The aim of this study was to detect and describe the trends in shape variability of proximal and distal human tibia related to sex, age, social status and time period. The variability of its shape and form was analysed first in an early medieval sample, then in two modern populations, an early 20th century sample and the contemporary Czech population. Finally, data from the whole studied time span were analysed. The initial raw data were acquired by optical scanning and computed tomography (CT) scanning of the lower limbs; the three-dimensional bone surfaces of the contemporary tibias were segmented from the clinical CT scan sequences. Geometric morphometrics and multivariate statistical methods were applied to study the variations in shape and form quantitatively. Proximal and distal tibias were evaluated independently, and the potential influence of sex, age at death and time period were investigated. In the early medieval population, we also explored the relationship between tibial morphology and presumed social status derived from the respective grave location within the settlement. Because traditional morphometric analysis revealed statistically significant sex differences in the parameters of both tibial extremities (e.g., Steyn and Işcan, 1997; Šlaus et al., 2013), we thus assumed the...

The importance of sex hormones in formation, development and regulation of sexually dimorphic behavior does not need to be stressed. However, their actual organizational and activational effects and interactions in sexual differentiation and determination are not fully understood yet. The aim of our study was to explore the effects of hormonal manipulation in eyelid-geckos (family Eublepharidae) and enlighten the role of steroid hormones in formation of sexual differences. In the first part of our work we tried to reverse sex of Yucatán banded gecko (Coleonyx elegans) by hormonal manipulation in the early embryogenesis. This species has genotypic sex determination with chromosome set X1X2Y. In reverted individuals we aimed to examine the effects of steroid hormones on sexually dimorphic traits and in case of full sexual reversion and fertility of progeny, we would search for the sex-determining gene. In the second part, we studied masculinization effects of testosterone in females of leopard gecko (Eublepharis macularius). In contrast with the Coleonyx elegans mentioned above, this species has temperature dependent sex determination, even though these two species are closely related. Experimental females were implanted with testosterone implants and therefore their testosterone levels were increased in...

My study researches the individual male characteristics of Cordulegaster boltonii in relation to their epigamic behavior. The first part of this study analyzes the relations of the measured characteristics (length and height of the wing, wings area, body weight, age), in the second part I assess their possible effect on the epigamic behavior of males of Cordulegaster boltonii, specifically how they affect the intensity of searching for females. Males of this species perform distinctive scanning flights over a stream to find an ovipositing female to mate with her. I used individually marked males to quantify their performance which can be interpreted as reproductive success because more active males are more likely to meet and mate females. My work includes 3 methods of evaluating activity. The first is based on the actual number of flights, the second on the average daily order of the males (based on the number of flights in days when the males have been seen). The third method combines the average daily order with number of days when the males could be seen. In the second part of the study I evaluate the effect of the above-mentioned individual characteristics on the flight activity of males. The outcome of the GLM indicates that the only characteristic with significant effect is the age of the...

Ainda que existam diversos registros de formas extremas de dimorfismo sexual, a função do alongado quarto par de pernas nos machos de muitas espécies de opiliões permanece desconhecida. Neste estudo, testamos quatro previsões sobre a hipótese de que a seleção sexual está direcionando o alongamento do quarto par de pernas nos machos de Longiperna zonata e Promitobates ornatus: (1) o coeficiente alométrico do comprimento do fêmur IV em machos será maior do que o das fêmeas; (2) machos com pernas IV mais compridas vão residir próximos a grupos de fêmeas; (3) machos envolvidos em interações agressivas terão fêmures mais compridos do que o tamanho médio da população; (4) a diferença de tamanho de perna entre os oponentes será menor do que a diferença esperada entre pares de machos escolhidos ao acaso na população. Como o previsto, o coeficiente alométrico do fêmur IV foi significativamente maior em machos do que em fêmeas nas duas espécies. O comprimento do fêmur IV está positivamente relacionado à chance de um macho ser encontrado próximo a um grupo de fêmeas. Finalmente, a média do comprimento do fêmur IV dos machos envolvidos em brigas foi significativamente maior que a de machos selecionados ao acaso da população. Adicionalmente, a média da diferença de tamanho entre pares de machos que brigaram foi significativamente menor que a média da diferença de tamanho de perna entre pares de machos selecionados ao acaso na população. Assim, a seleção sexual na forma de competição entre machos parece estar direcionando o dimorfismo sexual extremo no comprimento do fêmur nessas duas espécies de opiliões. / Although there are many reports of extreme forms of sexual dimorphism in harvestmen, the function of the elongated fourth pair of legs in males of many species remains unknown. We tested four predictions to address the hypothesis that sexual selection is driving the enlargement of the fourth pair of legs in males of Longiperna zonata and Promitobates ornatus: (1) the allometric coefficient of femur IV length in males will be higher than in females; (2) males with longer legs IV will reside closer to groups of females; (3) males involved in aggressive interactions will have longer femur IV than the population average size; (4) the size difference between contenders will be smaller than the difference expected between randomly chosen pairs of males in the population. As predicted, the allometric coefficient of femur IV length was significantly higher in males than in females of both species. Femur IV length was positively related to the chance of a male being found close to a group of females. Finally, the mean femur IV length of the males involved in fights was significantly larger than the mean of random samples of males from the population, and the average difference between male contenders was smaller than the average random expected difference of the population. Therefore, sexual selection in the form of male-male competition seems to be driving the extreme sexual dimorphism in femur length in these species.

Enquanto muitas espécies de mosquitos são conhecidas por sua importância epidemiológica, a capacidade vetorial de algumas ainda não é clara. A identificação taxonômica, bem como a sexagem dos espécimes de Culicidae são essenciais para qualquer estudo ou ação, entretanto muitas vezes caracteres-chave estão danificados ou são restritos a uma fase de vida do animal. Em espécies crípticas, a identificação dos espécimes também pode ser prejudicada, o que dificulta, sobretudo, a compreensão da atividade vetorial em mosquitos. A morfometria geométrica alar, uma técnica barata e precisa para identificação de sutis dissimilaridades morfológicas, pode contribuir para a resolução destes tipos de problemas. O grupo de pesquisa MosquitoLab aplica esta técnica há mais de 10 anos e acumulou milhares imagens de asas com seus respectivos metadados. Estas informações, se organizadas como banco de dados relacional, podem permitir a sistematização do uso, consulta e armazenamento dos dados, além de viabilizar novos estudos e servir também como base para aplicações de identificação automática de mosquitos. Portanto, os objetivos deste trabalho foram avaliar a utilidade da morfometria geométrica alar para a resolução de dois problemas biológicos: dimorfismo sexual e espécies crípticas, e desenvolver um protótipo de plataforma para armazenamento de dados biológicos relacionados à morfometria de asa, por meio de um banco de dados relacional e um sistema web nomeado WingBank. Com base na técnica de morfometria geométrica alar, dois estudos de caso foram realizados: a) avaliação do dimorfismo sexual de 10 espécies de mosquitos de interesse médico e, b) diferenciação morfológica alar de Anopheles strodei s.s. e Anopheles arthuri s.l. com base em dois diferentes conjuntos de pontos anatômicos. Para construção do protótipo do WingBank uma equipe multidisciplinar realizou levantamento de requisitos, modelagem e criação do banco de dados relacional, e implementação de uma plataforma web. Os resultados referentes ao dimorfismo sexual alar apresentaram significativa diferenciação entre os sexos e padrões específicos de forma alar em todas as espécies estudadas. Os pontos anatômicos alares mais variáveis foram os das regiões proximal e distal das veias mediana e radial. Fêmeas apresentaram asas significativamente mais largas e curtas do que os machos. Diferenciação morfológica alar entre as espécies crípticas avaliadas foi observada em ambos os conjuntos de dados (18 e 22 pontos), sendo que no conjunto de 22 pontos com alometria, foi mais evidente. Os pontos anatômicos mais variáveis nas análises com os conjuntos de 18 e 22 pontos foram 1, 2 e 17, e 1, 2, 19, respectivamente. Finalmente, o protótipo WingBank foi implementado com dados referentes a 77 espécies pertencentes a 15 gêneros de Culicidae. Ao todo foram catalogados 13.287 registros de asas, dos quais 2.138 já estão disponibilizados a partir do presente trabalho, para uso de terceiros. Globalmente, este é o maior banco de dados de asas de Culicidae de que temos conhecimento. / While many species of mosquitoes are known for their epidemiological importance, the vector capacity of some is still unclear. Taxonomic identification and sexing of Culicidae specimens are essential for any study or action; however, often key characters are damaged or restricted to a stage of life of the animal. In cryptic species, the identification of specimens can also be damaged, which makes it difficult to understand the vector activity in mosquitoes. Geometric morphometry, an cheap and precise technique for identifying subtle morphological dissimilarities, may contribute to the resolution of these types of problems. The MosquitoLab research group has applied this technique for more than 10 years and has accumulated thousands of wing images with their metadata. This information, if organized as a relational database, may allow the systematization of the use, consultation and storage of the data, besides making possible new studies and lso serve as a basis for applications of automatic identification of mosquitoes. Therefore, the aims of this work were to evaluate the usefulness of the geometric morphometry to solve two biological problems: sexual dimorphism and cryptic species, and to develop a prototype of plataform for the storage of biological data related to wing morphometry, by means of a relational database and a web system named \"WingBank\". Based on the technique of wing geometric morphometry, two case studies were carried out: a) evaluation of the sexual dimorphism of 10 species of mosquitoes of medical importance and b) wing morphological differentiation of Anopheles strodei s.s. and Anopheles arthuri s.l. based on two different sets of landmarks. In order to build the WingBank prototype a multidisciplinary team performed requirements survey, modeling and creation of the relational database, and implemented a web platform. The results regarding wing sexual dimorphism showed significant differentiation between the sexes and specific patterns of wing shape in all species studied. The most variable landmarks were those of the proximal and distal regions of the medial and radial veins. Females showed slightly and significantly wider and shorter wings than males. Wing morphological differentiation between An. strodei s.s. and An. arthuri s.l. was observed in both sets of data (18 and 22 landmarks), but in the set of 22 with allometry, it was more evident. The most variable landmarks in the analyzes with the sets of 18 and 22 landmarks were 1, 2 and 17, and 1, 2, 19, respectively. Finally, the WingBank prototype was implemented with data referring to 77 species belonging to 15 genera of Culicidae. In all, 13,287 wing records were cataloged, of which 2,138 are from the present work, already available for use by third parties. Globally, as far as we know, this is the largest database of Culicidae wings.

Submitted by Mariana Dornelles Vargas (marianadv) on 2015-03-17T19:15:15Z No. of bitstreams: 1 caracterizacao_demografica.pdf: 744506 bytes, checksum: 42673cbee87c239733082fd6c361167a (MD5) / Made available in DSpace on 2015-03-17T19:15:15Z (GMT). No. of bitstreams: 1 caracterizacao_demografica.pdf: 744506 bytes, checksum: 42673cbee87c239733082fd6c361167a (MD5) Previous issue date: 2010 / Nenhuma / No presente estudo são apresentados os primeiros parâmetros populacionais para a população de Phrynops hilarii do Lago dos Pedalinhos no Parque Farroupilha (30º02'13"S; 51º13'03"W), Porto Alegre, Brasil. Esta população foi analisada quanto a sua estrutura, abundância, razão sexual e existência de dimorfismo sexual em tamanho. As capturas dos espécimes foram realizadas semanalmente entre 8:30h e 15:00h, em dois dias consecutivos, entre maio e dezembro de 2009. Todos os indivíduos capturados foram pesados, sexados (sempre que possível) e marcados com um número individual de identificação. Em adição, em cada espécime capturado foram realizadas nove medidas lineares externas. Após o fim do procedimento, todos os indivíduos capturados foram liberados no mesmo local onde foram coletados. A abundância da população foi estimada através do método para populações abertas de Jolly-Seber e a razão sexual foi obtida através da divisão do número total de machos pelo total de fêmeas. A existência de dimorfismo sexual nas medidas externas foi testada pelo teste-t, apenas para os indivíduos sabidamente adultos e de sexo conhecido. Como resultados foram capturados 53 espécimes de P. hilarii durante o período de estudo, dos quais 16 eram machos, 25 eram fêmeas e 12 indivíduos tiveram o sexo não determinado. Além disso, 77% eram adultos e 22% subadultos. A abundância populacional de P. hilarii no Lago dos Pedalinhos foi estimada em 282,67 indivíduos e a razão sexual foi significativamente diferente de 1:1 e inclinada a favor das fêmeas, com a existência de um macho para cada 1,56 fêmeas. O resultado do teste-t indicou a existência de um acentuado dimorfismo sexual no tamanho, sendo as fêmeas, de uma maneira geral, maiores que os machos, à exceção das medidas da distância máxima da base da cauda ao orifício cloacal e da distância máxima da base à ponta da cauda. Nos quelônios o dimorfismo sexual no tamanho é comum e isto poderia ser um dos fatores que influenciam na maturação e no crescimento diferencial entre os sexos de uma mesma espécie. Acredita-se que a população de P. hilarii do Lago dos Pedalinhos é resultante, principalmente, de indivíduos descartados pela comunidade local, após terem sido mantidos em cativeiro (como animais de estimação) por algum período. Os dados obtidos no presente estudo demonstram que apesar das populações de quelônios de parques urbanos estarem vivendo em áreas altamente antropizadas, elas ainda seriam capazes de manter parâmetros populacionais semelhantes aos das populações naturais de vida livre, sugerindo que estes animais seriam extremamente resistentes às pressões antrópicas. A maior causa de mortalidade dos quelônios em parques urbanos é em decorrência de maus-tratos, atropelamentos, predação e ataque de animais domésticos, bem como por poluição e competição com espécies afins que ocupam o mesmo ambiente (Trachemys dorbigni e T. scripta elegans). Por fim, as populações de P. hilarii de parques urbanos também poderiam servir de modelo na compreensão dos reais efeitos da atividade humana sob quelônios de vida livre em outras áreas impactadas. / In this study is presented the first population parameters to the population of Phrynops hilarii from “Lago dos Pedalinhos” (30º02'13"S; 51º13'03"W), an urban lake from the city of Porto Alegre – Brazil. The population structure, size, abundance, and sex ratio as well sexual dimorphism in size were analyzed. The captures and data collection were conduced weekly, between May and December 2009. All the captured specimens were weighed, sexed (whenever possible) and marked with a number of identification. In order to evaluate the differences in size between sexes nine body measurements were taken from adult males and females. After completed the procedure, all individuals captured were released in the same place that they were caught. The population abundance was estimated by Jolly-Seber method for open populations and the sex ratio was calculated by the division between the total number of males and females. The sexual dimorphism in body measurements were tested between sexes using t-test, just for adult individuals with known sex. As a result, 53 specimens of P. hilarii were captured, which 77% were adults and 22% subadults. From this total, 16 were males, 25 females and 12 were of unknown sex. The population abundance of P. hilarii in the study area was estimated in 282.67 specimens. The sex ratio was statistically different from the expected ratio 1:1 and was biased in favor of females (1 male to 1.56 females). The t-test results revealed pronounced sexual dimorphism in body size, with females being larger than males, with the exception of the tail’s measurements (CCD1 and CCD2). In chelonians the sexual dimorphism in size is common and it may be one of the factors that influence the maturation and differential growth between the sexes. It is believed that studied population is formed, mainly, by animals released by the local co mmunity, after being kept in captivity, like pets. The observed results suggest that the ch elonian populations that live in urban parks are able to keep the regular population parameters similar to the wild populations of the species, even living in highly impacted areas. In addition, it indicates that this population is extremely resistant to anthropogenic pressure. The mortality of chelonians in urban parks generally is due to direct human actions, such as maltreatment, running over, predation and by the attack of domestic animals, as well pollution and competition with related species that live in the same area (Trachemys dorbigni and T. scripta elegans). Finally, the study of chelonians from urban parks could be used as a model for under standing the real effects of the human activity on the wild populations of freshwater turtles

Submitted by Maicon Juliano Schmidt (maicons) on 2015-04-18T15:33:42Z No. of bitstreams: 1 Roberta da Cruz Piuco.pdf: 5094425 bytes, checksum: b68193551bc07bd504e42c0ebcc4e3e5 (MD5) / Made available in DSpace on 2015-04-18T15:33:42Z (GMT). No. of bitstreams: 1 Roberta da Cruz Piuco.pdf: 5094425 bytes, checksum: b68193551bc07bd504e42c0ebcc4e3e5 (MD5) Previous issue date: 2013-11-21 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / CNPQ – Conselho Nacional de Desenvolvimento Científico e Tecnológico / UNISINOS - Universidade do Vale do Rio dos Sinos / INCT-APA - Instituto Nacional de Ciência e Tecnologia Antártico de Pesquisas Ambientais / Programa Antártico Brasileiro / SECIRM - Secretaria Interministerial para os Recursos do Mar / MMA - Ministério do meio Ambiente / O pinguim-papua (Pygoscelis papua) reproduz a partir de 46°S a 65°S. Apesar de sua ampla distribuição são consumidores costeiros e não migratórios, possuem um alto nível de filopatria e as populações estão restritas a ilhas de reprodução e faixas de forrageamento e apresentam variações contrastantes entre populações. Esta tese tem como objetivos: 1) avaliar as respostas do tamanho da população reprodutiva de pinguim-papua de acordo com fatores climáticos em Stinker Point, Ilha Elefante; 2) identificar o dimorfismo sexual de tamanho em caracteres morfométricos em adultos reprodutores de pinguins-papua em Stinker Point, Ilha Elefante, comparando-se com a técnica de sexagem molecular. Além disso, verificar a variação morfométrica da espécie em três locais do Arquipélago das Shetlands do Sul e comparar com dados da literatura e 3) quantificar um tipo potencial de assimetria em pinguins-papua nas ilhas Elefante e Rei George, caracterizando seus níveis assimétricos como uma forma de avaliar a qualidade do ambiente. A população reprodutiva de pinguim-papua respondeu significativamente ao Índice de Oscilação Antártica e à anomalia de temperatura durante o início do período reprodutivo. Provavelmente pelas variações climáticas extremas interferirem na decisão dos indivíduos de reproduzir ou não em um determinado ano. Na avaliação do dimorfismo sexual, através de medidas morfométricas, o comprimento do bico foi a medida de maior dimorfismo sexual (5,3%) e classificou corretamente 76,7% das aves, sendo em média as fêmeas maiores que os machos. Dentre as medidas morfométricas analisadas, todas apresentaram diferenças entre os locais do Arquipélago das Shetlands do Sul e Península Antártica. Dada a pouca acurácia das funções discriminantes na sexagem e as diferenças das medidas morfométricas conforme a área geográfica de pinguim-papua, é preciso ter cautela ao classificar indivíduos com base em uma única avaliação, de forma que a sexagem molecular apresentou melhor resultado. Quanto ao tipo de assimetria, os níveis observados refletem um padrão de assimetria flutuante (AF), porém sem diferença significativa. A ausência de altos níveis de AF indica que não há níveis cumulativos suficientes de estresses ambientais que pudesse causar distúrbios fisiológicos e alterar a homeostase do desenvolvimento normal nesta espécie na Antártica. / Gentoo penguin (Pygoscelis papua) breed from 46ºS to 65ºS. Despite its wide distribution are inshore consumers and non-migratory, have a high level of philopatry and populations are restricted to island breeding and foraging ranges and shown variations contrasting among populations. This thesis aims to: 1) to evaluate the breeding population size responses of the Gentoo penguin according to climate factor at Stinker Point, Elephant Island; 2) to identify the sexual dimorphism of size in the morphometric characteristics of male and female adult Gentoo penguins at Stinker Point, Elephant Island, compared with the technique of molecular sexing. Furthermore, to verify morphometric variation of the specie at three sites f the South Shetlands Archipelago and compare with literature data and 3) to quantify one kind of potential asymmetry in Gentoo penguins, breeding at Elephant and King George Islands and attempt to characterize their extremes of variation as a way of evaluating the current living quality of the environment. The breeding population size of Gentoo penguin responded significantly to the Antarctic Oscillation Index and the temperature anomaly during the early reproductive period. Probably by extreme climatic variations affecting the decision on breeding or skipping breeding in a given year. In the assessment of sexual dimorphism using morphometric characters, the bill length was the larger measure of sexual dimorphism (5.3%) and correctly classified 76.7% of the birds, were found females larger than males. Among the morphometric measurements analyzed, all showed differences among the sites of the South Shetlands Archipelago and Antarctic Peninsula. Given the limited accuracy of the discriminant function sexing and differences of these morphometric measurements according to the geographical area of Gentoo penguin, is necessary have caution to classify individuals based on a single assessment, so that the molecular sexing presented best result. For the type of asymmetry, the levels of asymmetry reflect a fluctuating asymmetry (FA) pattern, however no significant difference. Absence of high levels of observed FA in our study led us to think it indicates there are not sufficient cumulative levels of environmental stresses such that they might cause physiological disturbances and alter the homeostasis of normal development in this species in Antarctica.

A wide variety of factors are predicted to influence the intensity and outcome of agonistic interactions in animals, including the resource holding potential of the opponents and the nature and value of the resource over which the individuals are competing. Field crickets (Orthoptera: Gryllidae) have been used extensively as model organisms with which to study animal contests, but relatively few studies have examined the effect of mandible size or structure, or the level of contact with females on the intensity and outcome of agonistic interactions. To do so was the aim of the present thesis, using Gryllus bimaculatus as the study species. The first finding of this study was that there is a significant degree of sexual dimorphism for anterior components of the anatomy in G. bimaculatus. The mandibles, head and pronotum of male crickets were all relatively larger than those of females. This indicates that these traits may be acted upon by intrasexual selection. In many animal species that show sexual dimorphism, a trade-off in development sees enhanced weapon growth at the expense of testes size, but no such relationship was seen in this species. A comparison of the mandible structure of males that either won or lost at flaring and or wrestling showed that a relatively wider mandible span was a significant predictor of success during mandible displays. It was also found that specific components of tooth structure, namely the length of the incisor and length to distal tip, were significantly associated with victory at the jaw flaring stage. This is the first time that mandible shape has been shown to affect fight outcome in the Gryllidae, and also the first confirmed identification of a visual cue component of fighting behaviour. Despite the effectiveness of their weapons in fighting, body mass is a primary predictor of victory in combat between G. bimaculatus males, with the greater the degree of asymmetry in weight the more likely the heavier fighter will win. However, a study of fighting behaviour between asymmetrically matched opponents found that even males who were out-weighed by 40% were still likely to escalate the fight to grappling. Furthermore, males who were able to fend off their larger opponent in their first clash were significantly more likely to win their overall encounter. This hyper-aggressive response may therefore represent an adaptive mechanism to extreme odds and is worthy of further study. Female contact is known to be a significant promoter of male aggression and fighting enthusiasm, and mate guarding aggression is well documented in G. bimaculatus. A recreation of two contradictory studies, including one which concluded that mating makes males lose fights, highlighted that female contact after spermatophore transfer can overcome the loser effect and cause a male to re-engage with a previously dominant opponent. Fighting behaviour in this species is therefore highly flexible and factors affecting the outcome of contests are complex. There is much scope for further studies on this topic.

O dimorfismo sexual varia consideravelmente entre populações dentro de uma mesma espécie. Essa variação na direção e na magnitude do dimorfismo sexual é, em parte, devida às diferenças sexuais na respostas plásticas às condições e aos recursos ambientais. Por meio de experimentos em laboratório, sabe-se que a temperatura e a disponibilidade de alimento são fatores importantes na geração de variações morfológicas inter-individuais e que seus efeitos diferem entre machos e fêmeas. Usamos indivíduos da tesourinha Labidura xanthopus (Dermaptera) coletados em 20 localidades ao longo da costa brasileira para investigar como o tamanho corporal e o tamanho do armamento de machos e fêmeas variam em um gradiente natural de temperatura. O tamanho do corpo diminuiu com o aumento da temperatura, mas o dimorfismo sexual se manteve constante ao longo do gradiente de temperatura. Para o tamanho do armamento, encontramos uma relação negativa para machos e positiva para fêmeas. Conseqüentemente, a magnitude do dimorfismo sexual no tamanho do armamento diminuiu ao longo do gradiente de temperatura. Para entender o efeito da disponibilidade de alimento sobre a expressão de características morfológicas em cada um dos sexos, manipulamos a dieta durante o desenvolvimento de indivíduos provenientes de uma população de clima tropical e uma de clima temperado. Independente da população, o dimorfismo sexual foi causado por diferenças sexuais na dependência de condição. Machos e fêmeas diferiram não apenas na magnitude da resposta, mas também na direção. Em relação ao comprimento relativo dos fórceps, em particular, os resultados obtidos em laboratório não apóiam que a variação encontrada em campo se deve à disponibilidade de alimento. Outros fatores que não levamos em consideração, tais como densidade populacional, podem exercer um papel importante na resposta de machos e fêmeas em relação ao tamanho do armamento. Por fim, mais estudos experimentais comparando populações com diferenças marcantes de condições ambientais poderão lançar luz sobre quais fatores ecológicos podem ter favorecido a evolução do dimorfismo sexual dependente de condição / Sexual dimorphism varies considerably among populations within species. This variation in the direction and magnitude of sexual dimorphism is partially explained by sexual differences in phenotypically plastic responses to environmental conditions and resource availability. Laboratory experiments have already shown that temperature and food availability are important factors promoting inter-individual morphological variation and that their effects differ between males and females. We used individuals of the earwig Labidura xanthopus (Dermaptera) collected from 20 Brazilian localities to investigate how body size and weapon size of males and females vary across a natural temperature gradient. Body size decreased with increasing temperature, but sexual size dimorphism remained constant across the temperature gradient. For weapon size, we found a negative relationship for males and a positive relationship for females. Thus, the magnitude of sexual dimorphism in weapon size decreased across the temperature gradient. To understand the effect of food availability on the expression of morphological traits in each sex, we manipulated the diet of individuals from a tropical and temperate population. Regardless of the population, sexual dimorphism was caused by sex-differences in condition dependence. Males and females differed not only in the magnitude of their responses, but also in the direction. Regarding the relative length of the forceps, in particular, our results do not support the interpretation that the morphological variation observed in the field is explained by differences in food availability. Other factors not considered here, such as population density, may play an important role in determining weapon size variation in males and females under natural conditions. Finally, more experimental studies comparing populations with marked differences in environmental conditions may shed light on which ecological factors have favored the evolution of condition-dependent sexual dimorphism

No description available.