RESPIRATORY METABOLISM DURING EMBRYONIC SUBITANEOUS AND DIAPAUSE DEVELOPMENT IN PONTELLA-MEDITERRANEA (CRUSTACEA, COPEPODA)

Oxygen consumption and ATP content are reported for the planktonic mar ine copepod Pontella mediterranea during normal and diapause embryonic development. In subitaneous embryos that hatched without delay within 48 h, O-2 uptake increased linearly after spawning to reach maximum l evels about 25 h later. By contrast, ATP levels were initially very hi gh but decreased rapidly within the next 5 h to reach stable values th ereafter. In diapause embryos, O-2 consumption followed the typical U- shaped curve described for insect diapause. An initial period of pre-d iapause, which lasted for about 25 days, was characterized by elevated O-2 uptake. This was followed by a period of diapause in which O-2 co nsumption dropped to 25% of the values recorded during pre-diapause. T his protracted period of dormancy, which lasted about 4 to 5 months, w as followed by a period of high O-2 consumption possibly due to the br eaking of diapause and resumption in development. ATP content during t he pre-diapause period showed a similar trend as in subitaneous embryo s with high initial levels that decreased with time for the first 20 d ays and remained stable afterwards.