Bioluminescence emissions from the Indian winter species of firefly Diaphanes sp

Numerous studies have been carried out on different aspects of the light from summer-active fireflies. Characteristics of this light have led to very interesting conclusions on the chemiluminescence reaction as well as on the nature of the light from live fireflies. Here we present a first report on bioluminescence emissions from a newly found winter-active Indian species of firefly Diaphanes sp. The steady-state emission spectrum from this species comes out to be apparently similar to those from the other two Indian summer species, Luciola praeusta and Asymmetricata circumdata: asymmetric in nature with a little bit of change in the position of the peak wavelength and in the width of the full width at half maximum. An increase in temperature to approximately 28°C causes a red-shift in the peak wavelength, which probably indicates denaturation of the enzyme luciferase in the live, flashing condition. Emissions in the time domain reveal that the light is never completely off - it decreases in intensity to a low value, sometimes very close to zero, and then increases - a characteristic unheard-of till date. Flash durations are considerably longer than those from the two Indian summer species; those become shorter at about 28°C and increase to noticeably larger values at higher temperatures.