Characterization of Firefly Flashes at Various Temperatures in Different Wavelength Regions.

Chemiluminescence reaction efficiently produces light, and that is where its scientific importance lies. For investigating the reaction in live fireflies, we introduce a few protocols that exert light emission at different temperatures and in different color sectors. From the changes in the peak position and the duration of flashes, the light can be characterized. As the firefly emits in green, yellow, and red color sectors, three color-filters are used for getting emissions in these three regions. Emission spectra are recorded in a high-resolution spectrometer, and flashes are obtained in an oscilloscope, after amplification in a photo multiplier tube, in the range of temperature 20-40 °C.

Light from a firefly at temperatures considerably higher and lower than normal.

Bioluminescence emissions from a few species of fireflies have been studied at different temperatures. Variations in the flash-duration have been observed and interesting conclusions drawn in those studies. Here we investigate steady-state and pulsed emissions from male specimens of the Indian species Sclerotia substriata at temperatures considerably higher and lower than the ones at which they normally flash. When the temperature is raised to 34 °C, the peak wavelength gets red-shifted and the emitted pulses become the narrowest which broaden considerably thereafter for small increases in temperature; this probably indicates denaturation of the enzyme luciferase catalyzing the light-producing reaction. When the temperature is decreased to the region of 10.5-9 °C, the peak gets blue-shifted and the flash-duration increased abnormally with large fluctuation; this possibly implies cold denaturation of the luciferase. We conclude that the first or hot effect is very likely to be the reason of the species being dark-active on hot days, and the second or cold one is the probable reason for its disappearance at the onset of the winter. Our study makes the inference that these two happenings determine the temperature-tolerance, which plays a major role in the selection of the habitat for the firefly.

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.

Manifestation of Peaks in a Live Firefly Flash.

Several studies have been carried out on flashing of fireflies till now. From patterns of its flashes in different ambient conditions, different conclusions have been drawn and hypotheses put forward. Here we observe flashes emitted by two Indian species of firefly Luciola praeusta and Asymmetricata circumdata. For the species L. praeusta, as the temperature is lowered below about 21 °C, simple pulses become compound or combination ones. Males begin to emit bi-modal flashes while females emit both bi- and tri-modal flashes, along with the simple ones, in a regular manner. For the species A. circumdata, this feature is evident even at their normal flashing temperatures. Though rare, three-peaked flashes do appear from male specimens of both these species, and decay times of all the three peaks in a male- or a female-flash come out to be a few tens of, or a hundred-odd, milliseconds - in contrast to the nanosecond lifetimes determined by different workers for different analogs of the light emitter molecule oxyluciferin. We propose that the tri-modal feature in a flash represents three luminescent forms of the excited state of oxyluciferin, which in the normal flashing state in the living firefly decays via a pathway followed by molecules exhibiting phosphorescence.

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.

Modulations in the light of the firefly.

Continuous light could be produced from the firefly by making it inhale vapours of ethyl acetate. Here we perform such a control experiment on the Indian species of the firefly Luciola praeusta Kiesenwetter 1874 (Coleoptera : Lampyridae : Luciolinae), and analyse the light in the microsecond time scale. The amplitude of the continuous train of triangular pulses is apparently altered in accordance with the instantaneous values of a hypothetical signal, which exhibits pulse amplitude modulation (PAM). In addition to sampling in amplitude, this scheme apparently provides sampling in time, representing pulse width modulation (PWM). A Fourier transform spectrum of this waveform shows the 'carrier' frequency and the accompanying 'side bands'.

Firefly flashing under strong static magnetic field.

Firefly flashing has been the subject of numerous scientific investigations. Here we present in vivo flashes from male specimens of three species of fireflies-two Japanese species Luciola cruciata, Luciola lateralis and one Indian species Luciola praeusta-positioned under a superconducting magnet. When the OFF state of the firefly becomes long after flashing in an immobile state under the strong static magnetic field of strength 10 Tesla for a long time, which varies widely from species to species as well as from specimen to specimen, the effect of the field becomes noticeable. The flashes in general are more rapid, and occasionally overlap to produce broad compound flashes. We present the broadest flashes recorded to date, and propose that the strong static magnetic field affects the neural activities of fireflies, especially those in the spent up or 'exhausted' condition.

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.

Interaction of a laser beam with the rotational lines of nitrogen in the wavelength region of 5700 A.

Propagation of a dye laser beam of wavelength 5700 A through nitrogen is considered. Values of transmittance, averaged over intervals of 0.5 cm(-1), are obtained for absorber thicknesses of 0.1, 1, and 10 atm-cm, using the quasi-random model of molecular band absorption. From these values, intensities of the absorption lines in the first positive system of N(2) are simulated in the frequency interval of 17,540-17,548 cm(-1).