ABSTRACT
The responses of Daphnia to the presence of predators that have been reported in the literature include several behavioural (e.g. phototactic behaviour, aggregation) and life history traits (e.g. size at maturity). It is suggested that showing all responses together may be maladaptive, at least under certain circumstances, and that the responses to the presence of predator-mediated chemicals may be clone-specific qualitatively as well as quantitatively. To test this hypothesis, studies are needed that analyze the response to the presence of predator kairomones in more than one trait for a set of genotypes. A comparison of the results on changes induced by the presence of fish kairomones in two behavioural characteristics, phototactic behaviour and alertness, of Daphnia clones isolated from contrasting habitats, indicates that the two responses may be uncoupled to some extent.
