Nutrition and the regulation of egg production in the calanoid copepod Acartia tonsa

Abstract

The nutritional composition of the copepod diet is determined by the feeding response, often through complex interactions with the food environment. On the time scales at which studies of copepod feeding and egg production are typically conducted (hours to weeks), variations in the nutritional composition of the food supply may be responsible for considerable variability in egg production. A substantive portion of this variability can be accounted for when the nutritional composition of the diet is known. In a laboratory study in which we measured the amino and fatty acids in the diet of Acartia tonsa in six 'food environments,' we detected differences in egg production that were apparently associated with amino acid deficiency, differences in the proportions and types of fatty acids in the diet, and differences in the kinds of food organisms taken from a mixture and in the effort required to capture a ration. Egg production varied systematically with the concentrations of 3 fatty acids (of 18 present in the diet) and 4 amino acids (of 16 present) in the diet.