THE IMPACTS OF IONIZING RADIATION ON INVERTEBRATE GROWTH, DEVELOPMENT, AND REPRODUCTION.

Abstract

Ionizing radiation (IR) as an environmental stressor has become a topic of great interest due to both nuclear disasters and other contamination sites. Although IR impacts on human and other mammalian species are well studied, much less is understood about impacts to invertebrate species. Here, I investigate the impacts of IR exposure on the House Cricket Acheta domesticus, with a focus on sexual signalling, generational impacts, and bystander effects. Initial experiments were conducted to determine the optimal living conditions for this species (< 0.93 cricket/cm2) which were used in subsequent experiments. Mating is multifaceted in this species, males court females using chemical pheromone production and acoustic signaling. Males were shown to have IR induced changes to wing morphology/acoustic signaling and chemical pheromone production, ultimately resulting in reduced mating success. In females, similar alterations were observed due to IR exposure. Females were more susceptible to pheromone alternations, however males, likely due to the complexity of wing structures were shown to be more susceptible to wing alterations than females. Further experimentation aimed to examine the possibility of paternal and/or maternal inheritance of stress on various life-history features of F1 and F2 offspring. Results here were varied, with offspring for the most part recovering from F0 exposure. Finally, research was conducted to observe potential bystander effects; the impacts on life-history of exposure to irradiated individuals on non-irradiated individuals. Here, results indicated that bystander individuals can adjust their life history features in response to exposure to irradiated individuals. However, this work is preliminary as whole-body bystander effect research in insects is lacking. The results here indicate that although generally more radioresistant than mammals, insects can be profoundly affected by IR exposure. It is therefore prudent that further research in invertebrates, expanding on endpoints and species be conducted.