Search results for "Sensitive index"

Radial and peripheral clines in northern polymorphic populations of Philaenus spumarius

2009

Geographic variability in the colour polymorphism of Philaenus spumarius (Homoptera) was investigated in the northern parts of Finland, Norway and Sweden. The investigation was directed mainly at peripheral populations south of the Baltic—Arctic divide. The colour phenotypes were found to differ in their “north tolerance”. The phenotypes typ (pt/pt) and lat (pt/pt) were the most, and the phenotype tri (pt/pT) the least tolerant to marginal conditions. Differences in “north tolerance” between the phenotypes cause radial clines to be present in allele frequencies. The radial clines may be caused by the combined effect of several different factors. These include shortness of the thermal growth…