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

2005 ◽  
Vol 208 (10) ◽  
pp. 1803-1815 ◽  
Author(s):  
P. Sumner
Keyword(s):  
Visual Pigment ◽  
Australian Marsupial ◽  
Honey Possum

Redefining the activity pattern of the honey possum (Tarsipes rostratus).

2001 ◽  
Vol 23 (2) ◽  
pp. 169 ◽  
Author(s):  
C Arrese ◽  
PB Runham
Keyword(s):  
Activity Pattern ◽  
Activity Patterns ◽  
Diurnal Activity ◽  
Numerous Species ◽  
Daytime Activity ◽  
In Captivity ◽  
In The Wild ◽  
Australian Marsupial ◽  
Diurnal Species ◽  
Honey Possum

ANIMALS are commonly separated into two major categories based on their activity patterns: diurnal and nocturnal. However, evidence of numerous species exhibiting diverse periods of activity, including arhythmic and crepuscular habits, broadens the description. The honey possum (Tarsipes rostratus), a small West-Australian marsupial feeding exclusively on nectar and pollen, has been described as strongly nocturnal (Wooller et al. 1981; Russell and Renfree 1989). However, infrequent daytime activity in captivity (Russell 1986) and in the wild under cold, cloudy conditions, has been reported (Hopper and Burbidge 1982; du Plessis and du Plessis 1995). During trapping exercises in the region of Jurien Bay (250 km north of Perth, Western Australia), several animals were observed foraging after sunrise and before sunset, with occasional diurnal activity. To date, no study has investigated directly the activity periods of the species. Furthermore, studies of the visual capabilities of T. rostratus revealed that its retinal organisation is not compatible with a nocturnal lifestyle, but presents features comparable to those found in diurnal species (Arrese 2002; Arrese et al. 2002). Such discrepancies warranted the monitoring of activity periods (rhythmicity) of T. rostratus in its natural environment, a study reported here. We discuss our results in the context of the visual ecology of the species.

First identification and localization of a visual pigment in Hydra (Cnidaria, Hydrozoa)

2001 ◽  
Vol 187 (1) ◽  
pp. 79-81 ◽  
Author(s):  
C. Musio ◽  
S. Santillo ◽  
C. Taddei-Ferretti ◽  
L.J. Robles ◽  
R. Vismara ◽  
...  
Keyword(s):  
Visual Pigment

Insights from a lost visual pigment

1997 ◽  
Vol 15 (2) ◽  
pp. 115-117 ◽  
Author(s):  
Gabriel H. Travis
Keyword(s):  
Visual Pigment

scholarly journals Direct Action of Light in Naturally Pigmented Muscle Fibers

1962 ◽  
Vol 46 (2) ◽  
pp. 333-342 ◽  
Author(s):  
Howard H. Seliger
Keyword(s):  
Visual Pigment ◽  
Absorption Maximum ◽  
Pupil Diameter ◽  
Direct Action ◽  
Pigment Epithelium ◽  
Action Spectrum ◽  
Square Root ◽  
Light Reaction ◽  
First Order ◽  
Iris Sphincter

Contraction due to light in excised eel irises appears to follow a simple first order law. The action spectrum for contraction has a maximum which agrees with the eel rhodopsin absorption maximum. Inasmuch as rhodopsin is the rod pigment-opsin complex and the iris sphincter pupillae evolves from the pigment epithelium of the retina in the region of the iris, the muscle pigment might be the same as the visual pigment. In the human eye the contraction of the iris sphincter is activated only by light incident on the retina and the pupil diameter varies inversely with the square root of the light intensity. The inverse first power relation observed in the present experiments suggests a more primitive origin for the light reaction in eel irises. Relaxation is a much slower process and can be approximated as the sum of two first order processes.

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