physa acuta preferred to act as males and large ones as both male and female; thus, we did not show clear genderrole switching pattern associated with body size. In the present study, we tested whether a trade-off exists between future growth and current reproduction depending on body size and whether small snails allocate more resources to growth rather than reproduction. A multiple regression analysis indicated that small snails show a higher growth rate than large snails, while the large ones produce more eggs than the small ones. Thus, a trade-off was observed between current reproduction and future growth, which indicates that gender adaptation are associated with body size in Physa acuta.