"That these pathways can be hijacked and run in reverse in a simple organism might suggest that that could also happen in more complex organisms," said Murphy. "So the work can help us understand male-female interactions and how they influence female longevity and reproduction."
Normally the females of the species C. elegans have no need for males, Murphy explained, because they are hermaphrodites their bodies contain both sperm and egg cells so they can reproduce without coming in contact with males.
"The hermaphrodites try to avoid the males they will try to sprint away from them. The males have to hunt them down to get them to mate," said Murphy.
Males, however, require females if they are to pass on their genes to future generations. Once inseminated, the female can give birth to hundreds of progeny, and these offspring do not require maternal care after they are born. Killing off the mother makes her unavailable to mate with other males, giving a genetic advantage to the father.
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.
"I saw a dramatic reduction in the size of the females," said Shi, "so I started taking additional images and measuring the effect." Shi began exploring how the sperm or its surrounding seminal fluid could cause the shrinkage and death.
He discovered that seminal fluid acts on a biological process that helps the worms conserve energy during times of stress. The seminal fluid acts on a transcription factor, or protein, called DAF-16 in the nucleus of cells that turns on the genes necessary to respond to stresses such as heat or low nutrients. In mated females, the factor is somehow driven out of the nucleus so it cannot activate the stress response sy
|Contact: Catherine Zandonella|