25 research outputs found

    Experimental nest cooling reveals dramatic effects of heatwaves on reproduction in a Mediterranean bird of prey

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    Future climatic scenarios forecast increases in average temperatures as well as in the frequency, duration, and intensity of extreme events, such as heatwaves. Whereas behavioral adjustments can buffer direct physiological and fitness costs of exposure to excessive temperature in wild animals, these may prove more difficult during specific life stages when vagility is reduced (e.g., early developmental stages). By means of a nest cooling experiment, we tested the effects of extreme temperatures on different stages of reproduction in a cavity-nesting Mediterranean bird of prey, the lesser kestrel (Falco naumanni), facing a recent increase in the frequency of heatwaves during its breeding season. Nest temperature in a group of nest boxes placed on roof terraces was reduced by shading them from direct sunlight in 2 consecutive years (2021 and 2022). We then compared hatching failure, mortality, and nestling morphology between shaded and non-shaded (control) nest boxes. Nest temperature in control nest boxes was on average 3.9 degrees C higher than in shaded ones during heatwaves, that is, spells of extreme air temperature (>37 degrees C for =2 consecutive days) which hit the study area during the nestling-rearing phase in both years. Hatching failure markedly increased with increasing nest temperature, rising above 50% when maximum nest temperatures exceeded 44 degrees C. Nestlings from control nest boxes showed higher mortality during heatwaves (55% vs. 10% in shaded nest boxes) and those that survived further showed impaired morphological growth (body mass and skeletal size). Hence, heatwaves occurring during the breeding period can have both strong lethal and sublethal impacts on different components of avian reproduction, from egg hatching to nestling growth. More broadly, these findings suggest that the projected future increases of summer temperatures and heatwave frequency in the Mediterranean basin and elsewhere in temperate areas may threaten the local persistence of even relatively warm-adapted species

    Men, sex, and homosociality: how bonds between men shape their sexual relations with women

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    Male-male social bonds have a powerful influence on the sexual relations of some young heterosexual men. Qualitative analysis among young men aged eighteen to twenty-six in Canberra, Australia, documents the homosocial organization of men's heterosexual relations. Homosociality organizes men's sociosexual relations in at least four ways. For some of these young men, male-male friendships take priority over male-female relations, and platonic friendships with women are dangerously feminizing. Sexual activity is a key path to masculine status, and other men are the audience, always imagined and sometimes real, for one's sexual activities. Heterosexual sex itself can be the medium through which male bonding is enacted. Last, men's sexual storytelling is shaped by homosocial masculine cultures. While these patterns were evident particularly among young men in the highly homosocial culture of a military academy, their presence also among other groups suggests the wider influence of homosociality on men's sexual and social relations
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