UNSTABLE FOREWING POLYMORPHISM IN A STRAIN OF PYRRHOCORIS-APTERUS (HEMIPTERA, PYRRHOCORIDAE)

Wing length polymorphism in Pyrrhocoris apterus (L.) was analyzed morp hometrically. Spring and autumn wild population samples as well as sev eral laboratory strains (Apricot [Ap], mosaic [mo], macropterous [ma], and unstable micropterous [ump]) were included in the analysis. All p opulations but two were found uniformly brachypterous; ma segregated b oth brachypterous and macropterous individuals and ump was characteriz ed by unusual destabilization of wing length (left and right unequal) and segregation of a high percentage of micropterous individuals. Wher eas the decision of brachypterism versus macropterism is based mainly on environmental control of a major gene whose recessive allele is res ponsible for the macropterism, a new mode of wing length regulation is suggested, engaged in conspicuous destabilization of ump wings and co nsisting presumably in transpositions of mobile genetic elements.