On May 29, 2024, Alison Pischedda, assistant professor of biology, published new research in The Journal of Evolutionary Biology, alongside Barnard staff member and alumna Avigayil Lev ’22 and several colleagues from Canisius University. The article, “Life history changes associated with over 400 generations of artificial selection on body size in Drosophila,” examines the impacts of artificial selection on body size in the common fruit fly, Drosophila melanogaster.
An animal’s body size influences many aspects of its development, evolution, and behavior, so Pischedda and her colleagues set out to investigate the changes in life history traits related to the evolution of extremely large and extremely small body sizes in insects. The researchers studied populations of D. melanogaster that had undergone over 400 generations of artificial selection on body size.
Study results show that populations selected for small body size experienced strong trade-offs, including low levels of female fecundity and juvenile survival rates. Changes in egg size were also found to positively correlate with selection for both large and small body sizes. After adjusting for female body size, however, the researchers found that females from populations selected for large size had the lowest relative investment per egg, while females from populations selected for small size had the highest relative investment per egg. As Pischedda and her colleagues explain, these results suggest egg size may be a key constraint on the evolution of body size in D. melanogaster, offering greater insight into body size evolution in insects.