Original Paper

Cone Photoreceptor Diversity in the Retinas of Fruit Bats (Megachiroptera)
Brigitte Müller^a, Steven M. Goodman^{b, c}, Leo Peichl<sup>a

a</sup>Max Planck Institute for Brain Research, Frankfurt am Main, Germany;
^bField Museum of Natural History, Chicago, Ill., USA;
^cWWF, Antananarivo, Madagascar

Address of Corresponding Author

Brain Behav Evol 2007;70:90-104 (DOI: 10.1159/000102971)

  Key Words

• Megachiroptera
• Fruit bats
• Flying foxes
• Retina
• Photoreceptors
• Cone opsins
• Visual pigments
• Color vision

  Abstract

Older studies have claimed that bats including the Megachiroptera (fruit bats or flying foxes) have pure-rod retinas and possess no cone photoreceptors. We have determined the presence and the population densities of spectral cone types in six megachiropteran species belonging to four genera: Pteropus rufus, P. niger, P. rodricensis, Rousettus madagascariensis, Eidolon dupreanum, and Epomophorus gambianus. Spectral cone types and rods were assessed immunocytochemically with opsin-specific antibodies. All six species have rod-dominated retinas but possess significant cone populations. The high rod densities (range 350,000-800,000/mm², depending on species and retinal location) provide good scotopic sensitivity in these predominantly nocturnal animals. With the cones (density range 1,300-11,000/mm², corresponding to 0.25-0.6% of the photoreceptors, depending on species and retinal location) the retinas also possess the prerequisite for vision at photopic light levels. The three Pteropus species have two spectral cone types, a majority of middle-to-long-wave sensitive (L-) cones, and a minority of short-wave sensitive (S-) cones, indicating the potential for dichromatic color vision. This conforms to the pattern found in most mammals. In contrast, Rousettus, Eidolon and Epomophorus have L-cones but completely lack S-cones, indicating cone monochromacy and color blindness. The discussion relates these findings to the visual behavior of fruit bats.

Copyright © 2007 S. Karger AG, Basel

  Author Contacts

Dr. Brigitte Müller
Max Planck Institute for Brain Research, Deutschordenstrasse 46
DE-60528 Frankfurt (Germany)
Tel. +49 69 96769 236, Fax +49 69 96769 206
E-Mail bmueller@mpih-frankfurt.mpg.de

  Article Information

Received: August 24, 2006
Accepted after revision: November 13, 2006
Returned for revision: September 24, 2006
Published online: May 18, 2005
Number of Print Pages : 15
Number of Figures : 7, Number of Tables : 1, Number of References : 52