Effect of temperature and photoperiod on the early development of nudibranch Diaulula punctuolata (d’Orbigny, 1837) under laboratory conditions

Abstract

Temperature plays an important role in both the development and growth of marine invertebrates; furthermore, it has been observed that photoperiod significantly affects feeding, growth and larval survival. In this study we evaluated the effect of temperatures of 10° and 16°C and photoperiods of 8:16 and 16:8 on early development, hatching and larval survival in the nudibranch Diaulula punctuolata, under laboratory conditions. At 16oC/8:16, hatching occurred between 10 and 11 days post-spawning (dps), with a physiological time of 162.3 ± 10.1 degree day (d°C); while at 10°C/8:16, hatching took place between 17 and 20 dps; 200.5 ± 27.4 d°C (F = 366.6; P ˂ 0.05). The highest hatching percentage, 82.9%, was obtained at 10°C (F = 16.63; P ˂ 0.05) coinciding with environmental conditions present during the adult collection season. Larvae obtained at 16°C were larger (146.3 ± 0.8 µm) than those at 10°C (140.4 ± 0.5 µm) (F = 212; P ˂ 0.05). Nevertheless, survival time was greater at 10°C/8:16 (21 dps), which could be associated with greater nutrient accumulation during embryonic development. Both embryonic and larval development are dependents on temperature, but not on photoperiod; an increase in temperature from 10º to 16°C, reduced the chronological time required up to hatching by 45.6 ± 3.4%. Photoperiod only affected larval survival at 10°C.