The Lightning Worm
The lightning worm,
Amynthas adtonitus, is a
close relative of the common earthworm, found primarily in the
central plains of northern America. Venerated by native Indians as a
magical creature in contact with the gods, the lightning worm
inhabits mainly flat plains, with little or no tall-growing plants to
attract lightning strikes.
When
thunderstorms approach its burrow, the lightning worm will stick out
its head, stretching it straight up into the air. Adult lightning
worms can reach a height of up to fifty centimeters ( ~20 inches)
from their burrow, with a total length of almost two meters (six
feet). The goal of this behavior, of course, is to maximize the
chances of being struck by lightning.
Due
to a as-of-yet poorly understood mechanism, the lightning worm is
able to transform the electric energy of lightning strikes into
chemical energy that its metabolism can store and retrieve freely.
The surge of electrical current generated is channeled by a
specialized group of cells, called “generators”. This helps to
minimize cell damage to other tissues of the worm, and assures that
the current only comes into contact with cells that have the
capability of transforming its electric charge into a difference in
potential between the outer and inner cell membrane. This difference
in potential, much like the one obtained in the photosystems of
plants, will then be used to turn ADP into ATP using proton pumps
(for a detailed explanation of this process, please refer to the
wikipedia article on photosynthesis).
Although
the electrical charge in itself is not enough to ensure the survival
of the worms, since it does not give them the building bricks
necessary to repair damaged cells, or grow, it is critical to their
reproductive success. During their mating period, lightning worms
spend most of their time defending their territory or copulating, and
have almost no time to find food. The energy they can gain from a
lightning strike can give them a definite advantage in their quest
for progeny, and evolution has favored those genes that give them an
advantage in attracting lightning strikes. This is one of the reasons
why lightning worms live mostly in iron-rich soils. They are capable
of extracting and storing the metal in special compartments in their
head, which allows them to better capture lightning.
Due
to the fact that his native habitat is unsuited for agriculture, the
lightning worm has been little affected by human intervention in the
past century, and even today, it is not uncommon to see hundreds of
lightning worms sticking their head into the air in
southern Arizona, in
anticipation of an electric discharge.
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