The planarian flatworm is one of the simplest animals to develop two eyecups that enable them to detect the presence and direction of light, which they typically avoid. In this study we assessed responses of planaria to different intensities of light. We found that they exhibited a graded, sigmoidal, photonegative response to light intensity. A two-octave increase in luminance (on the upward slope of the sigmoid) corresponded to a 9% increase in the speed planaria travelled to avoid light.
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References
1.
AzumaKIwasakiNOhtsuK, 1998“Absorption spectra of planarian visual pigments and two states of metarhodopsin intermediates”Photochemistry and Photobiology6999–104
2.
BrownH MItoHOgdenT E, 1968“Spectral sensitivity of the planarian ocellus”Journal of General Physiology51255–260
3.
DasheiffB DDasheiffR M, 2001“Photonegative response in brown planaria (Dugesia tigrina) following regeneration”Ecotoxicology and Environmental Safety53196–199
4.
EgethM, 2011“Behavioral responses to light by headless anesthetized Drosophila melanogaster”Perception40247–248
5.
GriffardC DPeirceJ T, 1964“Conditioned discrimination in the planarian”Science1441472–1473
6.
InoueTKumamotoHOkamotoKUmesonoYSakaiMAlvaradoA SAgataK, 2004“Morphological and functional recovery of the planarian photosensing system during head regeneration”Zoological Science21275–283
7.
MarriottF H C, 1958“The absolute light-sensitivity and spectral threshold curve of the aquatic flatworm Dendrocoelum lacteum”Journal of Physiology (London)143369–379
8.
Van DeventerJ MRatnerS C, 1964“Variables affecting the frequency of response of planaria to light”Journal of Comparative and Physiological Psychology57407–411
9.
XiangYYuanQVogtNLoogerLJanLJanY, 2010“Light avoidance-mediating photoreceptors tile the Drosophila larval body wall”Nature468921–926
