ROSE, Michael R.; CHIPPINDALE, Adam K.; PHELAN, John P.; ARCHER, Margaret A.; BRADLEY, Timothy J.; University of California, Irvine; Queen’s University, Canada; University of California, Los Angeles; University of California, Irvine; University of California, Irvine: The Devil and the Evolutionary Physiology of Life-History in Drosophila

Laboratory evolution has been used to reveal the physiological foundations of Drosophila life history. A number of different, replicated lines have been produced that have enhanced adult survival, developmental speed, or stress resistance. The initial evolution of these enhanced features suggested an overall syndrome of Drosophila life-history evolution in which increased stress resistance was associated with longer life, slower development, larger body size, increased viability, and reduced early fertility. But further laboratory evolution of these characters has undermined many of these associations. Continued increases in stress resistance eventually result in reduced longevity. Continued increases in developmental rate result in reduced growth rates. Initial patterns of evolutionary correlation were wholly undermined by further selection. Genetic or selective correlations between characters can completely break down. The use of artificial selection or quantitative genetics to extrapolate to the evolution of populations or species over long periods of selection therefore seems unwarranted. This pattern of unpredictability in fruit fly evolution may be common to functional evolution at all levels, in all systems.