A somatic transformation gene vector that exploits the genomic integration properties of Junonia coenia lepidopteran densovirus (JcDNV) sequences in vivo has been developed. JcDNV somatic transformation vectors are derivatives of plasmids containing an interrupted genome of JcDNV that provide efficient, robust vectors that can be used to examine regulation of chromosomally integrated transgenes in insects. Microinjection of JcDNV plasmids into syncytial embryos of Drosophila melanogaster or the lepidopterans Plodia interpunctella, Ephestia kuehniella or Trichoplusia ni resulted in persistent transgene expression throughout development. Inclusion of transgenes with tissue-specific promoters resulted in expression patterns canonical with phenotypes of piggyBac germline transformants. Somatic transformation required the presence of the viral inverted terminal repeat in cis only and did not depend upon non-structural viral proteins.