Hermaphrodites hook up free
, is determined by relative body size in a manner predicted by the size-advantage model.We observed the body-size combinations of pairs in the laboratory by using field-collected populations.The size advantage model predicts that sex change is observed when the reproductive success of one sex increases more with the body size than that of the opposite sex (Charnov, 1979, 1982; Ghiselin, 1969, 1974; Warner, 1975).Many have suggested that the model is theoretically applicable in predicting gender-allocation strategies in simultaneous hermaphrodites (Angeloni et al., 2002; Charnov, 1979, 1982, 1996; De Witt, 1996; Schärer et al., 2001; St. In simultaneous hermaphrodites, adults have mature male as well as mature female reproductive organs, and can adopt either the male or the female role in mating (the gender role).In this case, the larger one takes the female role, the small one the male role. Less energy is required to produce sperm than to produce eggs.
We can distinguish individual gender roles easily in this case.
Small individuals had a significant tendency to act as the male and positively selected large snails as the female partner in both triple combinations.