Abstract
Abstract: The purpose of this study was to investigate the effect of a change in food availability on the growth and reproduction of the hermaphrodite sea hare Aplysia juliana. All groups of A. juliana were fed algae for five days(conditioning period), and then we stopped feeding half of each group for the subsequent five days(experimental period)while the other half of each group were fed algae. There was a negative relationship between the initial body weight of A. juliana and the increment rate in body weight under the fed condition, and positive relation ships were found between the weight of A. juliana and fecundity: i. e., the number of egg masses and the weight of them. When we stopped feeding, small individuals had more copulations than their counterparts which were under the food-rich condition although there was no increase in the number of copulations with large individuals. However, both the number of egg masses and the egg mass weights decreased when we stopped feeding. This implies that the degree to which small individuals divide energy into reproductive activity as males, though not as females, might increase when food availability decreases.
