A cute and highly contrast-sensitive superposition eye: The diurnal owlfly Libelloides macaronius
| Autor: | Primož Pirih, Gregor Belušič, Doekele G. Stavenga |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2013 |
| Předmět: |
Microscope
Insecta genetic structures Physiology INSECTS Signal-To-Noise Ratio law.invention Root mean square DESIGN law Contrast (vision) media_common Dynamic range NEUROPTERA Achromatic lens Female Photoreceptor Cells Invertebrate UV sensitivity LIMITATIONS Ascalaphus MANTISPA-STYRIACA acceptance angle COMPOUND EYES Ultraviolet Rays media_common.quotation_subject sky contrast APPOSITION EYES interommatidial angle superposition pupil Aquatic Science Biology Contrast Sensitivity Superposition principle Optics OMMATIDIA Animals Compound Eye Arthropod Molecular Biology Ecology Evolution Behavior and Systematics business.industry photoreceptor eye diseases Light intensity Insect Science Animal Science and Zoology Acceptance angle sense organs DORSAL EYE OPTICS business |
| Zdroj: | Journal of Experimental Biology, 216(11), 2081-2088. COMPANY OF BIOLOGISTS LTD |
| ISSN: | 0022-0949 |
| Popis: | Summary The owlfly Libelloides macaronius (Insecta: Neuroptera) has large bipartite eyes of the superposition type. The spatial resolution and sensitivity of the photoreceptor array in the dorsofrontal eye part was studied with optical and electrophysiological methods. Using structured illumination microscopy, the interommatidial angle in the central part of the dorsofrontal eye was determined to be Δφ = 1.1°. Eye shine measurements with an epi-illumination microscope yielded an effective superposition pupil size of about 300 facets. Intracellular recordings confirmed that all photoreceptors were UV-receptors (λmax = 350 nm). The average photoreceptor acceptance angle was 1.8°, with a minimum of 1.4°. The receptor dynamic range was two log units, and the Hill coefficient of the intensity-response function was n = 1.2. The signal-to-noise ratio of the receptor potential was remarkably high and constant across the whole dynamic range (RMS noise = 0.5% Vmax). Quantum bumps could not be observed at any light intensity, indicating low voltage gain. Presumably, the combination of large aperture superposition optics feeding an achromatic array of relatively insensitive receptors with a steep intensity-response function creates a low-noise, high-spatial-acuity instrument. The sensitivity shift to the UV range reduces the contrasts within the sky image. These properties of the visual system are optimal for detecting small insect prey as contrasting spots against both clear and cloudy skies. |
| Databáze: | OpenAIRE |
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