Purchase this article with an account.
B. Müller, L. Peichl; Retinal Cone Photoreceptors in Microchiropteran Bats . Invest. Ophthalmol. Vis. Sci. 2005;46(13):2259.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose: The echolocating microchiropteran bats (microbats) are strongly nocturnal. Their eyes are commonly small, and older work has claimed pure rod retinae in some species. Our comparative study across microbat superfamilies aims at elucidating their photoreceptor complements and their prospects for cone–based vision, including colour vision. Methods: We studied 20 species from the superfamilies Emballonuridea (2), Rhinolopoidea (6), Phyllostomoidea (2) and Vespertilionidea (10). Eyes were obtained from animals sacrificed for unrelated studies (provided by S.M. Goodman, Chicago; M. Kössl, Frankfurt/M., Germany; K. Esser, Hannover, Germany). In paraformaldehyde–fixed retinae, middle–to–long–wave sensitive L–cones and short–wave sensitive S–cones were assessed using the L–opsin specific antiserum JH492 and the S–opsin specific antiserum JH455 (provided by J. Nathans). Rod densities were assessed by conventional histology. Results: The retinae of all studied species are rod–dominated but possess substantial cone populations. All vespertilionids and emballonurids have L–cones and S–cones. Depending on the species, L–cone densities ranged from 5.000/mm² to 10.000/mm² and S–cone densities from 1.000/mm² to 5.000/mm². L–/S–cone ratios were around 2:1. These species have the cone basis for dichromatic colour vision. In contrast, the six studied rhinolopoids had L–cones but showed no S–opsin immunoreactivity, indicating L–cone monochromacy. Of the two phyllostomoids studied, one had both cone types, the other only L–cones. A limited assessment in some species revealed rod densities of 130.000/mm² to 330.000/mm² across species. Conclusions: All studied microbats possess cones in addition to rods. Actually, our data indicate lower rod densities and higher cone proportions than found in many other nocturnal mammals. It appears that the eyes of microbats have adapted to somewhat higher light levels and may be useful for visual orientation at dusk and dawn. Behavioral studies have shown that vision is important in various bat activities. Most species appear to be conventional cone dichromats. The absence of S–cones in some bats indicates species–specific and perhaps superfamily–specific differences in visual capabilities.
This PDF is available to Subscribers Only