60-Second Science

Male Spiders "Chastity Belt" Females

Male wasp spiders have developed an ingenuous technique to make sure that females can't be impregnated by other males. But don't try it at home.

March 9, 2007 -- Male Spiders "Chastity Belt" Females

You know, every time I watch the movie Alien I think, eh, sure, that Alien is weird, but we have way weirder stuff here on Earth.  Bacteria that live in boiling water temperatures.  Male fish that burrow into the flesh of much bigger females and live out their lives as attached sperm donors.  Tape worms. 

Now comes further confirmation for my “life on earth is weird” position.  This time from the spider world. 

Male wasp spiders have a vested interest in making sure that they are the fathers of whatever offspring spring forth from a female.  The males can’t prevent females from trying to mating with other males.  So after mating a male in effect puts a chastity belt on the female.  Gird your loins now—they do this by breaking off and leaving the tip of their male genitalia, basically corking up the female.  Four of every five matings apparently ends this way.  The finding is reported in the journal Behavioral Ecology.

By the way, the male can make this sacrifice because it usually doesn’t matter if they stay intact—in most cases the female kills them anyway.  Was it good for you?  No.

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