Meeting Abstract
Investment in life history traits such as immune function, reproduction, and soma maintenance is determined by limited available resources, resulting in trade-offs within these traits to maximize lifetime fitness of an individual. One consequence of this is a cost of immune defense: wherein an upregulated immune response to combat an infection may further restrict energy investment into reproductive efforts and reduce reproductive success. Pathogenic infections may produce lesions or deficiencies that affect mating performance, or deprive the individual of energy necessary for high levels of exertion, metabolism, and locomotion necessary for male courting, thus reducing mating success. Alternatively, the Terminal Investment Hypothesis suggests that an infected individual may enhance energy investment in reproductive efforts to maximize terminal reproductive success in response to the survival threat inherent to infection. In the latter case, females are predicted to prefer mating with infected males, preferring dishonest epigamic signals despite the male’s lack of immunological resistance (being infected by a pathogen). To determine whether infected males will display honest or dishonest reproductive signaling, binary-choice mating trials were conducted with an Aedes aegypti female and 2 males: a control (unmanipulated), and an immune-stimulated male (either infected with Escherichia coli, heat killed E. coli, or sham injected with saline). Male and female reproductive success and survivorship were monitored to determine fitness differences between treatments. Immune defense was measured 48 hours post-infection to compare immune responses between treatments. The outcome of this study may be important in understanding current population control efforts, especially those that that act to interfere with reproduction.
