Bauer Thomas, Brauner Ulrike, Fischerleitner Edith
Abteilung Ökologie und Morphologie der Tiere der Universität Ulm, Oberer Eselsberg, D-7900, Ulm, Federal Republic of Germany.
1. Zoologisches Institut der Universität Wien, Wien, Austria.
Oecologia. 1977 Mar;30(1):63-73. doi: 10.1007/BF00344892.
Carabid species of the visually hunting type living in dim habitats have larger frontal ommatidia and gain their optimal visual performance with lower light intensity than species inhabiting bright places.The latter phenomenon is based upon the mechanisms of light adaptation, which reduce the acceptance angles of the ommatidia thus increasing their visual acuity. In more sensitive ommatidia adaptation occurs with lower light intensity.The differences between the species concerning the intensity dependence of their visual performance are regarded as an effect of natural selection. Thereafter an apposition eye more sensitive to light should be advantageous in a dim environment.This hypothesis has been investigated and verified by observation of the predation behaviour of Notiophilus biguttatus confronted with Collembola: From 1 to 500 lux the hunting success of the beetles increased proportionally to the light intensity.Measurements of the activity at dawn and at dusk under natural conditions showed that the beginning and the conclusion of activity are correlated with a critical level of illumination. Notiophilus biguttatus starts being active if the illumination is sufficient for successful hunting.
生活在昏暗栖息地的视觉捕猎型步甲物种具有更大的额小眼，并且与生活在明亮地方的物种相比，它们在较低光强度下就能获得最佳视觉性能。后一种现象基于光适应机制，该机制会减小小眼的接受角，从而提高其视觉敏锐度。在更敏感的小眼中，适应在较低光强度下发生。物种之间视觉性能对光强度的依赖性差异被视为自然选择的结果。因此，在昏暗环境中，对光更敏感的并列眼应该具有优势。通过观察双斑青步甲捕食弹尾虫的行为，对这一假设进行了研究和验证：从1勒克斯到500勒克斯，甲虫的捕猎成功率与光强度成正比。在自然条件下对黎明和黄昏时活动的测量表明，活动的开始和结束与临界光照水平相关。当光照足以成功捕猎时，双斑青步甲就开始活动。
