Fleas, mites, mosquitoes, and other small-scale “living microsystems” have found an ecological niche that is in many ways unparalleled in nature. In the last few years, the convergence of a number of advances in micro-electro-mechanical-systems (MEMS) technology (including power generation, energy storage, communications, sensing, microfluidics, and subcomponent assembly) has opened the door to creating artificial autonomous microsystems that have many of the same capabilities of their living counterparts.