Effect of interaction between population size and copper exposure - studies on the flour beetle Tribolium castaneum
Scientific relevance
Organisms living in polluted areas, despite exposure to toxic metal concentrations, can be also endangered by a fragmentation of an environment, leading to loss of genetic variability. The most immediate threat due to the loss of genetic diversity is inbreeding depression, manifested in decreased reproductive capability and viability. However, such interaction has not been adequately investigated experimentally. An understanding of significance of these stressing factors are fundamental for elaboration better methods of environmental risk assessment (ERA).
Aim of the taks
In this project, we will address the interaction between environmental stress caused by pollution with copper and genetic stress of inbreeding in causing extinction in experimental populations of Tribolium castaneum:
- 1) The first aim of the proposed studies is to investigate whether pollution affects genetic diversity. Pollution can have direct effects on reproductive performance, and thus on population size. We will investigate how different levels of pollution affect population dynamics and genetic diversity at neutral markers.
- 2) The second aim is to study the interaction between pollution and inbreeding in causing extinction. We will use factorial design allowing us to assess relative contributions of inbreeding and pollution, and their interaction, on the risk of extinction and population dynamics. In the inbreeding treatment, we will use either outbred populations, or populations inbred to the degree characteristic of endangered species (F=0.25), and these replicated populations will be reared either in unpolluted environment, or in environment polluted at the realistic level of copper.
- 3) The third aim will be to test whether limited genetic diversity affects the rate of adaptation to polluted environment. Reduced genetic diversity is thought to limit evolutionary potential of populations and prevent their adaptation to changing environmental conditions. Using our inbred and outbred lines evolving in a polluted environment we will be able to test this prediction.