Sexual dimorphism in immune function and oxidative physiology across birds: The role of sexual selection

Sex-specific physiology is commonly reported in animals, often indicating lower immune indices and higher oxidative stress in males than in females. Sexual selection is argued to explain these differences, but empirical evidence is limited. Here, we explore sex differences in immunity, oxidative physiology and packed cell volume of wild, adult, breeding birds (97 species, 1997 individuals, 14 230 physiological measurements). We show that higher female immune indices are most common across birds (when bias is present), but oxidative physiology shows no general sex-bias and packed cell volume is generally male-biased. In contrast with predictions based on sexual selection, male-biased sexual size dimorphism is associated with male-biased immune measures. Sexual dichromatism, mating system and parental roles had no effect on sex-specificity in physiology. Importantly, female-biased immunity remained after accounting for sexual selection indices. We conclude that cross-species differences in physiological sex-bias are largely unrelated to sexual selection and alternative explanations should be explored

The Relationship between Hormones, Glucose, and Oxidative Damage Is Condition and Stress Dependent in a Free-Living Passerine Bird

Physiological state is an emergent property of the interactions among physiological systems within an intricate network. Understanding the connections within this network is one of the goals in physiological ecology. Here, we studied the relationship between body condition, two neuroendocrine hormones (corticosterone and insulin-like growth factor 1 [IGF-1]) as physiological regulators, and two physiological systems related to resource metabolism (glucose) and oxidative balance (malondialdehyde). We measured these traits under baseline and stress-induced conditions in free-living house sparrows (Passer domesticus). We used path analysis to analyze different scenarios about the structure of the physiological network. Our data were most consistent with a model in which corticosterone was the major regulator under baseline conditions. This model shows that individuals in better condition have lower corticosterone levels; corticosterone and IGF-1 levels are positively associated; and oxidative damage is higher when levels of corticosterone, IGF-1, and glucose are elevated. After exposure to acute stress, these relationships were considerably reorganized. In response to acute stress, birds increased their corticosterone and glucose levels and decreased their IGF-1 levels. However, individuals in better condition increased their corticosterone levelsmore and better maintained their IGF-1 levels in response to acute stress. The acute stress–induced changes in corticosterone and IGF-1 levels were associated with an increase in glucose levels, which in turn was associated with a decrease in oxidative damage. We urge ecophysiologists to focus more on physiological networks, as the relationships between physiological traits are complex and dynamic during the organismal stress response

Oxidative physiology of reproduction in a passerine bird: a field experiment

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Pembelajaran Seni Kriya Dengan Cara Mozaik Bahan Pelepah Pisang Kering Di Kelas VIII B SMP Neri 22 Bantimurung Kabupaten Maros

ABSTRAK Penelitian ini bertujuan (i) Untuk mendeskripsikan pembelajaran seni kriya dengan cara mozaik bahan pelepah pisang kering siswa kelas VIII B SMP Negeri 22 Bantimurung Kabupaten Maros, dalam berkarya seni kriya dengan cara mozaik bahan pelepah pisang kering; (ii). Untuk mendeskripsikan adanya kendala siswa kelas VIII SMP Negeri 22 Bantimurung Kabupaten Maros dalam berkarya seni kriya dengan teknik mozaik. Adapun manfaat penelitian terdiri atas manfaat teoritas yakni hasil penelitian diharapkan bisa memperkaya dan menambah wawasan bagi pengembang ilmu dalam bidang seni, terutama menerapkan teknik mozaik dalam berkarya seni kriya dan manfaat praktis yakni hasil penelitian dapat bermanfaat bagi guru seni rupa sebagai dasar untuk menerapkan metode pembelajaran seni rupa di kelas, khususnya metode pembelajaran seni kriya dengan cara mozaik. Penelitian ini menggunakan penelitian survey. Penelitian dilakukan di SMP Negeri 22 Bantimurung Kabupaten Maros pada tahun ajaran 2015/2016. Subjek penelitian adalah siswa kelas VIII B SMP Negeri 22 Bantimurung Kabupaten Maros dan jumlah siswa yang diamati sebanyak 31 orang. Data dan hasil penelitian diperoleh melalui pengamatan terhadap kegiatan menerapkan cara mozaik dalam berkarya seni kriya diperoleh peneliti dalam proses pembelajaran maupun hasil kegiatan guru dan kegiatan siswa menunjukkan bahwa pada tahap perencanaan guru mrmberikan arahan tentang pengertian seni kriya, pengenalan alat dan bahan yang digunakan, proses pembuatan karya terlaksana dengan keaktifan siswa yang sangat baik. Hasil penelitian menunjukkan bahwa (i) proses berkarya seni kriya dengan cara mozaik pada pertemuan I, II, III dan IV terlaksana dengan baik ; (ii) siswa mampu berkarya seni kriya dengan teknik mozaik dilihat dari nilai yang diperoleh antara 75-100; (iii) pada kriteria penilaian I, 6 siswa mendapat nilai sedang, 20 siswa mendapatkan nilai tinggi dan 5 siswa mendapatkan nilai sangat tinggi, pada kriteria penilaian II, 5 siswa mendapat nilai sedang, 22 siswa mendapat nilai tinggi dan 5 siswa yang mendapat nilai sangat tinggi, pada kriteria penilaian III, 7 siswa mendapat nilai sedang, 19 siswa mendapatkan nilai tinggi dan 5 siswa mendapat nilai sangat tinggi dan pada kriteria penilaian IV, 5 siswa mendapat nilai sedang, 21 siswa mendapatkan nilai tinggi dan 5 siswa mendapat nilai sangat tinggi; (iv) kendala/kesulitan yang dihadapi siswa dalam berkarya seni kriya adalah pada waktu menempel harus hati-hati, dan penggunaan waktu pada pertemuan II dan III yang memerlukan ketelitian. Ditemukannya sejumlah siswa yang kurang berbakat dalam menciptakan karya seni kriya dengan cara mozaik, solusi pada pertemuan I, II, III dan IV, memberikan motivasi pada siswa dengan cara membimbing satu persatu, agar siswa memahami lebih jelas berkarya seni kriya dengan cara mozaik

Longevity and life history coevolve with oxidative stress in birds

1. The mechanisms that underpin the evolution of ageing and life histories remain elusive. Oxidative stress, which results in accumulated cellular damages, is one of the mechanisms suggested to play a role. 2. In this paper, we set out to test the “oxidative stress theory of ageing” and the “oxidative stress hypothesis of life histories” using a comprehensive phylogenetic comparison based on an unprecedented dataset of oxidative physiology in 88 free‐living bird species. 3. We show for the first time that bird species with longer lifespan have higher nonenzymatic antioxidant capacity and suffer less oxidative damage to their lipids. We also found that bird species featuring a faster pace‐of‐life either have lower non‐enzymatic antioxidant capacity or are exposed to higher levels of oxidative damage, while adult annual mortality does not relate to oxidative state. 4. These results reinforce the role of oxidative stress in the evolution of lifespan and also corroborate the role of oxidative state in the evolution of life histories among free‐living birds

Social groups with diverse personalities mitigate physiological stress in a songbird

Social groups often consist of diverse phenotypes, including personality types, and this diversity is known to affect the functioning of the group as a whole. Social selection theory proposes that group composition (i.e. social environment) also influences the performance of individual group members. However, the effect of group behavioural composition on group members remains largely unexplored, and it is still contentious whether individuals benefitmore in a social environmentwith homogeneous or diverse behavioural composition. We experimentally formed groups of house sparrows Passer domesticus with high and low diversity of personality (exploratory behaviour), and found that their physiological state (body condition, physiological stress and oxidative damage) improved with increasing group-level diversity of personality. These findings demonstrate that group personality composition affects the condition of group members and individuals benefit from social heterosis (i.e. associating with a diverse set of behavioural types). This aspect of the social life can play a key role in affiliation rules of social animals and might explain the evolutionary coexistence of different personalities in nature

Data from: How feathered are birds? environment predicts both the mass and density of body feathers

1.Studies modelling heat transfer of bird plumage design suggest that insulative properties can be attributed to the density and structure of the downy layer, while waterproofing is the result of the outer layer, comprised of contour feathers. In this study, we test how habitat and thermal condition affect feather mass and density of body feathers (contour, semiplume and downy feathers) measured on the ventral and dorsal sides of the body, using a phylogenetic comparative analysis of 152 bird species. 2.Our results demonstrate that feather mass and the density of downy feathers are higher in species that inhabit colder environments, while total feather density is higher of species breeding under intermediate temperatures compared to the ones breeding under more extreme conditions. The density of contour feathers, depending on the body region, is either quadratically related or negatively correlated to minimum winter temperature. 3.The density of contour and downy feathers, measured on both sides of the body, is higher in aquatic than in terrestrial birds. However, among the former, diving behaviour does not select for further increases in body feather mass or density. 4.The results of this study provides key insights into how the plumage of birds is adapted to different environments and lifestyles and provides a basis for understanding the diverse range and the evolution of variation in these characteristics

Data from: How feathered are birds? environment predicts both the mass and density of body feathers

1.Studies modelling heat transfer of bird plumage design suggest that insulative properties can be attributed to the density and structure of the downy layer, while waterproofing is the result of the outer layer, comprised of contour feathers. In this study, we test how habitat and thermal condition affect feather mass and density of body feathers (contour, semiplume and downy feathers) measured on the ventral and dorsal sides of the body, using a phylogenetic comparative analysis of 152 bird species. 2.Our results demonstrate that feather mass and the density of downy feathers are higher in species that inhabit colder environments, while total feather density is higher of species breeding under intermediate temperatures compared to the ones breeding under more extreme conditions. The density of contour feathers, depending on the body region, is either quadratically related or negatively correlated to minimum winter temperature. 3.The density of contour and downy feathers, measured on both sides of the body, is higher in aquatic than in terrestrial birds. However, among the former, diving behaviour does not select for further increases in body feather mass or density. 4.The results of this study provides key insights into how the plumage of birds is adapted to different environments and lifestyles and provides a basis for understanding the diverse range and the evolution of variation in these characteristics

Oxidative physiology is weakly associated with pigmentation in birds

he mechanistic link between avian oxidative physiology and plumage coloration has attracted considerable attention in past decades. Hence, multiple proximal hypotheses were proposed to explain how oxidative state might covary with the production of melanin and carotenoid pigments. Some hypotheses underscore that these pigments (or their precursors, e.g., glutathione) have antioxidant capacities or function as molecules storing the toxic excess of intracellular compounds, while others highlight that these pigments can act as pro-oxidants under specific conditions. Most studies addressing these associations are at the intraspecific level, while phylogenetic comparative studies are still scarce, though needed to assess the generality of these associations. Here, we tested whether plumage and bare part coloration were related to oxidative physiology at an interspecific level by measuring five oxidative physiology markers (three nonenzymatic antioxidants and two markers of lipid peroxidative damage) in 1387 individuals of 104 European bird species sampled during the breeding season, and by scoring plumage eumelanin, pheomelanin, and carotenoid content for each sex and species. Only the plasma level of reactive oxygen metabolites was related to melanin coloration, being positively associated with eumelanin score and negatively with pheomelanin score. Thus, our results do not support the role of antioxidant glutathione in driving variation in melanin synthesis across species. Furthermore, the carotenoid scores of feathers and bare parts were unrelated to the measured oxidative physiology parameters, further suggesting that the marked differences in pigmentation across birds does not influence their oxidative state