title: Benefits of a predtor-induced morphology in crucian carp.
abstract: Crucian carp (Carassius carassius) develop a deeper body in response to chemical cues from piscivores. This change in body morphology has been suggested to be a predator-induced defence. Here we investigate the possible benefits of the induced body morphology in laboratory experiments. Pike foraging behaviour when feeding on crucian carp of different body depths was recorded using video. Further, in a preference experiment pike were allowed to choose between shallow-bodied and deep-bodied crucian carp of similar lengths. Crucian carp body morphology did not affect predatory behaviours (activity, searching, following, observing, capture success) in northern pike, but an increase in crucian carp body depth led to an increase in handling time in pike. In the preference experiment, pike preferred shallow-bodied crucian carp over deep-bodied. Thus, a change in body morphology, induced by the presence of piscivores, benefits crucian carp by increasing piscivore handling times and an avoidance of the deep-bodied phenotype.
authors.affiliation: Department of Ecology, Lund University, Ecology Building, S-223 62, Lund, Sweden. anders.nilsson@zooekol.lu.se.
authors.forename: P Anders
authors.initials: PA
authors.lastname: Nilsson
authors.affiliation: Department of Ecology, Lund University, Ecology Building, S-223 62, Lund, Sweden.
authors.forename: Christer
authors.initials: C
authors.lastname: Brönmark
authors.affiliation: Department of Ecology, Lund University, Ecology Building, S-223 62, Lund, Sweden.
authors.forename: Lars B
authors.initials: LB
authors.lastname: Pettersson
keywords: Body depth; Carassius carassius; Induced defence; Phenotypic plasticity; Predator-prey interactions