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The objective of this study was to evaluate the effect of plant densities, nitrogen levels and foliar diseases control on grain yield and seed quality of irrigated rice. An experiment was conducted in Santa Maria RS Brazil, during 2003/2004 growing season aiming to evaluate the effects, plant populations, nitrogen levels and fungicide application on grain yield (Chapter I) and seed quality (Chapter II) of irrigated rice. Were evaluated grain yield and seed quality under three plant densities (150, 265 and 380 plants m-2), five nitrogen levels (0, 40, 80, 120 and 160 kg ha-1) with and without fungicide application. There was no triple interaction among the parameters evaluated. Higher plant populations resulted in fewer tillers per plant and seeds per panicle increasing interspecific competition and grain yield was not significantly affect as result os yield components compesation. Nitrogen increased seed yield up to 97 kg ha-1 wich was not affected by plant population and an hanced the nutritional quality as result of increased protein content. Diseases control had a positive effect on grain yield and quality as well as of the rice seeds by reducing its incidence and increased germination percentage. / Com o objetivo de avaliar a influência da população de plantas, doses de nitrogênio e controle de doenças sobre a produção e qualidade de grãos e sementes de arroz irrigado foi conduzido um experimento em campo na Universidade Federal de Santa Maria, RS, no ano agrícola 2003/2004. Avaliou-se a produtividade (Capítulo I) e a qualidade de grãos e sementes (Capítulo II) em função de três populações de plantas (150, 265, 380 plantas m-2), cinco doses de nitrogênio (0, 40, 80, 120 e 160 kg ha-1 de N) e o controle ou não de doenças da parte aérea. Para todas as avaliações realizadas não se verificou interação tríplice. O incremento da população de plantas diminui o número de colmos por planta e o número de grãos por panícula aumentando a competição interespecífica. A produtividade não é influenciada pela população de plantas de 150 a 380 plantas m-2, pois os componentes da produção se compensam. A aplicação de nitrogênio contribui incrementando a produção até 97 kg ha-1 de N, não sofrendo influência da população de plantas, bem como melhorando a qualidade nutricional do produto, pois se verifica um aumento no teor de proteína com o aumento da dose de N. O controle de doenças influencia positivamente a produção e qualidade de grãos e sementes de arroz através da redução da incidência e elevação do poder germinativo de sementes de arroz.

The aim of the present study was to study the occurrence of scavenging behavior among different species and strains of entomopathogenic nematodes. Another part of the study was focused on scavenging of the selected entomopathogenic nematodes in insects killed by various non-native strains of Xenorhabdus bovinenii. Further aim was to investigate the interspecific competition of the selected entomopathogenic nematodes with the nematode Oscheius myriophila for dead hosts. The final aim was the search for possible toxicity of the selected X. bovienii strains against nematode Oscheius myriophila.

p. 1-36 / Submitted by Santiago Fabio (fabio.ssantiago@hotmail.com) on 2013-04-10T19:35:49Z No. of bitstreams: 1 Dissert seg.pdf: 694064 bytes, checksum: 71543c6f42e170ca67484228abf2d815 (MD5) / Approved for entry into archive by Alda Lima da Silva(sivalda@ufba.br) on 2013-04-15T20:18:28Z (GMT) No. of bitstreams: 1 Dissert seg.pdf: 694064 bytes, checksum: 71543c6f42e170ca67484228abf2d815 (MD5) / Made available in DSpace on 2013-04-15T20:18:28Z (GMT). No. of bitstreams: 1 Dissert seg.pdf: 694064 bytes, checksum: 71543c6f42e170ca67484228abf2d815 (MD5) Previous issue date: 2005 / A existência de competição interespecífica está associada à sobreposição no uso de recursos limitados por espécies e à redução na disponibilidade de recurso para uma espécie pelo uso de recursos ou a apropriação antecipada por uma outra. Interações competitivas podem produzir um padrão de uso diferencial de recursos pelas espécies envolvidas, como aquele previamente detectado entre Tropidurus psammonastes (Tropiduridae) e Eurolophosaurus divaricatus (Tropiduridae) e Cnemidophorus sp n (Teiidae), espécies endêmicas de lagartos das dunas de Ibiraba, Bahia. Para testar as hipóteses de que a presença de T. psammonastes reduz a densidade local das outras duas espécies (o que indicaria existência de competição contemporânea forte) e o padrão de uso de micro-hábitat das mesmas (o que indicaria existência de competição contemporânea, embora fraca), realizei um experimento de campo com duração de 76 dias durante um período do ano em que o potencial para interações competitivas é alto (i.e., entre o final de seca e início das chuvas). Manipulei a densidade de T. psammonastes pela remoção de seus indivíduos de quatro unidades amostrais experimentais, avaliando o efeito sobre as outras duas espécies em comparação a quatro unidades amostrais não alteradas. Na situação controle, o padrão de uso de micro-hábitat das espécies foi o mesmo descrito em um estudo realizado entre 1995 e 1996 na mesma área. As situações controle e experimental foram comparadas através de testes de randomização (MRPP) com base nos dados totais e da última metade do experimento. Não detectei diferença significativa das densidades entre as unidades amostrais controle e experimentais para nenhuma das duas espécies, indicando que, caso estivesse ocorrendo competição, ela não foi suficientemente forte para gerar efeitos de curto prazo. Não detectei diferenças dos padrões de uso multivariado de 2micro-hábitat pelas espécies entre controle e experimento. Como as disponibilidades de micro-hábitat não variaram entre tratamentos, esse resultado indica que não fui capaz de detectar mesmo interações competitivas fracas entre T. psammonastes e as demais espécies. Um estudo anterior refutou a hipótese de que o padrão diferencial de uso de recursos por essas espécies pode ser explicado por inércia filogenética. O presente estudo corroborou o padrão de uso de micro-hábitat descrito anteriormente para as espécies, sugerindo que ele não é estocástico, e refutou a hipótese de que o padrão deriva de competição contemporânea. Desse modo, esse conjunto de evidências sugere que o padrão observado pode derivar de interações ecológicas competitivas passadas, o que, embora não testável, é plausível visto que as espécies envolvidas são endêmicas das dunas, apresentando distribuição geográfica restrita. / Salvador

The presented thesis deals with interspecific competition and host range of entomopathogenic nematodes and assess the mechanisms enabling coexistence of multiple EPN species. The thesis further studied the scavenging ability of EPNs and their defense mechanisms against invertebrate scavengers. The results revealed that coexisting EPN species share the same niche and their interaction are complex and may be asymmetric. EPNs were found to be able to colonise and multiply in cadavers of different insects and scavenging seems to be an important alternative to normal infection. The defence of EPNs against scavengers seems to be an adaptation of the nematode-bacteria complex.

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第18826号 / 理博第4084号 / 新制||理||1587(附属図書館) / 31777 / 京都大学大学院理学研究科生物科学専攻 / (主査)教授 曽田 貞滋, 准教授 渡辺 勝敏, 教授 高橋 淑子 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

Drosophila suzukii (Matsumura) (Diptera: Drosophila) is an invasive frugivore and has become a significant pest of small fruit, cherry and grape throughout the United States. It may be possible to determine if a Virginia vineyard is at risk of D. suzukii infestation by analyzing the biotic and abiotic factors around each vineyard. This pest is known to utilize a wide range of cultivated and wild host plants. A host plant survey was conducted at four vineyards in the Piedmont Region of Virginia to identify hosts used by D. suzukii around vineyards. The seasonal availability of host plants and adult emergence from them were tracked. Six host plant species of D. suzukii were identified, some available season-long. Monitoring D. suzukii in cultivated crops is crucial for the timing of spray applications. Homemade and commercially available baits and traps were deployed in two vineyards to determine the efficacy and selectivity towards D. suzukii. The homemade and commercially available baits that contained red wine caught the most D. suzukii, but none were exclusively attractive to D. suzukii. Wine grape susceptibility was assessed in laboratory choice and no-choice ovipositional bioassays. Ovipositional susceptibility was determined by measuring the physiological and morphological parameters using six wine grape varieties. More eggs were laid in grapes as penetration force decreased. Penetration force and not skin thickness was the limiting factor for oviposition. Survivorship of eggs laid in intact grapes was analyzed and survivorship to adulthood was dependent upon variety and survivorship usually exceeded 9% survival seen in previous studies. Larval developmental parameters of D. suzukii were affected by grape variety and the density of Z. indianus. D. suzukii mortality was increased in most cases when in competition with Z. indianus, but was less pronounced when reared in Viognier grapes. My Z. indianus oviposition study demonstrated that they will follow injury created by D. suzukii, and then the Z. indianus larvae may outcompete D. suzukii within the berries. These studies greatly improved our understanding of D. suzukii biology and ecology in Virginia vineyards. / Ph. D.

Les interactions multi-trophiques jouent un rôle clé dans la structuration des agrosystèmes et régissent la dynamique des populations qui les composent. L’objectif de cette thèse fut (i) d’étudier la perturbation des interactions liée à une espèce invasive (Tuta absoluta) dans les cultures de tomates européennes, (ii) de rechercher de nouveaux auxiliaires autochtones, puis (iii) d’évaluer l’efficacité de ces auxiliaires lorsqu’ils sont intégrés dans l’agrosystème. Nous avons montré que de nouvelles interactions sont apparues suite à l’invasion, notamment la compétition apparente entre les aleurodes et T. absoluta en présence du prédateur généraliste et omnivore M. pygmaeus. Dans un second temps, nous avons recherché de nouveaux auxiliaires, en se focalisant d’abord sur les trichogrammes, Trichogramma achaeae étant déjà commercialisé contre T. absoluta en France. Les expérimentations de laboratoire et de terrain n’ont pas permis de mettre en évidence un trichogramme plus intéressant que celui déjà commercialisé. De plus, nous avons observé une prédation intra-guilde de M. pygmaeus sur les trichogrammes juvéniles i.e. œufs parasités, et nous avons montré que T. absoluta n’était pas un hôte approprié pour ces parasitoïdes. Les trichogrammes ne s’installant pas sur la culture, les études concernant les parasitoïdes oophages se sont arrêtées là et nous nous sommes intéressés aux parasitoïdes larvaires. La biologie de deux parasitoïdes larvaires a été étudiée et a souligné l’intérêt de Stenomesius japonicus (Eulophidae) en tant que potentiel agent de lutte biologique contre T. absoluta. Malgré les interactions négatives subies par le parasitoïde, des expérimentations sous serre en conditions réalistes ont montré que le prédateur et le parasitoïde larvaire pouvaient coexister pendant plusieurs mois. Cela a été montré y compris en présence d’une proie alternative pour le prédateur omnivore. / Multi-trophic interactions play a key role in structuring agro-ecosystems and regulating arthropod population dynamics. The objective of the PhD was (i) to study the possible disruptions of biotic interactions owing to the recent invasion by T. absoluta in European tomato crops, (ii) to identify local natural enemies attacking T. absoluta, (iii) to evaluate their effectiveness against T. absoluta when integrated into the agro-ecosystem. We showed that new interactions occurred after the arrival of T. absoluta, mainly apparent competition between whiteflies and T. absoluta, in presence of the omnivorous and generalist predator M. pygmaeus. We recorded possible new biocontrol agents and focused first on Trichogramma parasitoids, as Trichogramma achaeae was promptly commercialized against T. absoluta in France. Laboratory and field experiments failed to detect promising Trichogramma strains. In addition, intraguild predation of M. pygmaeus on parasitoid juveniles i.e. parasitized eggs, was observed and we demonstrated that T. absoluta was not a suitable host for Trichogramma parasitoids. Therefore, further studies switched on parasitoids of larval stages of T. absoluta. We demonstrated the importance of Stenomesius japonicus (Eulophidae) as a possible biological control agent against T. absoluta. The parasitoid was able to reproduce on T. absoluta over several generations under laboratory and greenhouse conditions. Despite negative interactions between the predator and the larval parasitoid, further greenhouse experiments demonstrated that two competitors can coexist for several months. Moreover, the presence of an alternative prey for the omnivorous predator (whitefly) in the agro-ecosystem did not prompt larval parasitoid exclusion, and the parasitoid remained in the crop even in the presence of other prey for the predator.

Orientador: João Frederico da Costa Azevedo Meyer / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Matemática Estatística e Computação Científica / Made available in DSpace on 2018-08-23T13:46:24Z (GMT). No. of bitstreams: 1 Santos_CarlosFrankLimados_M.pdf: 3104358 bytes, checksum: a690d16041a50b1c06291d1d64615b29 (MD5) Previous issue date: 2013 / Resumo: O propósito deste trabalho é desenvolver uma modelagem matemática que descreverá computacionalmente o convívio entre duas espécies competidoras sem característica migratória diante da variação de densidade de vegetação. As equações utilizadas nesta modelagem incluíram os fenômenos de difusão de vegetação, processos de dispersão populacional, dinâmicas vitais e um decaimento proporcional a variação de densidade de mata, no sentido de que quanto maior a densidade de mata menor o decaimento populacional quanto menor a densidade de mata maior a mortalidade populacional. Para as espécies competidoras usaremos as clássicas modelagem do tipo Lotka-Volterra (não- linear) combinado a equação diferenciais parciais de difusão-advecção. Primeiramente faremos a descrição do modelo matemático e a descrição do domínio visando o uso do método de diferenças finitas para o espaço combinados a um modelo de Crank-Nicolson no tempo. Em seguida, desenvolveremos um algoritmo em ambiente MATLAB , que aproxima as soluções relativas a difusão de vegetação e a cada população em cada ponto e ao longo do tempo considerado nas simulações. Por fim, foram obtidos resultados gráficos que foram analisados o efeito da recuperação da mata no convívio das espécies competidoras consideradas. De modo que se disponha de ferramentas mais acessíveis a profissionais e pesquisadores ligados aos estudos de ecologia matemática e meio ambiente, bem como aos responsáveis pelas adoções de medidas de emergências e contingências de áreas destruídas pelas ações antrópicas / Abstract: The main objective of this work is that of obtaining an adequate mathematical model and, consequently, a computational algorithm to describe the interaction between two competing species in face of a density variation in vegetation. Population dispersal and dynamics and the presence of a term relating the loss of vegetation density to higher mortality for both competing species must be considered, as well as the inverse: a raise in vegetation density is bound to increase the survival of species. In order to describe the interaction between vegetation and animals, a classic Lotka-Volterra system is used, coupled with the use of the diffusion-reaction partial differential equation for all three participants considered in the model: vegetation density and both animal species. For the interacting animal species, no migration is considered, although the possibility of a preferential direction similar to an advective component is permitted in the dispersal of plants. Numerical discretization include centered finite differences in order to obtain second order approximations in space variables, as well as a Crank-Nicolson method, also second order, for approximations in time. In order to qualitatively analyze possible results, a MATLAB environment was used, with the possibility of exhibiting graphical results based on the numerical ones. This is done in order to create a numerical auxiliary tool which can be used by researchers and professional agents in the evaluation of ecological and environmental policies and decisions, as well as the description of some of the effects of anthropic a actions / Mestrado / Matematica Aplicada / Mestre em Matemática Aplicada

Abstract Social information use is a widespread phenomenon across the animal kingdom and it affects various important aspects of animal behaviour. Animals observe and copy the behaviour of conspecifics and other species on the same trophic level in their own decision-making, e.g., in habitat or mate choice. Copying is adaptive only when it is selective. Thus, it would be important to understand when and which individuals should copy others, and which individuals they choose to copy and what are the consequences of social information use. In this thesis, I experimentally study these questions in wild animals living in natural conditions. By simulating arbitrary preference of great tits (Parus major), I demonstrated that the portrayed fitness does not affect the nest site choices of conspecifics, but the tit pairs with an old male prefer the nest site choices of good and poor conspecifics. Social information use among tits appears to be age- and sex-dependent. Pied flycatchers (Ficedula hypoleuca), however, selectively copy or reject a novel nest site feature preference (symbol attached to the nest box) of great tits experimentally manipulated to exhibit high or low fitness (clutch size), respectively. By offering pied flycatchers choice in nest boxes with alternative contents, I showed that nest take-overs of flycatchers are not a form of social information use, but seem to result from the reduced building effort required. Furthermore, by conducting a decoy and playback experiment, I showed that great tits covered eggs more efficiently in the presence of pied flycatchers. One function of egg covering behaviour seems to be a counter-adaptation to reduce information parasitism by pied flycatchers. My results demonstrate that the social transmission of behaviours across species can be highly selective in response to observed fitness, plausibly making the phenomenon adaptive. In contrast with the current theory of species coexistence, overlap between realized niches of species could dynamically increase or decrease, depending on the observed success of surrounding individuals. The social information revealed by success and behaviour of animals is a resource that can be used or concealed. It is a new kind of evolutionary and ecological factor which may affect the formation of ecosystems and species coevolution. / Tiivistelmä Sosiaalinen informaationkäyttö on yleinen ilmiö eläinkunnassa, ja sitä tavataan aina hyönteisistä valaisiin. Yksilöt tarkkailevat ja kopioivat sekä lajitovereiden että toisen ekologialtaan samankaltaisen lajin yksilöiden käyttäytymistä erilaisissa tilanteissa, kuten pesäpaikan tai parittelukumppanin valinnassa. Sosiaalinen informaationkäyttö on adaptiivista ainoastaan ollessaan valikoivaa. Siksi on tärkeää selvittää kenen, koska ja ketä kannattaa kopioida, ja mitä ekologisia ja evolutiivisia seurauksia siitä koituu informaation lähteelle ja käyttäjälle. Väitöskirjassani tutkin kokeellisesti informaation hankkijan (kirjosieppo Ficedula hypoleuca) valikoivaa kopioimista ja siitä mahdollisesti johtuvaa informaation lähteen (talitiainen Parus major) vasta-adaptaatiota luonnonoloissa. Symbolikokeilla selvitin, että talitiaisten lajinsisäinen kopiointi on iästä ja sukupuolesta riippuvaa, mutta informaationlähteen havaittu kelpoisuus ei vaikuta kopioinnin todennäköisyyteen. Kirjosiepot puolestaan kopioivat valikoivasti keinotekoisesti luotuja tiaisten mieltymyksiä pesäpönttöön kiinnitettyjä symboleja kohtaan, riippuen tiaisten havaitusta manipuloidusta kelpoisuudesta (munamäärästä pesässä). Siepot kopioivat tiaisia, joiden pesässä on paljon munia (13 munaa), ja rejektoivat tiaisia (valitsevat vaihtoehtoisen symbolin), joilla munia on vähän (5 munaa). Tarjoamalla kirjosiepoille vaihtoehtoisia pesäpönttöjä osoitin, että sieppojen luontainen mieltymys vallata ja rakentaa pesänsä toisten pesien päälle ei ole sosiaalisen informaationkäytön muoto, vaan se näyttää olevan pesänrakennuksen kustannusten minimointia. Playback-kokeilla osoitin, että talitiaisten munienpeittelykäyttäytymisellä on useita funktioita. Se on vasta-adaptaatio kirjosiepon informaatioloisintaa vastaan ja toimii mahdollisesti suojana kylmää vastaan. Väitöskirjani tulokset osoittavat, että eläinten käyttäytymisen paljastama sosiaalinen informaatio on resurssi, jota voidaan hyödyntää tai salata. Se on myös uudenlainen ekologinen ja evolutiivinen tekijä, joka vaikuttaa eliöyhteisöjen muodostumiseen ja lajien koevoluutioon. Lajienvälinen valikoiva sosiaalinen informaationkäyttö -hypoteesi haastaa nykyisen koevoluutioteorian. Se ennustaa, että informaatiota hyödyntävän lajin ja informaationlähteen ominaisuudet voivat joko samankaltaistua tai erilaistua, informaationlähteen havaittavasta menestyksestä riippuen.