Karyotypable somatic metaphases obtained in Agrotis spinifera (Noctuidae, Lepidoptera) by application of in vitro colchicine air drying technique

A modified technique of in vitro colchicine treatment has been applied to the somatic chromosomes of a lepidopteran species, Agrotis spinifera. The aim to obtain highly elongated karyotypable elements has been achieved from the brain ganglia metaphase chromosomes of male and female revealing 2n=62 in both the sexes which were further confirmed by diakinesis and metaphase I in male meiotic prophase chromosomes. Further, female heterogamety with ZW:ZZ sex mechanism has been evidenced on the basis of somatic karyotypes prepared from brain ganglia, chromosomal slides by using air drying Giemsa staining procedure in contrast to the usual isodiametric chromosomes obtained by conventional method of acetolactic orcein squash preparation. This is the first report of identification of sex mechanism in the species, which can be used for further investigation by application of G- and C-banding techniques.