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Influência da pressão atmosférica no comportamento sexual dos insetos / Influence of atmospheric pressure on the sexual behavior of insectsAna Cristina Pellegrino 29 November 2011 (has links)
Tempestades acompanhadas por diferentes combinações de ventos, chuvas, variações bruscas de temperatura e de radiação solar são manifestações climáticas frequentemente associadas com queda na pressão atmosférica. Para os insetos, especialmente os pequenos insetos, estas condições de mau tempo são desfavoráveis e podem acarretar alta mortalidade na sua população. Neste trabalho foi demonstrado que as mudanças na pressão atmosférica influenciaram várias atividades do comportamento sexual nos insetos em ao menos três ordens, representados por Pseudaletia unipuncta (Haworth) (Lepidoptera: Noctuidae), Macrosiphum euphorbiae (Thomas) (Hemiptera: Aphididae) e Diabrotica speciosa (Germar) (Coleoptera: Chrysomelidae). Os parâmetros comportamentais observados foram: (i) Resposta de atração do macho ao feromônio sexual (para D. speciosa); (ii) comportamento de chamamento das fêmeas (para P. unipuncta e M. euphorbiae); e (iii) comportamento de cópula (para D. speciosa, P. unipuncta e M. euphorbiae). Estes parâmetros, por sua vez, foram analisados sob diferentes condições de pressão atmosférica no Brasil (Bra) e Canadá (Can). Levando-se em conta dados históricos nestes locais, foi definido como condições estáveis de pressão atmosférica variações de ±1,5mbar (Bra) e ±1,0mbar (Can); aumento de pressão variando de +2,0mbar (Bra) e +4,0mbar (Can); e queda de pressão variando de -2,0mbar (Bra) e -4,0mbar (Can), ao longo das seis horas anteriores a cada bioensaio. Os machos de D. speciosa responderam ativamente ao feromônio sexual em condições estáveis e de aumento da pressão atmosférica, porém permanecerem imóveis em condições de queda da pressão atmosférica. As fêmeas de P. unipuncta realizaram comportamento de chamamento sob condições estáveis e aumento da pressão atmosférica, reduzindo sensivelmente este comportamento quando houve queda da pressão atmosférica. As fêmeas de M. euphorbiae apresentaram comportamento de chamamento apenas em condições estáveis de pressão atmosférica, e permaneceram em repouso sob aumento e queda da pressão atmosférica. O comportamento de cópula em P. unipuncta e M. euphorbiae foi realizado preferencialmente sob condições estáveis de pressão atmosférica, e intensamente reduzidos em condições de queda e aumento de pressão atmosférica. Em D. speciosa, apesar dos casais terem realizado a cópula, independentemente das variações observadas de pressão atmosférica, o tempo investido e as sequências comportamentais durante essas cópulas foram encurtadas nas condições de queda da pressão atmosférica. Os resultados aqui apresentados demonstraram que o comportamento sexual dos insetos foi influenciado pelas variações da pressão atmosférica, e aparentemente, a percepção antecipada dessas variações teria um valor adaptativo importante, selecionando os indivíduos mais aptos, permitindo assim sua sobrevivência em razão das mudanças bruscas nas condições atmosféricas. / Storms accompanied by different combinations of wind, rain, sudden changes in temperature and solar radiation are climatic events often associated with decreasing atmospheric pressure. For insects, especially small insects, these weather conditions are unfavorable and can cause high mortality in a population. This study showed that changes in atmospheric pressure affected various activities of the sexual behavior in insects of at least three orders, represented by Pseudaletia unipuncta (Haworth) (Lepidoptera: Noctuidae), Macrosiphum euphorbiae (Thomas) (Hemiptera: Aphididae) and Diabrotica speciosa (Germar) (Coleoptera: Chrysomelidae). The behavior parameters observed were: (i) male response to sex pheromone (for D. speciosa), (ii) calling behavior of females (for P. unipuncta and M. euphorbiae) and mating behavior (for D. speciosa, P. unipuncta and M. euphorbiae). These parameters were analyzed under different atmospheric pressure conditions in Brazil (Bra) and Canada (Can). According to historic data in these locations, the variations in atmospheric pressure were determined as stable when varying ±1,5mbar (Bra) and ±1,0mbar (Can); increasing when varying +2,0mbar (Bra) and +4,0mbar (Can) and decreasing when varying -2,0mbar (Bra) and -4,0mbar (Can), throughout six hours preceding each bioassay. D. speciosa males responded to the sex pheromone in stable and increasing atmospheric pressures, but remained still in decreasing atmospheric pressure. P. unipuncta females called under stable and increasing atmospheric pressures, and reduced its behavior considerably when there was a decrease in atmospheric pressure. M. euphorbiae females called only under stable atmospheric pressure, and remained still under increasing and decreasing atmospheric pressures. The mating behavior in P. unipuncta and M. euphorbiae occurred preferably under stable conditions, and was reduced in increasing and decreasing atmospheric pressures. D. speciosa, despite mating under variations in atmospheric pressure, invested less time and shortened the behavioral sequences under decreasing pressure. The results presented here demonstrated that the sexual behavior of insects was influenced by variations in atmospheric pressure and, apparently, the early perception of these changes may add an important adaptive value to them, since it selects those who respond to these conditions, allowing their survival under changes in climatic conditions.
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Seleção sexual e evolução do dimorfismo sexual em duas espécies de opiliões (Arachnida: Opiliones) / Sexual selection on male weaponry in two neotropical harvestmen (Arachnida: Opiliones)Camila Zatz de Oliveira Santos 15 April 2010 (has links)
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.
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Sexo no espaço / Sex in spaceDanilo Germano Muniz da Silva 25 September 2015 (has links)
O objetivo geral desta tese foi investigar como a distribuição espacial dos indivíduos influencia a organização dos sistemas de acasalamento e a intensidade da seleção sexual. A tese contém dois capítulos em que analisamos dados empíricos e dois capítulo em que abordamos questões mais teóricas mais gerais. No primeiro capítulo, avaliamos como a distribuição espacial de haréns defendidos por machos territoriais influencia a rede de competição espermática que existe entre machos do opilião Serracutisoma proximum. No segundo capítulo, propusemos um modelo probabilístico de escolha de parceiros que leva em consideração o fato de que as fêmeas estão restritas a amostrar apenas alguns machos da população, e que essa restrição é imposta principalmente pela distribuição espacial dos indivíduos. Nosso modelo foi mais acurado do que modelos alternativos que ignoram o espaço. No terceiro capítulo, investigamos os movimentos de busca de parceiros do besouro Leptinotarsa undecimlineata. Encontramos que tanto machos quanto fêmeas se movimentam estrategicamente, saindo de onde estão quando não obtém cópulas buscando áreas próximas e com muitos parceiros em potencial. Finalmente, no quarto capítulo, voltamos a explorar o efeito de restrições espaciais sobre a escolha de parceiros. Usamos simulações baseadas em indivíduos para investigar como a restrição espacial influencia a seleção sexual e a evolução de ornamentos sexualmente selecionados. Encontramos que quanto maior o número de parceiros que as fêmeas podem amostrar durante a escolha, mais intensa é a seleção sexual, o que permite a evolução de ornamentos mais exagerados nos machos. Além disso, analisamos um conjunto de dados publicados sobre a intensidade de seleção sexual e observamos que estes se ajustam às previsões do modelo teórico. Concluímos que o espaço é muito mais importante para a organização de sistemas de acasalamento e para a intensidade da seleção sexual do que se acreditava previamente. Esperamos que as idéias propostas aqui encontrem terreno fértil na mente do leitor e que gerem novos e estimulantes desdobramentos no campo teórico e empírico / The main goal of this thesis was to investigate how the spatial distribution of individuals influences the organization of the mating systems and the intensity of sexual selection. The thesis contains two empirical chapters and two chapters with a theoretical scope. In the first chapter, we investigate how the spatial distribution of harems defended by territorial males influences the sperm competition network among males of the harvestman Serracutisoma proximum. In the second chapter, we proposed a probabilistic model of mate choice that includes the spatial constraint in the analyses of mate choice. This model takes into account the fact that females are restricted to sample only some males available in the population, and that this restriction is imposed primarily by the spatial distribution of individuals. In the third chapter, we investigate the mate searching movements of the leaf beetle Leptinotarsa undecimlineata. We found that both males and females move strategically, leaving the host plant when they do not obtain copulations and seeking neighboring areas with many potential mates. Finally, in the fourth chapter, we explore the effect of spatial restrictions on mate choice. We used individual based simulations to investigate how spatial restrictions influence sexual selection and the evolution of sexually selected ornaments. We found that the higher the number of potential partners female can sample during mate choice, the more intense is sexual selection, which leads to the evolution of more exaggerated male ornaments. In addition, we analyzed a published dataset of intensity of sexual selection and found that the data adjust to the predictions made by our simulations. We conclude that the space is much more important than previously thought to mating systems organization and the intensity of sexual selection. We hope the ideas proposed here can flourish in the minds of the readers, stimulating both empirical and theoretical follow ups
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Variabilidade genética e avaliação de sensibilidade a fungicidas em sclerotinia sclerotiorum proveniente de cultivo irrigado de feijoeiroArboleda, William Andrés López 27 March 2015 (has links)
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Previous issue date: 2015-03-27 / Sclerotinia sclerotiorum is a phytopathogenic fungus that infects more than 400 plant
species, including common bean. Genetic variability studies in connection with
phenotypic traits of agronomic interest are important to drive the control strategies
against this pathogen. The aims of this study were: to evaluate the genetic variability,
fungicide sensitivity, aggressiveness and to determine the proportion of MAT (Mating
Type) alleles of 79 isolates of S. sclerotiorum distributed in four populations from
common bean. Two populations represented a single sampling location in two
different times (2000 and 2013 growing seasons). To evaluate the fungicide
sensitivity a cell viability test based on the alamarBlue dye using mycelial growth was
standardized. Dose-response curves for fluazinam, procymidone and benomyl were
estimated using this test and were compared with dose-response curves estimated
by the mycelial growth inhibition on PDA plate and the FRAC (Fungicide Resistance
Action Committee) protocol. Despite the differences to assess the fungicide
sensitivity between the three methods, the dose-response curves showed similar
trends for the three fungicides. The fungicide sensitivity assessment at the four
populations showed low sensitivity to benomyl in the Planaltina population.
Furthermore, this population presented a principally clonal population structure, with
a haplotype represented by 18 out of 20 isolates. Significant population differentiation
in all pairwise comparisons of phi, except the comparison between EV_2013-NH,
was detected. Five genetically homogeneous groups were inferred by the DAPC
analysis. No group was conformed by isolates from the four populations. Only two
haplotypes between the two populations from the same sampling location were
shared. The hypothesis of random mating was rejected at the four populations;
however this hypothesis was not rejected at the two major populations inferred by the
DAPC analysis. The screening of mating type locus showed a dominance of Inv+
isolates and a high proportion of Inv+/Inv- isolates (presumable heterokaryons). / Sclerotinia sclerotiorum é um fungo fitopatogênico capaz de colonizar mais de 400
hospedeiras, sendo o agente causal do mofo branco no feijoeiro. Estudos de
variabilidade genética associados a características fenotípicas de interesse
agronômico, como a sensibilidade a fungicidas, oferecem informações importantes
para direcionar estratégias de controle sobre este patógeno. Os objetivos deste
trabalho foram avaliar a variabilidade genética, sensibilidade a fungicidas e
agressividade de 79 isolados de S. sclerotiorum distribuídos em quatro populações
procedentes de culturas de feijoeiro em pivô central. Duas destas populações
representaram um único local de coleta em duas épocas diferentes (2000 e 2013).
Para avaliar a sensibilidade a fungicidas foi padronizado um teste de viabilidade
celular baseado no corante alamarBlue® sobre o crescimento micelial em
microplaca de 96 poços. Curvas de dose-resposta para os fungicidas fluazinam,
procimidona e benomyl, usando um isolado de S. sclerotiorum, foram estimadas com
este método, e comparadas com curvas de dose-resposta obtidas com os métodos
de inibição do crescimento em placa e o proposto pelo Fungicide Resistance Action
Committee (FRAC). Apesar das diferentes abordagens as curvas dose-resposta
mostraram tendências semelhantes para os três fungicidas. A avaliação da
sensibilidade a fungicidas nas quatro populações indicou uma alta insensibilidade ao
benomyl na população de Planaltina. Por outro lado, a estrutura populacional foi
principalmente clonal com um haplótipo representado por 18 dos 20 isolados desta
população. Diferenciação populacional significativa foi detectada em todas as
comparações par a par do phi, com a exceção da comparação EV-2013-NH. A
analise DAPC identificou cinco grupos geneticamente homogêneos. Nenhum dos
grupos esteve constituído por isolados das quatro populações. Só dois haplótipos
foram compartilhados pelas populações EV_2000 e EV_2013. A hipótese de
acasalamento aleatório foi rejeitada nas quatro populações, no entanto não foi
rejeitada nas duas maiores populações sugeridas pelo DAPC. O screening do
Mating type locus (MAT) mostrou uma prevalência de isolados Inv+ e uma alta
proporção de isolados Inv+/Inv-
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Sistema reprodutivo e fluxo gênico via pólen em uma coleção de germoplasma de Eugenia dysenterica DC. / Mating system and pollen-mediated gene flow in a germplasm collection of Eugenia dysenterica DC.Rodrigues, Eduardo Borges 03 September 2012 (has links)
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Previous issue date: 2012-09-03 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The success of any breeding program or genetic resources conservation depends on the knowledge about gene flow, reproductive system and genetic variability in the studied populations. For perennial plants, germplasm collection maintained ‘in vivo’ and ‘ex situ’ can be an efficient method for conserving the genetic variability of a species is maintained outside its original habitat. This study aimed to evaluate the reproductive system and pollen-mediated gene flow in one generation of Eugenia dysenterica DC. from the germoplasma collection of the Escola de Agronomia e Engenharia de Alimentos from Universidade Federal de Goiás. We collected leaves from 404 adult plants and seeds from 23 mother-trees in the germplasm collection. Genotypes were obtained using eight microsatellite loci, four of them developed for E. dysenterica, and four transferred from Eucalyptus spp. The total number of alleles was 88, ranging from 4 to 20 for the eight loci analyzed (mean of 11 alleles per locus). The mean expected (He) and observed (Ho) heterozygosity were equal to 0.646 and 0.423, respectively. Additionally, the high combined paternity exclusion probability (QC= 0.99579), and the low combined probability of identity (IC = 7.9 x10-5) indicate that markers can be reliable for this kind of analysis. Multilocus outcrossing rates (t ̂_m= 0.957) and single locus outcrossing rates (t ̂_s= 0.848) were high. Biparental inbreeding (t_m-t_s =0,109) ) combined for all families analyzed was also high and significant, sugesting the occurrence of 10.9% of cross-fertilization between related individuals. Paternity correlation was also low (r ̂_p=0,119), with 11.9% of the progeny sired by cross-fertilization with the same pollen donor. On average 10.79% of the progeny analyzed were derived by biparental cross, whereas 84.70% were formed by multi-parental crosses, being related to the degree of half-sibs. Only 4.6% of the seeds were formed by selfing. Paternity was successfully assigned with 95% of confidence to 32% (171) of the seeds analyzed, most likely due to non-sampled candidate pollen donors or because the loci battery could not demonstrated the optimal values for the combined exclusion. The maximum pollen dispersal distance (224 m) corresponded to the length of the orchard. The “big-bang” flowering pattern and the aggregated spatial distribution of adults may have favored short distance pollen dispersal at the germplasm collection of E. dysenterica. Our results show that the E. dysenterica germplasm collection preserves the genetic diversity present in natural populations of southeastern Goiás and can be a reliable approach for maintenance of genetic diversity of the species for the future. / A definição de qualquer programa de melhoramento ou de conservação de recursos genéticos depende, inicialmente, do conhecimento do fluxo gênico, do sistema reprodutivo e da variabilidade genética existente nas populações. Nesse sentido, as coleções de germoplasma podem funcionar como um método de conservação in vivo e ex situ, em que amostras da variabilidade genética de determinada espécie é conservada fora do habitat da espécie. O objetivo geral desse estudo foi avaliar o fluxo via pólen de uma geração, o sistema reprodutivo e caracterizar molecularmente os indivíduos que compõem a coleção de germoplasma in vivo e ex situ de Eugenia dysenterica DC., mantida pela Escola de Agronomia e Engenharia de Alimentos da Universidade Federal de Goiás. Para tanto, foram coletadas folhas das 404 árvores e frutos de 23 árvores (matrizes) que compõem a coleção de germoplasma. Para a obtenção dos genótipos das árvores e das progênies foram utilizados oito locos microssatélites, quatro desenvolvidos para espécie e os outros quatro desenvolvidos para Eucalyptus ssp. e transferidos para E. dysenterica. Com base nos genótipos foram realizadas as análises descritivas de variabilidade genética, testes de paternidade, distância de dispersão de pólen e taxa de fecundação cruzada para todas as progênies. Para os oito locos analisados, o número de alelos foi igual a 88, variando entre 4 e 20 com uma média igual a 11 alelos por loco. Os valores médios de heterosigozidade esperada (He) e observada (Ho) foram iguais a 0,646 e 0,423. Avaliada a variabilidade genética nas duas gerações foi possível concluir que a coleção de germoplasma de E. dysenterica está preservando bem a diversidade genética oriunda das populações naturais da região sudeste do Estado de Goiás. Adicionalmente, a probabilidade de exclusão combinada (QC) foi igual a 0,99579 e a probabilidade de identidade combinada (IC) foi igual a 7,9x10-5. As taxas de cruzamento multiloco (t ̂_m) e uniloco (t ̂_s) foram altas e iguais a 0,957 e 0,848, respectivamente. A diferença da taxa de cruzamento multiloco e uniloco (t_m-t_s ) combinada para todas as famílias analisadas também foi positiva e significativa, indicando a ocorrência de 10,9% (t_m-t_s=0,109) de fecundação cruzada entre indivíduos aparentados. A correlação de paternidade foi baixa (r ̂_p=0,119) sugerindo que 11,9% dos indivíduos das progênies são filhos do mesmo doador de pólen. Em média 10,79% das progênies analisadas foram originadas por cruzamentos biparentais, sendo aparentados no grau de irmãos germanos, 84,70% foi formada por cruzamentos, sendo aparentados no grau de meios-irmãos e somente 4,6% das sementes foram formadas por autofecundação. Na análise de paternidade, apenas 32% (171) das sementes tiveram seus doadores de pólen atribuídos para um nível de confiança de 95%, o que pode ser explicado por três fatores: a presença de indivíduos juvenis não amostrados; a presença de outros indivíduos de E. dysenterica em outras estações experimentais próximas a coleção de germoplasma; ou pela bateria de locos, que não apresentou os valores considerados ótimos para a probabilidade de exclusão combinada. O efeito da floração “big-bang” e a distribuiçao agregada dos indivíduos adultos torna predominante os eventos de fecundação cruzada em curtas distâncias na coleção de germoplasma de E. dysenterica. O alcance máximo de dispersão de pólen foi de 224 m, esse valor abrange quase toda a área experimental da coleção de germoplasma.
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Influência das técnicas reprodutivas e tipo de acasalamento em programas de seleção de gado de corte e seu impacto no custo e na produção de tourinhos / Influence of the reproductive techniques and the kind of mating in programmes of beef cattle selection, and its impact on the cost and on the young bulls productionRicardo Carneiro Brumatti 30 June 2006 (has links)
A seleção e produção de touros para o mercado pecuário tornam-se foco de muitos estudos, e um grande desafio para o segmento em se tratando da constante busca de melhorias nos desempenhos produtivos dessa categoria animal. A tese teve por objetivo simular o que poderá acontecer com a produção de reprodutores, em termos de quantidades produzidas e custos operacionais efetivos, sob a influência dos métodos de acasalamentos e das biotécnicas reprodutivas disponíveis no mercado nacional. A hipótese em questão é a de testar se acasalar matrizes, classificadas por genótipo, suas produções serão melhores do que quando comparada à produção de matrizes classificadas por fenótipo. Foram simulados 42 cenários produtivos, divididos em 21 cenários com acasalamento genotípico e 21 com acasalamento fenotípico. Em cada divisão constam simulações com uso de Monta Natural, Inseminação Artificial padrão e com sêmen sexado para machos, Transferência de Embriões padrão e com sêmen sexado para machos, Fecundação in vitro padrão e com sêmen sexado para machos, sendo que em todos os casos três níveis diferentes de taxas de concepção foram testados. Os resultados apontaram que o sistema de acasalamento teve influência direta na produção de tourinhos, sendo que o acasalamento por genótipo foi mais eficiente do que o acasalamento por fenótipo. As taxas de concepção influenciaram negativamente mais os resultados dos sistemas de acasalamento fenotípico. Há um grande aumento no custo operacional efetivo dos sistemas que utilizaram as biotécnicas reprodutivas de Transferência de Embriões e Fecundação in vitro, e consequentemente uma redução na lucratividade destes sistemas. As simulações com Monta Natural apresentaram as maiores Margens Brutas e as simulações com Inseminação Artificial com uso de sêmen sexado para machos apresentaram os maiores Lucros Brutos. / The selection and production of bulls for the cattle market have both become the goal of many studies, as well as a great challenge for the segment, providing the constant search for performance improvement of that sort of animal. The target of this thesis is to simulate what may happen to the production of stud, in terms of quantity and effective operational costs, under the influence of the mating methods and the available reproduction biotechniques in the national market. The hypothesis under analysis consists of testing if mating matrices, classed by their genotype, their produce will be better than when compared to the produce of phenotype-classed matrices. 42 productive-scenes, divided into 21 genotype mating and 21 phenotype mating were simulated. In each of the scene divisions there were the following simulations: Natural Breeding, standard Artificial Insemination, Artificial Insemination with male-gendered semen, standard Embryo Transference, Embryo Transference with male-gendered semen, standard In-vitro Fecundation and In-vitro Fecundation with male-gendered semen, so that in all the cases, three different conception rates were tested. The results displayed that the mating system directly influenced the young bull production, once the genotype mating was more efficient than the phenotype mating. The conception rates negatively influenced the results of the phenotype mating mainly. There was a dramatic increase in the effective operational cost of the systems that used the reproductive biotechniques of Embryo Transference and In-vitro Fecundation, and, consequently, profitability reduction of those systems. The Natural Breeding simulations presented the highest Gross Margin, and the simulations of Artificial Insemination with male-gendered semen showed the highest Gross Profit.
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Diversidade genética em agregações de Nannotrigona testaceicornis Cockerell, 1922 (Hymenoptera, Apidae, Meliponini) através de marcadores microssatélites / Genetic diversity in aggregations of Nannotrigona testaceicornis Cockerell, 1922 (Hymenoptera, Apidae, Meliponini) by using microsatellites markersAline Simoneti Fonseca 12 May 2010 (has links)
As abelhas são insetos da ordem Hymenoptera e taxonomicamente estão reunidas na superfamília Apoidea. Os Meliponini, da subfamília Apinae, são popularmente chamados abelhas indígenas sem ferrão e algumas espécies são essenciais para a polinização de plantas selvagens e lavouras. As abelhas Nannotrigona testaceicornis, utilizadas neste trabalho, são pequenas, possuem o tórax marrom escuro e opaco e não são agressivas. No Brasil, elas são encontradas na Bahia, Espírito Santo, Goiás, Minas Gerais, Rio de Janeiro e São Paulo. Assim como muitas espécies de Hymenoptera, elas também podem nidificar em agregações e analisar a variabilidade genética dentro e entre os agregados foi um dos objetivos deste trabalho, além de avaliar os prováveis múltiplos acasalamentos que parecem ocorrer dentro dessa espécie de meliponíneos. Para tanto, foram coletados indivíduos de ninhos de N. testaceicornis no Campus da USP de Ribeirão Preto (SP), Campinas (SP), Bonfim Paulista (SP), Uberlândia (MG) e Caratinga (MG). 302 indivíduos (operárias) de um total de 32 ninhos foram macerados e tiveram seu DNA extraído. Foram utilizados oito loci microssatélites específicos para o estudo da variabilidade genética e múltiplos acasalamentos. Um total de 38 alelos foi observado. A diversidade genética média entre as agregações foi de 35,4%, a heterozigose média esperada foi de 41,4% e a observada foi de 28,3%. O coeficiente de endogamia (Fis) foi estatisticamente significativo para todas as agregações. Também foram observados desvios no equilíbrio de Hardy-Weinberg para todos os loci analisados. A análise do Fst mostrou diferenciação entre as agregações, porém, apesar da indicação pelo AMOVA de uma discreta estruturação entre as agregações, não foi possível agrupá-las. A partir dos dados obtidos foi possível observar que a diversidade genética nestas agregações está baixa, além disso, os desvios do equilíbrio, o valor significativo do Fis, e a heterozigose observada menor do que a esperada em todos os loci demonstrou a ocorrência de cruzamentos endogâmicos resultando em alto nível de homozigose nesta população. Com relação aos múltiplos acasalamentos, dos 32 ninhos estudados, somente 11 (34,4%) apresentaram uma patrilínea. A presença de alelos nulos, a inclusão acidental de machos na amostra, mudanças recentes de rainhas, operárias de outros ninhos e a contínua conexão entre ninho mãe-filho podem ser possibilidades para estes resultados, entretanto, a frequência de mais de uma patrilínea é muito alta para que a poliandria não seja considerada. / Bees are insects belonging to the Hymenoptera order and to the Apoidea superfamily. The Meliponini, from the subfamily Apinae, are popularly known as stingless bees and some species are essential to the pollination of wild and farming plants. Nannotrigona testaceicornis, studied in this work, are small bees presenting a dark brown and opaque thorax, and non-aggressive behavior. In Brazil, they are found at Bahia, Espírito Santo, Goiás, Minas Gerais, Rio de Janeiro and São Paulo states. As well as many other Hymenoptera species, they can nest on aggregations. To analyze the genetic variability within and among the aggregates was one of the objectives of this work, besides to evaluate the possibility of multiple matings which seem to occur in this species. For this purpose, samples of N. testaceicornis were collected from nests found at University of São Paulo Campus at Ribeirão Preto (SP), Campinas (SP), Bonfim Paulista (SP), Uberlândia (MG) and Caratinga (MG). Three hundred and two individuals (workers) from thirty-two sampled nests had their DNA extracted. Eight specific microsatellite loci were used to study the genetic variability and multiple matings. A total of thirty-eight alleles were observed. The mean genetic diversity among the aggregations was 35.4%, the mean expected heterozygosity was 41.4% and the observed was 28.3%. The inbreeding coefficient (Fis) was statistically significant for all the aggregations. Deviations from Hardy-Weinberg Equilibrium were observed in all studied loci. The Fst analysis showed differentiation among the aggregations but, despite the AMOVA indication of structuring among them, it was not possible to group them. From the obtained data we observed that the genetic diversity of the aggregations is low. The significant Fis value and the observed heterozygosity lower than the expected one in all the studied loci, demonstrated inbreeding events resulting in a high level of homozygosis in this population. In relation to the possibility of multiple mating, from the 32 studied nests, only 11 (34.4%) presented one patriline. The presence of null alleles, the accidental inclusion of males in the sample, recent queen changes, workers drifting among nests, continuing connections between mother and daughter nests or multiple matings might be possibilities for these results. However, the frequency of more than one patriline is very high to not consider the polyandry.
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Flowering time and natural selection in <em>Arabidopsis lyrata</em>Riihimäki, M.-A. (Mona-Anitta) 12 August 2005 (has links)
Abstract
Arabidopsis lyrata is a close outcrossing relative of Arabidopsis thaliana, the model organism of plant physiology and molecular biology. I studied variation in flowering time and the factors shaping the variation within and between A. lyrata populations in different environments. The role of the two important proximate factors determining flowering time, day length and temperature, were studied in climate chambers. The southern A. lyrata populations were found to flower in high frequency and quicker than northern A. lyrata populations in all studied environments, but the reaction of northern populations on long day length was found to be stronger than that of southern populations. Differences in vernalization requirement between A. lyrata populations were found in outdoor common garden, but in the climate chambers the results of vernalization experiments were not consistent. Strength and direction of selection on flowering time and other life history traits were studied in alpine and lowland A. lyrata populations in Scandinavia. Differences in selection were found both between populations and between years. Grazing sheep caused high levels of damage in inflorescences in the alpine population. In the lowland population there was less herbivory, caused by insects and hares. The difference in selection on flowering traits in the two study populations might be partly caused by selective grazing. Completely outcrossing mating system in A. lyrata is due to well developed self-incompatibility system. However, biparental inbreeding is likely to exist in natural populations and it may lead to spatial structuring of genetic variation within populations. I studied the effects of biparental inbreeding on components of fitness in A. lyrata in three different environments. I found inbreeding depression after sib-mating to be substantial. Stressful environment reduced the overall performance of the plants, but had no effect on the magnitude of inbreeding depression. A literature survey indicates that the observed levels of inbreeding depression in self-incompatible A. lyrata were higher than those of self-compatible species. This suggests that self-compatible species have purged some of their genetic load. The genetic basis of flowering time variation in A. lyrata can be further studied by using A. thaliana molecular tools.
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Secondary contact in the European wall lizardHeathcote, Robert James Phillip January 2013 (has links)
A critical mechanism underpinning current biological diversity is the extent to which one species mates with, or avoids mating with, another. However, little is known about the factors that mediate hybridisation, especially during the initial and rarely observed stages of secondary contact when interspecific interactions have not responded to selection. In particular, whilst hybridisation is ultimately a behavioural phenomenon, the role of behaviour in mediating hybridisation and how it is influenced by environmental and circumstantial factors is rarely investigated. Recently introduced species provide us with unequalled opportunities to study these factors. In this thesis I examine the role of behavioural mechanisms, in particular male-male competition and mate choice, in mediating mating patterns between two genetically and phenotypically distinct lineages of European wall lizard (Podarcis muralis) that have come into recent secondary contact through human introductions. In Chapter Two, I investigated how sexual selection during allopatry is responsible for creating stark differences in phenotypic traits such as body size and weapon performance evident in the two lineages today, ultimately explaining the strong biases in dominance during territorial disputes between males. However, I also show that even given this asymmetry in male competitive ability, the extent to which it extrapolates into greater access to females in naturalistic, outdoor enclosures depends strongly on the spatial clustering of basking sites, a critically important resource for many ectotherms. In contrast to initial predictions suggested by asymmetries in male competition outlined in the previous chapter, in Chapter Three I show that both paternity and courtship behaviour was strongly assortative in the outdoor enclosures. Further investigation through staged experiments on olfactory mate choice, mating trials and analyses on specific behavioural data obtained in an enclosure experiment, I show that lineage based dominance actually contributes to assortative mating patterns in conjunction with weak conspecific male choice. In contrast, female choice seems to play no role in mediating the mating patterns observed between the two lineages. In Chapter Four I had the rare opportunity to examine the morphological and behavioural factors that predict why animals should hybridise in the first place, using the data obtained in the enclosure experiment above. I found that hybridisation was particularly common between small individuals of the larger lineage and large individuals of the smaller lineage; a result that corroborates the mechanisms determining the assortative patterns uncovered in Chapter Three. Additionally, hybridisation rates were particularly high in less dominant individuals, which I suggest is due to subordinate males having reduced opportunities for courting conspecific females due to male-male competition, requiring them to become less ‘choosy’ and therefore more likely to mate with heterospecifics. Finally, secondary contact cannot occur without at least one lineage coming into a new environment, and yet relatively little attention is paid to how this environmental change can affect the signals involved in intraspecific communication and mate choice. In Chapter Five I show that a change in the amount of time male lizards spend thermoregulating (a likely consequence of arriving in a new environment) significantly changes the chemical composition of their scent marks. However, whilst female lizards were able to detect these effects, they did not seem to base their mating decisions on them. Nevertheless, this result raises interesting questions about the potential function and consequences of this plasticity, and highlights the importance of considering plasticity in chemical communication in heterogeneous environments. Overall, this thesis shows the critically important role of behaviour in mediating intra- and interspecific mating patterns during recent secondary contact. In particular, it highlights how the direction and extent of hybridisation and competition are influenced by the degree to which differing morphological and behavioural phenotypes interact over a heterogeneous environment, particularly during the initial stage of secondary contact when mate choice has not had the chance to respond to the selective pressures of hybridisation.
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Mate Choice, Mate Sampling And Baffling Behaviour In The Tree Cricket Oecanthus henryiDeb, Rittik January 2015 (has links) (PDF)
Among the different sensory modalities that play a role in sexual selection, acoustic
communication plays an important one. Acoustic communication has been known to be
used for male-male competition (territory maintenance, male aggression during
mating),for advertisement to the opposite sex (mating status, body condition, genetic
quality, nutritional status) and used by females to sample and choose conspecific
preferred males. The use of acoustic communication for sexual display and information exchange has been extensively studied in multiple taxa, including insects, anurans, birds and mammals. Among insects, crickets have proven to be good model systems to study sexual selection based on acoustic communication as most species have an elaborate acoustic communication system, male advertisements, diverse types of
mating incentives for females (such as glandular feeding) and a female dominated
mating system. Generally, in crickets males produce species-specific calls which are
used by females to localize conspecific males. Besides, calls show high levels of
intraspecific variation and are energetically costly to produce. Moreover, as in crickets predominantly the females show phonotaxis towards male calls, calls also can play a role in mate sampling and choice by acting as indicators of preferred male quality.
Despite being studied for many decades there are certain gaps in the studies examining
mate choice in crickets. Some of them are, lack of understanding of the variation of
male calling traits in nature and its role in signal evolution, lack of understanding
regarding the ecological context of mate sampling and the evolution of alternative
mating strategies. Hence, the tree cricket Oecanthus henryi was chosen as a study
system to address these gaps in the understanding of female choice based on acoustic signals.
In the tree cricket Oecanthus henryi, males call and females use calls to localize
conspecific males and hence potentially females can choose males based on acoustic
cues. To understand the evolution of female preference for male acoustic cues it is
important to understand the variation in the calling songs in the field and identify
repeatable call features that are reliable indicators of preferred male traits
(morphological, developmental or genetic). I measured repeatability of male call traits in
the field to understand their variation, reliability and consistency. Carrier frequency was the only call trait that was highly repeatable and hence was reliable and consistent.
Following this I examined whether any of these call traits were indicators of male
morphological traits (such as male size and fluctuating asymmetry) which are known to
be preferred by females. It was found that carrier frequency was negatively correlated
with body size; hence carrier frequency was both reliable and indicated male size. I also
found that females preferred larger males during mating, as revealed by the longer
mating durations and longer spermatophore retention time. Interestingly, though this
study indicated that females could in principle use lower call carrier frequency to localize preferred larger males, simultaneous choice experiments done in the laboratory revealed that the females do not use this cue. These contrasting results may be because females are incapable of discriminating small differences in frequency or because they use non-acoustic cues for mate choice.
However, whichever cues the females use to discriminate between males in the
laboratory conditions, often these preferences are not realized in the field. The main reason behind this is that searching for preferred mates in the field can be costly and this might force females to choose sub-optimal males. Theoretical models predict that male movement and spacing in the field should influence female sampling tactics and in turn, females should drive the evolution of male movement and spacing to sample them optimally. Moreover, simultaneous sampling of males using the best-of-n or comparative Bayes strategy should yield maximum mating benefits to females. Many of the theoretical mate sampling strategies involves recall of the quality and location of individual males, which in turn requires male positions to be stable within a night.
Calling males of O. henryi showed high site fidelity within a night, potentially enabling
female sampling strategies that require recall. To examine the possibility of
simultaneous acoustic sampling of males, I estimated male acoustic active spaces
using information on male spacing, call transmission and female phonotactic threshold.
Males were found to be spaced far apart and active space overlap was rare. I then
examined female sampling scenarios by studying female spacing relative to male
acoustic active spaces. Only 15% of sampled females could hear multiple males,
suggesting that simultaneous mate sampling is rare in the field. Moreover, the relatively large distances between calling males suggest high search costs, which may favor threshold strategies that do not require memory.
Using the insights gathered from these two studies I examined a unique calling
behaviour from leaf holes, baffling, observed in this species. Baffling behaviour has been found in multiple species of the genus Oecanthus where the males call from selfmade holes in leaves rather than calling from leaf edges (their natural calling surface) thus increasing their loudness many fold. I started by examining the natural history of baffling and found that baffling is an extremely rare behaviour in the field. However field observations and laboratory experiments revealed that many males can baffle and hence it is not an obligatory behaviour shown only by a few males. It was hypothesized that one reason for the rarity of baffling could be resource limitation. It was found that baffling males prefer larger leaves possibly due to higher SPL gains achieved by baffling on the larger leaves, which is a limited resource in the field. However this alone was insufficient to explain extreme rarity of bafflers in the field. Hence I examined which males were using this behaviour in the field. Using field observations and laboratory
experiments it was found that less preferred males (smaller and quieter) baffled more
which provided them with higher calling SPL and greater sound-field volume and thus a
higher number of potential mates. Moreover, baffling also increased the mating
duration for the less preferred males thus providing more time to these males for sperm
transfer. The females could not differentiate between an inherently loud caller and a caller whose SPL was increased artificially (as if it was baffling). Hence I concluded that baffling is probably a cheater strategy used by the less preferred males to fool the females into approaching them and mating for longer durations.
To my knowledge, this is the first study that has estimated male call variation in the field to understand its role in female choice in tree crickets. Moreover this is also the first study to examine the ecological context of mate choice in tree crickets. This is also the first study to examine the advantages of baffling behaviour and its potential evolutionary implications.
the different sensory modalities that play a role in sexual selection, acoustic communication plays an important one. Acoustic communication has been known to be used for male-male competition (territory maintenance, male aggression during mating),for advertisement to the opposite sex (mating status, body condition, genetic quality, nutritional status) and used by females to sample and choose conspecific preferred males. The use of acoustic communication for sexual display and information exchange has been extensively studied in multiple taxa, including insects, anurans, birds and mammals. Among insects, crickets have proven to be good model systems to study sexual selection based on acoustic communication as most species have an elaborate acoustic communication system, male advertisements, diverse types of mating incentives for females (such as glandular feeding) and a female dominated mating system. Generally, in crickets males produce species-specific calls which are used by females to localize conspecific males. Besides, calls show high levels of intraspecific variation and are energetically costly to produce. Moreover, as in crickets predominantly the females show phonotaxis towards male calls, calls also can play a role in mate sampling and choice by acting as indicators of preferred male quality.
Despite being studied for many decades there are certain gaps in the studies examining mate choice in crickets. Some of them are, lack of understanding of the variation of male calling traits in nature and its role in signal evolution, lack of understanding regarding the ecological context of mate sampling and the evolution of alternative mating strategies. Hence, the tree cricket Oecanthus henryi was chosen as a study system to address these gaps in the understanding of female choice based on acoustic signals.
In the tree cricket Oecanthus henryi, males call and females use calls to localize conspecific males and hence potentially females can choose males based on acoustic cues. To understand the evolution of female preference for male acoustic cues it is important to understand the variation in the calling songs in the field and identify repeatable call features that are reliable indicators of preferred male traits (morphological, developmental or genetic). I measured repeatability of male call traits in the field to understand their variation, reliability and consistency. Carrier frequency was the only call trait that was highly repeatable and hence was reliable and consistent. Following this I examined whether any of these call traits were indicators of male morphological traits (such as male size and fluctuating asymmetry) which are known to be preferred by females. It was found that carrier frequency was negatively correlated with body size; hence carrier frequency was both reliable and indicated male size. I also found that females preferred larger males during mating, as revealed by the longer mating durations and longer spermatophore retention time. Interestingly, though this study indicated that females could in principle use lower call carrier frequency to localize preferred larger males, simultaneous choice experiments done in the laboratory revealed that the females do not use this cue. These contrasting results may be because females are incapable of discriminating small differences in frequency or because they use non-acoustic cues for mate choice.
However, whichever cues the females use to discriminate between males in the laboratory conditions, often these preferences are not realized in the field. The main reason behind this is that searching for preferred mates in the field can be costly and this might force females to choose sub-optimal males. Theoretical models predict that male movement and spacing in the field should influence female sampling tactics and in turn, females should drive the evolution of male movement and spacing to sample them optimally. Moreover, simultaneous sampling of males using the best-of-n or comparative Bayes strategy should yield maximum mating benefits to females. Many of the theoretical mate sampling strategies involves recall of the quality and location of individual males, which in turn requires male positions to be stable within a night. Calling males of O. henryi showed high site fidelity within a night, potentially enabling female sampling strategies that require recall. To examine the possibility of simultaneous acoustic sampling of males, I estimated male acoustic active spaces using information on male spacing, call transmission and female phonotactic threshold. Males were found to be spaced far apart and active space overlap was rare. I then examined female sampling scenarios by studying female spacing relative to male acoustic active spaces. Only 15% of sampled females could hear multiple males, suggesting that simultaneous mate sampling is rare in the field. Moreover, the relatively large distances between calling males suggest high search costs, which may favor threshold strategies that do not require memory.
Using the insights gathered from these two studies I examined a unique calling behaviour from leaf holes, baffling, observed in this species. Baffling behaviour has been found in multiple species of the genus Oecanthus where the males call from self- made holes in leaves rather than calling from leaf edges (their natural calling surface) thus increasing their loudness many fold. I started by examining the natural history of baffling and found that baffling is an extremely rare behaviour in the field. However field observations and laboratory experiments revealed that many males can baffle and hence it is not an obligatory behaviour shown only by a few males. It was hypothesized that one reason for the rarity of baffling could be resource limitation. It was found that baffling males prefer larger leaves possibly due to higher SPL gains achieved by baffling on the larger leaves, which is a limited resource in the field. However this alone was insufficient to explain extreme rarity of bafflers in the field. Hence I examined which males were using this behaviour in the field. Using field observations and laboratory experiments it was found that less preferred males (smaller and quieter) baffled more which provided them with higher calling SPL and greater sound-field volume and thus a higher number of potential mates. Moreover, baffling also increased the mating duration for the less preferred males thus providing more time to these males for sperm transfer. The females could not differentiate between an inherently loud caller and a caller whose SPL was increased artificially (as if it was baffling). Hence I concluded that baffling is probably a cheater strategy used by the less preferred males to fool the females into approaching them and mating for longer durations.
To my knowledge, this is the first study that has estimated male call variation in the field to understand its role in female choice in tree crickets. Moreover this is also the first study to examine the ecological context of mate choice in tree crickets. This is also the first study to examine the advantages of baffling behaviour and its potential evolutionary implications.
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