The aim of this thesis was to understand the function of the frontal lobes during different types of decisions thusfar mostly neglected in cognitive neuroscience. Namely, I sought to understand how decisions are made when comparisons are not about a simple set of concrete options presented, but rather require a comparison with one specific encounter and a sense of the value of the current environment <b>(Chapter 2-3)</b>. Additionally, I wanted to understand how decisions between concrete options can be contextualized by the current environment to allow considerations about changing environmental constraints to factor into the decision making process <b>(Chapter 4-5)</b>. At last, I wanted to test how the potential for future behaviours within an environment has an effect on peoples decisions <b>(Chapter 6)</b>. In other words, how do people construct prospective value when it requires a sense of own future behaviours? All this work was informed by concepts and models originating from optimal foraging theory, which seeks to understand animal behaviours using computational models for different ecological types of choices. Thus, this thesis offers a perspective on the neural mechanisms underlying human decision making capacities that relates them to common problems faced by animals and presumably humans in ecological environments <b>(Chapter 1 and 7)</b>. As optimal foraging theory assumes that solving these problems efficiently is highly relevant for survival, it is possible that neural structures evolved in ways to particularly accommodate for the solution of those problems. Therefore, different prefrontal structures might be dedicated to unique ways of solving ecological kinds of decision problems. My thesis as a whole gives some evidence for such a perspective, as dACC and vmPFC were repeatedly identified as constituting unique systems for evaluation according to different reference frames. Their competition within a wider network of areas appeared to ultimately drive decisions under changing contexts. In the future, a better understanding of those changing interactions between these prefrontal areas which generate more complex and adaptive behaviours, will be crucial for understanding more natural choice behaviours. For this temporally resolved neural measurements as well as causal interference will be essential.

This study focused on how changes in food availability during the dry season, influenced various aspects of sable (Hippotragus niger niger) foraging and social ecology. The main purpose of this was to determine whether differences in their foraging ecology explained the reduction in population size compared to other more abundant herbivores (e.g. zebra, buffalos, hartebeest). Contrary to expectation, sable did not limit their foraging to woodlands, but also fed in open grasslands, provided these retained green grass during the dry season. Wetlands were key resource areas during the dry season, but sable did not limit their feeding to these bottomland areas. They also fed on hill slopes and upper plateaus that had been burnt. During the study, sable were attracted to burnt areas despite the reduced grass availability. My study highlights how these burnt areas were important in alleviating nutritional deficiencies during the dry season. At lower spatial levels, I looked at the factors that influenced the selection of feeding areas and plant species. Like other grazers, sable were attracted to green leaves but did not avoid brown leaves or stems. Grass species eaten were the same as those preferred by most domestic and wild grazers. Surprisingly, adult males stayed with the breeding herds despite their different activity budgets. Unlike most other African grazers, sub adult sable males did not form bachelor groups. Instead, they stayed within the breeding herds the whole time and had a similar activity budget to females. As adult males moved with the breeding herds, I was able to examine the costs and benefits involved with such a social structure. From this, I was able to relate my results to the bigger picture of factors influencing sexual segregation in ungulates. In conclusion, sable utilised a wide variety of habitat types and adjusted their foraging behaviour to accommodate different seasonal situations. I was unable to find anything in their feeding ecology that could explain the continued decline in population size. Therefore, I suggest that future research needs to focus on other potential causes such as a higher susceptibility to predation and disease as compared to more abundant herbivore species.

The fungal microbiome, or “mycobiome” of plants is diverse and important to host health, but the fluxes of fungi among plant hosts and with the surrounding environment are poorly understood. In chapter two, we employed sterile culture techniques and spatial sampling to examine leaves as possible vectors for transfer of their endophytic fungi from the canopy to substrate on the forest floor, as predicted by the Foraging Ascomycete hypothesis. Some foliar endophytic fungal species are also present as wood-decomposing fungi on the forest floor, that transfer of mycelium across these two life history stages can occur, that endophytic life history stages are buffered from environmental conditions in comparison to wood-decomposing fungi, and that spatial linkages between the two life history stages can be observed. In another study, described in chapter 3, wood and leaf wood endophytes were sampled across a 25 ha plot, to explore landscape patterns of mycobiomes, and to explore the concept of a core microbiome in aerial plant tissues. We found that core microbiomes may be observed in a real ecological setting, but that the concept of core must be carefully defined and that some level of buffering from disturbance may be necessary to allow core microbiomes to assemble. In chapter four, we return to examine some of the assumptions and implications of the Foraging Ascomycete hypothesis, with an agent-based model. We model the conditions under which dispersal through falling leaves may represent a fitness-enhancing dispersal strategy for fungi, and that deforestation as is currently underway throughout the world may have impacts on fungi that rely upon a canopy- inhabiting life stage for dispersal. In chapter five, some challenges associated with environmental sampling of microbes using illumina© MiSeq sequences are critically examined. We find that biases introduced by random sampling at various stages of IVenvironmental DNA extraction and illumina© MiSeq sequencing are not well corrected by currently accepted bioinformatic algorithms. In addition, information loss from differential extraction, PCR amplification, and sequencing success, requires that users of MiSeq read libraries to interpret read abundances carefully. This dissertation includes previously published, co-authored material.

Standardised systems of food production where food is brought into cities from far away is accompanied with high emissions from both production and transport. Simultaneously, food growing in the urban surroundings is not picked and left to rot. This thesis is concerned with urban foraging, the practice of picking edibles in the urban landscape, a practice often overlooked by research and policymakers. The case study area is Skarpnäck, southern Stockholm and the focus is specifically on foraging of fruit and berries from public vegetation. Using a qualitative mixed methods approach where a questionnaire was followed by interviews, the aim has been to assess how the practice is perceived in the case study area and if there are certain cultural norms that limit picking activities. Results suggest that foraging is perceived to be out of place in the urban area. Although some people do pick, others feel it is inappropriate and do not want to be seen picking fruit or berries and therefore limit picking. The thesis concludes that urban foraging has the potential to increase urban sustainability, but efforts are needed for foraging to be a culturally accepted practice.

O cleptoparasitismo é uma interação entre animais que consiste no furto ou roubo de itens alimentares já coletados ou processados. Este tipo de interação ocorre em diversos táxons animais. Entre aranhas, a subfamília Argyrodinae (Theridiidae) é um dos grupos com mais espécies cleptoparasitas. Neste estudo, apresentamos um apanhado de ações que o cleptoparasita Argyrodes elevatus foi capaz de realizar nas teias de aranhas hospedeiras. As principais espécies de hospedeiras observadas foram Latrodectus curacaviensis, Latrodectus geometricus e Achaearanea tepidariorum (Theridiidae); destas, apenas A. tepidariorum é uma hospedeira natural de A. elevatus. A maioria das observações se deu em laboratório, mas também relatamos dados de campo. Registramos que A. elevatus pode, na teia de sua hospedeira, furtar presas sem ser percebido ou roubá-las coercivamente. Ele pode ainda furtar ootecas; capturar presas por si próprio e até mesmo predar a aranha hospedeira. Em seguida, apresentamos as sequências de categorias comportamentais que A. elevatus executa durante o furto de presas em teias da hospedeira L. curacaviensis. A partir destas sequencias, o programa EthoSeq nos mostra os conjuntos de categorias com mais probabilidade de conexão entre si (rotinas comportamentais) e nos permite a elaboração de um fluxograma do comportamento de furto de presas. Posteriormente, comparamos as categorias e as rotinas comportamentais que ocorrem no furto de presas com as categorias e rotinas que ocorrem no forrageamento de aranhas não cleptoparasitas. Com isto, demonstramos que A. elevatus tem maior plasticidade comportamental e capacidade cognitiva mais alta que espécies não cleptoparasitas da mesma família. Esta maior plasticidade comportamental está associada à execução, em contexto de aquisição de alimento, de comportamentos que são típicos de outros contextos, como agonismo ou exploração de novos ambientes. A. elevatus, portanto, é adaptado a lidar simultaneamente com diferentes contextos na teia de uma hospedeira. Pudemos, desta maneira, acrescentar elementos às propostas atuais que procuram explicar a evolução do cleptoparasitismo em Argyrodinae, em especial no que se refere à plasticidade comportamental. Por fim, propomos um modelo que mostra que a causa imediata do aumento da capacidade cognitiva de A. elevatus pode ser um aumento na interação entre diferentes módulos cognitivos nesta espécie. / Kleptoparasitism is an animal interaction consisting in stealth of collected or processed food items. It occurs on many animal taxa. Among spiders, the subfamily Argyrodinae (Araneae) is one of the groups with more kleptoparasite species. In this study, we present a set of different actions that the kleptoparasite Argyrodes elevatus can do in host spiders webs. Observed host species were mainly Latrodectus curacaviensis, Latrodectus geometricus and Achaearanea tepidariorum (Theridiidae), but only A. tepidariorum is a natural host of A. elevatus. Most observations were made in laboratory, but we also included field data. We registered that A. elevatus, in a host web, can steal a prey item without being perceived by the host spider, or rob it coercively. We also observed A. elevatus stealing eggsac, capturing preys by himself, and killing the host spider. We present sequences of behavioural units that A. elevatus performs during the stealth of preys in L. curacaviensis webs. From these sequences, the software EthoSeq shows the sets of behavioural units with higher probability of connection. These sets are called behavioural routines. After that, we could build an ethogram and compare the units and routines of A. elevatus prey stealth behaviour with the units and routines of non-kleptoparasite spiders prey capture behaviour. With this comparison we show that A. elevatus has a higher behavioural plasticity and cognitive ability than non-kleptoparasite theridiid spiders. The higher behavioural plasticity is related to the occurrence; during foraging bouts, of behaviours typical of other contexts, such as agonism or site selection. Therefore, A. elevatus is adapted to behave in many different contexts simultaneously in a host web. Our results improve the current hypothesis concerning evolution of kleptoparasitism in Argyrodinae through the discovery of further plasticity in the taxa. Furthermore, we propose a model for the increase in the cognitive ability of A elevatus. In this model, cognitive increase is obtained through the interaction between distinct cognitive modules in this species.

O comportamento de forrageamento dos tiranídeos (Aves, Tyrannidae) é caracterizado por um modo estereotipado de \"procura e captura\", com sutis variações interespecíficas relacionadas com fatores morfológicos e ecológicos. Estas aves são predominantemente insetívoras e podem alternar entre modos distintos de forrageamento de acordo com variações climáticas que alterem a disponibilidade de presas. Neste estudo, procuramos quantificar o comportamento de forrageamento de Alectrurus tricolor, Gubernetes yetapa, Xolmis cinereus e Xolmis velatus, durante as estações seca e chuvosa dos anos de 2012 e 2013, na Estação Ecológica de Itirapina. Nosso objetivo foi verificar quão plásticos são os modos de forrageamento destas espécies diante de mudanças nas condições ambientais em diferentes escalas temporais. Buscamos verificar se: i) Estas espécies alteram sazonalmente as proporções entre os modos de ataques, o tempo de procura por presas e a distância entre um poleiro sem sucesso para um novo poleiro? Considerando que a disponibilidade de artrópodes pode variar consideravelmente em pequenas escalas temporais e espaciais, testamos se: ii) Existem correlações entre medidas diárias de fatores meteorológicos, como temperatura, insolação, pluviosidade, umidade relativa do ar e vento, e os comportamentos de forrageamento? iii) Existem correlações entre os diferentes tipos de habitats utilizados pelas aves e os comportamentos de forrageamento? iv) Diferenças entre os sexos e a idade do indivíduo influenciam no forrageamento de Alectrurus tricolor? Nossos resultados indicaram que as aves alteram seus padrões de comportamento entre as estações seca e chuvosa de modo a melhor aproveitar as especificidades de cada estação. Ataques aéreos foram predominantemente utilizados por Alectrurus tricolor e Gubernetes yetapa ao longo das duas estações, mas apenas durante a estação chuvosa para Xolmis velatus. Ataques direcionados ao solo foram predominantemente utilizado por Xolmis cinereus durante as duas estações e por Xomis velatus durante a estação seca. Ataques aéreos foram correlacionados principalmente com altas temperaturas, mas também com baixa cobertura de nuvens, tipo de habitat, fase do dia, ventos leves, maior umidade relativa do ar e presença de chuva, com variações de acordo com a espécie estudada. O tempo de procura por presas variou principalmente com a estrutura do habitat, e os maiores valores foram encontrados quando as aves forrageavam em áreas abertas. Fatores que reduzem a disponibilidade de presas aéreas, como baixas temperaturas, baixa insolação e vento moderado, foram correlacionados com as maiores distâncias percorridas entre poleiros. Porém, quando consideramos uma maior escala temporal, encontramos maiores valores de distâncias percorridas durante a estação chuvosa para Alectrurus tricolor e Xolmis velatus, quando as condições ambientais são mais favoráveis, o que pode estar relacionado com os requerimentos da fase reprodutiva. Assim, podemos observar que a interação entre fatores meteorológicos e estrutura do habitat influenciam os padrões de comportamento destas aves / The foraging behavior of tyrant flycatchers (Aves, Tyrannidae) is characterized by a stereotyped way of \"search-and-capture\" with subtle interspecific variations related to morphological and ecological factors. These birds are mainly insectivorous and can switch between different foraging modes according to weather variations that alter the availability of prey. In this study, we seek to quantify the foraging behavior of Alectrurus tricolor, Gubernetes yetapa, Xolmis cinereus and Xolmis velatus in the dry and wet seasons of the years 2012 and 2013, at the Ecological Station of Itirapina. The objectives of this study were to determine how plastics the foraging modes of these species are against environmental changing of conditions at different time scales. It seeks to determine whether: i) These species use foraging maneuvers, search time and the distances moved from one unsuccessful perch to a new perch (give-up flight) in different proportions between the two seasons? Arthropod availability may vary considerably in small spatial and temporal scales, then we tested whether ii) There is correlation between daily weather measurements, such as temperature, cloud cover, rainfall, relative humidity and wind, and the foraging behavior? iii) There are correlations between the different habitats used by birds and foraging behavior? iv) The foraging behavior of Alectrurus tricolor is influenced by sex and age of the individual? Our results indicated the birds change their behavior between the dry and wet seasons in order to benefit from specific features of each season. Aerial hawking was predominantly used by Alectrurus tricolor and Gubernetes yetapa during both seasons, but by Xolmis velatus only during the wet season. Perch-to-ground was the predominant hunting strategy for Xolmis cinereus during both seasons and for Xomis velatus during the dry season. Aerial hawking was mainly correlated with high temperatures, but also with lower cloud cover, habitat type, time of day, low wind speed, higher relative humidity and the rain, with variations according to the studied species. Search time varied mainly with habitat structure, and the highest values when the birds were foraging in open areas. Factors reducing the availability of aerial prey, such as low temperature, low insolation and moderate wind, were correlated with longer distances traveled between perches. However, when we consider a larger time scale, we fond Alectrurus tricolor and Xolmis velatus covered greater distances the wet season (when environmental conditions are more favorable) what may be related to breeding requirements. Thus, the interaction between weather and habitat structure influences the behavioral patterns of those birds

Para as abelhas com organização altamente eussocial, como são as abelhas sem ferrão (Meliponini), o pólen é a principal fonte de proteína que influencia diretamente na regulação social de suas colônias, tanto nos imaturos quanto nos indivíduos em fase adulta. O sucesso das operárias em localizar e coletar esse recurso, assim como a quantidade estocada no interior do ninho, garante um abastecimento nutricional permanente, assegurando a manutenção e sobrevivência da colônia durante longos períodos, incluindo os de escassez de alimento no ambiente. Dessa forma, o objetivo desse trabalho foi avaliar o efeito da quantidade de pólen estocado nos ninhos de Scaptotrigona depilis (Moure, 1942) sobre o número de forrageiras para a coleta desse recurso, a quantidade de pólen coletado pelas forrageiras e a taxa de produção de cria. Esses parâmetros foram avaliados em ninhos com e sem estoques de pólen durante 30 dias consecutivos em dois períodos, de março a abril e de setembro a outubro de 2016. Quando os ninhos sofreram reduções drásticas de suas reservas de pólen, as operárias de S. depilis ajustaram suas atividades e responderam comportamentalmente, de forma que houve: (a) alocação de maior número de forrageiras para coleta de pólen; (b) alocação de forrageiras mais pesadas para coleta de pólen; (c) transporte de cargas polínicas mais pesadas pelas forrageiras; (d) maior produção de céulas de cria. Em suma, nossos resultados mostram a importância de estudos sobre biologia básica, com manipulações experimentais, que não só têm potencial para responder questões ecológicas e/ou evolutivas, como também as aplicadas, provendo subsídios para o uso de abelhas sem ferrão em programas de polinização dirigida, que podem ser aliados a ações voltadas para conservação. / For highly eusocial bees, such as stingless bees (Meliponini), pollen is the main source of protein that directly influences the social regulation of their colonies, on both immature and adult stages. The workers\' success in locating and collecting pollen, as well as the amount of pollen stored within the nest, guarantees a permanent nutritional supply, ensuring the colony maintenance and survival for long periods, including those of food shortage in the environment. The aim of this study was to evaluate the effect of the amount of pollen stored within the nests of Scaptotrigona depilis (Moure, 1942) on the number of pollen forages, the pollen loads collected by forages and the rate of brood cell production. These parameters were evaluated in nests with and without pollen stores during 30 consecutive days in two periods, from March to April and from September to October 2016. When the nests suffered drastic reduction of their pollen reserves, the S. depilis workers adjusted their tasks and responded behaviourally, because there was: (a) additional allocation of pollen foragers; (b) allocation of heavier forages for pollen collection; (c) transport of heavier pollen loads by foragers; (d) higher brood cell production. In sum, our results highlight the importance of studies on basic biology, with experimental manipulations, that have widespread potential to help us to answer ecological and/or evolutionary questions, but also the applied questions, providing useful guidelines for the use of stingless bees as crop pollinators, which can be allied to conservation efforts.

As abelhas utilizam sinais visuais e olfatórios para encontrar plantas das quais utilizam recursos florais. Algumas abelhas adquiriram hábitos crepuscular ou noturno e forrageiam durante períodos de pouca luminosidade. Algumas espécies de abelhas noturnas são conhecidas por possuírem adaptações morfológicas do sistema visual que lhes permitem o voo noturno, e assim facilitam o encontro de plantas que podem ser utilizadas como recursos. No presente estudo investigamos se espécies crepusculares Megalopta sodalis, Megommation insigne e Ptiloglossa latecalcarata, que utilizam Campomanesia phaea como recurso, e possuem adaptações na morfologia externa do sistema visual. A hipótese principal é que seriam encontrados olhos compostos, omatídeos e ocelos maiores, assim como menor quantidade de omatídeos nos olhos compostos quando comparadas às abelhas diurnas. Para tanto, medimos o comprimento, área e número de omatídeos dos olhos compostos, assim como o diâmetro dos omatídeos e ocelos. A distância intertegular foi medida para ter um controle do tamanho corporal. Além das abelhas crepusculares acima citadas, utilizamos as abelhas diurnas Bombus brasiliensis, Bombus morio, Melipona bicolor e Euglossa cordata para comparação. Para a medida dos olhos fizemos um molde de esmalte e a partir deste obtivemos imagens que foram analisadas utilizando-se o software ImageJ e Matlab. Para as outras medidas, foram obtidas imagens em estereomicroscopio que foram analizadas com o ImageJ. Utilizamos a análise estatística de permutação para ver se havia diferença entre as abelhas crepusculares e diurnas, e correlação de Spearman para ver se a medida estava correlacionada à distância intertegular. Foi realizado um levantamento das espécies com registro de interação com abelhas crepusculares e noturnas e de suas características florais com uma respectiva análise descritiva. As abelhas crepusculares deste estudo possuem o diâmetro dos ocelos e omatídeos maiores e olhos compostos com maior comprimento e área, e menor número de omatídeos. Algumas variáveis estão correlacionadas com a distância intertegular. As flores visitadas por abelhas noturnas possuem em sua maioria cores claras, perfume acentuado e são odoríferas. As abelhas crepusculares deste estudo possuem adaptações na morfologia externa, o que lhes permite o voo no período de pouca luminosidade. Algumas espécies de abelhas que forrageiam em período de pouca luminosidade visitaram flores de cores fortes e uma não odorífera, isso pode estar relacionado à capacidade de reconhecer cores em ambientes pouco iluminados. Algumas espécies de abelhas forrageiam durante o dia e a noite, essa plasticidade do comportamento pode ser um caminho pelo qual caracteres vantajosos para esse ambiente sejam selecionados. Para as plantas, ter as abelhas noturnas como polinizadoras pode ser vantojoso. Então plantas que possuem sinais reconhecidos pelas abelhas noturnas podem se beneficiar com a polinização noturna, evitando o disperdício de pólen com as abelhas diurnas. A maioria das abelhas foi generalista na utlilização do recurso, mas parece haver preferência por certas espécies de plantas / The bees use visual cues and olfactory to find plants which own floral resources. Some bees acquired crepuscular or nocturnal habits and foraging during periods of low light. Some nocturnal bees species are recognized to possess morphological adaptations of the visual system that enable them to practice the night flight, and thus facilitate the matching of plants that can be used as resources. In the present study we investigated whether crepuscular species Megalopta sodalis, Megommation insigne e Ptiloglossa latecalcarata, using Campomanesia phaea as a resource, have adaptations in the external morphology of the visual system. The main hypothesis was that the eyes were composed of ommatidia and larger ocelli as well as lower amount of ommatidia in the compound eyes when compared to daytime bees. Therefore, we measure the length, the area and number of ommatidia of the compound eye and also the diameter of the ommatidia, ocelli, and intertegular distance to have a control of body size. In addition to the crepuscular bees mentioned above, we used the diurnal bees Bombus brasiliensis, Bombus morio, Euglossa cordata, and Melipona bicolor for comparison. For the measurement of eyes, we made a nail polish mold and from this mold was obtained images which were analyzed using ImageJ and Matlab software. For other measures, we obtained images in stereomicroscope that were analyzed only using ImageJ. We use the statistical analysis of permutation to observe if there was any difference between the crepuscular and diurnal bees, and Spearman correlation to see if the measure was correlated with distance intertegular. In addition, we conducted a survey of species interaction with record crepuscular and nocturnal bees and their floral characteristics with a descriptive analisys. The crepuscular bees in this research have lager diameter of omatidea and ocelli, and larger area and length of compound eyes, and less number of omatidea per eye. Most of the flowers visited by nocturnal bees have pale color, scent and nocturnal anthesis. Some bee species that forage in low light visit flowers with strong color, and one bee visited flower without scent, this can be related with capacibility to recoginized colors in environments with low light. Some bees forage during day and night, this phenotypic plasticity of behavior can be a way that advantageous characters for this environment are selected. For plants can be advantageous. Then plants that posses sinals recognized by nocturnal and crepuscular bees can be benefited through nocturnal pollination, avoiding daylight bees waste their polen. The most of bees were generalists in their utilization of flower resource but seems to have preference for some plant species

A formação, recrutamento e manutenção de trilhas em formigas cortadeiras do gênero Atta é controlada quimicamente e envolve a participação de diferentes castas. Todavia, são escassos os estudos sobre a dinâmica das castas sob diferentes fontes de estímulos para a colônia, e como isso interfere na deposição de trilhas químicas. O presente trabalho visou compreender a influência de diferentes fontes de estímulos no padrão químico de deposição das trilhas, bem como no comportamento de recrutamento, forrageamento e defesa das operárias em Atta sexdens rubropilosa (Hymenoptera: Formicidae). Os resultados indicaram que houve variação do perfil etológico e alocação de tarefas desempenhadas pelos indivíduos presentes na colônia, de acordo com a fonte de estímulo. Neste caso foram oferecidos uma fonte de estímulo atrativa (\"pétalas de rosas\") e outra de agressividade (\"rainha de outra colônia\"). Além disso, os perfis químicos observados nas trilhas variaram qualitativamente e quantitativamente de acordo com os estímulos oferecidos. Estes dados sugerem que as operárias de A. sexdens rubropilosa seriam capazes de manejar quimicamente seu feromônio de trilha para informar e alterar o comportamento de suas companheiras de ninho, de acordo com a fonte de estímulo em que foram expostas. / Formation, recruitment and maintenance of trail in Atta leaf-cutting ants are chemically controlled and involve participation of different castes. Nevertheless, studies on caste dynamic under different stimuli to the colony are scarce, and how it interferes in the chemical deposition of the trail. This investigation aimed to understand how different source of stimuli influence the chemical pattern of trail marking as well as the recruitment, foraging and defense behavior by workers in Atta sexdens rubropilosa (Hymenoptera: Formicidae). Results indicate variation in the ethological profile and task allocation performed by the colony individuals, according to the stimuli source. In this case, it was offered an attractive stimulus source (\"rose petals\") and an aggressive one (\"other colony queen\"). Moreover, the chemical profiles of the trail varied qualitatively and quantitatively in response to the stimuli they were exposed. These data suggest that A. sexdens rubropilosa workers would be able to chemically manipulate their trail pheromone with aim to inform and alter their nestmate behavior in response to the exposed stimuli source.

Tradicionalmente, nichos populacionais são descritos como a somatória de todos os recursos utilizados por uma população. Entretanto, diversos estudos mostram que indivíduos dentro de uma população podem usar recursos de forma distinta. Investigamos três maneiras pelas quais indivíduos podem variar quanto ao uso do recurso. Indivíduos podem apresentar a mesma preferência por presas, mas diferir na propensão à adição de novos itens alimentares em sua dieta (Preferências Compartilhadas); indivíduos podem apresentar a mesma presa preferida mas diferirem em suas presas alternativas (Refúgio Competitivo); ou indivíduos podem apresentar presas preferidas distintas (Preferências Distintas). Estudamos os padrões de interação que emergem sob os pressupostos de cada um dos modelos usando redes de interação entre indivíduos e os recursos que eles consomem. Dessa forma, para derivarmos as previsões de cada um dos modelos de uso de recurso, desenvolvemos modelos simples que geram redes de interação segundo regras que seguem os pressupostos dos modelos e confrontamos essas previsões com dados empíricos, comparando a estrutura dessa redes de interação. Encontramos que o modelo que menos se assemelha ao padrão de uso de recurso observado para as populações estudadas foi o modelo de Preferências Compartilhadas. Para as populações estudadas, a variação intrapopulacional na escolha de presas parece estar mais associada a diferenças nas sequências de preferências por presas entre indivíduos e não à propensão desses indivíduos em adicionarem novos recursos às suas dietas. / Traditionally, a population\'s niche is described as the sum of all resources consumed by a population. However, several studies have highlighted that individuals within a population can use resources differently. We investigate three ways in which individuals can vary in their resource use. Individuals can show the same preference for prey, but differ in their likelihood of adding new prey to their diets (Shared Preferences); individuals can share the same top-ranked prey but differ in their alternative prey (Competitive Refuge); or individuals can have different top-ranked prey (Distinct Preferences). We studied the pattern of interaction that emerges under each model\'s assumption using interaction networks between individuals and the resources they consume. In this sense, to derive the predictions associated with each model of resource use, we developed simple models that generates interaction networks according to a set of rules that represent the assumptions of each model and then confronted these predictions with empirical data on interaction networks, by looking at the structure of these interaction networks. We found that the model that least resembles the pattern of resource use observed in the populations studied was the Shared Preferences model. For the studied populations, intrapopulation variation is not associated with individuals sharing the same rank sequence and differing in their willingness to add new resources to their diets. Instead, it seems that differences in the rank sequence of prey choice are more important in structuring the pattern of resource use in these populations.