A trehalose/oxygen biofuel cell was implanted in Blaberus discoidalis to convert chemical energy stored within the insect hemolymph into electrical energy which was then used to power a custom-designed oscillator mounted on the back of the insect, capable of producing signals in the audible range. The ability of this cyborg to generate and transmit signals wirelessly was demonstrated by placing an external receiver up to a few centimeters away from the insect while it was tethered to a device that enabled it to walk in place on top of a light weight, air-suspended solid sphere. Wireless communication could also be established between the transmitter powered by the same type of biofuel cell implanted in the moth Manduca sexta and the receiver, while the live insect was being restrained with wax in a Petri dish. Possible means of reducing the weight and size of the transmitter so as to allow the moth to carry it in flight are discussed. Biofuel cells1,2 have emerged as promising devices for converting chemical into electrical energy in living organisms with potential application in a variety of areas of fundamental and technical relevance.1-6 Efforts in our laboratories have focused on the development of biofuel cells that could be implanted into insects 6 and provide the power required not only for the operation of electronics for sensing, information storage and wireless communication, but also for the stimulation of the nervous system, a strategy that will ultimately allow control of certain aspects of the insect behavior. An attractive feature of this approach is that it provides a continuous and autonomous source of power thereby avoiding the need for an external battery as implemented recently by Bozkurt et al., 7 who succeeded in controlling wirelessly the path of motion of a different species of cockroach Gromphadorhina portentosa. To this end, we designed, constructed and successfully tested an implantable biofuel cell incorporating a bienzymatic anode capable of dissociating trehalose, 8 a dissacharide found in very high concentrations, up to tens of mM, in the hemolymph of insects, 9 to yield glucose, which is then oxidized to gluconolactone by the enzyme glucose oxidase. As shown recently in our laboratories, this type of biofuel cell can generate up to 15.6 μW/cm 2 when implanted in a live cockroach Blaberus discoidalis.6 This contribution represents an extension of our earlier studies and is aimed at demonstrating that a single biofuel cell implanted in the insect can power a judiciously designed electronic oscillator mounted on the insect capable of sending wirelessly signals that can be captured by an external receiver, while the insect, tethered to a fixed structure, is allowed to walk on an air-suspended Styrofoam sphere. ExperimentalElectrochemistry.-Enzyme-modified electrodes were prepared by depositing either a mixture of glucose oxidase (Aspergillus niger, EC 1. pressed and purified in our laboratory), PVI-(dmbpy) 2 Cl 2 (10 mg/mL), and PEGDGE (2.5 mg/mL) (Polysciences, Inc.) where PVI denot...