No Tradeoff between Sexual and Asexual Investments in the Sea Anemone Aiptasia pulchella (Anthozoa: Actiniaria)

摘要

Classic examples of tradeoffs between sexual and asexual reproduction include rotifers, aphids, and water fleas, in which reproduction is either sexual or asexual depending on the season. In marine organisms capable of simultaneously reproducing in both modes, the same rules presumably apply despite a lack of evidence. In this study, we analyzed the sea anemone Aiptasia pulchella in southern Taiwan, which continuously produces asexual lacerates from pedal disks while developing gonads in the mesenteries. Investments in the 2 reproductive modes under different feeding frequencies, local densities, temperatures/photoperiods, and light intensities/presence of zooxanthellae were compared. Three of the 4 above comparisons revealed simultaneous increases in both reproductive investments, whereas no correlation was observed in controlling photoperiod and temperature. There may be little competition for resources when both reproductive modes are simultaneously exhibited. The critical resource that results in classic examples of tradeoff is apparently not energy or materials, but rather the organs shared by the 2 reproductive modes.