Asked by: Geoff Stevenson
The evidence suggests not. There are two main kinds of device: those that emit ultrasound and those that produce a pulsing electromagnetic field. Numerous studies have failed to show anything more than a very temporary effect from either. Very loud ultrasound can discourage mice from entering an area, but it generally won't make them leave a nest with young. Spiders and most insects don't have ears and are mostly sensitive to vibrations below 1KHz. As for the electromagnetic repellents, the current they draw is so low that they generate much less electromagnetic disturbance than even an ordinary light bulb.
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