Data from: Life history changes associated with over 400 generations of artificial selection on body size in Drosophila

Body size is a trait that shapes many aspects of a species’ development
and evolution. Larger body size is often beneficial in animals, but it can
also be associated with life history costs in natural systems. Similarly,
miniaturization, the evolution of extremely small adult body size, is
found in every major animal group, yet carries its own life history
trade-offs. Given that these effects can depend on an animal’s environment
and life stage and have mainly been studied in species that are already
specialized for their size, the life history changes associated with
evolutionary shifts in body size warrant additional investigation. Here,
we used Drosophila melanogaster populations that had undergone over 400
generations of artificial selection on body size to investigate the
changes in life history traits associated with the evolution of extremely
large and extremely small body sizes. Populations selected for small body
size experienced strong trade-offs in multiple life history traits,
including reduced female fecundity and lower juvenile viability. Although
we found correlated changes in egg size associated with selection for both
large and small body size, after adjusting for female body size, females
from populations selected for large size had the lowest relative
investment per egg and females from populations selected for small size
had the highest relative investment per egg. Taken together, our results
suggest that egg size may be a key constraint on the evolution of body
size in D. melanogaster, providing insight into the broader phenomenon of
body size evolution in insects.