The vinegar worm (officially known as Caenorhabditis elegans) is about as simple as an animal can be. When this soil-dwelling nematode reaches its adult size, it measures a millimeter from its blind head to its tapered tail. It contains only a thousand cells in its entire body. Your body, by contrast, is made of 36 trillion cells. Yet the vinegar worm divides up its few cells into the various parts you can find in other animals like us, from muscles to a nervous system to a gut to sex organs.
Its simplicity was what made it so enticing. Under a microscope, scientists could make out every single cell in the worm’s transparent body. It would breed contentedly in a lab, requiring nothing but bacteria to feed on. Scientists could search for mutant worms that behaved in strange ways, and study them to gain clues to how their mutations to certain genes steered them awry.
The more scientists examined the supposedly simple vinegar worm, the more complexity they uncovered. And some of the most fascinating complexity about the vinegar worm involves its sex life.
By comparison, our own sex life is pretty dull. In humans and many other animal species, individuals are typically either males or females. The males produce the sperm, and the females produce the eggs. In C. elegans, individuals can either be males or hermaphrodites.
The biology of the male worms is straightforward enough: they have sperm, which they can insert into a mate. But the biology of the hermaphrodites is unquestionably strange. They start out life essentially as males, producing sperm that they store in a special chamber deep inside their body. Later in life, their gonads undergo a radical transformation: now they only make eggs.
Read full, original article: Can Hermaphrodites Teach Us What It Means To Be Male?
