Butterfly radar tagging. Small tortoiseshell (Aglais urticae) trapped beneath mesh and foam being tagged with a radar transponder antenna. The tiny antenna glued on to the insect's thorax will allow its flight path to be tracked in real time. The antenna weighs 12mg and measures 2cm. It does not need a battery and works by reflecting a component (harmonic) of an incoming radar signal. A portable radar tracking station is used to both transmit the signal and gather the information sent back. Photographed at the Rothamsted Research, UK.