Long-term laboratory evolution experiment: Host shift changes the life-history strategies and the levels of phenotypic plasticity in seed beetle (Acanthoscelides obtectus

Abstract

Many phytophagous insects are able to exploit a novel food source in their diets. This process, known as the host shift, includes insects’ ability to recognise, utilise and ultimately persist on a new plant host. During the host shift process, insects are faced with many challenges and new conditions can change insects’ behaviour, physiology, life-history strategies and population dynamics. Adaptive phenotypic plasticity could help populations to receive signals from the new environment and constitute a functional phenotype. Using a long-term laboratory evolution experiment in seed beetles (Acanthoscelides obtectus) we have tested how different plant hosts (common beans, chickpeas and mung beans) change life-history strategies over many generations. Furthermore, we have established iso-female lines and conducted a reciprocal transplant experiment in order to test the level of plasticity in life-history traits. We have demonstrated that populations of seed beetles adapted to different hosts not only show changes in life-history traits, but also demonstrate clear differences in the levels of phenotypic plasticity for those traits. This research is discussed in the context of how plant hosts affect populations’ ability to influence long‐term (evolutionary) modes of populations’ change and allow survival and ecological competence of organisms in new conditions.