SOCIAL EVOLUTION IN ANTS: DIRECT AND INDIRECT GENETIC EFFECTS

Thesis (PhD) - Indiana University, Ecology and Evolutionary Biology, 2005When social interactions occur, the phenotype of an individual can be influenced both directly by its own genes and indirectly by genes expressed in social partners. Eusocial insect colonies are notable for extensive behavioral interactions among larval, worker, and queen nestmates. In particular, developing larvae are reliant on care provided by workers and queens. Social insect phenotypes are thus affected by zygotic genes expressed during development (direct genetic effects), genes expressed in care-giving adult workers (sibsocial genetic effects), and genes expressed in queens (maternal genetic effects). The purpose of this dissertation was to incorporate this complexity into models of social insect evolution and to empirically study the evolutionary importance of direct and indirect genetic effects on ant phenotypes. The first chapter reviews existing models for the evolutionary origin and maintenance of eusociality in social insects and proposes a new model incorporating both direct and indirect genetic effects. The second chapter uses a quantitative genetic approach to estimate variation for direct and indirect genetic effects on worker, gyne, and male mass, caste ratio, and sex ratio within a population of the ant Temnothorax curvispinosus. There was genetic variation for direct, maternal, and sibsocial effects for all traits, suggesting that larval, queen, and worker influences on mass, caste ratio, and sex ratio can respond to selection. However, there was also evidence for negative genetic correlations between each effect, demonstrating a potential constraint to the independent evolution of these effects. The third chapter uses the same ant colonies to study the effects of experimental queen removal and manipulation of relatedness among workers and larvae on mean colony worker, gyne, and male mass, caste ratio, and sex ratio. The fourth chapter examines the contribution of direct and sibsocial genetic effects to phenotypic differences between three Temnothorax species. The results demonstrate that among-species differences are influenced by the interaction of genes expressed in developing larvae and care-giving workers. Overall, this dissertation demonstrates the evolutionary importance of both direct and indirect genetic effects to social insect phenotypes

Enhanced Search for Educational Resources - A Perspective and a Prototype from ccLearn

Users of search tools who seek educational materials on the Internet are typically presented with either a web-scale search (e.g., Google or Yahoo) or a specialized, site-specific tool. The specialized search tools often rely upon custom data fields, such as user-entered ratings, to provide additional value. As currently designed, these systems are generally too labor intensive to manage and scale up beyond a single site or set of resources.However, custom (or structured) data of some form is necessary if search outcomes foreducational materials are to be improved. For example, design criteria and evaluative metrics are crucial attributes for educational resources, and these currently require human labeling and verification. Thus, one challenge is to design a search tool that capitalizes on available structured data (also called metadata) but is not crippled if the data are missing. This information should be amenable to repurposing by anyone, which means that it must be archived in a manner that can be discovered and leveraged easily.In this paper, we describe the extent to which DiscoverEd, a prototype developed by ccLearn, meets the design challenge of a scalable, enhanced search platform for educational resources. We then explore some of the key challenges regarding enhanced search for topic-specific Internet resources generally. We conclude by illustrating some possible future developments and third-party enhancements to the DiscoverEd prototype

The evolutionary genetic basis of social regulation of caste development

Dissertação de Mestrado Integrado em Arquitectura, apresentada ao Departamento de arquitectura da Faculdade de Ciências e Tecnologia da Universidade de Coimbra.A cidade do Porto serve de base a esta dissertação, na qual vou estudar a indissociabilidade entre a forma urbana da cidade e as pontes sobre o Douro. Entre as várias pontes existentes cinge-se o campo de estudo à ponte D. Luís e à ponte da Arrábida. Caracteriza-se o processo de evolução e de expansão da cidade que seguiu diferentes padrões na relação entre os atravessamentos sobre o rio e o desenvolvimento de novas entradas e novas centralidades. As evoluções tecnológicas, as infra-estruturas, os novos padrões de localização de actividades são os principais factores que alimentaram a forma de crescimento e apontaram para uma nova forma de apropriação e organização do espaço. “Este processo de crescimento e transformação interfere na identidade da própria cidade tal como já aconteceu noutros períodos da história. Coloca-se então a questão da leitura da forma da cidade, de como ela se vai progressivamente revitalizando em função do todo e das suas partes, variando a caracterização da sua identidade”1. O impacto no tecido urbano reflecte fracturas diferentes, em escalas e tempos também distintos. Uma das rupturas acontece no tecido urbano histórico e consolidado com a ponte D. Luís; a outra ruptura é criada no tecido em expansão com a construção da ponte da Arrábida, onde a auto-estrada cria uma ruptura no território a urbanizar. Pretende-se, com esta escolha, abordar as propostas de intervenção de Giovanni Muzio e Fernando Távora na resolução da inserção destas duas pontes nas margens e no tecido urbano envolvente. Através do percurso individual e da produção arquitectónica destes dois arquitectos abordo as propostas apresentadas para a Avenida da Ponte e para a zona do Campo Alegre

Ant Species Differences Determined by Epistasis between Brood and Worker Genomes

Epistasis arising from physiological interactions between gene products often contributes to species differences, particularly those involved in reproductive isolation. In social organisms, phenotypes are influenced by the genotypes of multiple interacting individuals. In theory, social interactions can give rise to an additional type of epistasis between the genomes of social partners that can contribute to species differences. Using a full-factorial cross-fostering design with three species of closely related Temnothorax ants, I found that adult worker size was determined by an interaction between the genotypes of developing brood and care-giving workers, i.e. intergenomic epistasis. Such intergenomic social epistasis provides a strong signature of coevolution between social partners. These results demonstrate that just as physiologically interacting genes coevolve, diverge, and contribute to species differences, so do socially interacting genes. Coevolution and conflict between social partners, especially relatives such as parents and offspring, has long been recognized as having widespread evolutionary effects. This coevolutionary process may often result in coevolved socially-interacting gene complexes that contribute to species differences

Genes associated with ant social behavior show distinct transcriptional and evolutionary patterns

Studies of the genetic basis and evolution of complex social behavior emphasize either conserved or novel genes. To begin to reconcile these perspectives, we studied how the evolutionary conservation of genes associated with social behavior depends on regulatory context, and whether genes associated with social behavior exist in distinct regulatory and evolutionary contexts. We identified modules of co-expressed genes associated with age-based division of labor between nurses and foragers in the ant Monomorium pharaonis, and we studied the relationship between molecular evolution, connectivity, and expression. Highly connected and expressed genes were more evolutionarily conserved, as expected. However, compared to the rest of the genome, forager-upregulated genes were much more highly connected and conserved, while nurse-upregulated genes were less connected and more evolutionarily labile. Our results indicate that the genetic architecture of social behavior includes both highly connected and conserved components as well as loosely connected and evolutionarily labile components.It was funded by University of Pennsylvania with grant name: University Research Foundation grant

Ant colonies prefer nest sites containing infectious corpses

The process of connected text reading has received very little attention in contemporary cognitive psychology. This lack of attention is in parts due to a research tradition that emphasizes the role of basic lexical constituents, which can be studied in isolated words or sentences. However, this lack of attention is in parts also due to the lack of statistical analysis techniques, which accommodate interdependent time series. In this study, we investigate text reading performance with traditional and nonlinear analysis techniques and show how outcomes from multiple analyses can used to create a more detailed picture of the process of text reading. Specifically, we investigate reading performance of groups of literate adult readers that differ in reading fluency during a self-paced text reading task. Our results indicate that classical metrics of reading (such as word frequency) do not capture text reading very well, and that classical measures of reading fluency (such as average reading time) distinguish relatively poorly between participant groups. Nonlinear analyses of distribution tails and reading time fluctuations provide more fine-grained information about the reading process and reading fluency