This image shows the nurse cells in the ovary of adult female fruit flies surrounding the relatively small eggs, synthesizing and depositing nutrients into eggs to support their development. The images were captured to compare female ovary development in different genotypes, especially focusing on if the mutation of certain genes would impact this process. In this image, the researcher swapped several genes in Drosophila melanogaster with versions from another species Drosophila simulans, to see if D.simulans versions of these genes are compatible with D.melanogaster genome. The ovary defects seen in those replacement mutants could reflect those genes’ roles in hybrid incompatibility.