A radiotelemetric 2-channel unit for transmission of muscle potentials during free flight of the desert locust, Schistocerca gregaria.

A new radio-telemetric technique for neuroethological investigation of the natural behaviour of insects is presented. The 2-channel miniature transmitter device allows the transmission of electromyograms of 2 muscles during free flight of a locust. The mass of this transmitter and power supply is 0.55 g and can be carried by a mature female without marked impairment of the free-flight behaviour. The radiated power of the transmitter is approximately 20 nW and is sufficient to cover a range of more than 20 m. The carrier-frequency (145 MHz) of the system is frequency-modulated by the inputs of the 2 different channels. Channel separation is achieved by a multivibrator circuit. The chopping frequency (2 kHz) allows a convenient resolution of both signal channels. The design of the 2-channel transmitter device is presented and tested. Its relevance for the studies of natural flight of locusts is given, however, other applications are also feasible.