497 research outputs found

    Blood Parasite Infection Differentially Relates to Carotenoid-Based Plumage and Bill Color in the American Goldfinch

    Get PDF
    Male and female American goldfinches (Spinus tristis) express condition-dependent carotenoid-based plumage and bill coloration. Plumage color is relatively static, as pigments incorporated into feathers during the spring molt cannot be mobilized thereafter. In contrast, bill color is dynamic, reflecting changes in condition over short time periods. Previous studies have shown that male and female ornaments, though similar in expression, are differentially related to measures of immunocompetence, suggesting that the relationship between ornamentation and parasite infection may differ between the sexes. In this study, we evaluate the relationship between condition-dependent ornamentation (plumage and bill color) and blood parasite infection in male and female American goldfinches. We captured goldfinches after completion of the pre-alternate molt and prior to the onset of nesting and assessed prevalence of Trypanosoma parasites via blood smears. Plumage color strongly predicted trypanosome infection: Birds with more colorful plumage were less likely to present infections. In contrast, we detected no relationship between infection and bill color, which in other studies has been shown to dynamically reflect current condition. Sex did not affect the relationship between infection status and either ornament. Together, these results suggest that physiological pathways linking carotenoid ornamentation and infection may vary even within a single species

    The cases for and against double-blind reviews

    Get PDF
    To date, the majority of authors on scientific publications have been men. While much of this gender bias can be explained by historic sexism and discrimination, there is concern that women may still be disadvantaged by the peer review process if reviewers’ biases lead them to reject publications with female authors more often. One potential solution to this perceived gender bias in the reviewing process is for journals to adopt double-blind reviews whereby neither the authors nor the reviewers are aware of each other’s identity and gender. To test the efficacy of double-blind reviews in one behavioral ecology journal (Behavioral Ecology, BE), we assigned gender to every authorship of every paper published for 2010–2018 in that journal compared to four other journals with single-blind reviews but similar subject matter and impact factors. While female authorships comprised only 35% of the total in all journals, the double-blind journal (BE) did not have more female authorships than its single-blind counterparts. Interestingly, the incidence of female authorship is higher at behavioral ecology journals (BE and Behavioral Ecology and Sociobiology) than in the ornithology journals (Auk, Condor, Ibis) for papers on all topics as well as those on birds. These analyses suggest that double-blind review does not currently increase the incidence of female authorship in the journals studied here. We conclude, at least for these journals, that double-blind review no longer benefits female authors and we discuss the pros and cons of the double-blind reviewing process based on our findings

    First light for avian embryos: eggshell thickness and pigmentation mediate variation in development and UV exposure in wild bird eggs

    Get PDF
    Article first published online: 29 JUL 20141. The avian embryo's development is influenced by both the amount and the wavelength of the light that passes through the eggshell. Commercial poultry breeders use light of specific wavelengths to accelerate embryonic growth, yet the effects of the variably patterned eggshells of wild bird species on light transmission and embryonic development remain largely unexplored. 2. Here, we provide the first comparative phylogenetic analysis of light transmission, through a diverse range of bird eggshells (74 British breeding species), in relation to the eggshell's thickness, permeability, pigment concentration and surface reflectance spectrum (colour). 3. The percentage of light transmitted through the eggshell was measured in the spectral range 250–700 nm. Our quantitative analyses confirm anecdotal reports that eggshells filter the light of the externally coloured shell. Specifically, we detected a positive relationship between surface eggshell reflectance (‘brightness’) and the percentage of light transmitted through the eggshell, and this relationship was strongest at wavelengths in the human-visible blue-green region of the spectra (c. 435 nm). 4. We show that less light passes through thicker eggshells with greater total pigment concentrations. By contrast, permeability (measured as water vapour conductance) did not covary significantly with light transmission. Eggs of closed-nesting species let more light pass through, compared with open nesters. 5. We postulate that greater light transmission is required to assist embryonic development under low light exposure. Importantly, this result provides an ecological explanation for the repeated evolution of immaculate, white- or pale-coloured eggshells in species nesting in enclosed spaces. 6. Finally, we detected correlative support for the solar radiation hypothesis, in that eggshells of bird species with a longer incubation period let significantly less of the potentially harmful, ultraviolet (UV) light pass through the eggshell. In summary, we demonstrate suites of avian eggshell properties, including eggshell structure and pigmentation, which are consistent with an evolutionary pressure to both enhance and protect embryonic development.Golo Maurer, Steven J. Portugal, Mark E. Hauber, Ivan Mikơík, Douglas G. D. Russell and Phillip Casse

    House price Keynesianism and the contradictions of the modern investor subject

    Get PDF
    This article conceptualises the marked downturn in UK house prices in the 2007-2009 period in relation to longer-term processes of national economic restructuring centred on a new model of homeownership. The structure of UK house prices has been impacted markedly by the Labour Government‟s efforts to ingrain a particular notion of financial literacy amid the move towards an increasingly asset-based system of welfare. New model welfare recipients and new model homeowners have thereby been co-constituted in a manner consistent with a new UK growth regime of „house price Keynesianism‟. However, the investor subjects who drive such growth are necessarily rendered uncertain as compared with the idealised image of Government policy because of their reliance on the credit-creating decisions of private financial institutions. The recent steep decline in UK house prices is explained here as an epiphenomenon of the disruptive effect on the idealised image caused by the dependence of investor subjects on pricing dynamics not of their making

    Effects of virtual reality erotica on ejaculate quality of sperm donors: a balanced and randomized controlled cross-over within-subjects trial

    Get PDF
    Background Previous research has shown that the type and duration of erotic material that men have access to during masturbation can influence semen parameters. To our knowledge, the use of virtual reality (VR) headsets to present erotica has not previously been studied. We reasoned that, because VR can provide a more immersive experience to the user, semen parameters of masturbatory ejaculates may be altered. Methods This study had a balanced and randomized controlled cross-over within-subjects design. 504 ejaculates were collected from 63 sperm donors at 4 locations in Denmark. During masturbation each donor was instructed to observe erotic material either on a touch screen monitor or using a VR headset. The order of each pair of within-subject treatments was randomized by the throw of a dice. Anonymized data were analysed with linear mixed and piecewise structural equation models. Results Both abstinence period and VR-use influenced the total number of motile spermatozoa ejaculated. For short abstinence periods, VR-use increased the number of motile sperm in the ejaculate. However, the difference between VR and non-VR ejaculates decreased as abstinence period increased such that there was no difference at the mean abstinence period of 58 h. For longer abstinence periods, total motile sperm counts were lower, on average, when men used VR compared to those that did not. Conclusion The use of VR headsets to view erotica had a strong positive effect on the number of motile sperm in an ejaculate when the donor’s abstinence time was short (< 24 h). VR-use could improve the ejaculate quality of men who are asked to provide samples after a short period of abstinence, such as men in infertile partnerships producing samples for ART or cancer patients depositing sperm before treatment

    Seeing-good-gene-based mate choice:From genes to behavioural preferences

    Get PDF
    1. Although vertebrates have been reported to gain higher reproductive outputs by choosing mates, few studies have been conducted on threatened species. However, species recovery should benefit if natural mate choice could improve reproductive output (i.e., pair performance related to offspring number, such as increased clutch size, numbers of fertilized egg and fledglings). We assessed the evidence for major histocompatibility complex (MHC)-based mate preference in the endangered crested ibis (Nipponia nippon), and quantified the impacts of such choice on reproductive output. 2. We tested the hypothesis that crested ibis advertise “good genes” through external traits, by testing whether nuptial plumage characteristics and body morphology mediate mate choice for underlying genetic MHC variation. 3. We found differences between males and females in preferred MHC genotypes, external traits used in mate choice, and contributions to reproductive outputs. Females preferred MHC-heterozygous males, which had darker [i.e., lower total reflectance and ultraviolet (UV) reflectance] nuptial plumage. Males preferred females lacking the DABd allele at the MHC classⅡDAB locus, which had higher average body mass. DABd-free females yielded heavier eggs and more fledglings, while MHC-heterozygous males contributed to more fertilized eggs and fledglings. Fledging rate was highest when both parents had the preferred MHC genotypes (i.e., MHC-heterozygous father and DABd-free mother). Comparisons showed that free-mating wild and seminatural pairs yielded more fertilized eggs and more fledglings, with a higher fledging rate, than captive pairs matched artificially based on pedigree. 4. Conservation programs seldom apply modern research results to population management, which could hinder recovery of threatened species. Our results show that mate choice can play an important role in improving reproductive output, with an example in which an endangered bird selects mates using UV visual capability. Despite the undoubted importance of pedigree-based matching of mates in conservation programs, we show that free-mating can be a better alternative strategy

    Child protection contact among children of culturally and linguistically diverse backgrounds: A South Australian linked data study

    Get PDF
    First published: 06 February 2023AIM: To describe the cumulative incidence of child protection (CP) system contact, maltreatment type, source of reports to age 7 years, and socio-demographic characteristics for culturally and linguistically diverse (CALD) Australian children. METHODS: We used CP, education, health, and birth registrations data for children followed from birth up to age 7 from the South Australian Better Evidence, Better Outcomes, Linked Data (SA BEBOLD) platform. PARTICIPANTS: SA born children enrolled in their first year of school from 2009 to 2015 (n = 76 563). CALD defined as non-Aboriginal or Torres Strait Islander, spoken language other than English, Indigenous or Sign, or had at least one parent born in a non-English speaking country. OUTCOMES MEASURES: For CALD and non-CALD children, we estimated the cumulative incidence (risk) of CP contacts up to age 7, relative risk and risk differences for all levels of CP contact from notification to out-of-home care (OOHC), primary maltreatment type, reporter type, and socio-economic characteristics. Sensitivity analyses explored different population selection criteria and CALD definitions. RESULTS: By age 7, 11.2% of CALD children had 'screened-in' notifications compared to 18.8% of non-CALD (risk difference [RD] 7.6 percentage points (95% confidence interval: 6.9-8.3)), and 0.6% of CALD children experienced OOHC compared to 2.2% of non-CALD (RD 1.6 percentage points (95% confidence interval: 1.3-1.8)). Emotional abuse was the most common substantiated maltreatment type for CALD and neglect for non-CALD. Among both groups, the most common reporter sources were police and education sector. Socio-economic characteristics were broadly similar. Sensitivity analyses results were consistent with primary analyses. CONCLUSION: By age 7, CALD children had lower risk of contact with all levels of CP. Estimates based on primary and sensitivity analyses suggested CALD children were 5-9 percentage points less likely to have a report screened-in, and from 1.0 to 1.7 percentage points less likely to have experienced OOHC.Razlyn Abdul Rahim, Rhiannon Pilkington, Alexandra M Procter, Alicia Montgomerie, Murthy N Mittinty, Katina D, Onise and John Lync
    • 

    corecore