The elemental composition of organisms belongs to a suite of functional traits that change during development in response to environmental conditions. This phenomenon, known as ecological stoichiometry, may be interlinked with developmental programming, which hypothetically creates phenotypes that are better adapted to the environment. However, associations between adaptive variation in developmental speed and elemental body composition are not well understood. We compared body mass, elemental body composition, food uptake and fat metabolism of Drosophila melanogaster male fruit flies in relation to their larval development speed.
Results/Conclusions
The results showed that flies with intermediate and rapid developmental speeds were heavier than slowly developing flies. The latter flies had higher body carbon concentration than rapidly developing and intermediate flies. Rapidly developing flies had the highest body nitrogen concentration, while slowly developing flies had higher body nitrogen levels than flies with intermediate speed of development. The carbon-to-nitrogen ratio was therefore lower in rapidly developing flies than in slow and intermediate flies. We also had a group of flies grown individually and their body mass and elemental body composition were similar to those of rapidly developing individuals grown in fly groups. This suggests that rapid growth is not suppressed by stress. Feeding rates were lowest in the slowly developing flies. The amount of triacylglycerides was highest in the flies with intermediate developmental speed which optimize fitness under many climatic conditions. Although low food intake may slow down development and the accumulation of body fat reserves in slowly developing flies, their phenotype conceivably facilitates survival under higher stochasticity of their ephemeral environments spoiled by the metabolic waste. Rapidly developing flies grew with less emphasis on storage build-up, suggesting bet-hedging in the larval development. Overall, this study shows that bet-hedging may be a common developmental strategy that enables fruit flies to respond adaptively to environmental uncertainty.