Adult Drosophila legs do not regenerate after amputation

Abstract

A recent paper by Abrams et al. (2021) claimed that a simple dietary supplement is sufficient to induce appendage regeneration in jellyfish, flies, and mice. This would be remarkable, if true, because it was previously thought that flies and mice lack the capacity for regeneration after injury. We therefore sought to replicate their provocative results. We amputated one tibia of over 1000 fruit flies, fed them control or supplemented diets, and carefully examined their legs three weeks post-injury. We did not, however, observe any instances of leg regeneration. We conducted additional experiments that confirmed the complete absence of neurons, muscles, or other living cells in amputated tibias. Abrams et al. also reported the formation of a white blob at the amputation site, which they interpreted as an intermediate regeneration morphology. We tested this hypothesis more rigorously and conclude that the white blob consists of bacteria. Overall, we failed to find any evidence for leg regeneration in Drosophila, even when flies were fed the supplemented diet. Our results therefore contradict the overarching conclusion of Abrams et al. that dietary supplements are sufficient to unlock an ancestral mechanism that induces appendage regeneration.