Fat-body remodeling in Drosophila melanogaster.

The remodeling of the larval fat body is observed in many insects during metamorphosis, but little is known about the physiological importance or the regulation of this process. In Drosophila melanogaster, fat-body remodeling involves the dissociation of the fat body into individual fat cells, which persist throughout pupal development but are later removed by cell death in the young adult. Inhibition of fat-body dissociation is associated with pharate adult lethality and thus is likely to be an essential developmental event. As a start toward understanding the role of fat-body remodeling in the life history of insects, we carried out a detailed study of fat-body disassociation in D. melanogaster using fluorescent microscopy, and tested whether this process is mediated by hemocytes as proposed for fat-body remodeling in Sarcophaga peregrina. We identified and correlated stereotypic events in fat-body dissociation with developmental changes during metamorphosis, and have demonstrated by cell ablation studies that fat-body remodeling in D. melanogaster is a hemocyte independent process.