Unexpectedly low UV-sensitivity in a bird, the budgerigar.
Photoreceptor adaptation ensures appropriate visual responses during changing light conditions and contributes to colour constancy. We used behavioural tests to compare UV-sensitivity of budgerigars after adaptation to UV-rich and UV-poor backgrounds. In the latter case, we found lower UV-sensitivity than expected, which could be the result of photon-shot noise corrupting cone signal robustness or nonlinear background adaptation. We suggest that nonlinear adaptation may be necessary for allowing cones to discriminate UV-rich signals, such as bird plumage colours, against UV-poor natural backgrounds.
Department of Biology, Lund University, SE-221 00 Lund, Sweden.
Johanna
J
Chavez
Department of Biology, Lund University, SE-221 00 Lund, Sweden.
Almut
http://orcid.org/0000-0003-3937-2808
A
Kelber
Department of Biology, Lund University, SE-221 00 Lund, Sweden.
Misha
M
Vorobyev
Department of Biology, Lund University, SE-221 00 Lund, Sweden olle.lind@lucs.lu.se.
Olle
O
Lind
D000818:Animals; D008027:Light; D008297:Male; D046408:Melopsittacus / Q000502:physiology*; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology*; D014466:Ultraviolet Rays; D014796:Visual Perception
UV-vision; bird senses; colour constancy; receptor adaptation; spectral sensitivity