Submitted to: Journal of Insect Physiology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/13/2004
Publication Date: 11/1/2004
Citation: Beckemeyer, E.F., Shirk, P.D. 2004. Development of the larval ovary in the moth, Plodia interpunctella. Journal of Insect Physiology. 50:1045-1051. Interpretive Summary: The protection of crops and stored commodities from insect pests is in jeopardy. The expected loss of most insecticides because of acquired resistance or environmental hazard has left the industry with fewer options for pest control. Scientists at the USDA ARS, Center for Medical, Agricultural and Veterinary Entomology examined the development of germ cells in the ovaries of the stored product pest Indian meal moth, Plodia interpunctella, larvae. The germ cells were imaged using immunofluorescent Confocal microscopy to describe their developmental profile during ovarian morphogenesis. The investigation provides a new understanding of germ cell growth in moths that is critical to the development of new strategies to disrupt egg production and cause sterility in this moth.
Technical Abstract: The morphogenesis of ovaries and the organization of germ cells within them was visualized during the larval stages of the moth, Plodia interpunctella. The germ cells were visualized utilizing immuno- fluorescence Confocal microscopy coupled with the antiserum for #CP25 which has been previously observed to be produced constitutively in germ cells in the pupal and adult stages (Zimowska et al., 1991). A cluster of 28 germ cells that stain for #CP25 was found in the gonads of newly hatched first instar larvae demonstrating that the protein is present in germ cells at all stages of development. The founding germ cells were segregated into four clusters by somatic cell intrusion by the beginning of the second instar. Division of the primary germ cells began by the end of the second instar and the formation of all cystoblasts within the four ovarioles appeared to be completed by the end of the third instar. The germ cells within the ovarioles of third instar larvae were organized with a distal cap of seven germ cells segregated from the majority of the germ cells which were arranged around a central germ cell free core in a spiral. Cystocyte divisions were nearly completed during the fourth (last) larval instar. These features suggest that the strategy to produce follicles is fundamentally different from the fruitfly, Drosophila. It appears that follicles are mass produced in a stage wise process in the moth while follicles are produced individually as resources are available in the fly.