ABSTRACT
RESUMEN: La presente revisión entrega una visión actualizada del estudio de la morfometría geométrica y sus aplicaciones más actuales en ecología y biología evolutiva, metodología con una amplia variación en los últimos 5 años de su primera versión en International Journal of Morphology. La Morfometría geométrica es una herramienta que permite evaluar las variaciones morfológicas con factores subyacentes, siendo una herramienta más sensible que la morfometría tradicional, lo que permite detectar mínimos cambios de variación morfológica. Lo que la ha vuelto una herramienta notable para responder preguntas de biología comparada centradas en caracteres anatómicos. En sus comienzos fue una herramienta usada principalmente para responder preguntas taxonómicas, y para diferenciar a nivel de individuos, poblaciones o especies. No obstante, en los últimos años la cantidad de preguntas y problemáticas en las que se aplica, ha diversificado considerablemente, pasando a ser una herramienta muy precisa para responder preguntas de variación morfológica en contextos ecológicos y evolutivos. Ya ha pasado casi media década desde la última revisión del método, por lo que éste trabajo tiene como objetivo analizar los cambios metodológicos y los nuevos enfoques usados en Morfometría geométrica, y presentar una pequeña guía introductoria a éstos nuevos métodos, sus usos y aplicaciones.
SUMMARY: This study provides an updated vision of the study of Geometric Morphometrics and its most recent application in ecology and evolutionary biology, covering a wide variation in methodology occurring in the last 5 years since the first version published in the International Journal of Morphology. Geometric Morphometrics is a tool that allows evaluating morphological variations with underlying factors, with a higher sensitivity than traditional morphology, so that minimum changes of morphological variation can be detected. Therefore, it has turned into an outstanding tool to answer questions of comparative biology focused on anatomic characters. At the beginning, it was a tool mainly used to answer taxonomic questions and for differentiation at individual, population or species level. However, in the last years, the number of questions and problematic on which it is applied, has diversified considerably, turning it into a very accurate tool to answer questions of morphological variation in ecologic and evolutionary contexts. Almost half a decade has elapsed since the last revision of the method, so this work is intended to analyze the methodological changes and the new approaches used in Geometric Morphometrics, including a brief introductory guideline to these new methods, their uses and applications.
Subject(s)
Anatomy/methods , Developmental Biology , EcologyABSTRACT
La comparación de caracteres anatómicos entre organismos ha sido un elemento central de la biología comparada. Históricamente, la clasificación taxonómica y la comprensión de la diversidad biológica se han basado en descripciones morfológicas. En base a una revolución matemática cuantitativa, el estudio de la morfología ha tenido un importante énfasis gracias al desarrollo del análisis de la forma mediante la combinación de métodos estadísticos multivariados y nuevas maneras de visualización. El objetivo de la presente revisión es dar una visión actualizada sobre los avances del estudio de la morfometría geométrica (MG) en biología evolutiva, así como introducir a temáticas en fuerte desarrollo (e.g. estabilidad del desarrollo, integración y modularidad morfológicas, entre otras). Se espera proporcionar una visión amplia del uso de la MG en biología evolutiva, destacando la necesidad de aumentar el esfuerzo de investigación en esta disciplina, junto con llamar la atención acerca de la utilidad de la MG como una herramienta efectiva, precisa, amigable y barata para cuantificar y estudiar la variación morfológica.
The comparison of anatomical traits between organisms has been a central topic in comparative biology. Historically, taxanomic classification and biological diversity understanding have been based on morphological descriptions. Derived from a mathematical quantitative revolution, morphological studies have experienced an important renewal due to the development of shape analysis rooted in statistical multivariate methods and novel visualisation techniques. The aim of the present review is to provide an updated perspective regarding the progress in geometric morphometrics (GMM) applied to evolutionary biology, as well as introducing to cutting-edge subjects (e.g. developmental stability, modularity, morphological integration, among other themes). Thus, it is expected to provide a broad point of view with respect to the appliaction of geometric morphometrics in evolutionary biology, highlighting its usefulness as an effective, accurate, user-friendly and inexpensive method to quantify and study shape variation.
Subject(s)
Sex Characteristics , Biological Evolution , Anatomy/methods , MathematicsABSTRACT
Habitat change in Rhodnius spp may represent an environmental challenge for the development of the species, particularly when feeding frequency and population density vary in nature. To estimate the effect of these variables in stability on development, the degree of directional asymmetry (DA) and fluctuating asymmetry (FA) in the wing size and shape of R. prolixus and R. robustus–like were measured under laboratory controlled conditions. DA and FA in wing size and shape were significant in both species, but their variation patterns showed both inter-specific and sexual dimorphic differences in FA of wing size and shape induced by nutrition stress. These results suggest different abilities of the genotypes and sexes of two sylvatic and domestic genotypes of Rhodnius to buffer these stress conditions. However, both species showed non-significant differences in the levels of FA between treatments that simulated sylvan vs domestic conditions, indicating that the developmental noise did not explain the variation in wing size and shape found in previous studies. Thus, this result confirm that the variation in wing size and shape in response to treatments constitute a plastic response of these genotypes to population density and feeding frequency.
ABSTRACT
The aim of this study was to comparatively characterize the monthly variation and the sex ratio of Euxesta stigmatias (Loew) and Euxesta sororcula (Wiedermann) populations from a natural reserve and from a guava orchard. It was also investigated whether density and the climate factors affected the individuals' size and fluctuating asymmetry (FA). In both environments, E. sororcula predominated over E. stigmatias. The number of individuals of E. sororcula collected in the ecological station was significantly lower than the number of individuals caught in the orchard. However, the number of captured individuals of E. stigmatias did not differ between environments. Significant sex ratio differences were detected between the collection sites. Female's frequency of E. stigmatias was significantly higher than male's frequency in the ecological station, but not in the orchard. An opposite pattern was encountered for E. sororcula population, showing a significant larger number of females only in the orchard. The species populations also differed in the degree of asymmetry presented. Euxesta stigmatias individuals showed no change on size or on FA along the captures and between environments. Moreover, E. sororcula tended to be more susceptible to climatic variations, considering the significant observed correlation between temperature and body size and the expressive body size and FA variations. This study illustrates the influence of the environment in some structural and dynamic parameters of the studied populations.
Subject(s)
Animals , Female , Male , Animal Distribution , Body Size , Diptera/anatomy & histology , Psidium , Brazil , Population DensityABSTRACT
Are larger and/or more symmetrical Drosophila melanogaster (Diptera, Drosophilidae) males more successful in matings in nature? Sexual selection in Drosophila melanogaster, related to body size and fluctuating asymmetry in wing length and number of sex comb teeth in males, was tested in natural conditions. Males collected in copula were significantly larger than those collected as a single, while no difference in mean number of sex comb teeth between copulating and single males was observed. On the other hand, single males had greater asymmetry both for wing length and number of sex comb teeth than their mating counterparts. It looks like that symmetry of these bilateral traits also may play a role in sexual selection in this dipteran species in nature.
São maiores e/ou mais simétricos os machos de Drosophila melanogaster (Diptera, Drosophilidae) com mais sucesso nos acasalamentos na natureza? A seleção sexual em Drosophila melanogaster foi testada em condições naturais. Os machos coletados em cópula foram significativamente maiores do que na amostra controle, enquanto que diferenças no número médio de dentes do pente sexual não foram estatisticamente significativas. Por outro lado, os machos que não estavam copulando no momento da coleta foram mais assimétricos, tanto em relação ao comprimento das asas como em relação ao número de dentes do pente sexual. Parece que a simetria dos traços bilaterais pode ter um papel na seleção sexual desta espécie na natureza.
ABSTRACT
This study analyses the role of body size and symmetry in the sexual selection and courtship behavior of Dysdercus maurus Distant. Sexual conflicts signaled by coercive mating, female resistance, and pre-copulation fights illustrate the mating system. Male-female struggles were observed in all mating attempts. Females tried to reject males by pushing or running and even by vigorously shaking their bodies, in attempts to dislodge the male from their dorsum. In spite of sexual conflicts during courtship, females actively chose their mates based on morphological and behavioral traits. Larger males with more symmetrical tibiae and longer tarsi that are better copula imposers were more successful in sexual competition. Evidence is presented that sexual conflict and female mate choice should not be mutually excluded.
Subject(s)
Animals , Female , Male , Body Size , Hemiptera , Sexual Behavior, AnimalABSTRACT
Este estudo foi desenvolvido visando verificar respostas fisiológicas, morfológicas e comportamentais em duas diferentes populações de Zabrotes subfasciatus (Boheman) confinadas a diferentes variedades de feijão (Phaseolus vulgaris) (Fabaceae). Avaliaram-se a longevidade, fertilidade e preferência de fêmeas por sítios de oviposição, bem como o tamanho e os níveis de assimetria flutuante de machos e fêmeas. Foram observadas respostas fisiológicas plásticas relacionadas ao tipo de dieta, sendo consideradas importantes habilidades adaptativas para manutenção do hábito generalista do inseto no consumo e uso de sítios para oviposição. As populações estudadas apresentaram respostas distintas a tratamentos similares, o que indica variações genéticas, fisiológicas e comportamentais no seu potencial plástico. O princípio de Hopkins, que mostra a influência da experiência prévia na escolha de sítios para oviposição, não foi confirmado. A ocorrência de assimetria flutuante é variável em machos e fêmeas, o que evidencia a influência de fatores genômicos na determinação desse caráter.
This study was developed aiming to verify physiological, morphological and behavioral responses of two different Zabrotes subfasciatus (Boheman) populations to different beans varieties (Phaseolus vulgaris) (Fabaceae). Female longevity, fertility and oviposition preference site, as well as size and levels of fluctuating asymmetry for males and females were described. Zabrotes subfasciatus displayed physiological plasticity in response to the diet, which was considered an important adaptive ability to maintain the insect generalist habit for food consumption and oviposition sites. The populations studied had different responses to the same treatments, indicating genetic, physiological and behavioral variation on their plastic potential. The Hopkins principle, which determines the influence of previous female experience in the choice of oviposition sites, was not confirmed. The occurrence of fluctuating asymmetry in males and females was variable, probably as a consequence of genomic factors determining this trait.
Subject(s)
Animals , Female , Male , Behavior, Animal , Coleoptera/anatomy & histology , Coleoptera/physiology , Phaseolus/parasitologyABSTRACT
BACKGROUND: More has been written about the epidemiology of breast cancer than any other form of cancer affecting mankind. The specific breast cancer predisposing genes are BRCA1, BRCA2 and p53. BRCA2, the second breast cancer susceptibility gene, was mapped to chromosome 13q12-q13.The human p53 gene, located on the short arm of chromosome 17, is known to be a tumor suppressor gene that can be inactivated by point mutations. AIMS: To determine the fluctuating asymmetry and to predict the occurrence of carcinoma of breast in females. MATERIALS AND METHODS: Rolled finger and palmar prints of 100 female patients of carcinoma of breast were compared with 100 controls. Fluctuating asymmetry measures derived from quantitative parameters (finger ridge counts, a-b ridge counts and palmar angles) were analyzed. RESULTS: Fluctuation asymmetry measures were significantly higher in female patients of carcinoma of breast for the thumb (FA = 2.01), subtotal ridge count (FA = 2.10) and for palmar atd angle (FA = 2.01). CONCLUSION: These findings suggest that digital dermatoglyphics may have a future role in identifying women at increased risk for breast cancer.
ABSTRACT
Background: The aetiology of NIDDM is believed to be as a consequence of genetic and environmental factors that impair metabolism. While little can be done on the genetic component, much can be done as a preventive measure in NIDDM. Because nothing much can be done prenatally, researchers have resorted to studying physical variables like dermatoglyphics (DGs). Dermatoglyphic patterns form on the finger pad and the palm prenatally and remain unchanged throughout life, thus these features may serve as markers for fetal origin of adult disease like NIDDM. Thus the concept of fluctuating asymmetry (FA) which has been defined as random differences between the right (R) and left (L) sides of a morphological trait has gained prominence in diseases like schizophrenia. When the distribution of R-L differences in a population sample approximates a normal curve with a mean approximately equal to zero, the variance of distributions of R-L difference is a measure of FA. Studies have shown that genetic factors may also have a link to FA in finger and a-b ridge counts. No studies have been reported on FA in NIDDM. FA derived from quantitative parameters in DGs of NIDDM may throw light on fetal origins of an adult disease. Hence this study has been undertaken. Aim: The present study aims at deriving FA from quantitative parameters in DGs of NIDDM compared to controls in the Bangalore based population. Materials and Methods: Bilateral rolled finger and palm prints of 150 NIDDM patients (Males - 75, Females - 75) were compared to 120 controls (Males - 60, females -60) from Bangalore based population. FA measures derived from quantitative parameters (finger ridge counts, a-b ridge counts, main line index and palmar angles) were analysed. Results: Comparisons were made in all parameters between homologous fingers of both hands using Pearson's product moment correlation coefficients (r). The difference in correlation coefficients between cases and controls was calculated using Fisher's Z transformation. 1-r2 an estimate of error variance thus measures FA. FA measures were significantly higher in NIDDM males for the 5th finger (FA=2.04) and for the palmar angle 'dat' (FA=2.24); for the NIDDM female a high FA was found in the 2nd finger (FA=2.17) compared to controls. CONCLUSION: Overall measures of the above ridge counts and angles and their derived measures of FA were prominent features of NIDDM in this sample.
ABSTRACT
This study aimed to assess the effect of sub-lethal concentrations of the insect growth regulator (IGR), diflubenzuron, on the body size of the horn fly Haematobia irritans (L.) and on its developmental stability, by fluctuating asymmetry (FA) analysis. Breeding media with different sub-lethal diflubenzuron concentrations and a control medium, were prepared to obtain morphometric measures on adult individuals. Principal component analysis was used to generate an index of general body size, using the correlation matrix of the original characters. Levels of FA and the multivariate index of size were compared among treatments. Contrary to the expectations, the exposure to diflubenzuron did not result in a significant and concomitant increase in the level of FA across treatments or in the number of individuals showing developmental instability. Nevertheless, a significant reduction of size due to the diflubenzuron may reflect the ability of H. irritans to perform physiological and morphological adjustments allowing phenotype compensation, at least to some extent, for stressful environmental conditions. On the other hand, the IGR may be selecting more symmetrical and resistant individuals. From the pest control point of view, the reduction of size may be a positive effect of the IGR since size is usually directly related to fitness
Este trabalho teve como objetivo verificar o efeito de concentrações sub-letais do regulador de desenvolvimento de insetos (IGR), diflubenzurom, no tamanho e na estabilidade do desenvolvimento da mosca-dos-chifres, Haematobia irritans (L.), por meio da análise de assimetria flutuante (AF). Adultos criados em substratos com diferentes concentrações sub-letais de diflubenzurom e em meios-controle foram submetidos a medidas morfométricas. Utilizou-se a análise de componentes principais para se obter um índice multivariado de tamanho, a partir de uma matriz de correlação dos caracteres originais. Os níveis de AF e o índice multivariado de tamanho foram comparados entre os tratamentos. Contrariamente ao esperado, a exposição ao diflubenzurom não resultou em aumento significativo e proporcional às concentrações utilizadas nos níveis de AF entre os tratamentos. Entretanto, a redução no tamanho devido ao efeito deste IGR pode estar refletindo a capacidade de H. irritans de realizar ajustes fisiológicos e morfológicos, de modo que os fenótipos compensem, pelo menos até certo ponto, as condições ambientais de estresse. Há ainda a possibilidade de o IGR estar selecionando indivíduos mais simétricos e resistentes. Do ponto de vista do controle de pragas, a redução no tamanho de indivíduos submetidos a concentrações sub-letais deste IGR pode ser vantajosa, uma vez que tamanho está usualmente diretamente relacionado à aptidão do indivíduo
ABSTRACT
Phenotypic variations on developmental period, size and fluctuating asymmetry (FA) of Musca domestica L., induced by larval competition for food were described and correlated. Ten densities, varying from 100 to 1000 larvae per 75 g of wheat medium, were established in the laboratory and observed until adult emergence. The adjusted curve of survival was similar to a hyperbola. The developmental period extended with increasing densities, and the size was inversely proportional to the degree of larval crowding. Males and females responded differently to the selection pressures of competition, being size of the males much more variable than those of the females. Although morphological and physiological adjustments caused by environmental interaction were detected, the levels of fluctuating asymmetry remained invariable. Genetic correlation between these types of phenotypic variation was not detected. It can be supposed, however, that levels of FA, which are stress indicative, were minimized by the considerably plastic potential of the species. Thus, physiological and morphological adjustments reduced developmental difficulties and promoted survival of a greater number of individuals.
Foram descritas e correlacionadas as variações fenotípicas no período de desenvolvimento, tamanho e variações causadas por assimetria flutuante em Musca domestica L., induzidas por seleção para competição larval por alimento. Dez densidades de 100 a 1000 larvas por 75 g de farelo de trigo umedecido foram estabelecidas em laboratório e acompanhadas até a emergência dos adultos. A curva ajustada de sobrevivência foi semelhante a uma hipérbole. O período de desenvolvimento se estendeu com o aumento da densidade, mas o tamanho foi inversamente proporcional ao grau de agregação larval. Machos e fêmeas respondem de modo distinto às pressões de seleção para competição, sendo machos mais variáveis que fêmeas quanto ao tamanho. Embora ajustes morfológicos e fisiológicos provocados por ação ambiental tenham sido detectados, os níveis de assimetria flutuante permaneceram invariáveis. Não foram, portanto, detectadas correlações genéticas entre estes tipos de variações fenotípicas. Pode-se supor, entretanto, que níveis de assimetria flutuante, que podem ser indicativos de estresse, tenham sido minimizados pelo grande potencial plástico da espécie. Assim, ajustes fisiológicos e morfológicos estariam diminuindo dificuldades no desenvolvimento e promovendo a sobrevivência de maior número de indivíduos.