Unlike mammals, "Drosophila" have innate immunity but lack an adaptive immune response. However, the core elements of this innate immune response are conserved between humans and fruit flies. As a result, the fruit fly offers a useful model of innate immunity for disentangling genetic interactions of signalling and effector function, as flies do not have to contend with interference of adaptive immune mechanisms that could confuse results. Various genetic tools, protocols, and assays make "Drosophila" a classical model for studying the innate immune system, which has even included immune research on the international space station.