Phylogenetic relationships of immune function and oxidative physiology with sexual selection and parental effort in male and female birds
Data files
Aug 21, 2025 version files 39.57 KB
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dryad_table1.csv
6.50 KB
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dryad_table2.csv
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README.md
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Abstract
Sexual differences in physiology are widely regarded as potential proximate mechanisms that underlie sex differences in mortality, life history, and disease risk of vertebrates. However, little is known about the causes of sex-specific variation in physiology. Sexual selection and parental workload are two key components suggested to play a role. Theory predicts that, within males, species with stronger male sexual selection (greater sexual dichromatism and more frequent social polygyny) and higher male parental effort should have lower immune capacity and stronger oxidative imbalance. Within females, a weak or no direct effect of male sexual selection on physiology is expected, but species where females invest more in parental care should have lower immune capacity and higher oxidative imbalance. We tested these predictions by phylogenetic comparative analyses conducted separately for the two sexes and based on 11,586 physiological measurements of samples collected in the field from 2,048 individuals of 116 and 106 European species for males and females, respectively. For males, we found that the degree of dichromatism, polygyny and male parental effort correlated negatively with multiple immune indices, and the level of antioxidant glutathione correlated positively with polygyny score. In contrast, female immune and oxidative variables were unrelated or weakly related to both male sexual selection or female parental effort. We conclude that sex roles can drive inter-specific variation in immune function (primarily in male birds), but less so in oxidative physiology. These findings support earlier claims that males pay higher physiological costs of sexual selection than females, but apparently also of caregiving. We discuss how females might avoid such costs.
Description
The dataset contains species-specific values for body mass and parental effort of males and females, sexual dichromatism, male polygyny score, extra pair paternity, diet and average physiology measures (heterophils, lymphocytes, white blood cells, heterophile: lymphocyte ratio, agglutination, lysis, bacteria-killing activity, total antioxidant status, uric acid, total glutathione, reactive oxygen metabolites, malondialdehyde) of males and females provided as best linear unbiased estimates (BLUE scores) and sample sizes for each measured physiological parameters. Note that cells from Table 2 with NA represent missing values. Physiological measures were collected from 116 and 106 European bird species for males and females, respectively, captured at various sites across Romania during the breeding season between 2011 and 2013, and between 2016 and 2019. The sources of all morphological, behavioural, and ecological traits from Table 1 are provided in the Methods.
Data Files
dryad_table1.csv
Data on body mass (g) of males and females, the amount of parental effort of males and females, sexual dichromatism based on plates in the Handbook of the Birds of the World Alive (del Hoyo, Elliott, & Christie, 2017), male polygyny score (0 - no or very rare polygamy (< 0.1% of individuals), 1 - rare polygamy (0.1–1%), 2 - uncommon polygamy (1–5%), 3 - moderate polygamy (5–20%), and 4 - common polygamy (> 20%)), extra pair paternity (% offspring) and diet. See Materials and methods for further information.
dryad_table2.csv
Data on species and sex-specific sample sizes and BLUE scores for each measured physiological parameter.
Variable Dictionary – dryad_table2
Heterophils_Male – Mean BLUE score for the heterophil cell count for males.
Heterophils_Nmale – Sample size for male heterophil cell count (number of individuals).
Heterophils_Female – Mean BLUE score for the heterophil cell count for females.
Heterophils_Nfemale – Sample size for female heterophil cell count (number of individuals).
Lymphocytes_Male – Mean BLUE score for the lymphocyte cell count for males.
Lymphocytes_Nmale – Sample size for male lymphocyte count (number of individuals).
Lymphocytes_Female – Mean BLUE score for the lymphocyte cell count for females.
Lymphocytes_Nfemale – Sample size for female lymphocyte count (number of individuals).
White_blood_cells_Male – Mean BLUE score for the total white blood cell count for males.
White_blood_cells_Nmale – Sample size for male white blood cell count (number of individuals).
White_blood_cells_Female – Mean BLUE score for the total white blood cell count for females.
White_blood_cells_Nfemale – Sample size for female white blood cell count (number of individuals).
Heterophile_Lymphocyte_ratio_Male – Mean BLUE score for the heterophil to lymphocyte ratio for males.
Heterophile_Lymphocyte_ratio_Nmale – Sample size for male heterophil to lymphocyte ratio (number of individuals).
Heterophile_Lymphocyte_ratio_Female – Mean BLUE score for the heterophil to lymphocyte ratio for females.
Heterophile_Lymphocyte_ratio_Nfemale – Sample size for female heterophil to lymphocyte ratio (number of individuals).
Agglutination_Male – Mean BLUE score for the natural antibody agglutination titre for males.
Agglutination_Nmale – Sample size for male agglutination score (number of individuals).
Agglutination_Female – Mean BLUE score for the natural antibody agglutination titre for females.
Agglutination_Nfemale – Sample size for female agglutination score (number of individuals).
Lysis_Male – Mean BLUE score for the complement-mediated lysis titre for males.
Lysis_Nmale – Sample size for male lysis score (number of individuals).
Lysis_Female – Mean BLUE score for the complement-mediated lysis titre for females.
Lysis_Nfemale – Sample size for female lysis score (number of individuals).
Bacteria_killing_activity_Male – Mean BLUE score for the bactericidal activity for males.
Bacteria_killing_activity_Nmale – Sample size for male bactericidal activity (number of individuals).
Bacteria_killing_activity_Female – Mean BLUE score for the bactericidal activity for females.
Bacteria_killing_activity_Nfemale – Sample size for female bactericidal activity (number of individuals).
Total_antioxidant_status_Male – Mean BLUE score for the total antioxidant status for males.
Total_antioxidant_status_Nmale – Sample size for male total antioxidant status (number of individuals).
Total_antioxidant_status_Female – Mean BLUE score for the total antioxidant status for females.
Total_antioxidant_status_Nfemale – Sample size for female total antioxidant status (number of individuals).
Uric_acid_Male – Mean BLUE score for the uric acid concentration for males.
Uric_acid_Nmale – Sample size for male uric acid concentration (number of individuals).
Uric_acid_Female – Mean BLUE score for the uric acid concentration for females.
Uric_acid_Nfemale – Sample size for female uric acid concentration (number of individuals).
Total_glutathione_Male – Mean BLUE score for the total glutathione concentration for males.
Total_glutathione_Nmale – Sample size for male total glutathione concentration (number of individuals).
Total_glutathione_Female – Mean BLUE score for the total glutathione concentration for females.
Total_glutathione_Nfemale – Sample size for female total glutathione concentration (number of individuals).
Reactive_oxygen_metabolites_Male – Mean BLUE score for the reactive oxygen metabolites for males.
Reactive_oxygen_metabolites_Nmale – Sample size for male reactive oxygen metabolites (number of individuals).
Reactive_oxygen_metabolites_Female – Mean BLUE score for the reactive oxygen metabolites for females.
Reactive_oxygen_metabolites_Nfemale – Sample size for female reactive oxygen metabolites (number of individuals).
Malondialdehyde_Male – Mean BLUE score for the malondialdehyde concentration for males.
Malondialdehyde_Nmale – Sample size for male malondialdehyde concentration (number of individuals).
Malondialdehyde_Female – Mean BLUE score for the malondialdehyde concentration for females.
Malondialdehyde_Nfemale – Sample size for female malondialdehyde concentration (number of individuals).
Contact
For questions about this dataset, please contact:
Peter Laszlo Pap – Babes-Bolyai University – peterlpap@gmail.com
All morphological, behavioural, and ecological parameters provided in Table 1 and used in the analyses were extracted from published articles as stated in the Methods. For all physiological traits, species- and sex-specific average physiology measures as best linear unbiased estimates (BLUEs) are provided. The blood samples for physiological measures were collected from wild birds captured during the breeding season.