Effects of the colour of photophase light on locomotor activity in a nocturnal and a diurnal South African rodent

Ingrid Van Der Merwe, Nigel C. Bennett, Abraham Haim, Maria K. Oosthuizen

Research output: Contribution to journalArticlepeer-review


Many physiological and behavioural responses to varying qualities of light, particularly during the night (scotophase), have been well documented in rodents. We used varying wavelengths of day-time (photophase) lighting to assess daily responses in locomotor activity in the nocturnal Namaqua rock mouse (Micaelamys namaquensis) and diurnal four-striped field mouse (Rhabdomys pumilio). Animals were exposed to three light–dark cycle regimes: a short-wavelength- (SWLC, blue), a medium-wavelength-(MWLC, green) and a long-wavelength light–dark cycle (LWLC, red). Overall, daily locomotor activity of both species changed according to different wavelengths of light: the diurnal species displayed most activity under the SWLC and the nocturnal species exhibited the highest levels of activity under the LWLC. Both species showed an increase in diurnal activity and a decrease in nocturnal activity under the LWLC. These results indicate an attenuated responsiveness to long-wavelength light in the nocturnal species, but this does not appear to be true for the diurnal species. These results emphasize that the effect of light on the locomotor activity of animals depends on both the properties of the light and the temporal organization of activity of a species.

Original languageEnglish
Article number20190597
JournalBiology Letters
Issue number10
StatePublished - 1 Oct 2019
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2019 The Author(s) Published by the Royal Society. All rights reserved.


  • Diurnal
  • Locomotor activity
  • Micaelamys namaquensis
  • Nocturnal
  • Photophase wavelength
  • Rhabdomys pumilio

ASJC Scopus subject areas

  • General Agricultural and Biological Sciences
  • Agricultural and Biological Sciences (miscellaneous)


Dive into the research topics of 'Effects of the colour of photophase light on locomotor activity in a nocturnal and a diurnal South African rodent'. Together they form a unique fingerprint.

Cite this