Sexual intercourse is `kiss of death` for certain female worms

Washington – Researchers have said that the presence of male sperm and seminal fluid trigger pathways that cause females to dehydrate, prematurely age and die.

Senior author Coleen Murphy, an associate professor of molecular biology and the Lewis-Sigler Institute for Integrative Genomics, said that their lifespans are cut by about a third to a half.

She said that the death of the female after she gives birth fits into a general framework of sperm competition that has been observed often in nature, asserting that the males compete to have their genomes propagated, and this often occurs at the expense of the female.

The researchers found that over the course of seven days, females who have mated (bottom panel) shrivel up and die, whereas females who have not mated (top panel) remain healthy.

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.

Murphy said that the males are taking these pathways and running them in reverse, causing the acceleration of aging and death.

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 those of humans.

Graduate student Cheng Shi, lead author on the paper, discovered the effect unexpectedly while carrying out studies to look at the effect of aging on reproductive health. He was conducting experiments that required him to mate female and male worms.

The paper has been published in journal Science.