On the use of microwave radar devices in chronobiology studies: An application withPeriplaneta americana
ABSTRACT Modified motion detectors can be used to monitor locomotor activity and measure endogenous rhythms. Although these devices
can help monitor insects in their home cages, the small size of the animals requires a very short wavelength detector. We
modified a commercial microwave-based detection device, connected the detector’s output to the digital input of a computer,
and validated the device by recording circadian and ultradian rhythms.Periplaneta americana were housed in individual cages, and their activity was monitored at 18°C and subsequently at 28°C in constant darkness.
Time series were analyzed by a discrete Fourier transform and a chi-square periodogram. Q10 values and the circadian free-running period confirmed the data reported in the literature, validating the apparatus. Moreover,
the spectral analysis and periodogram revealed the presence of ultradian rhythmicity in the range of 1–8 h.