Hereditary Viruses of Heliothis? Chromatin-Associated Virus-like Particles in Testes of Six Species of Heliothis and Helicoverpa, F1, and Backcross Males

Abstract

Examination of testes of 14 species and strains of Heliothis and Helicoverpa , including those from F1 and backcross males resulting from the hybridization of Heliothis subflexa females × H. virescens males and backcross males from a Helicoverpa assulta × H. zea cross, revealed the presence of virus-like particles (VLPs) in eupyrene spermatocyst cells. A moderate to high correlation (53-98%) between deformed eupyrene sperm and the presence of VLPs existed in some of the groups, while in others, the correlation was much lower (11-44%). A consistent feature among the three groups of F1 testes and the first backcross generation (BC1) involving the H. viresceus × H. subflexa cross was the multiple-tailed nature of eupyrene sperm. In later generations of backcrossing (BC126-130 and BC168-170), deformation of the sperm mitochondrial derivative was the predominant form of sperm abnormality. Virus-like particles were found in the nuclei of apyrene spermatocyst cells as well as in several other cell types within the testis. Comparison of Heliothis VLPs with those from a wild-type strain of Drosophila melanogaster showed much similarity. The widespread occurrence of VLPs in testes from various geographical locations, their presence in laboratory strains as well in native moths, their association with chromatin within the nucleus, and their similarity with Drosophila VLPs suggest that the particles are transposable elements similar to the copia -like family of retrotransposons of Drosophila and other organisms.