Cell and Tissue Research

, Volume 232, Issue 1, pp 53–63

Zonation of the optical environment and zonation in the rhabdom structure within the eye of the backswimmer, Notonecta glauca

  • Rudolf Schwind

DOI: 10.1007/BF00222373

Cite this article as:
Schwind, R. Cell Tissue Res. (1983) 232: 53. doi:10.1007/BF00222373


In the compound eye of Notonecta glauca, the backswimmer, there is a small ventral region in which the rhabdoms differ in structure from those in the other parts of the eye. Here, among other unusual features, there is a special orientation of the microvilli of the central rhabdomeres, i.e., in most of the median eye region that has been examined, the microvilli of the two central rhabdomeres are aligned with one another, at an acute angle to the transverse axis of the body. In the small ventral region, the microvilli of these rhabdomeres are perpendicular to one another, those of one rhabdomere being almost exactly in parallel with the median plane of the animal, and those of the other, almost exactly at right angles to the median plane.

When Notonecta is hanging under the water surface, the field of vision of the ventral part of the eye coincides with the transparent part of the water surface. Within the ventral eye region there is a bandlike zone only four ommatidia wide; the ommatidia here differ from the others in the ventral eye region by the unique orientation of their central rhabdomeres. With this zone the animal views the area ahead of it just above the water surface. When the backswimmer is flying, the ventral part of the eye views a region that begins under the animal and extends forward from the vertical over ca. 35 °. Possible relationships between the special orientation of the microvilli in the ventral eye region and the polarization of the light by the water surface are discussed.

Key words

Insect retinaNotonectaCompound eyeMicrovilliEye zones

Copyright information

© Springer-Verlag GmbH & Co. KG 1983

Authors and Affiliations

  • Rudolf Schwind
    • 1
  1. 1.Institut für Zoologie, Universität RegensburgRegensburgBundesrepublik Deutschland
  2. 2.Institut für Zoologie der Universität RegensburgRegensburgGermany