WORM IS CREEPIER THAN A HALLOWEEN GHOUL
Halloween on the horizon, I am reminded of a mystery animal
someone once sent me.
creature was described like this in an email: A young boy discovered
a specimen that our neighborhood is unfamiliar with. It is about 24
inches long, has the diameter of a toothpick, is brown in color, and
has a flat nose and forked tail. It was found in a dirty puddle after
we had excessive rains. We live in a South Carolina farming community.
Do you have any idea what this might be?
the questioner if she could mail the specimen to me in a jar with tiny
air holes in the top and damp paper towels inside.
arrived at work two days later, my coworker Sarah Collie sat at her
desk with a jar in her hands and a bemused look on her face. Your
worm has arrived, she announced.
there it was, exactly as described 2 feet of slender worm that
looked like a tangled coil of thin copper wire with a forked tail. I
had never seen a live one before and neither had any of my ecologist
colleagues I checked with, although we knew about such animals. The
animal was a horsehair worm, belonging to a poorly understood group,
the hairworms, with more than 300 species.
are in their own separate phylum whose biological relationship to other
worms is ambiguous. The scientific name of one hairworm is Gordium,
after the Gordian knot, which could not be untied (a difficulty Alexander
the Great reportedly overcame by slicing the knot in half with his sword).
the twisted knotty mess that a 2-foot-long worm the diameter of a piano
wire could get itself in, I thought the name most appropriate. The forked
tail on this one meant it was a male.
which can reach a length of 3 feet, are in a free-living form, meaning
they are not parasitic. But the larvae are. Paradoxically, hairworms
are special because they are so unspecialized. They have no digestive
system, no respiratory system, and no circulatory system. Adult horsehair
worms do not eat.
the insects they grew up in, the males and females mate and reproduce
in water. The female lays eggs that float in the water. If an egg is
eaten by an insect, the egg hatches and the tiny parasite larva drills
its way out of the insects intestine and takes up residence in
the body cavity. It feeds on the inside of the insect until it grows
into a long worm ready to start the cycle again.
including spiders and insects serve as hosts for hairworm parasites.
In what might appear to be the inspiration for the movie Alien,
the larvae grow to the size of giant worms inside the unfortunate invertebrate
host before they emerge.
a 3-foot-long worm inside a grasshopper! Hairworm parasites have little
use for people, although rare infections of humans in China, Japan,
and Canada have been reported in medical and parasitological scientific
the worm know it will end up in water so it can mate? A remarkable study
by several French scientists on hairworms that infect crickets and grasshoppers
may offer a partial explanation.
studies that examined the brain of insects, the investigators found
that the hairworm parasite actually alters the behavior of the insect
by producing molecules that enter the insects central nervous
mechanisms are unknown, but chemical alterations in the brain make the
insect jump into water and drown. Such abnormal insect behavior puts
the now-developed worm where it wants to be. Brainwashing at its most
email from the woman with the horsehair worm displayed the kind of enthusiasm
about the natural world that I like to see in people. Thank you
for this information. I learn something new every day! That day,
so did I.
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