Temperature dependence of the flash duration of the firefly Luciola praeusta.

Firefly flashing has attracted the attention of both poets and scientists for over a century. Here we study the effect of temperature on the flash duration of the Indian species of the firefly Luciola praeusta Kiesenwetter 1874 (Coleoptera: Lampyridae: Luciolinae). Recording in vivo time-resolved spectra of specimens of this species of firefly over the temperature range 20 °C-40 °C, it is observed that the flash duration changes with the change in temperature, and the change is substantially linear. This finding implies that the speed of the enzyme-catalysed chemiluminescence reaction, which produces the light of the firefly, varies linearly with temperature.

The light of the firefly under the influence of ethyl acetate.

When a firefly is made to inhale ethyl acetate vapour, a constant glow appears after a few minutes from its abdominal lantern. This control experiment has been performed by a few workers to record the emission spectrum of the firefly. However, a time-resolved experiment performed by us on this continuous light emitted by the species Luciola praeusta Kiesenwetter 1874 (Coleoptera : Lampyridae : Luciolinae) reveals that it is composed of a continuous train of tiny pulses! The nature of the pulses suggests that an oscillatory chemical reaction continues in the microsecond time scale in the lantern of the anaesthetized firefly.