QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online May 5, 2005
Journal of Experimental Biology 208, 1803-1815 (2005)
Published by The Company of Biologists 2005
doi: 10.1242/jeb.01610

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Related articles in JEB Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Sumner, P. Articles by Partridge, J. C. Search for Related Content PubMed PubMed Citation Articles by Sumner, P. Articles by Partridge, J. C.

The ecology of visual pigment tuning in an Australian marsupial: the honey possum Tarsipes rostratus

Petroc Sumner^1,*, Catherine A. Arrese² and Julian C. Partridge³

¹ Department of Visual Neuroscience, Division of Neuroscience, Faculty of Medicine, Imperial College London, St Dunstan's Road, London W6 8RP, UK
² School of Animal Biology, University of Western Australia, Crawley, WA 6009, Australia
³ School of Biological Sciences, University of Bristol, Bristol, BS8 1UG, UK

^* Author for correspondence (e-mail: p.sumner{at}imperial.ac.uk)

Accepted 16 March 2005

While most mammals have no more than two types of cone photoreceptor, four species of Australian marsupial have recently been shown to possess three types, and thus have the potential for trichromatic colour vision. Interestingly, the long-wave cones of the honey possum Tarsipes rostratus are tuned to longer wavelengths than those of the other species measured to date. We tested whether the honey possum's long-wave tuning is adaptive for visual tasks associated with its almost unique diet of nectar and pollen. We modelled three tasks: (1) detecting food-rich `target' flowers against their natural background of foliage or other vegetation; (2) discriminating target flowers from flowers of non-target species; (3) discerning the maturity of the most important target flowers. Initial comparisons of trichromacy vs dichromacy generally favoured the former, but interestingly dichromacy was no disadvantage in some cases. For tuning, we found that overall the honey possum's long-wave tuning is more adaptive than that of the other marsupial species. Nevertheless, the optimal tuning for tasks 1 and 2 would be at longer wavelengths still, implying that a different pressure or constraint operates against a further long-wave shift of the honey possum's L cone tuning. Our data show that a possible ecological pressure may be provided by the third task - the difficult and potentially critical discrimination of the maturity of the animal's major food supply, the flowers of Banksia attenuata.

Key words: colour vision, ecology of vision, trichromacy, dichromacy, mammal, long wave cone, middle wave cone, optimisation

Related articles in JEB:

THE COLOUR OF DINNER

Yfke van Bergen
JEB 2005 208: iii. [Full Text]  

This article has been cited by other articles:

				Y. van Bergen THE COLOUR OF DINNER J. Exp. Biol., May 15, 2005; 208(10): iii - iii. [Full Text] [PDF]