Influence of temperature and temperature shifts on the development of chiton larvae,Mopalia muscosa

Abstract

Summary Larvae of the mossy chiton, Mopalia muscosa, were reared either at 10–12°C or 16°C throughout larval development, or were reared at one of the two temperatures for about 400 h (17 days) and then transferred to the other temperature for the remainder of larval development. Temperature regime was found to influence developmental rate, maximum duration of planktonic existence and incidence of spontaneous metamorphosis. The effect of temperature on length of larval life may reflect exploitation of a finite nutritional source by these lecithotrophic larvae. More rapid development was correlated with shorter larval life. The effect of temperature on incidence of spontaneous metamorphosis probably does not have a nutritional basis. In 3 of the 4 treatments, at least 80% of the larvae eventually died, although some larvae metamorphosed spontaneously in all of the treatments. Approximately 50% spontaneous metamorphosis was attained in the fourth treatment, in which larvae initially were reared at the coole...