Effects of dietary essential fatty acids on reproduction rates of a subtropical calanoid copepod, Acartia erythraea

To understand the role of food quality in planktonic trophic interactions and marine copepod reproduction, we conducted laboratory experiments to investigate the effect of different prey with specific fatty acid profiles on the reproduction of Acartia erythraea. Copepod egg production rates and hatching success were assessed using a mixed diet combining Dunaliella sp. (containing no long-chain polyunsaturated fatty acids, PUFAs) with the diatom Thalassiosira weissflogii (high eicosapentaenoic acid, EPA), the dinoflagellate Prorocentrum dentatum (high docosahexaenoic acid, DHA), the cryptophyte Rhodomonas sp. (moderate EPA and DHA) or the ciliate Strombidium sulcatum (high nitrogen), respectively. Copepods fed a mono-diet of Duna - liella sp. were used as controls. The results showed that a food mixture with dinoflagellates provided the highest egg production rate and hatching success. The bacterivorous ciliate was not a good prey for copepod reproduction because of the deficit in fatty acid composition, despite its low C:N ratio. Generalized additive models indicated that food quality (ingested PUFAs) was important for egg production in addition to food quantity. Among PUFAs, DHA was the most important specific fatty acid based on its high partial correlation coefficient for egg production rate. Egg hatching success was significantly correlated with the percentage of the 3 major ?3 unsaturated fatty acids (alpha-linolenic acid ALA, EPA and DHA) in diets.