Evolving Specialization in an Agent-Based Model without Task-Switching Costs

This work examines the possibility of evolving the phenotypic specialization associated with division of labor in an agent-based model without task-switching costs. The model examines two groups competing for vital resources, where members of one group are capable of sharing resources with other agents in their group. Agents attempt to collect resources which allow them to reproduce, with more resources leading to a greater number of offspring by asexual reproduction. Four variants of the model are examined, with combinations of one or two resources and the presence of a foraging risk. The presence of the foraging risk can lead to agents in the sharing group specializing in each trait but, by looking at the fraction of foragers per generation, this event appears to be a transient state. Division of labor is quantified by calculating the normalized mutual entropy, and is shown to be higher when a population contains agents which specialize on different tasks

Evolving specialization in an agent-based model without task-switching costs

This work examines the possibility of evolving the phenotypic specialization associated with division of labor in an agent-based model without task-switching costs. The model examines two groups competing for vital resources, where members of one group are capable of sharing resources with other agents in their group. Agents attempt to collect resources which allow them to reproduce, with more resources leading to a greater number of offspring by asexual reproduction. Four variants of the model are examined, with combinations of one or two resources and the presence of a foraging risk. The presence of the foraging risk can lead to agents in the sharing group specializing in each trait but, by looking at the fraction of foragers per generation, this event appears to be a transient state. Division of labor is quantified by calculating the normalized mutual entropy, and is shown to be higher when a population contains agents which specialize on different tasks --Abstract, page iii

The Role of ATP-Sensitive Inward Rectifier Potassium Channels In The Regulation of Reactive Oxygen Species In The Western Honey Bee, APIS Mellifera L.

Colonies of managed honey bees are annually being lost at an unsustainable rate, partly due to reduced immunocompetence that leads to acute viral outbreaks and mortality. To aid in restoring honey bee health despite the myriad of environmental stressors, this thesis focuses on identifying novel physiological pathways that can mitigate virus-mediated mortality through increased immune function. Previous work has demonstrated that a family of potassium ion channels, termed KATP channels, mediate the survival of honey bees during infection from a model virus, suggesting KATP channels may drive antiviral immunity. Interestingly, these channels have been linked to the regulation of reactive oxygen species (ROS), which are known to function as an immune system stimulator during virus infection. Thus, the overarching goal of this thesis study was to validate the linkage between KATP channels, ROS, and bee survivorship. Our findings in this thesis provide evidence that pinacidil, a KATP channel activator, is capable of dramatically reducing antioxidant levels in bees during chemically-induced ROS, suggesting KATP channels play a part in regulating levels of ROS. Further, mortality was significantly reduced in bees from colonies that had heavy mite infestations, which supports the notion that ROS is an intermediate molecule for immune health. While additional investigation is required to fully characterize the relationship between KATP channels, ROS, and antiviral immunity, this study has begun to fill significant gaps in knowledge pertaining to mechanisms honey bees use to regulate their antiviral immune response

The Evolution of Temporal Polyethism

Thesis (Master's)--University of Washington, 2012