Diurnal variations in natural light conditions at summer time in arctic and subarctic areas in relation to light detection in insects

• Published in: Ecography
• Main Authors: Nordtug, Trond, Mela, Thor Bernt
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1988
• Subjects: Ecology, Evolution, Behavior and Systematics; Arctic; Norway; Subarctic
• Online Access: http://dx.doi.org/10.1111/j.1600-0587.1988.tb00802.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1600-0587.1988.tb00802.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1600-0587.1988.tb00802.x

Measurements of daily variations in the intensity, spectral composition and polarization of the direct and the indirect sunlight are presented, and the physics of light propagation through the atmosphere is discussed. Observations of daily changes in these properties of the skylight are presented from two different locations in Norway. Probable adaptations of the light detection systems of insects living at high latitudes are predicted from the observations. The adaptation processes under consideration are (1) changes in the light absorption characteristics of the visual pigments, (2) changes in the visual sensitivity to light and (3) a switch in Zeitgeber from the daily intensity changes to changes in the spectral comptisition of the light in polar regions. It is shown that in particular the intensity ratio between the ultraviolet and the green part of the diffuse light is well suited as a Zeitgeber for insects living at high latitudes.