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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Effekten av predatorinducerade morfologiska förändringar hos Rana temporaria / The effect of predatorinduced morphological changes in Rana temporaria

Tjärnlund Norén, Lindy January 2017 (has links)
Phenotypic plasticity is the ability of an organism to express different phenotypes depending on the biotic or abiotic environment. In many cases, the response to the environment is beneficial to the individual and can therefore represent adaptive phenotypic plasticity. An example includes morphological and life-historical response to predators. Because there has been a weak interest in the effect of these morphological changes, and it often assumes, but rarely shown, that predator-induced changes are adaptive. I tested how different variables, such as maximum acceleration and velocity, were related to each other in different Gosner stages. Eggs and tadpoles of the species Rana temporaria were exposed to various predator enclosures, a control, a stalking predator (European Perch, Perca fluviatilis), and an ambush predator (dragonfly larvae). The tadpoles mean weight, maximum acceleration and velocity, mobility, boldness, and morphological changes in various Gosner stages were analyzed. My tests showed a significant difference in tadpole weight and their morphology, however, there were no differences in speed, acceleration, boldness or mobility. The morphometric analysis of the tadpoles showed a significant change of tadpoles in the perch treatment compared to the tadpoles in the control. The tadpoles in the perch treatment showed a higher TH/TL (tail height/tail length) ratio, and were overall heavier, than the tadpoles in the control, but no significant change compared to the tadpoles in the dragonfly treatment. This shows that the kairomones and alarm cues triggered a large morphological change, but the effect of the change requires more research.

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