Thesis (Ph.D.)--University of Melbourne, Dept. of Zoology, 2006. / Typescript. Includes bibliographical references (leaves 79-91).

Thesis (Ph.D. (Zoology & Entomology)) - Rhodes University, 2007.

LD2668 .T4 1941 M33 / Master of Science

LD2668 .T4 1954 M8 / Master of Science

Orientador: Ana Eugência de Carvalho Campos-Farinha. / Banca: Odair Correa Bueno / Banca: Maria Santina de Castro Morini / Resumo: Monomorium floricola é uma das principais espécies de formigas exóticas presentes nas cidades brasileiras e ocorre, em ambientes residenciais, em fábricas de alimentos e em hospitais. As espécies de formigas que ocorrem em ambientes urbanos podem agir como vetor mecânico de disseminação de microrganismos patogênicos e por esse motivo há um grande interesse no estudo de novas formulações de inseticidas visando o controle dessas espécies. Diante disso, o objetivo do presente trabalho foi avaliar a eficácia de produtos na formulação microencapsulada para o controle de Monomorium floricola mantidas em laboratório. Os produtos testados neste trabalho foram o Demand 2,5 CS (Syngenta) e o Dursban 20 ME (Dow Agrosciences) e para tanto, foram realizadas três etapas de testes sendo que em cada uma foi verificada a mortalidade das formigas e o efeito de repelência causado por esses inseticidas. Estas etapas foram divididas em aplicação imediata dos produtos, aplicação residual três meses e aplicação residual seis meses. Paralelamente, foi averiguado o comportamento das formigas que entraram em contato com os produtos. Foram utilizadas 30 colônias para cada etapa de testes, sendo 10 para cada produto e 10 para o controle. Essas colônias foram depositadas em bandejas plásticas, e nelas, foram colocados dois azulejos, sendo que a colônia de Monomorium floricola foi disposta entre eles. O alimento e a água foram colocados sobre cada um dos azulejos. Nas 20 bandejas destinadas aos testes, um dos azulejos foi tratado com o inseticida e o outro não recebeu qualquer tratamento. Nas bandejas controle, um azulejo foi deixado sem qualquer tratamento e o outro foi pincelado com água. As avaliações para o efeito de repelência foram realizadas diariamente por um período de 16 dias... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Monomorium floricola is one of the main exotic ant species in Brazilian cities and it occurs in households, food services and hospitals. The ant species that occur in urban environments can be a potential mechanical vector of pathogenic microorganisms and thus there is a great interest in studying new types of insecticide formulations for the ant control. The aim of this work was to evaluate the microencapsulated formulation effectiveness for the Monomorium floricola control in laboratory conditions. The products tested in this work were Demand 2,5 CS (Syngenta) and Dursban 20 ME (Dow Agrosciences) and therefore, three stages of tests were carried out. In each test the mortality of the ants and the repellent effect caused by those insecticides were verified. These stages were divided into immediate application of the products, three-month as well as six-month residual application. At the same time, the ants’ behavior was evaluated when they got in contact with the products. Thirty colonies were used for each test, being 10 for each product and 10 for the control. The colonies were put in plastic trays, and inside of them, two tiles were placed, and the Monomorium floricola colony was put among them. The food and the water were placed on each one of the tiles. In the 20 trays used for the tests, one of the tiles was treated with the insecticide and the other did not receive any treatment. In the control trays, one tile did not receive any treatment and the other was treated with water. The evaluations for the repellent effect were made daily for 16 days, and the number of the ants present on each tile was counted during the observation. For the mortality analysis the number of dead ants was counted for 13 weeks. The ants’ behavior observations were made for three hours. The ants that died when getting in contact with... (Complete abstract, click electronic address below) / Mestre

I investigate collective behaviour using a wide range of theoretical and experimental approaches. Individual-based (Lagrangian) computer modelling is used extensively to reveal how individual movement and interactions result in group characteristics. This technique is used to gain insight into the structured patterns of movement within human crowds and the development of trail networks by ants. These models reveal the importance of interactions among individuals to density-dependent group behaviour. A simulation of animal groups in three-dimensional space reveals the existence of several robust collective patterns. Simulated groups show similar group-level behaviour and internal structure to natural groups. The model also reveals how differences among individuals influence group structure, and how individuals employing simple, local rules of thumb, can accurately change their relative position within a group (for example, to move to the centre, or to the periphery) without necessitating information regarding their current position within the group. New techniques in computer vision are introduced that can facilitate the automatic analysis of collective motion. This software can simultaneously track and analyse the movement of a large number (hundreds) of organisms. Computer vision is used to reveal the spatio-temporal patterns of activity in ant colonies for the first time. I also show how it can record detailed aspects of individual behaviour, including the movement of, and production of honeydew and offspring by, aphids. This technique is used in a detailed analysis of ant exploratory behaviour, revealing temporal and spatial information about the movement patterns of individual ants, and the relationship between individual behaviour and collective exploration. Simultaneous digital tracking of organisms is a powerful technique that in the future is likely to provide insight into the behaviour of many animal groups.

In mutualisms, individuals exchange goods and services for net benefit. However, many sources of variation in these interactions remain unexplored. To examine why plantdwelling ants protect their host plants by killing herbivores, I shifted the macronutrient balance of their background diets. Providing ants with supplemental protein caused them to invest less in patrolling and defence activities, likely because the availability of lowcost protein made hunting for herbivores relatively less profitable. In contrast, supplemental sugar caused an increase in ant activity, possibly because carbohydrates serve as ‘fuel’ for patrolling. To examine a second source of variation in this interaction, I treated ants with an activator of PKG, a protein encoded by foraging, a gene with behavioural functions in other taxa. PKG activation caused ants to become more aggressive towards herbivores, causing their host plants to experience less herbivory. This suggests that an ortholog of foraging may influence cooperation in this system.

In mutualisms, individuals exchange goods and services for net benefit. However, many sources of variation in these interactions remain unexplored. To examine why plantdwelling ants protect their host plants by killing herbivores, I shifted the macronutrient balance of their background diets. Providing ants with supplemental protein caused them to invest less in patrolling and defence activities, likely because the availability of lowcost protein made hunting for herbivores relatively less profitable. In contrast, supplemental sugar caused an increase in ant activity, possibly because carbohydrates serve as ‘fuel’ for patrolling. To examine a second source of variation in this interaction, I treated ants with an activator of PKG, a protein encoded by foraging, a gene with behavioural functions in other taxa. PKG activation caused ants to become more aggressive towards herbivores, causing their host plants to experience less herbivory. This suggests that an ortholog of foraging may influence cooperation in this system.

Studies of symbiotic bacteria have demonstrated that they provide multiple benefits to their hosts. These studies, however, have overlooked the importance of interactions with other bacteria and environmental factors that affect bacterial assemblages. To understand what shapes bacterial assemblages, I manipulated the diet of ants from the genus Cephalotes and disturbed their gut microbiome. I found that a deficit of nitrogen reduces bacterial densities. Furthermore, the data suggest that bacterial abundance may influence ant survival. I followed this experiment up by manipulating a putative protein source in the field. Our lab assigned Allomerus octoarticulatus ant colonies to treatments in which potential prey were present or absent. I collected data on foraging behaviour, colony performance, and composition of the bacterial community. The absence of prey increased ant recruitment to protein-rich baits; these ants were also less fit than ants that had insect prey but their bacterial assemblages were not affected.

Studies of symbiotic bacteria have demonstrated that they provide multiple benefits to their hosts. These studies, however, have overlooked the importance of interactions with other bacteria and environmental factors that affect bacterial assemblages. To understand what shapes bacterial assemblages, I manipulated the diet of ants from the genus Cephalotes and disturbed their gut microbiome. I found that a deficit of nitrogen reduces bacterial densities. Furthermore, the data suggest that bacterial abundance may influence ant survival. I followed this experiment up by manipulating a putative protein source in the field. Our lab assigned Allomerus octoarticulatus ant colonies to treatments in which potential prey were present or absent. I collected data on foraging behaviour, colony performance, and composition of the bacterial community. The absence of prey increased ant recruitment to protein-rich baits; these ants were also less fit than ants that had insect prey but their bacterial assemblages were not affected.