Experiments were performed to investigate the influence of water availability on the diel patterns of nectar secretion (volume, concentration, sugar production) in male squash flowers as well as to discover what physical component of nectar honey bees use to trigger their time-memory. Squash plants were grown in the greenhouse and in the field under both constant and variable watering regimes. Throughout anthesis, nectar volume and sugar concentration were recorded. In the field, the temporal distribution of arrivals to squash was observed with and without blossoms present. In the greenhouse and in the field, squash flowers exhibit a consistent diel pattern of nectar secretion that does not significantly alter during drought conditions; flowers open just before sunrise (with low volume and sugar and high concentration) and close at midday (with high volume and sugar and low concentration). Honey bees preferentially arrived early in anthesis possibly cueing on either the sugar concentration or the first availability of nectar.

Experiments were performed to determine the influence of the honey bee time-memory on a forager bee's sensitivity to recruitment. Two groups of foragers from one colony were trained to separate food stations at the same restricted time of day for several consecutive days. Feeding then was canceled at one station but continued for four more days at the other. Bees with more days of training at a non-productive source were significantly less likely than foragers with less training to be recruited to an alternative food source presented at the same time of day. Furthermore, the ability of a forager to be recruited recovered after several days, but this recovery period was longer for bees with greater experience. These findings demonstrate a long-term influence of time-memory on subsequent foraging behavior, in contrast to currently accepted models for the allocation and re-allocation of honey bee foragers to food patches in the environment.

No description available.

Nest survival often is lower at habitat edges than in habitat cores because of greater nest predation and parasitism near edges. I studied nest survival of breeding birds in bottomland hardwood forests of the lower Roanoke River, North Carolina. Nesting success was monitored in two forest width classes: narrow bands of levee forest that were dominated by two edge types, and wide, continuous levee forest stands that have edges but most forest is relatively far from edge. Nest success of Acadian Flycatchers and Prothonotary Warblers was similar in narrow and wide levees; nest success of Northern Cardinals was greater in narrow levees. Results of my study indicate that edge effects are not universal, and that amount of contrast at edges may interact with landscape context to alter ecological processes, such as nest predation. Bird populations are remarkably constant over time relative to other taxa, implying strong regulation. Avian population ecologists, however, have not studied regulatory mechanisms as often as seasonal limiting factors. Conversely, avian behavioral ecologists seldom emphasize the population dynamic consequences of habitat selection and reproductive success. This study describes the intersection of individual behavior and population regulation in the context of a new model of population regulation, site dependence, which is based on characteristics of breeding sites and behavior of individuals. I studied habitat distribution, age structure, reproductive output, and breeding site fidelity of Prothonotary Warblers (Protonotaria citrea) in two different bottomland hardwood forest habitats of the lower Roanoke River in North Carolina. Older males (³ 2 yr old) were equally common in cypress-gum swamps and mixed oak hardwood levee forest. Pairing success and success of first nests indicated that older males occupied the most suitable territories available in each habitat. Bird density was three times greater in swamps, and birds nesting in swamps averaged greater clutch sizes and fledged more young per nest than birds in levees. Greater reproductive output was the result of greater fecundity because nest survival and predation pressure appeared equal in the two habitats. Annual return rates for plot immigrants vs. previous residents did not differ in swamps. In levees, newly arriving birds were less likely to return the following year than previous residents. Immigrants most likely occupied low quality sites and dispersed in an attempt to improve breeding site quality. Habitat-specific demography and density patterns of this study indicate ideal preemptive distribution. Variance in site quality, between and within habitats, and preemptive use of sites are consistent with theory of population regulation via site dependence. Foraging behavior often reflects food availability. For example, in habitats where food availability is high, predators should move more slowly and attack prey more often than in habitats where food availability is low. I studied the foraging behavior of breeding Prothonotary Warblers in two habitat types to assess relative food availability and implications for habitat quality. The two habitats, levee and swamp forest, differ in hydrology, forest structure, and tree species composition. I quantified foraging behavior with focal animal sampling and continuous recording during foraging bouts. I measured two aspects of foraging behavior: 1) prey attacks per minute, using four attack types (glean, sally, hover, strike), and 2) number of movements per minute (foraging speed), using three types of movement (hop, short flight [£ 1 m], long flight [>1 m]). Male warblers made significantly more prey attacks per minute in swamp forest than in levee forest; the same trend was evident in females. Foraging speed, however, was not different between habitats for males or females. Results indicate that foraging effort is similar in swamps and levees, but that warblers encounter more prey in swamps. Greater food availability may be related to greater reproductive success of warblers nesting in cypress-gum swamps than in coastal plain levee forest. / Ph. D.

The Rota bridled white-eye (Zosterops rotensis)(Aves, Passeriformes) has experienced a severe population decline and range restriction over the last four decades. Little is known about this species and factors involved in the decline and range restriction are unclear. This study examined the potential roles of habitat alteration, introduced black drongos (Dicrurus macrocercus), and introduced rats in the decline and gathered more information on the behavior and breeding biology of this species. New life history data were collected and Rota and Saipan bridled white-eyes were found to differ in nest site characteristics and some behaviors. The importance of habitat alteration was assessed by examining Rota bridled white-eye habitat relationships at the microhabitat, within-range, Sabana-wide, and island-wide levels. Rota bridled white-eyes show a preference for high elevation wet forest but what drives their distribution within their current range was unclear. However, the alteration of this forest type by supertyphoon Roy in 1988 was probably the major factor in the decline of Rota BWEs between 1982 and 1996. Black drongo and Rota bridled white-eye relationships were addressed using current and historical survey data. Black drongos were found to prey on Rota bridled white-eyes but they probably only played at most a partial role in the decline of the Rota bridled white-eye. Introduced rats densities were assessed in Rota bridled white-eye areas and on other areas of the island and no evidence for rat numbers limiting Rota bridled white-eyes to their current range was found. / Master of Science

A presente pesquisa teve como objetivos aprimorar a amostragem de Spodoptera frugiperda através do uso de armadilhas com feromônio sexual, verificar a capacidade de dispersão de Trichogramma atopovirilia como agente de controle biológico desta praga bem como avaliar a atratividade de Amaranthus sp. às fêmeas de T. atopovirilia. Para aprimorar a amostragem de S. frugiperda, os estudos foram conduzidos em dois campos comerciais de produção de milho, sendo um composto de 36,3 ha (denominado de MIP e com 30 pontos de amostragem) e outro de 10 ha (denominado de convencional e com 10 pontos de amostragem). Nestes campos foram instaladas armadilhas com feromônio sexual, distribuídas de forma aleatória e na proporção de 1 armadilha / ha. As avaliações foram realizadas duas vezes por semana durante todo o desenvolvimento das plantas, considerando-se: número de adultos machos coletados pelas armadilhas, injúria dos insetos às plantas, número de posturas e de larvas (pequenas, médias e grandes). O número de adultos coletados nas armadilhas foi correlacionado com os níveis de injúrias, número de posturas e densidade larval. O número de larvas observadas não apresentou diferença entre áreas e pontos de amostragem. A injúria dos insetos às plantas, número de posturas e de larvas pequenas não apresentaram correlação com os adultos capturados pelas armadilhas. Houve correlação significativa entre o número de larvas grandes (4o e 5o ínstares) e o número de plantas apresentando o cartucho furado ou destruído. Não houve correlação da coleta de adultos nas armadilhas com a infestação ou níveis de injúria, demonstrando que as larvas ainda precisam ser contadas para determinar o momento do seu controle. A capacidade de dispersão de T. atopovirilia foi estudada em 3 fases distintas de desenvolvimento das plantas de milho, quando estas possuíam de 4 a 6 folhas, 8 a 10 folhas e pendoamento. Em cada fase foi realizada uma infestação artificial com posturas (até 24 h) de S. frugiperda nas plantas localizadas em distâncias que variaram de 6 a 24 m do ponto de liberação do parasitóide. Logo após esta infestação, foi realizada somente uma liberação de adultos do parasitóide para cada fase da cultura e sempre no período mais fresco do dia (manhã ou entardecer). O parasitismo foi permitido durante até 48 horas quando as posturas eram recolhidas e acondicionadas em câmara climatizada até a emergência dos adultos. Os resultados indicaram que as plantas em suas diferentes fases de desenvolvimento afetaram a capacidade de dispersão dos parasitóides. As posturas localizadas nos pontos mais distantes somente foram atingidas pelos parasitóides durante a fase de desenvolvimento da cultura em que as plantas de milho estavam menores (4 a 6 folhas). Nas outras fases, os índices de parasitismo foram maiores naquelas posturas localizadas mais próximas do ponto de liberação. A atratividade de quatro espécies de Amaranthus (A. retroflexus, A. viridis, A. hybridus e A. spinosus) às fêmeas de T. atopovirilia foram avaliadas utilizando-se olfatômetro Peterson. Estas plantas foram testadas em período de desenvolvimento vegetativo e reprodutivo. Adotou-se o delineamento inteiramente casualizado com 40 repetições (considerando-se um inseto/ repetição) e cada inseto foi observado durante o tempo máximo de 600 segundos. As espécies mais atrativas foram A. viridis e A. retroflexus, nos estádios vegetativo e reprodutivo, respectivamente. Quando testadas simultaneamente, as espécies de plantas não demonstraram atratividade ao parasitóide. Estes resultados sugerem a viabilidade do uso destas plantas ou seus derivados no manejo de habitats de hospedeiros e aumento de parasitismo em programas de manejo integrado de pragas. / The objectives of this research were the improvement of cross-section Spodoptera frugiperda using pheromone traps to verify the capacity of dispersion of Trichogramma atopovirilia as an agent for biological pest control as well as evaluating the attractiveness of Amaranthus sp. to T. atopovirilia females. To improve cross-section of S. frugiperda, the studies were carried out in two commercial corn field plantations, one made up of 36,3 ha (called MIP and with 30 points of sampling) and another of 10 ha (called conventional and with 10 points of sampling). In these fields pheromone traps were randomly displaced (ratio of 1 trap/ha). The evaluations were realized twice a week during the whole plant development, considering : number of male adults collected by the traps, insect injury to plants, egg masses and larval densities (small, medium and large). The numbers of adults collected were correlated to the insect injury, egg masses and larval density. The larval occurrence did not show difference between areas and sampling points. The injury levels, egg masses and small larva densities did not show correlation to adult caught by traps. There was significant correlation between large larvae (4th and 5th instars) and the number of plants showing whorl holes and/or destroyed ones. There were no correlations observed among adults caught by traps and insect infestation or injury, so demonstrating that larvae should be counted for timing pest control. The capacity of dispersion of T. atopovirilia was studied in 3 distinct phases of corn plant development, when they had 4 to 6 leaves, 8 to 10 leaves and tassel. In each stage was applied an artificial infestation with egg masses (< 24 h) of S. frugiperda on plants located 6 to 24 m from a parasitoid release point. Right after this artificial infestation, was applied only one parasitoid adult release to each distinct corn plant phase , always early in the morning or late in the afternoon. The parasite contamination was allowed during 48 h and then the egg masses were retrieved and taken into a climatic chamber until emerging adulthood. The results showed that plants affected the parasitoid dispersal. The egg masses placed farthest from the release point were parasited only during the 4 to 6-leaf stage. In the others stages, only egg masses next to the release point were parasited. The attractiveness of four species of Amaranthus (A. retroflexus, A. viridis, A. hybridus and A. spinosus) to the females of T. atopovirilia was evaluated by a Petersons olfactometer. These plants were evaluated in both vegetative and reproductive stages. Complete randomized procedure was adopted with 40 replications (considering one insect/replication) and each insect was observed during 600 seconds. The most attractive species were A. viridis and A. retroflexus during vegetative and reproductive stage, respectively. When plants were tested simultaneously, the species did not show attractive properties to the parasitoids. These results suggest the viability of the use of these plants or its derivatives to change host habitat and parasite increase for biological control in integrated pest management.

O comportamento de insetos sociais, em especial de formigas, tem sido muito estudado nos últimos tempos, devido à capacidade destes insetos realizarem tarefas complexas a partir de interações entre indivíduos simples. Ao se moverem sobre um ambiente na busca de alimento, as formigas depositam no solo uma substância química, denominada feromônio, que atrai as formigas que se encontram no ninho e as guia em direção ao alimento encontrado. O processo de construção e seguimento destas trilhas permite que as formigas descubram os menores caminhos e as melhores fontes de alimento no ambiente. Com o objetivo de estudar as características das formigas que contribuem para a sua adaptação a diferentes condições do meio, diversos experimentos vêm sendo realizados com estes insetos. Dentro deste contexto, esta tese apresenta experimentos inéditos realizados com formigas em laboratório, sobre uma rede artificial de túneis, onde diversos caminhos interconectados conduzem a uma fonte de alimento. As decisões das formigas foram analisadas nos níveis individual e coletivo, sob mudanças no meio, compreendendo o bloqueio/desbloqueio de ramos. A medição de diversas características individuais das formigas permitiu desenvolver dois modelos matemáticos sobre o seu comportamento, que foram aplicados à situação em que não se alterou a condição do ambiente com relação ao acesso aos ramos (estática), como também a mudanças no meio (dinâmica). A análise realizada do comportamento coletivo foi utilizada na comparação dos resultados obtidos pelas simulações dos modelos. De forma geral, o segundo modelo proposto foi mais eficiente que o primeiro na situação estática, porém ele ainda necessita de ajustes nas demais situações. O bom desempenho do segundo modelo proposto levou a aplicação de sua principal característica, a função de escolha que considera a concentração de feromônio sobre os ramos do meio e a capacidade de orientação das formigas, a um problema de otimização combinatorial, o roteamento em redes de telecomunicações. O algoritmo de roteamento proposto foi avaliado sob variações no nível de tráfego e topologia da rede, e seu desempenho foi comparado ao de dois algoritmos usados por concessionárias de telecomunicações, considerando diversas medidas de desempenho. O algoritmo desenvolvido obteve resultados encorajadores, sugerindo a aplicabilidade da estrutura do modelo proposto a outros problemas complexos de otimização. / The behavior of social insects, particularly of ants, has been intensively studied in the last years, due to their capacity to perform complex tasks through interactions among simple individuals. When moving in the environment searching for food, ants deposit on the ground a chemical substance, called pheromone, to attract ants in the nest and guide them towards the source of food that was found. The process of laying/following the pheromone trails allows ants to find the shortest paths and best sources of food of the environment. With the aim to study the characteristics of the ants that contribute to their adaptation to different environment conditions, several experiments with ants have been performed and reported in this research. In this context, this thesis presents novel experiments with ants in the laboratory, in an artificial network of tunnels, where several interconnected paths lead the insects from the nest to the food source. Ants\' decision were analyzed according to the individual and collective levels, under changes in the environment, comprising the blockage/release of branches. The measure of several individual characteristics of ants allowed the development of two mathematical models of their behavior, which were applied to the non-changing (static) environment access to all branches and to changing (dynamic) access. The analysis of the collective behavior of ants in the experiments was used to compare the results derived from the simulations of the models. In general, the second proposed model was more accurate than the first one in simulating ants behavior for the static situation, however, it needs some improvements for the other situations. The satisfactory behavior of the second model led to apply its main feature, the choice taking into consideration the pheromone concentration over the branches and the ants ability to orient themselves, to solve an optimization problem, the routing in telecommunications networks. The proposed routing algorithm was evaluated under variations on the traffic level and topology of the network, and its performance was compared with two routing algorithms used by telecommunications companies, considering several performance measures. The developed algorithm produced encouraging results, suggesting the possibility to apply the framework of the proposed model to other optimization problems.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / A pesquisa foi realizada no NÃcleo de ProduÃÃo ComunitÃria Santa Clara, idealizado e administrado pela Brasil Ecodiesel IndÃstria e ComÃrcio de BiocombustÃveis e Ãleos vegetais S. A., localizado no municÃpio de Canto do Buriti, estado do Piau, e na Universidade Federal do CearÃ, localizada em Fortaleza, no estado do CearÃ. A coleta de dados ocorreu durante o perÃodo de Abril de 2006 a Janeiro de 2007 com o objetivo de investigar a polinizaÃÃo da mamoneira (Ricinus communis L.), o papel de agentes polinizadores biÃticos e a utilizaÃÃo de abelhas Apis mellifera na sua polinizaÃÃo, visando contribuir para minimizar as perdas de produtividade desta cultura. Foram avaliados a biologia floral e requerimento de polinizaÃÃo da mamoneira; eficiÃncia da polinizaÃÃo por Apis mellifera e comportamento de pastejo de Apis mellifera e Scaptotrigona bipunctata H.(canudo) em inflorescÃncia de mamoneira, bem como os frutos e sementes produzidas na cultura. Os resultados mostraram que as abelhas coletam pÃlen e nÃctar durante todo o dia, tendo a abelha canudo, preferÃncia pelo pÃlen. A mamoneira aceita polinizaÃÃo cruzada, porÃm vingando significativamente (p<0,05) menos que a autopolinizaÃÃo. O vento mostrouse o principal vetor de pÃlen na plantaÃÃo. Ãreas com introduÃÃo de abelhas melÃferas produziram marginalmente (p = 0,08) mais frutos que Ãreas sem a introduÃÃo de abelhas. De forma semelhante, tambÃm levaram a significativa (p<0,05) produÃÃo de racemos com mais frutos (22,39) e sementes mais pesadas (0,54g) com maior percentual de Ãleo (54,48%) e maior energia bruta (9006,81kcal/kg) do que o obtido em Ãreas sem abelhas (15,84, 0,47g, 49,94% e 8843,29kcal/kg, respectivamente). A avaliaÃÃo fisiolÃgica das sementes nÃo encontrou diferenÃas entre os dois tratamentos, ambos apresentaram mÃdia de 84% de germinaÃÃo. Pode-se concluir que o principal agente polinizador da mamoneira à o vento e que a espÃcie pode ser polinizada, vingando seus frutos tanto por meio de autopolinizaÃÃo quanto polinizaÃÃo cruzada, embora apresente melhores resultados com autogamia. A introduÃÃo de colÃnias de Apis mellifera em cultivos de mamona contribui para incremento significativo de produtividade da cultura, tanto ao aumentar o nÃmero de frutos por cacho quanto o rendimento de Ãleo dos mesmos, provavelmente porque ao coletar pÃlen as abelhas melÃferas aumentam a quantidade de autopÃlen em suspensÃo no ar nas proximidades da panÃcula, favorecendo uma maior percentagem de autopolinizaÃÃo. Palavras-chave: polinizaÃÃo da mamoneira, rendimento de Ãleo, anemofilia, comportamento de pastejo, biodiesel. / The research was carried out in the NÃcleo de ProduÃÃo ComunitÃria Santa Clara, idealized and administered by the Brasil Ecodiesel IndÃstria e ComÃrcio de BiocombustÃveis e Ãleos vegetais S. A., county of Canto do Buriti, state of PiauÃ, Brazil, and at the Universidade Federal do CearÃ, located in Fortaleza, state of CearÃ. Data were collected from April 2006 to January 2007 investigating castor bean (Ricinus communis L.) pollination, the role of biotic pollinating agents and the use of the honey bee Apis mellifera in its pollination. The study aimed to contribute in mitigating yield productivity losses in this crop. The following parameters were evaluated: floral biology, castor bean pollination requirements, A.mellifera pollination efficiency, foraging behavior of A.mellifera and Scaptotrigona bipunctata in castor bean inflorescences, and physiological evaluation of fruits and seeds produced. Results showed that both bee species harvested pollen and nectar throughout the day, but S. bipunctata prefers pollen much more than nectar. The castor bean plant accepts cross pollination, but it sets significantly (p<0.05) less fruits than self-pollination. The wind appeared as the main pollen vector in the plantation. Areas where honey bee colonies were introduced produced marginally (p = 0.08) more fruits than areas where no colony was made available. Similarly, they also led to significantly (p<0.05) more fruits per raceme (22.39) heavier seeds (0,54g) greater oil percentage (54.48%) and greater gross energy (9006.81kcal/kg) than those produced in areas without introduction of honey bee colonies (15.84, 0.47g, 49.94% e 8843.29kcal/kg, respectively), Physiological evaluation of seeds found no significant differences among treatments and produced an average 84% germination. It is concluded that the wind is the major pollinator of castor bean, and this species can be pollinated and set fruits both by means of cross and self-pollination, though showing better results under autogamy. The introduction of A. mellifera colonies in castor bean plantations contributes to increase crop productivity significantly, both increasing the number of fruits set per raceme and their oil content, probably because when collecting pollen honey bees increase the amount of self-pollen floating in the air around the panicles, favoring greater proportion of self-pollination.

The effect of environmental modification of predator sensory abilities remains largely unknown, despite the importance of predators to ecosystem function. I conducted a series of experiments to investigate effects of hydrodynamics on the chemosensory search behavior and foraging success of two species of marine gastropods, knobbed whelks (

I characterized dusky dolphin (Lagenorhynchus obscurus) underwater bait-balling behaviors and acoustic signals, and compared data between Argentina and New Zealand (NZ) to investigate the roles of ecology versus social learning. I quantified prey herding and capturing behaviors from video footage, and I analyzed acoustic signals from narrowband recordings. In both locations, I related bait-balling behaviors and acoustic signals to group and prey ball sizes. In NZ, I also related dolphin behaviors to prey ball escape behaviors and acoustic signal parameters to examine proximate functions. Observed herding behaviors typically involved dolphins swimming around or under a prey ball using a side body orientation, while dolphins typically captured fish from the side of a prey ball using a ventral orientation. Coordinated prey-capture behaviors may have made it easier for dolphins to capture fish by trapping fish between dolphins. Signals were categorized as click trains, burst pulses, and combinations due to a bimodal inter-click interval distribution. I observed 3 whistle-like chirp-screams, but no whistles. Sequences of burst pulses also occurred that contained 2-14 burst pulses that aurally and visually appeared closely matched. Similarities between locations suggest that ecological context related to broad behavioral and acoustic parameters, while social learning differences may occur on a finer scale. In NZ, prey balls exhibited horizontal and vertical movements, but the only behavior that preceded escape was “funneling”, the brief formation of a ball shape where the height was at least twice the width. Dolphin behaviors that related to prey balls ascending were type of herding pass, location of prey-capture attempts, and body orientation during attempts. These behavioral parameters may also be used to counter vertical prey escape behaviors. In NZ, all signal categories had a direct or indirect role in capturing prey. Click train-burst pulses were likely used for echolocating on prey, burst pulses and sequences appeared to have communication roles, and the role of click trains was ambiguous. No signal categories appeared to have a herding function, but the sheer number of signals emitted may have caused fish to cluster together more tightly and therefore facilitated capture.