Chronology of phenotypic change in three- and nine-spined sticklebacks – Comparing lateral plate change in ancestral and novel anthropogenic environments

Ole Bjørn Brodnicke

Studenteropgave: Bachelorprojekt


Understanding to what extend and at what rate contemporary evolution takes place in novel habitats is crucial as to predict the ecological impacts of anthropogenic influences on the environment. This project investigated the extent and rate of phenotypic change of lateral armour plate number in three- and nine-spined stickle back populations colonizing anthropogenic water bodies. The lateral plate phenotypes were classified into three morph types; low, partially and completely plated morphs. A Chi-square test of independence showed a statistically significant (p<0.001) association between sampling system (habitat) and lateral plate phenotype. This was the case for both stickleback species. The low plated phenotypes seemed to be selected against in the marine habitat, possibly due to high predation pressure. Salinity by itself was argued not to have the strongest influence on the lateral plate phenotype, but calcium availability might. In freshwater-like habitats with abundant shelter and predators, less lateral plates and the connected increase in flexibility might be more favourable than heavy armour plates, possibly also due to low calcium availability in this freshwater. Additionally, it was argued that lateral plate expression was affected by a complex interaction between the specimen and biotic and abiotic factors. The highest rate of change observed in lateral plates was a reduction of 0.44 plates per generation. The change had happened in a maximum of 7 generations with a generation time of one year. A much lower rate (0.035plates/generation) of change was found in the older system with a maximum population age of 71 generations. This result suggested that the rate in phenotypic change was highest in the first generations after colonization of a novel habitat in regard to lateral plates in the three-spined stickleback. An elaboration on these findings with the addition of other species groups could help to predict contemporary and future evolution influenced by anthropogenic effects.

UddannelserBasis - International Naturvidenskabelig Bacheloruddannelse, (Bachelor uddannelse) Bachelor
Udgivelsesdato30 maj 2016
Antal sider35
VejledereMorten Foldager Pedersen, Kim Præbel & Kjartan Østbye


  • Three-spined stickleback
  • Adaptive radiation
  • Adaptation
  • Morph
  • Evolution
  • nine-spined stickleback
  • Ecology
  • Populations