MORPHOLOGICAL DEFENSES OF DAPHNIA AGAINST COPEPOD PREDATION ON EGGS

In laboratory experiments, the small cyclopoid copepods Eucyclops agilis increased the rate of loss of eggs from the brood chambers of Daphnia probably by attacking daphniids to feed on the eggs. Several morphological traits of Daphnia reduced predation by the copepods on Daphnia eggs. A comparison of three species of Daphnia (D. pulex, D. pulicaria, D. galeata mendotae) suggests that egg mortality is reduced by the presence of a long second abdominal process, a long tail spine, and a small adult body size, which may interfere with the copepod invasion of the Daphnia brood chambers.