Research We currently focus on the nutritional control of growth and aging, and on body size homeostasis. Do animals find an optimal balance between growth and aging? Environmental conditions affect the rates of growth and aging. Most famously, animals delay aging when environmental nutrients are scarce, and grow more slowly. We want to understand if this control of growth and aging increases the long term evolutionary success of a genotype, or is merely a passive consequence of a slow metabolism. Our research builds on mathematical models of life history theory stating that animals face tradeoffs between growth and aging and need to balance their investment between these two tasks. Specifically, theory predicts that a different compromise between growth and aging is optimal in different nutritional conditions. Using genetics, we experimentally modulate the rates of growth and aging of C. elegans to test these theoretical predictions. We ask which balance between growth and aging presents the best compromise and study the molecular mechanisms by which animals compute optimal tradeoffs in different environments. We believe that this research will unravel functions of metabolic signaling networks that are only apparent when studied at the scale of an entire animal or even population. How do animals reach the right size? Genetically identical individuals never look completely the same due to the stochasticity of biological processes. We want to understand how animals prevent that small differences among individuals at birth amplify to much larger differences during the development of an animal. Specifically, we focus on the relation between heterogeneity in growth and body size of C. elegans. In principle, two individuals that differ even only slightly in their growth rate are expected to differ increasingly in their body size during development due to the exponential nature of growth. This effect is comparable to small differences in the interest rate on a bank account that over the years amplify to large differences in savings due to the benefit of compound interest. We study if and how animals maintain a constant body size despite heterogeneity in their growth rate. To address this question, we use micro chambers to grow hundreds of individuals of C. elegans in parallel (see movie here) and track each individual's rates of growth, development and size.