In the organs that produce sperm cells in fruit flies a strange phenomenon occurs; when one type of stem cell is killed off another comes out to replace it.

The finding could help researchers gain insight into how stem cell tumors regenerate themselves, a Johns Hopkins Medicine news release reported.  The study could also help scientists better-understand the tiny ""environments" that stem cells reside in, such as the niches that separate them.

The niches hold three types of cells: "germ line stem cells, which divide to produce sperm; somatic cyst stem cells, which make a kind of cell that helps the sperm-producing cells out; and hub cells, which make signals that keep the other two kinds of cells going," the news release reported.

In the past researchers believed hub cells were not able to further divide. The researchers tried killing of the somatic cells in the fruit flies to see what would happen.

"When we finally figured out a way to kill all of the somatic stem cells, we thought that the rest of the tissue would probably just empty out," study leader Erika Matunis, Ph.D., a professor of cell biology at the Johns Hopkins University School of Medicine, said in the news release.

This only happened in 35 percent of testes, while the somatic cells grew back in the rest of the samples. The team found these new cells were being regenerated from the hub cells. The hub cells started to divide when the somatic cells were killed off.

The new hub cells proved to be slightly different from the old ones. The team also noticed the damaged testes were creating more niches, meaning it would have more pockets of stem cells than a healthy organ.

The research could help unlock secrets of how cancerous stem cells behave.

"We're very curious to unravel the signals that are changing when we damage this niche and it undergoes these unexpected behaviors," Matunis said.