Abstract
In previous studies, regional structural variations in the firefly compound eye were described.(1,2) These variations prompted us to conduct electrophysiological experiments to record and correlate neural activity in the optic lobes of Photuris firefly evoked in response to light flash directed at specific region of the compound eye. Electrophysiology was used to relate activity in the firefly visual neuro-sensory system to the eye structure. Electrophysiological responses obtained from optic lobes of the nocturnal Photuris fireflies in response to wavelength and region specific stimuli showed that they have a maximum spectral sensitivity in the green spectrum (lambda central = 540 nm). These findings suggested variations of visual performance across the eye of the Photuris sp. firefly. The variation in the visually-evoked potential (EP) recordings from optic lobes (OL) in response to fixed intensity of light stimuli was not related to the facet size of the omitidial lens except in the central region. The variation in the evoked potential (EP) recordings from optic lobes (OL) in response to region-specific stimulus showed a correlation with facet size. The regional facet size was seen to be positively associated with region-specific EP amplitudes (r = +0.56). On the other hand there was no correlation of the facet size with region-specific EP latency. The electrophysiological experiments in Photuris sp. indicate various EP activities in response to stimulus intensity, wavelength, and region in the firefly compound eye. Within study sample, neural activities, light adaptation in photoreceptors, and latency versus each eye (region (facet size) are presented here to investigate the regional variations in the compound eye. This study illustrates the effectiveness of applying a bioengineering system for analyzing visual performance in the compound eyes which reflect their visual behavior and specialization.