10 research outputs found
The analysis of facial beauty: an emerging area of research in pattern analysis
Much research presented recently supports the idea that the human perception of attractiveness is data-driven and largely irrespective of the perceiver. This suggests using pattern analysis techniques for beauty analysis. Several scientific papers on this subject are appearing in image processing, computer vision and pattern analysis contexts, or use techniques of these areas. In this paper, we will survey the recent studies on automatic analysis of facial beauty, and discuss research lines and practical application
The role of fluctuating asymmetry in sexual selection
SIGLEAvailable from British Library Document Supply Centre- DSC:DX181573 / BLDSC - British Library Document Supply CentreGBUnited Kingdo
Fluctuating Asymmetry in Body Traits Increases Predation Risks: Tawny Owl Selection Against Asymmetric Woodmice
During the last decade, the study of fluctuating asymmetry (FA) in relation to different fitness aspects has become a popular issue in evolutionary biology. There has been much recent debate in subtle departures from perfect symmetry in bilaterally paired morphological characters, and the extent to which such departure actually reflects aspects of individual quality and fitness. We used data from pellet collection and trapping sessions involving the trophic system Apodemus - Strix aluco, to test the hypothesis that asymmetric woodmice disproportionately fell prey to the tawny owl compared with "normal" woodmice. We found that woodmice preyed on by owls had significantly more asymmetric leg bones than survivors, particularly hind legs, those devoted to jumping. Thus asymmetry in locomotory traits apparently increased predation risks due probably to minor efficiency of asymmetric woodmice in evading predators or to their general low quality. These results suggest that FA affects fitness and consequently may be a good predictor of survival chances for woodmice, i.e. their quality; on the other hand, by removing asymmetric individuals, tawny owls can exert a stabilising selection on prey populations
Links between male quality, male chemical signals, and female mate choice in Iberian Rock Lizards
Zebra finch females prefer males with redder bills independent of song rate--a meta-analysis
Male zebra finches display multiple secondary sexual traits such as song and red bill coloration. This color is dependent on carotenoids, which enhance immune function and are antioxidants. A red bill may thus function as an indicator signal. The zebra finch is extensively used in the study of carotenoid-dependent signaling. However, studies of female mate preferences for redder bills show mixed results. Here, we report a meta-analysis of mate-choice studies that reveals that female zebra finches do prefer males with redder bills (r = 0.61), except when there was reduced opportunity for imprinting or when bill color was experimentally manipulated, which both reduced preference for red bills to approximately zero. The latter may either be due to aspects of the experimental design or due to bill color being correlated with another trait such as song rate as was previously suggested. We show, however, in a separate meta-analysis on a different set of studies that the correlation between bill coloration and song rate (r = 0.14) was significantly lower than the r = 0.61 between bill color and attractiveness. We conclude, therefore, that the role of bill coloration in mate choice cannot be solely due to an association with song rate. Thus, we conclude that females do prefer males with redder bills when there was sufficient opportunity for sexual imprinting, but to what extent this is causally related to the bill color remains to be established. Copyright 2011, Oxford University Press.
Comunidade de aves de sub-bosque em uma área de entorno do Parque Nacional do Itatiaia, Rio de Janeiro, Brasil Understory bird community in a surrounded area of Itatiaia National Park, Rio de Janeiro, Brazil
Este trabalho foi realizado em mata secundária no MunicĂpio de Itatiaia, Estado do Rio de Janeiro (22Âş30'S e 44Âş30'W) prĂłximo ao Parque Nacional do Itatiaia, com o objeitvo de descrever a comunidade de aves ali presente. Foram amostrados trĂŞs tipos vegetacionais distintos: reflorestamento, bosque e pomar, tendo sido realizadas 19 excursões entre 1984 e 1999. As aves foram amostradas atravĂ©s de capturas com redes de neblina e anilhamento, tendo sido utilizadas de 15 a 31 redes de 12 x 2 m e malha 36 mm. Foram tambĂ©m obtidas medidas morfomĂ©tricas (comprimento total, asa, bico, cauda e tarso) e dados biolĂłgicos (sexo, idade reprodução e muda). Depois de 5.621,79 horas-rede, foi registrado um total de 553 capturas, com 71 recapturas (12,84%); 417 indivĂduos foram anilhados, e 65 beija-flores deixaram de ser marcados por falta de anilhas especĂficas. A comunidade estudada esteve representada por 77 espĂ©cies e 18 famĂlias, apresentando Ăndice de diversidade H' = -1,594 e a curva do coletor com tendĂŞncia Ă estabilização. As famĂlias com maior nĂşmero de espĂ©cies foram Emberizidae (n = 21; 27,27%) e Tyrannidae (n = 15; 19,48%). As espĂ©cies com maior abundância relativa foram Turdus leucomelas (n = 40; 9,59%) e Turdus rufiventris (n = 36; 8,63%). Seis das espĂ©cies amostradas (7,8%) sĂŁo endĂŞmicas do bioma Mata Atlântica. Na estação chuvosa foram amostradas 68 espĂ©cies, e na estação seca, 42; e as capturas estiveram relacionadas com as chuvas (rs = -0,6778; p = 0,05). O perĂodo reprodutivo ocorreu de outubro a março estando correlacionado com o inĂcio da estação chuvosa (rs = -0,702; p = 0,052).<br>This study was conduced in a second growth woodland close to Itatiaia National Park (22Âş30'S e 44Âş30'W), Rio de Janeiro state, Brazil, and aimed to describe the understory bird community living in this area. We sampled three different vegetation types, reforestation, wood and orchard, through 19 field trips between 1984 and 1999. Birds were sampled by mist-netting and bird-banding, using from 15 to 31 12 x 2 36 mm mesh mist-nets, and we also collected information on morphological (total, wing, bill, tail and tarsus length), and biological data (sex, age, reproduction and molt). After 5,621.79 net hours, we got 553 captures and 71 recaptures (12.8%); 417 individuals were banded and 65 hummingbirds were not, due to the absence of specific rings. The studied community was represented by 77 species and 18 families, showing a diversity index of H' = -1.59 and curve of new species tending to stabilization. The most well-represented families were Emberizidae (n = 21; 27.27%), and Tyrannidae (n = 15; 19.48%); the species with highest number of capture were Turdus leucomelas Vieillot, 1818 (n = 40; 9.59%) and Turdus rufiventris Vieillot, 1818 (n = 36; 8.63%). Six of the sampled species (7.8%) are endemic to Atlantic forest. In the rainy season we sampled 68 species, and in the dry season, 42; and the captures were correlated with rainfall (rS = -0.68; p = 0.05). The breeding season occurred from October to March, and also was correlated with the beginning of the rainy season (rS = -0.70; p = 0.05)