Male Spiders Evolved to Lose Genitals and Die after Mating [VIDEO]

The final hours of a male dark fishing spider's life are spent in a state of reproduction-induced comatose that ultimately leads to death -- unless, of course, the spider is cannibalized by its mate instead.

Either way, according to a new study, once the male spider mates, the clock begins ticking down the moments to the end of its life. What's more, the spiders appeared to have evolved this macabre mating system all on their own.

Steven Schwartz, a behavioral ecologist at the University of Nebraska-Lincoln, has studied the mating patterns of the dark fishing spiders for years and believes the male spider willingly sacrifices himself to ensure the health of his future offspring.

"It's almost like an extreme nuptial gift," Schwartz told Discovery News. "He is donating his body. That allows her to produce more offspring or better offspring."

The term for such a grim act romance is monogyny, and it's relatively common among arachnids, bees and ants. One species of spider is known to crawl into the mouth of its mate after copulating.

But the strange thing about the male dark fishing spider is how it's engineered to die. Its semen is stored in two feeler-like appendages near its head called pedipalps. Once it is released, the spider immediately seizes up, legs curled, motionless and unresponsive.

From there, the spider will lie in a coma until it dies or is eaten by the female.

Schwartz theorized that the sexual cannibalism is linked to reproductive effects.

"Females that eat their partners are less likely to mate with another spider," he said, according to ABC News.

That's good news for a spider that wants to ensure its legacy continues on, especially since there are many more male dark fishing spiders than females.

But in a rather dark turn, it turns out that that the male spider can also lose part of its genitalia during copulation. When the organ that carries the male spider's sperm expands, it often gets broken off inside the female, creating a plug that prevents the female from mating again and ensuring the male's sperm will reach as many eggs as possible.

"If the male dies and gets stuck in there, his whole body prevents ... male number two from mating," Schwartz told National Geographic.

Schwartz and his colleagues' research is published in the journal Biology Letters.