Tiny transmitter could help scientists understand surprisingly social wasps

https://spectrum.ieee.org/rf-tags-wasps 

An ultralightweight radio-frequency tag designed to be worn by a paper wasp may help scientists get a glimpse at some basic behavioral information that’s long been missing: where do the animals go when they leave the nest?

 

Getting the right combination of light weight, long range, and positional accuracy was key. Jettisoning the battery was the first step. “Batteries don’t scale,” says Blaauw. A miniaturized battery can’t provide enough current to generate a strong radio signal. Capacitors, which store energy by accumulating charges on surfaces, do better at small scales, Blaauw says. “Really small capacitors can store enough charge now to send a radio pulse,” he says. The capacitor used in the wasp tag weighs just 0.86 mg. A tiny photovoltaic array slowly charges up the capacitor until it has enough energy to generate a radio signal.