Fig. 7. A trade-off between energy efficiency and information coding in insect photoreceptors. The information rates (bits s^–1) versus the energy efficiency of information transmission (ATP molecules bit^–1x10⁶) of photoreceptors from four fly species (smallest to largest): Drosophila melanogaster, D. virilis, Calliphora vicina and Sarcophaga carnaria. Larger photoreceptors can transmit higher rates of information but are less energy efficient. Adapted from Niven et al. (Niven et al., 2007).