Monday, March 14, 2016

"Don't have sex, cause you will get pregnant and die!"

If the Coach from Mean Girls knew about Nursery Web Spiders, he'd say tell the male nursery web spiders not to have sex, because once the females get pregnant, the males die.

An article by the New York Times, focused on female Nursery Web spiders engaging in Sexual Cannibalism, either after the act or during. Thus, the males have evolved to find some pretty creative ways to get some and get out alive.

Some ways are to spring upon the females while they're grabbing a snack, and quickly copulate and get out of there while she's preoccupied. Some even bring their girl dinner, hoping she's in the mood for that over them.

Another evolutionary response, is to bind the females up with their silk and hope they don't get free until after its done. 

Alissa G. Anderson, a graduate student in biology at the University of Nebraska, had not seen cannibalism in their Nursery Web spiders. She postulated that this was due to the males always tying up the females. The experiment she conducted with another colleague used  dental silicone to block some male spiders’ spinnerets, or where the silk gets shot out. The males began to become devoured exponentially. 

However those that survived held some favorable traits, such as long legs.

She finalized her research, alluding to benefits for the females with being tied up. As some may eat the males during copulation, this can lead to a lower number of successful fertilized eggs. When the males are able to finish and leave, more eggs are fertilized. 

As a feminist, I would like my beliefs to cover all females intersecting through species. But here, I think the biological benefits of consuming males in order to protect the young are present, as well as the benefits to binding the female in order to have the highest probability of passing on traits. 


  1. The title of your post is awesome and so is the content. I have heard about sexual cannibalism in species before but I never understood the evolutionary purpose of this act. It seems a bit counterproductive for the female to eat the male during fertilization if this is the act that the future of the species is dependent. However, as you mentioned some benefits to this unconventional practice may increase fitness such as longer legs in males and web spinning ability.

  2. Thanks! I've heard about sexual cannibalism with praying mantises. I wonder if any experiments have been done regarding that species, and if the benefits have been evaluated in the manner of this study.

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  4. Haha, your title is very clever! I have never really heard of sexual cannibalism, so this article was definitely fascinating