| | 1 | Author
| Kuno Kirschfeld | Requires cookie* | | | Title
| The Absolute Sensitivity of Lens and Compound Eyes  | | | | Abstract
| The numbers of light quanta available to photoreceptors of lens-and different types of com pound eyes are calculated on the basis of photometric considerations. It is shown that the results depend upon the situation in the optical environment: For point-like lightsources such as stars receptors in compound eyes generally receive considerably less numbers of light quanta compared n. g. with the human eye. This is due to the small sizes of the ommatidial facets. For extended optical surroundings, however, the numbers of quanta reaching the receptors in typical insect compound eyes of the apposition type are comparable to those in the human eye. In this respect the optical superposition eye of nocturnal insects like E ph estia is an exceptional case, where there is an improvement in the numbers of quanta reaching the receptors by a factor 100 to 1000 com pared to the eyes of bee or man. | | | |
Reference
| (Z. Naturforsch. 29c, 592 [1974]; received July 10 1974) | | | |
Published
| 1974 | | | |
Keywords
| Lens Eyes, Compound Eyes, Absolute Sensitivity | | | |
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| default:Reihe_C/29/ZNC-1974-29c-0592.pdf | | | | Identifier
| ZNC-1974-29c-0592 | | | | Volume
| 29 | |
| 2 | Author
| EricJ W Arrant, RobertB. Pinter | Requires cookie* | | | Title
| | | | | Abstract
| Intracellular recordings o f angular sensitivity from the photoreceptors o f Aeschnid dragonflies (Hemianax papuensis and Aeschna brevistyla) are used to determine the magnitude and time course o f acuity changes follow ing alterations o f the state o f light or dark adaptation. Acuity is defined on the basis o f the acceptance angle, A q (the half-width o f the angular-sensitivity function). The maximally light-adapted value o f A q is half the dark-adapted value, indicating greater acuity during light adaptation. Following a change from light to dark adaptation, A q increases slowly, requiring at least 3 min to reach its dark-adapted value. In contrast, the reverse change (dark to light) induces a rapid reduction o f A q , and at maximal adapting luminances, this reduction takes place in less than 1 0 sec. | | | |
Reference
| Z. Naturforsch. 45c, 137—141 (1990); received September 14 1989 | | | |
Published
| 1990 | | | |
Keywords
| Compound Eye, Adaptation, Photoreceptors, Spatial Acuity, Dragonfly | | | |
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| default:Reihe_C/45/ZNC-1990-45c-0137_n.pdf | | | | Identifier
| ZNC-1990-45c-0137_n | | | | Volume
| 45 | |
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