scholarly journals Environmental gradients predict the ratio of environmentally acquired carotenoids to self-synthesised pteridine pigments

2021 ◽  
Author(s):  
Devi Stuart-Fox ◽  
Katrina Rankin ◽  
Adrian Lutz ◽  
Adam Elliott ◽  
Andrew Hugall ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Environmental Gradients ◽  
Arid Environments ◽  
Vegetation Productivity ◽  
Colour Variation ◽  
Phylogenetic Comparative Analysis ◽  
Pigment Concentrations

Carotenoids are important pigments producing integument coloration; however, their dietary availability may be limited in some environments. Many species produce red to yellow hues using a combination of carotenoids and self-synthesised pteridine pigments. A compelling but untested hypothesis is that pteridines replace carotenoids in environments where carotenoid availability is limited. Based on a phylogenetic comparative analysis of pigment concentrations in agamid lizards, we show that environmental gradients predict the ratio of carotenoids to pteridines; carotenoid concentrations are lower and pteridine concentrations higher in arid environments with low vegetation productivity. Both carotenoid and pteridine pigments were present in all species, but only pteridine concentrations explained colour variation among species and there were no correlations between carotenoid and pteridine pigments with similar hue. These results suggest that pteridine pigments replace carotenoids in carotenoid-limited environments, irrespective of skin hue, presumably because it is metabolically cheaper to synthesise pteridines than to acquire and sequester carotenoids when carotenoids are rare.

scholarly journals Pteridine pigments compensate for environmental availability of carotenoids

2021 ◽  
Author(s):  
Devi Stuart-Fox ◽  
Katrina Rankin ◽  
Adrian Lutz ◽  
Adam Elliott ◽  
Andrew Hugall ◽  
...  
Keyword(s):  
Sexual Selection ◽  
Comparative Analysis ◽  
Skin Tissue ◽  
Honest Signalling ◽  
Colour Variation ◽  
Phylogenetic Comparative Analysis ◽  
Environmental Availability ◽  
Pigment Concentrations ◽  
Production Mechanisms

Carotenoid-based colours are a textbook example of honest signalling because carotenoids must be acquired from the environment. However, many species produce similar colours using self-synthesised pteridine pigments. A compelling but untested hypothesis is that pteridines compensate for low environmental availability of carotenoids because it is metabolically cheaper to synthesise pteridines than to acquire and sequester carotenoids. Based on a phylogenetic comparative analysis of 11 pigment concentrations in skin tissue of agamid lizards, we show that pteridine concentrations are higher and carotenoid concentrations lower in less productive environments. Both carotenoid and pteridine pigments were present in all species, but only pteridine concentrations explained colour variation among species. Furthermore, pigment concentrations were uncorrelated with indices of sexual selection. These results suggest that variation among species in pteridine synthesis compensates for environmental availability of carotenoids and challenge the paradigm of honest carotenoid signalling in vertebrates with complex colour production mechanisms.

scholarly journals Myxospermous seed-mucilage quantity correlates with environmental gradients indicative of water-deficit stress: Plantago species as a model

2019 ◽  
Vol 446 (1-2) ◽  
pp. 343-356 ◽  
Author(s):  
António Teixeira ◽  
Pietro Iannetta ◽  
Kirsty Binnie ◽  
Tracy A. Valentine ◽  
Peter Toorop
Keyword(s):  
Seed Germination ◽  
Water Deficit ◽  
Stress Responses ◽  
Environmental Gradients ◽  
Seedling Survival ◽  
Water Deficit Stress ◽  
Arid Environments ◽  
Seedling Mortality ◽  
The Relationship ◽  
Seed Mucilage

Abstract Aims Myxospermous seed mucilage is multifunctional and is often found in seeds (or achenes) of species occupying arid environments where the trait may influence seed-dispersal and -germination of seeds. The seed mucilage may also enhance soil-water retention, −hydraulic conductivity and -stability. However, the relationship between seed mucilage quantity, seed germination and seedling traits across environmental gradients which determine water-deficit stress has not yet been ascertained. Methods Therefore, we characterised and tested the relationship between seed mucilage quantity, water-deficit stress responses of seeds and seedlings of 36 accessions of four different Plantago species (P. albicans L., P. coronopus L., P. lagopus L. and P. anceolata L.). These were gathered from six regions across Europe, which presented environmental gradients (of rainfall and temperature), and varying soil qualities. Results Seed mucilage was significantly greater in seeds of accessions experiencing: highest summer temperatures; lowest summer precipitation; soils of the same warm dry regions which had greater capacity to retain water within narrow pore spaces. Under water-deficit stress, seeds with most mucilage exhibited a lower base water potential for germination, suffered least seedling mortality and exhibited the most successful seedling development. Conclusions The findings indicate that seed mucilage quantity appeared as an ‘adaptive’ trait and there is a relationship between seed-mucilage quantity, seed germination plus seedling survival and development under environmental conditions of highest water-deficit stress.

Phylogenetic comparative analysis and the secondary structure of ribonuclease P RNA — a review

Gene ◽  
1989 ◽  
Vol 82 (1) ◽  
pp. 65-75 ◽  
Author(s):  
Norman R. Pace ◽  
David K. Smith ◽  
Gary J. Olsen ◽  
Bryan D. James
Keyword(s):  
Comparative Analysis ◽  
Secondary Structure ◽  
Ribonuclease P ◽  
Phylogenetic Comparative Analysis ◽  
Ribonuclease P Rna

scholarly journals Colour dimorphism in labrid fishes as an adaptation to life on coral reefs

2020 ◽  
Vol 287 (1923) ◽  
pp. 20200167 ◽  
Author(s):  
J. R. Hodge ◽  
F. Santini ◽  
P. C. Wainwright
Keyword(s):  
Sexual Selection ◽  
Comparative Analysis ◽  
Coral Reefs ◽  
Environmental Context ◽  
Marine Fishes ◽  
Clear Water ◽  
Phylogenetic Comparative Analysis ◽  
Selective Forces ◽  
Colour Dimorphism

Conspicuous coloration displayed by animals that express sexual colour dimorphism is generally explained as an adaptation to sexual selection, yet the interactions and relative effects of selective forces influencing colour dimorphism are largely unknown. Qualitatively, colour dimorphism appears more pronounced in marine fishes that live on coral reefs where traits associated with strong sexual selection are purportedly more common. Using phylogenetic comparative analysis, we show that wrasses and parrotfishes exclusive to coral reefs are the most colour dimorphic, but surprisingly, the effect of habitat is not influenced by traits associated with strong sexual selection. Rather, habitat-specific selective forces, including clear water and structural refuge, promote the evolution of pronounced colour dimorphism that manifests colours less likely to be displayed in other habitats. Our results demonstrate that environmental context ultimately determines the evolution of conspicuous coloration in colour-dimorphic labrid fishes, despite other influential selective forces.

scholarly journals Phylogenetic-comparative analysis of the eukaryal ribonuclease P RNA

RNA ◽  
2000 ◽  
Vol 6 (12) ◽  
pp. 1895-1904 ◽  
Author(s):  
DANIEL N. FRANK ◽  
CATHERINE ADAMIDI ◽  
MARISSA A. EHRINGER ◽  
CHRISTIAN PITULLE ◽  
NORMAN R. PACE
Keyword(s):  
Comparative Analysis ◽  
Ribonuclease P ◽  
Phylogenetic Comparative Analysis ◽  
Ribonuclease P Rna
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