Do Female Praying Mantises Really Decapitate Mates?

The female praying mantis: maneater or misaligned? Learn the science behind this popular semi-myth in this episode of BrainStuff.

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Episode Transcript

Speaker 1 (00:02):
Welcome to brain Stuff from how Stuff Works. Hi brain
Stuff Lauren vocal bamb here. It's long been an excitedly
repeated myth that female praying mantis is have no problem
engaging in violent, cannibalistic murder when confronted with a friendly mate,
perhaps because school classrooms often host terrariums with mantis subjects.
It's one of those rumors that even children seem to know.

(00:23):
Don't breed with a female mantis lest your head becomes
her dinner. Sounds scary, but is it true. Do the
females of the species actually eat or decapitate their mates,
or are they simply being maligned by alarmed men who
perhaps empathize a little too much with their insect brethren.
The key to understanding these questions is the word species,
because while we might have a picture of a standard

(00:44):
looking green mantis in our head, there are actually two thousand,
four hundred species of the sucker. Some are colorful, some
are creepy, and some, yes, some are cannibals. But before
we get into the occasionally cruel lifestyle of the female mantis,
let's take a second to examine the basis of the
naybe myth. What we discover is that the myth is
rooted in well documented science. In an eight six observation

(01:08):
from the journal Science, entomologist Leland Assian Howard noted that
on placing a male mantis with a female, the female
systematically proceeded to eat the male's left leg, left eye,
and right leg, and then decapitate him and eat his head.
The male, keep in mind, was attempting to mate with
her the whole time, which she eventually acquiesced to with
her headless and mostly legless partner. While Howard stressed that

(01:31):
he had never seen it before, he also rather breathlessly stated,
it seems to be only by accident that a male
ever escapes alive from the embraces of his partner. We
see how this could make everyone think that mantis ladies
were nothing but bloodthirsty harpies. But remember Howard saw this
once with one species of mantis, Mantis Carolina. Decapitation or

(01:51):
cannibalism went on to be observed in Mantis religiosa as well,
and a few other scientists studied the question of why
decapitation would be useful for mating. Some theories the decapitation
might cause sexual movements in the male abdomen, or perhaps
part of the thorax, might actually inhibit sexual movements. Both
theories were later proved false. So here's the real deal.
Female mantises have occasionally been observed to cannibalize and decapitate

(02:15):
their mates, but by and large doesn't seem to be
the case. Study in animal behavior made it forty pairs
of mantis is only one was decapitated in almost seventy encounters.
Bottom line, you can stop with the cliche female mantis jokes.
Dating is hard enough. Nobody needs reputation as a man eater.

(02:38):
Today's episode was written by Kate Kirshner and produced by
Tristan McNeil. For more on this and lots of other
myth busting topics, visit our home planet has to Works
dot com