AbstractNauplii and immature copepodites ofBoeckella triarticulata, B. hamataandB. dilatatawere tested for their ability to survive and grow on monospecific diets of four species of filamentous cyanobacteria,Cyclotella (Cy)andCryptomonas (Cr)at 2 mg dry weight 1−1.Crsupported the development from nauplius to adult of all three calanoid species; complete development on other diets occurred only inB. dilatataonCyandAnabaena oscillarioides (Ao). Differences between nauplii and copepodites ofB. dilatataandB. hamatain survivorship and development on diets ofCy, Anabaena flos‐aquae (Af), AoandNostocsp. 2 (N2) imply ontogenetic shifts in resource utilization with developmental phase. Ranked in order of their ability to support the development of juvenile boeckellids the foods wereCr>Cy>Ao>N2>Af>Nostoc calcicola= no f