The simple act of making sperm substantially shortens a mal worm's life span, a researcher has discovered in results that overturn accepted biological dogma about the relative cheapness of a male's ejaculation compared with the preciousness of a female's egg.
The scientist studying simple but revealing worms called nematodes found that males live much shorter lives than their mates, and he has traced that discrepancy to sperm production.
When he experimentally manipulated males so they lost their capacity to make sperm while retaining their taste for intercourse, the altered nematodes lived at least 50 percent longer than the normal, fertile males.
The results suggest that creating sperm is far more difficult than scientists had imagined, demanding a diversion of resources that might otherwise go into assuring a male's long-term health.
"These results are the last thing I had expected when I started doing the experiment," said Wayne A. Van Voorhies of the University of Arizona in Tucson. His report appears today in the journal Nature.
Other scientists familiar with the new work have expressed their astonishment at the discovery, and they are unsure what its wider implications may be.