Competition in Cladoceran Communities: The Cost of Evolving Defenses against Copepod Predation
1977
Kerfoot, W Charles
An intimate relationship is apparent between fecudity and predator resistance in clones of the parthenogenic cladoceran Bosmina longirostris. Young of certain clones possess spines slightly larger bodies, the thicker carapaces, all of which frustrate the handling tactics of predatory copepods. During periods of abundant resources, the resistance is purchased at considerable cost, since eggs and developing young are carried n a restricted space, a special brood chamber formed from the dorsal portion of the carapace. The energy used in the development of protective defenses comes from the egg yolk supply, leading to larger eggs and small broods. During the spring algal bloom in Union Bay, Lake Washington, long—featured lines carry few large eggs, while short—featured lines fill their pouches with many small lines in the inshore regions after fisher remove predatory copepods.
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