THE INHERITANCE OF FEMALE DIMORPHISM IN THE DAMSELFLY, ISCHNURA DAMULA

Abstract

Female dimorphism involving a color pattern in the damselfly Ischnura damula does not vary with age and environmental factors. Frequencies existing in natural populations occurred also in population samples cultured under a variety of constant laboratory environments, and the characteristic dimorphic features are retained throughout time intervals approximating life expectancies in nature. The dimorphism is sex-controlled (sex-limited) in expression. Breeding data indicate that the phenomenon is governed by a single allelic autosomal gene pair. Females with the male-like pattern are homozygous recessive, and females of the other pattern type are heterozygous and homozygous dominant.