Inducible defences in Daphnia: responses to two closely related predator species

The predator-induced responses of two species of Australian Daphnia, with c ontrasting distributions and life history patterns, to the kairomones of tw o species of Anisops predators, were measured. Daphnia longicephella produc ed a large crest and attained a larger size when exposed to both predators. D. carinata sl matured earlier than D. longicephala and did not produce a crest. Surprisingly, kairomones of both predators inhibited the production of ephippia in D. carinata sl. Anisops stali, the larger of the two predato r species, induced a significantly! larger crest size in D. longicephala, a nd larger brood size in both species compared with the smaller A. gratus, i ndicating a quantitative but not qualitative effect of predator species on inducible defences.