EFFECTS OF TEMPERATURE AND FOOD QUANTITY ON POSTEMBRYONIC DEVELOPMENT OF TISBE-BATTAGLIAI (COPEPODA, HARPACTICOIDA)

The effects of temperature (15, 20 and 25-degrees-C) and food concentration (83-3250 mug of carbon per litre) on postembryonic development of Tisbe battagliai Volkmann-Rocco was investigated in the laboratory. Individual copepods were reared from hatching to adult on a diet of the algal species Isochrysis galbana Parke. All copepods survived in algal concentrations of 1300 and 3250 mugC/l, however, at lower concentrations (83, 208 and 520 mugC/l) there was a general trend of increased mortality with a reduction in food supply and this was enhanced with a rise in temperature from 15-25-degrees-C. Development times decreased with increasing temperature and quantity of food. Food concentration had a more pronounced effect on copepodid compared with naupliar development, and changes in the relationship between total naupliar and copepodid durations (Dc/Dn ratio) were attributed to prolonged development of the copepodid stages at low food concentrations. The potential importance of these environmental factors for influencing the development of copepod populations in the natural environment is discussed.