In vivo bioluminescence emissions of the firefly Luciola praeusta at low temperatures

Dependences of light emission from fireflies on external factors like temperature and magnetic field have been studied in recent times. Interesting conclusions have been drawn and hypotheses put forward in those studies. Here we report steady-state and time-resolved emissions of the Indian species of the firefly Luciola praeusta Kiesenwetter 1874 (Coleoptera: Lampyridae: Luciolinae) at temperatures below 20°C. Intensity profiles of emission spectra remain the same as those recorded at normal or high temperatures. Two-flash combinations are frequently formed, giving the appearance of the resolution of a simple flash into two. Simple flashes also become abnormally broad with no uniformity in the increase of their durations. The flashes obtained from fireflies at low temperatures are compared and contrasted with the ones under a strong static magnetic field.