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Long-Term Laboratory Evolution of a Genetic Life-History Trade-Off in Drosophila melanogaster. 1. The Role of Genotype-by-Environment Interaction
Armand M. Leroi, Adam K. Chippindale and Michael R. Rose
Vol. 48, No. 4 (Aug., 1994), pp. 1244-1257
Published by: Society for the Study of Evolution
Stable URL: http://www.jstor.org/stable/2410382
Page Count: 14
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Trade-offs among life-history traits are often thought to constrain the evolution of populations. Here we report the disappearance of a trade-off between early fecundity on the one hand, and late-life fecundity, starvation resistance, and longevity on the other, over 10 yr of laboratory selection for late-life reproduction. Whereas the selected populations showed an initial depression in early-life fecundity, they later converged upon the controls and then surpassed them. The evolutionary loss of the trade-off among life-history traits is considered attributable to the following factors: (1) the existence of differences in the culture regimes of the short- and long-generation populations other than the demographic differences deliberately imposed; (2) adaptation of one or both of these sets of populations to the unique aspects of their culture regimes; (3) the existence of an among-environment trade-off in the expression of early fecundity in the two culture regimes, as reflected in assays that mimic those regimes. The trade-off between early and late-life reproductive success, as manifest among divergently selected populations, is apparent or not depending on the assay environment. This demonstration that strong genotype-by-environment interactions can obscure a fundamental trade-off points to the importance of controlling all aspects of the culture regime of experimental populations and the difficulty of doing so even in the laboratory.
Evolution © 1994 Society for the Study of Evolution