City Research Online

Abstract

The spectral characteristics of vertebrate ocular lenses affect the image of the world that is projected onto the retina, and thus help shape diverse visual capabilities. Here, we tested whether amphibian lens transmission is driven by adaptation to diurnal activity (bright light) and/or scansorial habits (complex visual environments).
Spectral transmission through the lenses of 79 species of frogs and six species of salamanders was measured, and data for 29 additional frog species compiled from published literature. Phylogenetic comparative methods were used to test ecological explanations of variation in lens transmission and to test for selection across traits.
Lenses of diurnal (day-active) and scansorial (climbing) frogs transmitted significantly less shortwave light than those of non-diurnal or non-scansorial amphibians, and evolutionary modelling suggested that these differences have resulted from differential selection.
The presence of shortwave-transparent lenses was common among the sampled amphibians, which implies that many are sensitive to shortwave light to some degree even in the absence of visual pigments maximally sensitive in the UV. This suggests that shortwave light, including UV, could play an important role in amphibian behaviour and ecology.
Shortwave-absorbing lens pigments likely provide higher visual acuity to diurnally active frogs of multiple ecologies and to nocturnally active scansorial frogs. This new mechanistic understanding of amphibian visual systems suggests that shortwave-filtering lenses are adaptive not only in daylight conditions but also in those scotopic conditions where high acuity is advantageous.

Publication Type:	Article
Additional Information:	This is the peer reviewed version of the following article: Thomas, K. N., Gower, D. J., Streicher, J. W. , Bell, R. C., Fujita, M. K., Schott, R. K., Liedtke, H. C., Haddad, C. F. B., Becker, C. G., Cox, C. L., Martins, R. A. & Douglas, R. H. (2022). Ecology drives patterns of spectral transmission in the ocular lenses of frogs and salamanders. Functional Ecology, 36(4), pp. 850-864, which has been published in final form at https://doi.org/10.1111/1365-2435.14018. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.
Publisher Keywords:	activity period, Anura, Caudata, diurnal, scansorial, sensitivity, vision, UV
Subjects:	Q Science > QH Natural history > QH301 Biology R Medicine > RE Ophthalmology
Departments:	School of Health & Psychological Sciences > Optometry & Visual Sciences

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