The effect of temperature on developmental rates in the nudibranch Cadlina luteomarginata

Abstract

Egg masses of the nudibranch Cadlina luteomarginata, which were spawned in the laboratory from adults held at 10 °C, were reared at four experimental temperatures, 5, 10, 15, and 20 °C. To determine the effect of temperature on developmental rates, the time required to develop the following stages or structures at these four temperatures was determined: polar body formation, first cleavage, second cleavage, third cleavage, fourth cleavage, gastrulation, closure of the blastopore, cilia formation, oral invagination, rudiment of the foot, shell formation, ciliation of the foot, statocyst formation, collapse of the egg capsule, and hatching as a veliger. The data show that as the temperature decreases the time required for a particular stage to develop increases. Embryos reared at 20 °C degenerated after the fourth cleavage stage. Total time required to reach the hatching stage (veliger) at the control temperature (10 °C) was 35 days, whereas the time required at 15 °C was 25 days and at 5 °C was 86 days. These data show that development is temperature dependent.