Scer\GAL4Dot.PK-mediated over-expression of Klf15 leads to an increase in nephrocyte numbers due to the accumulation of small nephrocytes close to the conical chamber, but does not affect the function of the nephrocytes in young (1-week-old) flies. However, in stark contrast to nephrocytes in wild type and control flies, there is no age-related decline in nephrocyte function in 7-week-old flies over-expressing Klf15.