White plumage color as an honest indicator: feather macrostructure links reflectance with reproductive efort and success, Miklós Laczi et al., 2022
Context-> The white wing patch of the collared flycatcher (Ficedula albicollis) is an important sexual trait, and changes in its reflectance are partly due to macrostructural condition. The structural condition of feathers may generally have a decisive role in shaping the color properties of the plumage but the information content of structurally mediated color differences is poorly known.
Aim-> examine whether wing patch macrostructure lends information content to actual reflectance in terms of reproductive effort and success, determine the meaning of color variation in pigment-free white plumage patches.
Method-> used 2 years of macrostructural, reflectance, and breeding data from both sexes
Results-> macrostructure strongly predicted actual reflectance in males but only weakly in females. Furthermore, in males, feather vane width was related positively to current year reproductive effort, and negatively to previous year reproductive effort.
Conclusions-> macrostructurally mediated reflectance attributes may inform the receiver not only of actual reproductive capacity but also of individual quality via reproductive costs.
Mite load predicts the quality of sexual color and locomotor performance in a sexually dichromatic lizard, Richard W. Orton et al., 2019
Context-> maintenance of bright sexual colors has recurrently been linked to mate preference- communicate to mates the ability to survive despite a “handicap”, act as honest signals of individual quality, the breakdown of the relationships between the variables associating sexual color and infection resistance is argued
Question-> is sexual colour in male Florida scrub lizards (Sceloporus woodi) an honest signal of resistance to chigger mite infection?
Methods-> linear modeling to explore relationships between mite load, different components of sexual color, ecological performance, body size, and habitat type.
Results-> the brightness of sexual color in scrub lizards is negatively associated with the interaction between mite load and body size, and scrub lizards suffer decreased endurance capacity with increases in mite load. mite load, performance, and sexual color in male scrub lizards can vary between habitat types.
Conclusions-> sexual color in scrub lizards is an honest indicator of individual quality and further underscore the importance of considering multiple factors when testing hypotheses related to the maintenance of sexual color
recap of colour and honest signals
question about signals that aren’t about genetic quality
explanation of paper 1→
males that have brighter colours have more testosterone but also less immune system functionality, is a trade-off between immune defence and matings, those with brighter colours are mated with more
proves the good genes hypothesis
question about past vs current breeding success
explanation of paper 2→
comparing white patch vein width and wornness
males with wider veins had more reflectance, was a visual signal, appear more striking, is sexually selected, females had a smaller correlation between vein width and reflectance
those that had a larger clutch size the year before had narrower veins and lower quality feathers the next year, is not shown in females
question on environmental vs genetic signals
similarities vs differences of the two papers
question on benefits and costs of signals
summary + kahoot
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