DEVELOPMENT AND PHEROMONE COMMUNICATION-SYSTEMS IN HYBRIDS OF AGROTIS-IPSILON AND AGROTIS-SEGETUM (LEPIDOPTERA, NOCTUIDAE)

Hybrids were obtained by crossing males of the turnip moth Agrotis seg etum, which has a period of arrested development in the larval stage, with females of the migrant and nondiapausing black cutworm, Agrotis i psilon. No progeny were obtained by crossing females of A. segetum wit h males of A. ipsilon. Backcrosses were successful only by crossing hy brids with both sexes of A. ipsilon. No larval oligopause occurred whe n hybrid larvae were reared under conditions inducing arrest in A. seg etum (12L:12D, 21 degrees C). Wind tunnel tests showed interattractive ness of F-1 hybrids with A. ipsilon but not with A. segetum. Single se nsillum recordings of pheromone-sensitive hairs on the antennae of mal es of the parent species revealed differences in the distribution of s ensilla. F-1 and F-2 hybrids exhibited the same receptor cell types an d distribution as A, ipsilon. Gas chromatographic analysis of female p heromone gland extracts revealed that F-1 hybrids were also very close to A. ipsilon.