The effects of food and temperature regimes on life-history responses to fish kairomones in Daphnia hyalina x galeata*

Life-history responses to two concentrations of fish released info-chemical s at two temperature and food regimes were investigated for one clone of Da phnia hyalina x galeata. The presence of fish kairomones had a negative imp act on size at maturity, carbon allocation to individual eggs and size of n eonates in all treatments. Food concentration and temperature had positive effects on size of adult stages, independent of kairomone treatment. Howeve r, kairomone treatment were not found to interact with food or temperature. Age at maturity was positively influenced by increased temperature and foo d concentrations, whereas no direct kairomone effects were detected for thi s trait. Clutch size was not directly influenced by kairomone treatment, wh ereas both food concentration and temperature had strong, positive effects.