Researchers from Japan find that different cell types and variation within these cells promote muscle breakdown and rearrangement during Drosophila development

Osaka, Japan – All living beings, big or small, are formed through the hard work of many different cells. To keep the body ready for any challenge, cells need to be dynamic. Often, this means the same types of cell – for example, red blood cells – look and function differently to one another to work together en masse. While researchers know that these varied, or micro-heterogenous, cells exist in multiple bodily systems, the benefits of being heterogenous for how systems function are not yet known.

However, in a study due to be published in PLOS Computational Biology, researchers from The University of Osaka, The University of Tokyo, Tohoku University, and Future University Hakodate have revealed that teamwork makes the dream work, even at the cellular level. The findings revealed several different types of cells work together to make big changes in the bodies of a common model organism used for research, the fruit fly.
Fruit flies undergo dramatic changes in their body structure throughout their lifespan, from larvae to adults. During the critical pupal stage, cells collaborate to break down larval muscles and scatter the fragments all over the tissue.
“The two major players in muscle breakdown are sarcolytes, which are muscle fragments, and hemocytes, which are immune cells that engulf these fragments,” says senior author, Dr. Daiki Umetsu at The University of Osaka. “However, it was unclear how interactions between these different cell types, as well as variation within each cell type, affected muscle remodeling during fruit fly development.”
To address this, the researchers used a sophisticated real-time microscopy approach to track the movement of heterogenous cells in pupal fruit fly muscles. Meanwhile, a computational model of sarcolytes, hemocytes, and a third type, fat body cells, evaluated factors affecting muscle remodeling. Combining both the biological and computational methods provided researchers with the opportunity to visualize this process.

“The results were very intriguing,” explains Umetsu. “We found that sarcolytes initially moved quickly, then slowed down and adopted a more ordered arrangement, while the fat body cells appeared to help provide structure and spacing to the sarcolyte arrangement.”

Interestingly, hemocytes, which carry sarcolytes, varied considerably in their speed of movement and the number of turns made. The computer model showed that the presence of all three cell types was essential for correct sarcolyte rearrangement, and that a combination of hemocytes that meandered and those that moved in a straight line reinforced the stability of the new arrangement.

“Our findings suggest that heterogeneity both within and among cell types is crucial for achieving two different purposes in fruit fly muscle development: rapid redistribution of sarcolytes and precise placement of these cells into a new structural order,” says lead author, Dr. Daiki Wakita at The University of Tokyo.

The benefits of being able to visualize multiple different cell types and their behavior during muscle breakdown in fruit fly pupae can link to non-living beings, too. The findings generated could potentially be applied to robotics. “The research’s conclusion suggests that heterogeneous robot swarms could be more efficient at multitasking, which is more representative of real-world tasks, than groups of robots with identical features,” says senior author, Dr. Takeshi Kano at Future University Hakodate.

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The article, “Dual-purpose dynamics emerge from a heterogeneous cell
population in Drosophila metamorphosis,” will be published in PLOS Computational Biology at DOI: https://doi.org/10.1371/journal.pcbi.1013331



Movie.
Simulations of larval muscle (yellow) breaking down into fragments (green). Breakdown proceeds faster with heterogeneous hemocytes in turning frequency (bottom) than with homogeneous hemocytes (top). Fat body cells (gray) appear midway in both cases.
License：CC BY
Credit: D Wakita, S Yamaji, D Umetsu and T Kano (2025)