Sexual Cannibalism: The Ultimate Investment in your Child’s Future??

While researching different kinds of insects and arthropods, I came across a phenomenon I found particularly interesting.  In some species, particularly groups of spiders, mantids, and scorpions, the female can be seen devouring their mate before, during, or after sex.  While it’s a little brutal, it wasn’t horribly surprising on the female’s part.  If it’s a cannibalistic species and you got a little guy half your size vulnerable in front of you, why not just gobble him up, right?

A male black widow on a much larger female black widow

The really strange part came on behalf of the males.  Some males don’t even bother resisting their doom—in fact, after sex some species of males just kinda curl up and wait for the inevitable, just killing themselves anyway if they don’t get eaten.

WHYYYY WHOULD THEY DO THAT????  Is what I’m sure you’re asking.  Because I sure was.

Science Blog’s article “Ultimate Sacrifice: Spider’s post-sex cannibalism aids offspring” sheds a little light on the phenomenon.  They examine the male dark fishing spider, a species in which the male spider waits to be eaten after mating with a female.  In studying why, they found that the male’s sacrifice “appears to increase the number, size, and survival odds of his future spiderlings.”  The females produced twice as many spiderlings that were 20% larger and survived 50% longer after snacking on her mate.

But why not eat something else?? You may also be asking.  Apparently it doesn’t work that way.  In the same study they tried feeding the female crickets right after mating instead of her mate, but the crickets did not give the same boost as the male spiders.

So there you have it.  It’s all for the good of the kids!  Heartwarming stuff right here guys.  Fellas, would you let your significant other devour you whole for the good of your unborn children?  If you say no you’re a horrible father and these spiders are putting you to shame! ***


*** Neither I nor this blog encourage cannibalism stay safe



(2016) “Ultimate Sacrifice: Spider’s post-sex cannibalism aids offspring”.  Science Blog.  Retrieved Oct 18 2016.

Black widow photo:

Mantis photo:

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