Fertilization is often described as a race among millions of sperm, but new research suggests the process may be more cooperative than scientists once thought. A team led by evolutionary biologists at Syracuse University, along with researchers in Italy and Hungary, found that in some species sperm may work together to improve reproductive success, according to ScienceDaily.
The study focused on arthropods, the huge animal group that includes insects, spiders, crabs and centipedes. The researchers looked at cases where sperm formed organized groups or structures, a behavior known as sperm conjugation, and found that it has appeared many times over evolutionary history.
According to the study, sperm-associated material, or SAM, can help attach sperm to one another or arrange them into groups. The researchers said this material may have played a role in the evolution of sperm cooperation by first serving as a way to package or protect sperm.
Lead author R. Antonio Gomez said the findings show evolution has repeatedly tried out sperm cooperation across different arthropod lineages. Senior author Scott Pitnick said sperm are the fastest-evolving cell type because they must function in the challenging environment of the female reproductive tract.
The researchers said the work could help broaden understanding of fertility across animals and may also point to new ways to control harmful pests, including the invasive spotted lanternfly. However, they said one major question remains unanswered: why sperm cooperation develops in the first place.
