Performance of blue- and green-sensitive photoreceptors of the cricket Gryllus bimaculatus

J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2014 Mar;200(3):209-19. doi: 10.1007/s00359-013-0879-6. Epub 2014 Jan 8.

Abstract

The compound eye of the cricket Gryllus bimaculatus contains a specialized dorsal rim area (DRA) populated by distinct blue-sensitive photoreceptors responsible for perception of polarized light. The rest of the eye is dominated by green-sensitive photoreceptors. Using patch clamp we studied dissociated ommatidia of nocturnal adults and diurnal eight-instar nymphs with the goals (1) of characterizing the biophysical properties of cricket photoreceptors in general and (2) describing the functionally dissimilar blue- and green-sensitive photoreceptors in terms of voltage-gated channel composition and signal coding. Despite different lifestyles, adult and nymph photoreceptors were indistinguishable. No significant circadian changes were observed in K⁺ currents. In contrast, prominent differences were seen between blue- and green-sensitive photoreceptors. The former were characterized by relatively low absolute sensitivity, high input resistance, slow quantum bumps with long latencies, small light-induced and K⁺ currents and low steady-state depolarization. Information rate, a measure of photoreceptor performance calculated from voltage responses to bandwidth-limited white noise-modulated light contrast, was 87 ± 8 bits s⁻¹ in green-sensitive photoreceptors vs. 59 ± 14 bits s⁻¹ in blue-sensitive photoreceptors, implying a limited role of DRA in the perception of visual contrasts. In addition, evidence of electrical coupling between photoreceptors is presented.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biophysics
  • Color Perception / physiology*
  • Color*
  • Electric Stimulation
  • Gryllidae / anatomy & histology*
  • Gryllidae / physiology
  • Light
  • Membrane Potentials / physiology
  • Patch-Clamp Techniques
  • Photic Stimulation
  • Photoreceptor Cells, Invertebrate / physiology*
  • Potassium / metabolism
  • Reaction Time
  • Spectrum Analysis

Substances

  • Potassium