Lifestyles and metabolism of Drosophila lutzii, a floridosa group of species, and sympatric D. simulans, a generalist specie
Authors: Juan Manuel Murillo-Maldonado; Juan R. Riesgo-Escovar
Affiliation: Universidad Nacional Autónoma de México
Keywords: b. metabolism; m. adaptation
The Drosophila genus of the family Drosophilidae comprises around 1600 described species. These species differ in their geographic distribution and ecologies, and consequently, in ecological niches and lifestyles. As they evolved in different environments, species may differentially regulate their metabolism and behavior as they adapt to these local conditions. Here, we characterize Drosophila lutzii, a Neotropical Phloridosa group of species of Drosophila. As its group of species implies, they are not saprophytic, but rather feed on flowers. We made a comparative study between D. lutzii, aspecialist, and sympatric D. simulans, ageneralist. We analyzed metabolic and behavior parameters. Drosophilasimulans is a saprophytic generalist, with feeding based on rotting plants and fruits, while Drosophila lutzii isa phytophagous specialist. We have found D. lutzii eggs, larvae, pupae and adults inside Ipomoea sp. flowers. This suggested a restricted diet, and thus, an interesting avenue for research in metabolism, in comparison to generalist species of flies. We found that freshly caught D. lutzii from the wild have higher carbohydrates levels, but similar lipid content, as compared to sympatric freshly caught D. simulans. Consistent with a restricted diet and specialist lifestyle, D. lutzii flies are less capable of surviving in culture in diets that differ in the amounts of carbohydrates, and when fed diets with high sugar concentrations, contrary to D. simulans, they significantly accumulate them. Triglycerides levels also were differentially affected in both species when fed with diets that varied in sugar content. D. lutzii flies are significantly and dramatically less motile, but possess a circadian activity rhythm akin to D. melanogaster or D. simulans. These three species showed a differential feeding behavior when exposed to food with different amounts of sugar in 30 minutes periods. Taken together, our results show that, in contrast to generalists, this specialist species, with more restricted habitat and feeding, is less capable of metabolic adjustments.