title: Clines in the colour polymorphism of Philaenus spumarius in Eastern Central Europe.
abstract: Populations of Philaemus spumarius (Homoptera) have been investigated in the Baltic States of the USSR, in Czechoslovakia and in Hungary. Colour morph frequencies in these highly polymorphic populations are compared with those reported earlier from northern Italy. Gradual changes in allele frequencies (clines) transect the study area, which lies in the most central part of the range of Philaenus in Europe. From north to south the allele pM increases, but pO decreases, in frequency. In their distribution, some of the other alleles also showed regional gradients. The possibility that visual selection varies regionally is dismissed on indirect grounds. Gradients in climatic severity, or in other environmental variables changing concomitantly with climate, are regarded as the primary cause of the observed clines and other differences between regions.
mesh_terms: D000483:Alleles; D000818:Animals; D001454:Baltic States; D002980:Climate; D003604:Czechoslovakia; D005787:Gene Frequency; D006814:Hungary; D007313:Insecta / Q000502:physiology*; D007558:Italy; D010858:Pigmentation; D011110:Polymorphism, Genetic