Metabolic differences between tropical and temperate Drosophila species after cold-induced reproductive arrest

MENSCH, J.; SCHILMAN, P.E.; HASSON, E; COLINET, H. ; KREIMAN, L.; RENAULT, D.

Simposio; 8th International Symposium on the Environmental Physiology of Ectotherms and Plants; 2019

The capacity for delayed reproduction along with the improvement of cold tolerance suggest that cold-induced reproductive arrest could be part of an overwintering strategy in the life cycle of females´ cactophilic Drosophila species. On the contrary, when flies maturate an energetic bias towards reproduction limits the metabolic investment for stress survival during winter. Tropical counterparts, on the other hand, do not experience environmental temperatures that arrest development of their ovaries during winter. The aim of this work is to investigate the metabolic signatures of cold acclimation in tropical and temperate species of cactophilic Drosophila from South America. To do so, we compare an array of metabolites expressed at the end of different thermal treatments, in order to correlate cold tolerance with particular metabolic signatures. We found that reproductively arrested females of temperate species accumulated proline and some polyols (e.g. glycerol), while tropical do not, showing for these metabolites clear interactive effects between biogoegraphic origin and reproductive state. Accordingly, reproductively arrested females of temperate species showed the lowest CTmin. Others metabolites showed different patterns: carbohydrates such as glucose and gluconolactone increased in temperate species, both in mature and arrested females, while trehalose and gliceric acid increased in tropical ones. No clear-cut changes were observed for TCA cycle components, suggesting maintenance of metabolic homeostasis across species and treatments. Our results show that different sugars, polyols or free amino acids are important players of cold acclimation for tropical and temperate species.