Abstract

Background: Morphological differentiation between populations resulting from local adaptations to environmental conditions is likely to be more pronounced in populations with increasing genetic isolation. In a previous study a positive clinal variation in body size was observed in isolated Roesel's bush-cricket, Metrioptera roeselii, populations, but were absent from populations within a continuous distribution at the same latitudinal range. This observational study inferred that there was a phenotypic effect of gene flow on climate-induced selection in this species.Methods: To disentangle genetic versus environmental drivers of population differences in morphology, we measured the size of four different body traits in wild-caught individuals from the two most distinct latitudinally-matched pairs of populations occurring at about 60 degrees N latitude in northern Europe, characterised by either restricted or continuous gene flow, and corresponding individuals raised under laboratory conditions.Results: Individuals that originated from the genetically isolated populations were always bigger (femur, pronotum and genital appendages) when compared to individuals from latitudinally-matched areas characterised by continuous gene flow between populations. The magnitude of this effect was similar for wild-caught and laboratory-reared individuals. We found that previously observed size cline variation in both male and female crickets was likely to be the result of local genetic adaptation rather than phenotypic plasticity.Conclusions: This strongly suggests that restricted gene flow is of major importance for frequencies of alleles that participate in climate-induced selection acting to favour larger phenotypes in isolated populations towards colder latitudes.

Keywords

Adaptive divergence; Body size; Climate; Genetic isolation; Orthoptera

Published in

PeerJ
2020, Volume: 8, article number: e10036
Publisher: PEERJ INC

SLU Authors

• Kiehl, Berrit

  • Department of Ecology, Swedish University of Agricultural Sciences
    
  • Uppsala University

• Lundhagen, Anna

  • Department of Ecology, Swedish University of Agricultural Sciences
    

• Laugen, Ane

  • Department of Ecology, Swedish University of Agricultural Sciences
    
  • Novia University of Applied Sciences
  • University of Agder

• Low, Matthew

  • Department of Ecology, Swedish University of Agricultural Sciences
    

• Berggren, Åsa

  • Department of Ecology, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Ecology


Publication identifier

DOI: https://doi.org/10.7717/peerj.10036

Permanent link to this page (URI)

https://res.slu.se/id/publ/108638