Evolution and effects of decision-making in an insect

Abstract

Animals in the natural world face many choices, and their decisions with respect to food and habitat have major consequences for their fitness. Many factors influence these behavioural decisions, including the ecological and life history context of individuals. I will present our work analysing how females of a cosmopolitan and generalist pest — the red flour beetle Tribolium castaneum — choose where and how to lay eggs. When presented with a choice of an optimal (wheat flour) vs. a non-optimal resource (finger millet), females sometimes allocate more eggs in finger millet. However, we find that this preference depends on their age and density context, and is tuned to optimize distinct fitness components for their offspring, likely mediated via differential nutrient provisioning. During laboratory evolution in wheat-finger millet habitats, the founder female context also determines evolutionary changes in decision-making, though these maternal effects decline over time. Importantly, founder context also influenced population size and the effect of an inadvertent parasitic infection in our experiment. Our work highlights the role of ecological context in driving female decision-making, and demonstrates some wide-ranging effects of founder context on adaptation and trait evolution.