These Male Fruit Flies Have Sperm That Are Nearly as Long as Their Bodies. Here's How the Cells Don't Become a Tangled Mess
Key takeaways
- A time-lapse of an individual D. melanogaster sperm cell.
- Somehow, each insect holds thousands of sperm squeezed into two storage organs called seminal vesicles, each of which is ten times shorter than the cells.
- “Imagine putting thousands [of earbuds] in your pocket.
A time-lapse of an individual D. melanogaster sperm cell. The head is artificially colored pink, and the tail is teal. J. Imran Alsous et al., Nature Physics, 2026 via Simons Foundation's Flatiron Institute Out of all the animals on Earth, tiny fruit flies produce some of the longest male reproductive cells, or sperm. Males of the species that typically swarms your indoor trash, Drosophila melanogaster, are only about two millimeters long—equal to the width of a wooden pencil’s lead. Their sperm, primarily the tails, are almost the same length as their bodies and roughly 40 times the length of human sperm cells.
Somehow, each insect holds thousands of sperm squeezed into two storage organs called seminal vesicles, each of which is ten times shorter than the cells. Scientists have puzzled over this super-packaging. How does the tiny creature cram so much in its microscopic organs without creating a catastrophic, knotty mess?
“Imagine putting thousands [of earbuds] in your pocket. The sperm are, of course, different from passive wires: The sperm are active, generating bending waves along their long tails,” Jasmin Imran Alsous, a computational biologist at the Flatiron Institute, a New York City-based research center, tells Laura Baisas at Popular Science.