The physiology of neural tissue is greatly shaped by information processing efficiency vs. energy cost trade-offs. A good model for studies of energy demands with respect to sensory performance is the insect eye due to its relatively simple repetitive structure and easiness of genetic manipulation (e.g. Niven et al., 2007). In our study we examined the metabolic and electrical properties of Calliphora vicina (white-eyed strain chalky) photoreceptors with respect to their ontogenetic plasticity. We employed in vivo spectrophotometric measurements (Zupančič, 2003) to asses the metabolic activity of mitochondria in blowfly photoreceptors. By analyzing the differential absorption spectra recorded from the eyes under normoxic and anoxic conditions we estimated the dynamic range of redox states of electron transport chain components (haems in cytochromes: a, a3, b and c). We found that the range of redox states increased with post-eclosion age in all studied haems. The largest change was found in the first week. We attributed the change mostly to the changes in cytochromes’ (Cyt) concentration, which we confirmed by biochemical analysis of the Cyt c content in isolated retinal mitochondria in flies of different age. The results were in good agreement with our spectrophotometric measurements, showing a 5-fold increase in Cyt c concentration in the first two weeks post eclosion. Long-term light adaptation profoundly influenced the performance of mitochondria. The changes in haems’ dynamic redox range were significantly smaller in dark-bred animals (e.g. 2.9-fold increase for haem c in the first two weeks) compared to animals bred under 12/12h day/night cycle (4.8-fold increase).This implies that lower metabolic load results in smaller ontogenetic changes in the metabolic capacity of the photoreceptors. The maintenance of ion gradients over the membrane was shown to be the primary energy sink in the insect photoreceptors (Laughlin et al., 1998). Thus, we expected the plasticity of photoreceptors’ electrical properties to follow a similar ontogenetic time course as the one observed in the mitochondrial apparatus. We employed single electrode voltage- and current-clamp to compare the electrical parameters (cell resistance and capacitance) of blowfly photoreceptors at different age and rearing conditions. We observed significant differences in resting cell capacitance between age groups with a peak at 2 weeks after eclosion, but small changes in the resting conductance of photoreceptor cells. Our findings indicate the existence of relevant age related changes in both studied aspects of the photoreceptor’s functionality.