It is known that a fly embryo develops at a rate dependent upon temperature, it happens faster at higher temperatures. When one half of a fly embryo is grown at a higher temperature than the other half, the two halves of the embryo develop unequally with the warmer half developing more rapidly. In previous research, we demonstrated that endogenous small interfering RNAs (endo-siRNAs) could confer a protective effect against temperature fluctuations in Drosophila embryos. As a Pew Fellow in the lab of Dr. Carthew, I intend to determine the role of endo-siRNAs in developmental robustness against temperature perturbations. Using Drosophila as a model, I am employing techniques from genetics and molecular biology to test the hypothesis that the endo-siRNA pathway can buffer the genes regulating development. This work could have broad implications in our understanding of the role of small RNAs in development.