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

The effects of temperature (15, 20 and 25-degrees-C) and food concentr ation (83-3250 mug of carbon per litre) on postembryonic development o f Tisbe battagliai Volkmann-Rocco was investigated in the laboratory. Individual copepods were reared from hatching to adult on a diet of th e algal species Isochrysis galbana Parke. All copepods survived in alg al concentrations of 1300 and 3250 mugC/l, however, at lower concentra tions (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 devel opment, and changes in the relationship between total naupliar and cop epodid durations (Dc/Dn ratio) were attributed to prolonged developmen t of the copepodid stages at low food concentrations. The potential im portance of these environmental factors for influencing the developmen t of copepod populations in the natural environment is discussed.