Differential deposition of antimicrobial proteins in blue tit (Cyanistes caeruleus) clutches by laying order and male attractiveness

Female birds can influence offspring fitness by varying the relative quantities of egg components they deposit within and between clutches. Antimicrobial proteins (lysozyme, ovotransferrin, and avidin) are significant components of the avian albumen and likely aid in defense of embryos from microbial infection. Within clutches, females may enhance antimicrobial defense of early-laid eggs to protect them from the high risk of infection incurred before the onset of incubation. Among entire clutches, females may invest more resources in young sired by more attractive males because they have higher reproductive value. We tested these hypotheses by quantifying antimicrobial protein distribution within and among clutches in blue tit eggs. Contrary to our hypothesis, clutches showed no differential deposition of lysozyme or avidin within clutches, but eggs laid in the middle of the sequence had higher concentrations of ovotransferrin than eggs in the beginning and end. Consistent with our second hypothesis, we found that females produced eggs with higher concentrations of lysozyme (although not ovotransferrin or avidin) when mated to more attractive (more UV-reflective) males. Furthermore, females mated to polygynous males deposited less lysozyme than those mated to monogamous males. These data suggest that allocation of lysozyme at the clutch level may be a maternal effect mediated by male qualities

Wind Tunnel - Wing Surface Temperature

This data file contains wing surface temperatures measured on stuffed wings exposed to a light source in a wind tunnel. Temperatures were assessed for varying light intensities (Irradiance in W/m²) and wind speeds (m/s). We used differently coloured wings of ospreys, gannets and a lesser black-backed gull

Osprey Wing Surface Temperature

This data file contains wings surface temperatures of live ospreys assessed with thermal imaging. Temperature of 11 individuals (named after ring number) was measured for different wing parts and positioning: ODM = open dorsal wing (muscular part), ODF = open dorsal wing (flight feathers), OVM = open ventral wing (muscular part), open ventral wing (flight feathers), CDM = closed dorsal wing (muscular part), CDF = closed dorsal wing (flight feathers)

Substrate thermal properties influence ventral brightness evolution in ectotherms

Jonathan Goldenberg et al. use photographic data and ancestral state reconstruction of 126 viper species to show that substrate type influences the evolution of ventral brightness for efficient heat transfer. Their results suggest that these patterns may have been involved in the diversification of vipers during the Miocene, and highlight the importance of ventral body regions when considering behavioral ecology and evolution

Replication Data for: Substrate thermal properties influence ventral brightness evolution in ectotherms

The repository contains all the R-scripts, datasets, and the custom-made plugin “MacroBright” for brightness analyses in ImageJ to reproduce all the results and figures presented in the article

The microstructure of white feathers predicts their visible and near-infrared reflectance properties

<div><p>Abstract</p><p>Research on the optical properties of animal integuments, including fur, feather, skin and cuticle, has focussed almost exclusively on animal-visible wavelengths within the narrow range of 300–700 nm. By contrast, the near-infrared (NIR) portion of direct sunlight, spanning 700–2600 nm, has been largely ignored despite its potentially important thermal consequences. We quantified variation in visible and NIR reflectance and transmission for white body contour feathers of 50 bird species, and examined how well they are predicted by feather macro- and micro-structural morphology. Both visible and NIR reflectance of the feathers varied substantially across species. Larger, thicker, and sparser feathers that are characteristic of larger species, and feathers with rounder barbs and more closely spaced barbules, had high average reflectance, particularly within avian-visible wavelengths (300–700 nm). Feathers with rounder barbs and more closely situated barbules also had high average reflectance, particularly for NIR wavelengths. Barb roundness and barbule density were the only predictors of NIR reflectance after accounting for variation in visible reflectance and body size. Our results highlight the potential for adaptive variation in NIR reflectance mediated by feather structure, which may inform the design of functional materials to control light and heat.</p></div

Variation in average avian visible (300–700 nm) and average near-infrared (700–2100 nm) reflectance and transmission of white body contour feathers.

<p>(a) Representative transmission (top) and reflectance spectra (bottom) for species in this study (top to bottom: <i>Archilochus colubrisi</i>, ruby-throated hummingbird; <i>Accipiter cooperii</i>, Cooper’s hawk; <i>Anas clypeata</i>, northern shoveler; <i>Pelecanus erythrorhynchos</i>, American white pelican; <i>Bubo scandiacus</i>, snowy owl; <i>Pachycephala pectoralis</i>, golden whistler). (b) Dendrograms showing phylogenetic distributions of average avian visible (left) and average near-infrared reflectance. (c) Relationship between average avian visible reflectance and average near-infrared reflectance.</p

Eigenvectors and eigenvalues of the first three principal components (PC) from a PCA of 11 feather morphology measurements for 50 bird species.

<p>Eigenvectors and eigenvalues of the first three principal components (PC) from a PCA of 11 feather morphology measurements for 50 bird species.</p

Effect of feather structure (PC1, PC2, and PC3) on the visible and NIR reflectance and transmission of white feathers, and on body mass.

<p>Estimate (95% CI) refers to the average slope and 95% confidence intervals for analyses run over 100 trees.</p

Clade-specific frequency of melanin concentration gradients in feathers.

<p>Names in bold denote clades of birds with largely aquatic ecologies.</p