emission traces for the four species used in this study. The x-ray beam (25 keV, 80 μW/mm2) was incident on the insect's head. No qualitative changes are seen immediately after beam on. A major change in CO2 emission pattern after 1000–1500 s of x-ray exposure is marked by RS (respiratory signature). The RS was based on CO2 emission patterns and was corroborated with x-ray video behavioral data; the RS is a major change in CO2 release pattern associated with shaking of the head or mouthparts. For the grasshoppers (Schistocerca gregaria), no behavioral change was observed at RS.