(insects chirping)
- That's some hideous, viral footage
of a hairlike parasite
emerging from the body
of a praying mantis.
- Mmm, what's happening here?
Let's get some deets.
- [Man] Just watching this
long, black, tentacle-like
creature emerge from its far shorter host
calls to mind the horrors of The Strain,
Slither, and of course, Alien.
- [Woman] But of course,
as monstrous as it seems,
we're actually observing
a real-world organism
with a real-world parasitic agenda.
- [Man] What we see here
is a parasitoid worm
from the phylum Nematomorpha.
They're also known as horse hair worms
because these threadlike
roundworms do resemble
the hair of a horse's tail or mane.
- [Woman] And it squirms
around, it takes up residence
inside a cricket, mantis, beetle,
or other host organism.
- [Man] You may have observed
these creatures before,
either emerging from a squashed host
or living free in a puddle or stream.
- [Woman] See the adults are free living,
but the larvae are parasitic
and grow to adulthood in
the body of an insect.
And here's how it goes down.
- [Man] Horse hair worms
make their home in damp soil
and fresh water.
It's here that the male and females mate,
and it's here that the
female lays millions of eggs.
These eggs hatch and
the tiny larvae encyst
on vegetation near the water's edge.
- [Woman] Then when it
happens, while a cricket
or some other suitable host drops by
and eats that encysted larvae
or in the case of the carnivorous mantis,
it acquires the parasite by devouring
an already infected intermediate host
such as a mosquito larva.
- [Man] Once inside its final host,
the cyst covering dissolves
inside the insect's gut
allowing the juvenile worm to escape,
bore through the gut wall,
and then start absorbing
the host's nutrients.
- [Women] And then our horse
hair worm grows and grows
'til it's time to burst free.
Oh, sure.
It'll abandon ship if the host dies,
but what it needs is
fresh water or damp soil.
- [Man] And so here we see a bit of
parasitic hijacking in action.
That's one hypothesis, anyway.
That the worm instills a
crazed thirst in the host
so that it seeks out water.
An alternate hypothesis
states that the worm simply
waits 'til the host
finds water on its own,
and then bursts forth.
- [Woman] According to a 2001 paper
from German journal Zoologischer Anzeiger,
the thirst hypothesis is
supported by observations
of suicidal behavior by infected
mantises in southern France
who seemingly jump into the river
and give birth to the
worm that consumed them.
- [Man] But hey, at least this
ends the mantis's suffering.
Usually there's just one
ghastly black worm inside of it
eating it from the inside out.
Sometimes however, it's twins.
So what about you?
Have you ever seen a
horse hair worm in action?
The first time I saw one
it was in a junior high band room
and it was wriggling out of
the body of a dead cricket.
- [Woman] True story.
What about you?
Let us know in the comments below
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