Adult Life Span of Cactophilic Drosophila: Interactions among Volatiles and Yeasts

Abstract

-Volatile compounds found in rotting cactus tissue were investigated for their effect on the adult life span of cactophilic and generalist Drosophila under axenic conditions and in the presence of cactophilic yeasts. A low concentration of acetone vapors extended the longevity of axenic D. mojavensis females with or without the presence of yeast, but acetone extended the life span of males only in the presence of an acetone-utilizing yeast (Candida sonorensis). Methanol extended the adult life span of both sexes of D. mojavensis only in the presence of a yeast (C. sonorensis) that could use methanol as its sole carbon source. No increase in longevity was observed for flies exposed to low concentrations of propionic acid vapor. The interaction between methanol and C. sonorensis affected only the longevity of D. mojavensis (a cactophilic fly from a host with low levels of free sugars in fresh tissue) and not the longevity of D. buzzatii (a cactophilic fly from a host with higher levels of free sugars) or D. melanogaster (a strain of a generalist fly that was collected from sugary cactus fruit).