Disentangling the effects of neutral and adaptive processes in maintaining phenotypic variation across environmental gradients is challenging in natural populations. Song sparrows (
Animal signals evolve in an ecological context. Locally adapting animal sexual signals can be especially important for initiating or reinforcing reproductive isolation during the early stages of speciation. Previous studies have demonstrated that dewlap colour in
- Award ID(s):
- 1927194
- NSF-PAR ID:
- 10445476
- Publisher / Repository:
- Oxford University Press
- Date Published:
- Journal Name:
- Journal of Evolutionary Biology
- Volume:
- 35
- Issue:
- 5
- ISSN:
- 1010-061X
- Format(s):
- Medium: X Size: p. 680-692
- Size(s):
- ["p. 680-692"]
- Sponsoring Org:
- National Science Foundation
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Abstract Colours relay information to conspecifics and predators unique to an environment and are shaped by natural selection favouring colours that enable higher fitness. For decades, ecologists have grappled with various methods of quantifying colour. Spectrophotometers offer precise and accurate data, but their high price limits accessibility. Here we test the validity of an accessible method of quantifying colour. We analysed photographs from four species of Anolis lizards from urban and forest habitats. We compared dewlap colour in order to determine if photographic analysis can detect inter- and intraspecific differences with the same power as a spectrophotometer. We hypothesized that photographs would capture colour data comparable to a spectrophotometer within the visible light range, and that habitat divergence would be associated with intraspecific differences in dewlap. We demonstrate, as hypothesized, that photographic colour data are consistent with spectrophotometer data and capable of differentiating dewlap variation within the visible light spectrum. Differences in colour between urban and forest populations were significant for some but not all species, and the part of the colour spectrum that shifted was not consistent across species. Our results support photographic analysis as an alternative for quantifying colour to study both inter- and intraspecific variation in visible colour.
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Premise The drivers of isolation between sympatric populations of long‐lived and highly dispersible conspecific plants are not well understood. In the Hawaiian Islands, the landscape‐dominant tree,
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M. polymorpha var.newellii observed previously.Conclusions These findings suggest that disruptive selection across a sharp ecotone contributes to the maintenance of an incipient riparian ecotype from within a continuous population of a long‐lived and highly dispersible tree species.
