The presence of male sperm and seminal fluid causes female worms to shrivel and die after giving birth, Princeton University researchers reported this week in the journal Science. The demise of the female appears to benefit the male worm by removing her from the mating pool for other males.
The researchers found that male sperm and seminal fluid trigger pathways that cause females to dehydrate, prematurely age and die.
"Their lifespans are cut by about a third to a half," said senior author Coleen Murphy, an associate professor of molecular biology and the Lewis-Sigler Institute for Integrative Genomics.
The death of the female after she gives birth fits into a general framework of sperm competition that has been observed often in nature, said Murphy. "Males compete to have their genomes propagated, and this often occurs at the expense of the female."
Shortened female lifespans following mating have been observed before for roundworms, but the study is the first to document the body shrinkage and identify the underlying biological pathways, Murphy said.
"The fact that sex essentially kills the mothers after they have produced the males' progeny has never been reported before and is shocking to most people who hear this story for the first time, including researchers who study these worms," Murphy said.
The team found that the pathways by which the male kills the female are ones that researchers think exist for the purpose of slowing down aging during times of low nutrients.
"The males are taking these pathways and running them in reverse, causing the acceleration of aging and death," Murphy said.
The researchers discovered the effect in the Caenorhabditis elegans (C. elegans) roundworm, which is found in soil and rotting fruit and is about the size of a piece of lint. The roundworm is commonly used in research because many of its genetic pathways are similar to
|Contact: Catherine Zandonella|