Selon la théorie de la sélection de la parentèle, les individus peuvent transmettre des copies de leurs gènes à la génération suivante sans accéder eux-mêmes à la reproduction, mais en aidant des apparentés à augmenter leur propre succès reproductif. Ce concept reste aujourd'hui l'explication la plus probable pour justifier l'évolution de l’altruisme de reproduction dans le règne animal. Les coefficients de corrélations génétiques entre les membres d’un groupe ont une importance capitale, puisqu'ils influencent directement les bénéfices génétiques indirects associés au comportement altruiste. Trois principaux facteurs sont cependant connus pour influencer profondément l'architecture des sociétés: (i) le nombre de reines présentes dans un nid (polygynie), (ii) le nombre d'accouplements des reines (polyandrie), et (iii) l’accouplement entre apparentés (consanguinité).<p>\ / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

Thesis (MScAgric (Conservation Ecology and Entomology))--Stellenbosch University, 2008. / ENGLISH ABSTRACT: Ant infestations comprising the Argentine ant Linepithema humile (Mayr), common pugnacious ant Anoplolepis custodiens (F. Smith) and cocktail ant Crematogaster peringueyi Emery are a widespread pest problem in South African vineyards. Integrated Pest Management (IPM) programmes aimed at suppressing the problematic honeydew excreting vine mealybug Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae) on grapes must include ant control to optimize the effectiveness and efficacy of mealybug natural enemies. If ants are eliminated, natural enemies are able to contain mealybugs below the Economic Threshold Level (ETL). Current strategies for ant control are limited and generally include the application of long term residual insecticides that are detrimental to the environment, labour intensive to apply and can disrupt natural biological control if applied incorrectly. A more practical method of ant control using low toxicity baits was therefore investigated. Field bait preference and bait acceptance assessments aimed at determining bait repellency and palatability, respectively, were carried out during spring, summer and autumn in three vineyards of the Cape winelands region during 2007/08. Five toxicants comprising gourmet ant bait (0.5%), boric acid (0.5%), fipronil (0.0001%), fenoxycarb (0.5%) and spinosad (0.01%) dissolved in 25% sugar solution were tested against a 25% sucrose solution control. Gourmet ant bait was significantly more preferred and accepted by all ant species than the other baits. Laboratory bait efficacy assessments using four insecticides (gourmet, boric acid & spinosad) at concentrations of 0.25; 0.5; 1; 2 and 4 times the field dose and fipronil at 0.015625; 0.03125; 0.0625; 0.125; 0.25 times the field dose were carried out. Results revealed that boric acid (2%), gourmet ant bait (2%) and fipronil (1.0 X 10-5%) exhibited delayed toxicity for L. humile and C. peringueyi while spinosad (0.01%) showed delayed action on L. humile. Field foraging activity and food preference tests were also carried out for the three ant species during 2007/08. Foraging activity trials revealed that vineyard foraging activity of L. humile is higher relative to A. custodiens and C. peringueyi. This means fewer bait stations are required for effective L. humile control making low toxicity baits a more affordable and practical method of controlling L. humile than the other two ant species. Food preference trials showed that L. humile and C. peringueyi have a high preference for sugar while A. custodiens significantly preferred tuna over other baits. However, all ant species had a preference for wet baits (25% sugar water, 25% honey, tuna & agar) as opposed to dry ones (fish meal, sorghum grit, peanut butter & dog food). This research concludes that low toxicity baits show potential in ant pest management and can offer producers with a more practical, economical and environmentally friendly method of ant control which is compatible with vineyard IPM programmes. / AFRIKAANSE OPSOMMING: Mierbesmetting wat uit die Argentynse mier Linepithema humile (Mayr), die gewone malmier Anoplolepis custodiens (F. Smith) en die wipstertmier Crematogaster peringueyi Emery bestaan, is ’n plaagprobleem wat wydverspreid in Suid-Afrikaanse wingerde voorkom. Programme vir geïntegreerde plaagbeheer (GPB) wat daarop gemik is om die wingerdwitluis Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae) – wat ’n probleem is weens die heuningdou wat dit afskei – op druiwe te beheer, moet mierbeheer insluit om sodoende die uitwerking en doeltreffendheid van die witluis se natuurlike vyande die beste te benut. As miere uitgeskakel kan word, sal dit vir die natuurlike vyande moontlik wees om die witluis sodanig te beheer dat dit onder die ekonomiese drempelvlakke (EDV) bly. Huidige strategieë om miere te beheer, is beperk en sluit gewoonlik die toediening van insekdoders in wat lank neem om in die grond af te breek, wat skadelik vir die omgewing is, waarvan die toediening arbeidsintensief is en wat die natuurlike biologiese beheer kan versteur indien dit verkeerd toegepas word. Daarom is ’n meer praktiese metode ondersoek waar miere deur die gebruik van lae toksisiteit lokase beheer word. Ondersoeke na lokaasvoorkeure en lokaasaanvaarbaarheid in die praktyk, wat daarop gemik is om te bepaal of die lokaas onderskeidelik afstootlik en smaaklik bevind word, is oor lente, somer en herfs in drie verskillende wingerde in die Kaapse wynlandstreek gedurende die 2007/08-seisoen uitgevoer. Vyf gifstowwe, bestaande uit gourmet ant bait (0.5%), boorsuur (0.5%), fiproniel (0.0001%), fenoksiekarb (0.5%) en spinosad (0.01%) wat in ’n 25%-suikeroplossing opgelos is, is getoets teenoor ’n kontrole wat uit ’n 25%-sukrose-oplossing bestaan. Al die mierspesies het gourmet ant bait bo die ander lokase verkies en aanvaar. In die laboratorium is ondersoeke gedoen om die doeltreffendheid van die lokase te bepaal deur vier insekdoders (gourmet ant bait, boorsuur en spinosad) te gebruik in konsentrasies van 0.25; 0.5; 1; 2 en 4 keer die dosis in die praktyk en fiproniel teen 0.015625; 0.03125; 0.0625; 0.125; 0.25 keer die dosis in die praktyk. Resultate het getoon dat boorsuur (2%), gourmet ant bait (2%) en fiproniel (1.0 X 10-5%) vertraagde toksisiteit getoon het vir L. humile en C. peringueyi, terwyl spinosad (0.01%) ’n vertraagde uitwerking getoon het op L. humile. Toetse om kossoekaktiwiteite in die praktyk en die voedselvoorkeure van die drie mierspesies te ondersoek, is ook gedurende die 2007/08-seisoen gedoen. Proewe oor kossoekaktiwiteite het getoon dat hierdie aktiwiteite in die wingerd by L. humile hoër is in verhouding met A. custodiens en C. peringueyi. Dit beteken dat minder lokaasstasies nodig is om L. humile doeltreffend te beheer en lei daartoe dat lae toksisteit lokaas ’n beter manier is om L. humile te beheer as die ander twee mierspesies. Proewe oor voedselvoorkeure het aangedui dat L. humile en C. peringueyi ’n groot voorkeur toon vir suiker, terwyl A. custodiens ’n duidelike voorkeur vir tuna het. Alle mierspesies het egter ’n voorkeur vir nat lokaas (25% suikerwater, 25% heuning, tuna en agar), eerder as droë lokaas (vismeel, sorghumgruis, grondboontjiebotter en hondekos) getoon. Uit hierdie navorsing word afgelei dat lae toksisteit lokaas potensiaal toon in mierbeheer en dat dit produsente ’n meer praktiese, ekonomiese en omgewingsvriendelike metode van mierbeheer kan bied wat met GPB-programme in die wingerd versoenbaar is.

The determination of a symbiotic association as beneficial requires good assessment of the costs and benefits involved in the maintenance and transmission of these microbes across generations. In social insects, symbiotic associations are complex as they may involve a network of interactions between individual and colony that result in stable associations over evolutionary time. My goal was to investigate the roles of behavior and morphology as integrators that have enabled the benefits of harboring gut microbes to reach both adult and growing brood in a colony. To achieve this goal, I used turtle ants (Cephalotes), a group that has co-evolved with their gut microbes since the Eocene (Sanders et al. 2014) and that shows a variety of morphological and behavioral specializations likely connected to this symbiotic association. In my dissertation I present evidence that the specialized behavior and morphology of Cephalotes are indeed strongly associated with mechanisms that ensure stability of ant-gut microbe interactions over evolutionary time. In Appendix A, I show that a valve between the crop and midgut (proventriculus) of C. rohweri works as a filtration organ, capable of excluding possible pathogens from the mostly liquid diet consumed by turtle ants. In addition, the proventricular filter is also associated with the structuring of the gut microbiota, dividing it in at least two great groups: one upstream and another downstream of the proventriculus. Through behavioral observation and microscopy, we also suggest that the formation of the proventricular filter is only complete after young and sterile workers (callows) are inoculated with the core group of symbiotic bacteria. In Appendix B, I present results confirming that the compartmentalization of gut microbiota is also present in the congener C. varians. I compare these results with previously published data, defining the meta-communities of the gut microbiota, and demonstrate that the previously recognized core microbiota is composed of compartment-specific microbial communities and lineages. This compartmentalization of the gut microbiota is similar to the one found in highly specialized herbivores, both vertebrates and invertebrates. In addition, I also sampled the infrabuccal pocket, a characteristic oral cavity found in ants and that has largely been ignored in studies of gut symbiosis. Based on my results, I provide compelling evidence that hindgut microbes are inoculated into food particles trapped in the infrabuccal pocket, aiding in digestion of this substrate. Moreover, I suggest that trophallaxis olays a central role in inoculation of food and individuals, and might be responsible for the transmission of nutrients that are predicted to result from the gut bacteria metabolism. Finally, in Appendix C I characterize abdominal trophallaxis in C. rohweri to gain insight on its role in the context of symbiotic associations with gut microbes. I show that the hindgut contents, including bacteria, can be transmitted via abdominal trophallaxis. This interaction is found to occur between all combinations of major and minor workers, in addition to callows. The rate of solicitation of abdominal trophallaxis is higher when individuals are protein starved, indicating that hindgut content may also be nutritive. Using shotgun metagenomic data, we show that the microbiota present in the infrabuccal pocket (mostly hindgut bacteria) are indeed capable of re-utilizing nitrogen and synthesizing essential amino acids, in addition to breaking down plant material. We also report that oral trophallaxis is a possible route for transmission of crop-specific bacteria for callows, as this group has performed oral trophallaxis at a relatively higher rate than older workers. Put together, these results highlight the importance of nestmate interactions and gut morphology in the establishment and maintenance of symbiotic microbes in a social insect, introducing a new model for explaining the evolution and functioning of ant-gut microbe symbiosis.

The following dissertation presents the history of myrmecology from the times of Ulisse Aldrovandi up to the works of Edward O. Wilson in the 20th century. The oldest mentions of ants in the Antiquity and the Middle Ages are also partially elaborated upon. A special emphasis is given to the general idea about ants as developed by each of the authors, as well as to the mapping out of the contemporary ideas about social insect. This work points out that the portrait of the ant has always been related to the contemporary conception of human society and humanity as such. Throughout its history, myrmecology has always been strongly influenced by anthropomorphism, as the picture of the ant would be derived from the social order, political system and the general opinion on what constitutes human nature. On the other hand, though, myrmecology has also helped to shape the picture of humanity, because the conclusions drawn from myrmecological studies were applied to humans. Therefore, entomology started to influence anthropology and vice versa. In the Antiquity, ants were viewed basically as farmers; only harvester ants were known, they were seen as working on a field, going to the marketplace or holding celebratory festivals. The medieval picture of the ant drew heavily on the Antiquity ideas, but it added...

Orientador: Odair Correa Bueno / Coorientador: Vanderlei Geraldo Martins / Banca: Maria Santina de Castro Morini / Banca: Priscila Cintra Socolowski / Resumo: Wasmannia auropunctata é uma espécie de formiga generalista e nativa da região Neotropical que tem se dispersado mundialmente. Quando introduzida em novas áreas, muitas vezes por ação antrópica, pode causar problemas ambientais, econômicos e de saúde pública. Diferenças encontradas entre populações introduzidas e nativas, ou sexuais e clonais tem aumentado o interesse por essa espécie, assim como alternativas para seu controle. O endossimbionte Wolbachia, além de ser amplamente distribuído entre os artrópodes e ser responsável por causar alterações reprodutivas em seus hospedeiros, tem sido considerado como um possível agente de controle para diversas espécies. Buscando compreender melhor a relação existente entre esses dois organismos e aumentar os perfis moleculares de populações na América do Sul, operárias de W. auropunctata de 31 pontos de coleta provenientes do Brasil e da Colômbia foram analisadas através da amplificação por PCR e sequenciamento de Sanger dos genes nuclear (28S rDNA) e mitocondrial (COI, IGS, tRNA e COII), assim como do gene wsp e coxA do endossimbionte. Através da caracterização molecular das operárias e de seus endossimbiontes e da análise das redes de haplótipos para ambos, observou-se que há evidências de que: o Leu-tRNA e o IGS entre o COI e COII podem ser utilizados para auxiliar na diferenciação inter e intraespecífica, respectivamente; o fragmento do gene 28S rDNA utilizado neste trabalho não deve ser utilizado sozinho para a identificação dessas formigas; amostras que apresentam IGS menor representam uma linhagem mais antiga; dispersão natural e por ação antrópica podem ter ocorrido entre as amostras analisadas; o gene coxA é o mais indicado para a detecção de Wolbachia nessas formigas do que o gene wsp; transmissão vertical e horizontal do endossimbionte são passíveis de estarem ocorrendo; dois dos alelos encontrados para o gene coxA podem estar envolvidos na / Abstract: Wasmannia auropunctata is a generalist ant, native of the Neotropical region that has being spread in worldwide scale and when introduced in new areas, many times by human transportation, can cause environmental, economics and health service troubles. Control alternatives and differences between introduced and native populations as well as between clonal and sexual colonies, has increased the interest about this species. The endosymbiont Wolbachia, the most widespread between arthropods, is responsible for many reproductive manipulations in its hosts and has been considered as a possibility of control agent for several species. Thus, the aim of this work was better understand the relationship between these two organisms and increase the molecular profiles of populations in South America. For this purpose, workers of 31 collection points were analyzed by PCR amplification and Sanger’s sequencing of the nuclear (28S rDNA) and mitochondrial (COI, IGS, tRNA e COII) genes, as well as wsp and coxA genes from the endosymbiont. The molecular characterization of workers and their endosymbionts and the Network analysis from both showed that there is evidences for believe that: the Leu-tRNA and the IGS between the COI and COII genes could be used to help in the inter and intraspecific distinction of these ants, respectively; the region of 28S rDNA should not be used alone as a marker to the identification of these ants; the samples that presented shorter IGS could represent ancient populations; natural dispersal and human transportation are likely to be occurring between the samples screened; the coxA gene is more appropriate than the wsp gene for detection of Wolbachia in this ants; vertical and horizontal transmission of the endosymbiont can be occurring; two of the alleles found in this work may be involved in ants specialization. Although this work brings new data and interesting hypothesis, more studies are needed to achieve a better... / Mestre

A preocupação com novos conceitos de produção é importante devido às mudanças observadas no mundo. Para isto, o conhecimento da diversidade dos ambientes se torna uma ferramenta de comparação entre diferentes ambientes, sendo onde se encaixa o uso das formigas como bioindicadoras, pela sua fácil coleta e identificação. O objetivo deste projeto foi identificar as espécies da família Formicidae (Hymenoptera), presentes no solo em cultivo orgânico de café (Coffea arabica), com a finalidade de determinar a riqueza e a diversidade de espécies, e as espécies que possam ser consideradas bioindicadoras dentro deste sistema. Os experimentos foram desenvolvidos em área de plantio do sistema de cultivo orgânico de café (Coffea arabica) no município de Dois Córregos, SP, em dois períodos distintos do ano: chuvoso (fevereiro/2008) coleta I e seco (julho/2008) coleta II. A coleta da mirmecofauna foi realizada utilizando-se dois tipos de armadilhas a de solo Pitfall e a do tipo Winkler. Posteriormente o material foi triado e identificado. As áreas de café foram separadas em duas a pleno sol e sombreada. Foram coletados 7101 espécimes distribuidos em 38 espécies. Poucas espécies foram constantes e freqüentes ao longo do estudo. Com relação ao índice de diversidade apenas dois pontos se destacaram ao longo do estudo na coleta I a pleno sol e na coleta II na sombra, de acordo com os índices de Shanon-Wiener e Simpson. O único ponto que teve maior dominância foi na coleta I a pleno sol. Através da análise de agrupamento dois grupos distintos foram formados a partir dos tipos de armadilha utilizados. Linepthema humile foi considerada como espécie bioindicadora para o cultivo orgânico de café. / This paper deals with a survey and identification of soil ant species (Hymenoptera, Formicidae) occurring in organic coffee (Coffea arabica) crop in order to determine species richness and diversity, as well as the ant species to be used as bioindicators of habitat disturbance in the coffee agroecosystem. Two experiments were set in an organic coffee (Coffea arabica) plantation in Dois Corregos, State of São Paulo, Brazil, one in rainy season (experiment I, February/2008) and other in the dry season (experiment II, July/2008). The ants were collected by using Pitfall trap and Winkler trap and the material was brought to the laboratory were the ant species were identified. There were two coffee areas: sun exposed crop and shadowed crop. One collected 7.101 specimens distributed in 38 species. Few species were constant and frequent ones along the research: Collect I-sun exposed and Collect II-shadowed crop, according to Shanon- Wiener and Simpson indices. The only point to present high dominance was observed in Collect I-sun exposed. One conclude that Linepthema humile is the ant species to be used as bioindicator of habitat disturbance in the organic coffee.

Orientador: Odair Correa Bueno / Coorientador: Mario Sergio Palma / Banca: Alexsandro Santana Vieira / Banca: Ana Eugenia de Carvalho Campos / Resumo: As glândulas pós-faríngeas estão presentes em todas as formigas e em algumas vespas solitárias. Localizam-se dorso-lateralmente na transição entre a faringe e o esôfago e sua morfologia é variável entre os diferentes grupos de Formicidae, podendo apresentarse na forma lobulada ou digitada. As funções atribuídas a essas glândulas são passíveis de discussão. São consideradas por diferentes autores como cecos gástricos, divertículo do trato digestório, como produtoras de feromônios ou de hidrocarbonetos cuticulares. Novas evidências tem dado suporte a função dessas glândulas na ingestão e retenção de lipídios. Com isto em vista, o presente trabalho teve como objetivo identificar as proteínas expressas nas glândulas pós-faríngeas de Atta sexdens rubropilosa buscando ampliar o conhecimento sobre uma possível função destas glândulas no metabolismo de lipídios por meio da comparação das proteínas diferencialmente expressas nas glândulas de formigas em três estágios alimentares: rainhas que não receberam nenhum tipo de tratamento alimentar e rainhas que receberam óleo de soja como suplementação lipídica, analisadas 4 e 120 horas após o tratamento. A utilização da abordagem proteômica envolveu técnicas de eletroforese bidimensional, estratégia shotgun e espectrometria de massas. Para a análise dos resultados obtidos foram usadas diferentes ferramentas de bioinformática para a identificação das proteínas e esclarecimento de suas funções. O algoritmo utilizado para pesquisa nos bancos de dados foi o MASCOT Ion Search versão 2.0 e os bancos de dados foram o Protein Data Bank, SwissProt e o GenBank. Foram identificadas 33 proteínas a partir do extrato de glândulas pós-faríngeas de rainhas Atta sexdens rubropilosa, envolvidas em diversas funções como metabolismo de lipídios, energético e de esteróides, bem como com os mecanismos de defesa, regulação metabólica, transdução de sinal e... / Abstract: The post-pharyngeal glands are present in all ants and some solitary wasps. These glands are located laterally in the back of the head, between the pharynx and esophagus, and their morphology varies among different groups of Formicidae. They may present themselves as lobulated or typed. The functions assigned to these glands are open to discussion, and are considered by different authors as gastric caeca, diverticulum of the digestive tract or as producer of pheromones or cuticular hydrocarbons. New evidence has supported the function of these glands to be in the intake and retention of lipids. The present study aimed to identify the proteins present in the post-pharyngeal glands of Atta sexdens rubropilosa seeking to expand knowledge about a possible function of these glands in the metabolism of lipids by comparing the differentially expressed proteins in the glands of ants food in three stages: queens who did not receive any treatment, and queens who received soybean oil as lipid supplementation analyzed 4h and 120h after treatment. Using the proteomic approach involving two-dimensional electrophoresis techniques, strategy and shotgun mass spectrometry. To analyze the obtained results various bioinformatics tools were used for protein identification and clarification of their duties. The algorithm used to search the databases was the MASCOT Ion Search version 2.0 and the databases were the Protein Data Bank, GenBank and SwissProt. In the end, 38 identified proteins were extracted of the post-pharyngeal glands of Atta sexdens rubropilosa queens, involved in several functions such as metabolism of lipid, energy and steroids, as well as defense mechanisms, metabolic regulation, signal transduction, cytoskeleton restoration and membrane protein. The expression of proteins related to lipid... (Complete abstract click electronic access below) / Mestre

Orientador: Fernando Carlos Pagnocca / Coorientador: Derlene Attili de Angelis / Banca: Márcia de Souza Carvalho Melhem / Banca: Odair Corrêa Bueno / Resumo: As formigas da tribo Attini são conhecidas como "cultivadoras de fungos" devido à complexa simbiose que mantém com um fungo basidiomiceto, cultivado como alimento. Além do fungo mutualista, cresce continuamente a lista de micro-organismos encontrados nos ninhos e na cutícula desses insetos. Recentemente, leveduras negras, relacionadas ao gênero Phialophora, foram consideradas componentes da simbiose formiga-fungo por comprometerem a habilidade das formigas em lidar com o micoparasita Escovopsis. Os fungos melanizados estão frequentemente relacionados a infecções humanas e, por isso, tem sido questionada a possibilidade desses insetos atuarem como vetores de dispersão de fungos negros patógenos no ambiente urbano. Esta dissertação marca o início de um esforço no qual procuramos investigar a diversidade de fungos negros presentes na cutícula de formigas cortadeiras, bem como verificar o grau de virulência das estirpes obtidas. Este último aspecto, ou seja, a possibilidade das formigas cortadeiras abrigarem e dispersarem micro-organismos patogênicos pode ser o início de um novo ramo de investigação. Analisando fêmeas aladas (içás) de Atta capiguara e A. laevigata, coletadas antes do início do voo nupcial, verificou-se que elas abrigam em suas cutículas uma comunidade diversa de fungos negros, como os gêneros Cladophialophora, Cladosporium, Cochliobolus, Exophiala, Ochroconis, Phaeococcomyces, Phialophora, Penidiella e Pyrenochaeta. Num segundo estudo, os resultados indicaram que leveduras negras do gênero Exophiala, presentes na cutícula de içás e em ambientes contaminados por derivados de petróleo, apresentam características que as tornam potenciais oportunistas humanos, como consistente crescimento a 40°C e produção de lacases. Espera-se que os resultados deste trabalho... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Attini ants are known as basidiomycete fungus cultivated as a food source. Besides the mutualistic fungus, there is a continuous growth in the list of microorganisms found in nests and cuticles of these insects. Phialophora-related black yeasts have recently been considered as components of the antfungus symbiosis by compromising the ability of ants to deal with the mycoparasite Escovopsis. Melanized fungi are frequently related to human infections and, therefore, the ability of these insects act as vectors for dispersal of pathogenic black fungi in the urban environment has been questioned. This dissertation makes a start at assessing the diversity of black fungi derived from the cuticle of leaf-cutting ants, as well as verifying the virulence degree of the strains obtained. The latter, i.e., the possibility of ants sheltering and dispersing pathogenic microorganisms can be the start of a new research field. Our microbial profile of Atta capiguara and A. laevigata winged females, collected prior to the mating flight, revealed that the cuticle of ants can harbor a diverse community of black fungi, such as the melanized genera Cladophialophora, Cladosporium, Cochliobolus, Exophiala, Ochroconis, Phaeococcomyces, Phialophora, Penidiella and Pyrenochaeta. Moreover, we demonstrated that Exophiala species, associated with gynes' cuticle and hydrocarbon-polluted environments, have characteristics that make them potential human opportunists, like consistent growth at 40°C and laccase production. Our results will certainly serve as a basis for more detailed future studies to explore how these fungi reach the interior of the nest, how they survive... (Complete abstract click electronic access below) / Mestre

Orientador: André Rodrigues / Coorientador: Fernando Carlos Pagnocca / Banca: Allen Norton Hagler / Banca: Maurício Bacci Junior / Resumo: As formigas cortadeiras (Hymenoptera: Formicidae: tribo Attini) mantêm um mutualismo com o fungo Leucoagaricus gongylophorus, utilizado como alimento por esses insetos. Nos jardins de fungo, as formigas abrigam o fungo mutualista, pupas, larvas, além de uma microbiota composta por bactérias, leveduras e outros fungos. Uma grande quantidade de machos (bitus) e fêmeas aladas (içás) é produzida anualmente em ninhos adultos de formigas do gênero Atta. Esses indivíduos deixam os ninhos para acasalarem durante o voo nupcial (revoada), onde provavelmente ocorre a transferência de micro-organismos entre os indivíduos. Neste trabalho, foi avaliado a diversidade de leveduras no integumento de 200 bitus provenientes de dois ninhos de Atta sexdens rubropilosa, nas revoadas de 2010 e 2011. Foram isoladas também leveduras do solo dos túneis e do solo adjacente aos ninhos na tentativa de descobrir a origem das leveduras no integumento dos bitus. Buscando entender o papel das leveduras nos ninhos, foi estudada a capacidade de degradação de polímeros vegetais presentes no jardim de fungo e no consumo de açúcares gerados da quebra desses substratos. Um total de 242 estirpes distribuídas em 29 espécies foi recuperado do integumento dos insetos. Bitus do ninho #1 (Rio Claro, SP) apresentaram maior riqueza e diversidade de espécies de leveduras do que bitus do ninho #2 (Botucatu, SP). Embora a riqueza e diversidade tenham variado entre as diferentes amostragens, a estrutura da comunidade foi semelhante, a qual não foi correlacionada com o local de coleta ou o ano em que ocorreram as revoadas. O isolamento de leveduras do solo dos túneis e do solo próximo aos ninhos revelou poucas espécies em comum com aquelas encontradas no integumento dos bitus; o que sugere que a maioria das leveduras presentes nos bitus... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Leafcutter ants (Hymenoptera: Formicidae: tribe Attini) maintain an obligate mutualism with Leucoagaricus gongylophorus, a basidiomycetous fungus cultivated for food. Attine fungus gardens harbor the mutualistic fungus, pupae, larvae and several additional microorganisms such as bacteria, yeasts and filamentous fungi. Annually, several alates are produced in Atta nests and leave their nests for the matting flight, when the transmition of microorganisms probably occur between them. Here, we evaluated the yeast diversity found on the integument of 200 males of Atta sexdens rubropilosa sampled from two different nests in the mating flights of 2010 and 2011. Yeasts were also isolated from the soil of tunnels and soil adjacent to nests in order to study if yeasts found on males were originated from this environment. In an attempt to understand the role of yeasts in the fungus garden, we study the degratation of plants polymers and the assimilation of sugars generated after hydrolysis of these substrates. A total of 242 strains distributed in 29 species were recovered on the integument of these insects. Males from nest #1 (Rio Claro, SP) showed the highest yeast species richness and diversity in comparison to males from nest #2 (Botucatu, SP). Although species richness and diversity varied between samples, the community structure was similar between nests. Thus, the community structure was not correlated with collection sites or the year when the mating flights occurred. Yeast isolation from soil samples suggested that few species were shared between this type of sample and the yeasts found on the integument of males; this result shows that most yeast species on the integument of males were derived from the fungus garden. Cryptococcus haglerorum and Trichosporon chiarellii isolated from males of nest #1 (in 2011) indicate a putative... (Complete abstract click electronic access below) / Mestre

Calculating hippocampal volume from Magnetic Resonance (MR) images is an essential task in many studies of neurocognition in healthy and diseased populations. The `gold standard' method involves hand tracing, which is accurate but laborious, requiring expertly trained researchers and significant amounts of time. As such, segmenting large datasets with the standard method is impractical. Current automated pipelines are inaccurate at hippocampal demarcation and volumetry. We developed a semi-automated hippocampal segmentation pipeline based on the Advanced Normalization Tools (ANTs) suite of programs to segment the hippocampus. We applied the semi-automated segmentation pipeline to 70 participant scans (26 female) from groups that included participants diagnosed with autism spectrum disorder, healthy older adults (mean age 74) and healthy younger controls. We found that hippocampal segmentations obtained with the semi-automated pipeline more closely matched the segmentations of an expert rater than those obtained using FreeSurfer or the segmentations of novice raters. Further, we found that the pipeline performed best when including manually- placed landmarks and when using a template generated from a heterogeneous sample (that included the full variability of group assignments) than a template generated from more homogeneous samples (using only individuals within a given age or with a specific neuropsychiatric diagnosis). Additionally, the semi-automated pipeline required much less time (5 minutes per brain) than manual segmentation (30-60 minutes per brain) or FreeSurfer (8 hours per brain).