Polyploidy, the possession of multiple chromosome sets, is a widespread phenomenon across the tree of life. Polyploidization is often seen as too costly in stable environments while regarded as an opportunity for adaptation under stressful conditions. Because of its impact on adaptation, polyploidization influences eco-evolutionary dynamics like population expansions and community assembly, and often results in increased cell and body size. In this project I will combine targeted experiments and theoretical modelling to understand to which extent increases in size have consequences for the growth and maintenance for polyploids. The main question is how metabolic processes and efficiencies will be affected by polyploidization, both alone and in combination with stress, in order to investigate the population dynamics of newly formed polyploids. The duckweed Spirodela polyrhiza will be used as a model system to quantify the effects of polyploidy and size on metabolic rates and life-history traits. Experiments will include 9 strains and their respective polyploids from 3 artificial polyploidization events. Based on the acquired data, I will develop a mechanistic model in which scaling relationships of body size with metabolism and energy-allocation will be central. This simulation model will be used to understand the polyploid persistence under temporal resource fluctuations and predict responses to future environmental changes.