The hypotheses that (1) the egg production (EP) of Acartia tonsa is enhanced by dietary diversity because, (2) dietary diversity increases the probability that a nutritionally complete diet will be obtained, were tested. A. tonsa was provided with a diatom, an approximately equivalent sized dinoflagellate, and a mixture of the two foods. EP, hatching success (H) and gross egg production efficiency varied as diatom < dinoflagellate < mixture. EP and H were then measured with diets consisting of Isochrysis galbana ( = Iso, an alga), or Debariomyces hanseni ( = Deb, a yeast), or Oxyrrhis marina (a heterotrophic dinoflagellate) cultured on either Iso or Deb. EP and H were also determined when each kind of O. marina culture was supplemented with Iso. Fatty acid and amino acid analyses indicated that the two O. marina cultures represented two nutritionally different food items. EP in the Iso, Deb and Iso-fed Oxyrrhis groups was low. In Deb-fed Oxyrrhis and Iso-supplemented groups, EP was high. H was > 60% in Iso-supplemented, yeast-fed O. marina group and < 30% in all others.
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G. S. Kleppel (1995) studied this question.