The inheritance of female colour morphs in the damselfly Ceriagrion tenellum (Odonata, Coenagrionidae)

Female-limited polychromatism is found in many species of Odonata. In Ceria grion tenellum (Coenagrionidae) one of the morphs is red-coloured, like the conspecific male (androchrome, erythrogastrum morph), whereas most females are red and black (typica morph) or black (melanogastrum morph). Virgin fe males of this species were mated in the laboratory and their progeny reared (13 crosses). Results of these crosses indicate that colour morphs are con trolled by one autosomal locus with female-limited expression. A second lab oratory generation (two crosses) confirmed this inheritance system. This lo cus has three alleles (one per phenotype) and a hierarchy of dominance: typ ica > melanogastrum > erythrogastrum. The dominance relationships of andro/ gynochrome alleles in polymorphic damselflies so far studied are discussed. The frequencies of female morphs in natural populations are highly variabl e, but in all cases typica females are the commonest.