Javascript is not activated in your browser. This website needs javascript activated to work properly.
You are here

Induced tolerance expressed as relaxed behavioural threat response in millimetre-sized aquatic organisms.

  • Samuel Hylander
  • Mikael Ekvall
  • Giuseppe Bianco
  • Xiuhong Yang
  • Lars-Anders Hansson
Publishing year: 2014
Language: English
Publication/Series: Royal Society of London. Proceedings B. Biological Sciences
Volume: 281
Issue: 1788
Document type: Journal article
Publisher: Royal Society

Abstract english

Natural selection shapes behaviour in all organisms, but this is difficult to study in small, millimetre-sized, organisms. With novel labelling and tracking techniques, based on nanotechnology, we here show how behaviour in zooplankton (Daphnia magna) is affected by size, morphology and previous exposure to detrimental ultraviolet radiation (UVR). All individuals responded with immediate downward swimming to UVR exposure, but when released from the threat they rapidly returned to the surface. Large individuals swam faster and generally travelled longer distances than small individuals. Interestingly, individuals previously exposed to UVR (during several generations) showed a more relaxed response to UVR and travelled shorter total distances than those that were naive to UVR, suggesting induced tolerance to the threat. In addition, animals previously exposed to UVR also had smaller eyes than the naive ones, whereas UVR-protective melanin pigmentation of the animals was similar between populations. Finally, we show that smaller individuals have lower capacity to avoid UVR which could explain patterns in natural systems of lower migration amplitudes in small individuals. The ability to change behavioural patterns in response to a threat, in this case UVR, adds to our understanding of how organisms navigate in the 'landscape of fear', and this has important implications for individual fitness and for interaction strengths in biotic interactions.


  • Ecology


  • Centre for Animal Movement Research
  • ISSN: 1471-2954
Lars-Anders Hansson
E-mail: lars-anders [dot] hansson [at] biol [dot] lu [dot] se


Aquatic ecology

+46 46 222 41 69






Research group

Aquatic Ecology

Other projects I´m involved in

Doctoral students and postdocs

PhD students, main supervisor

Downloads & links