This is surely a
wow and it does not survive the transition to adulthood where failure would be
fatal. It also does not show up
elsewhere or we may well have already tripped over it. At best it is extremely rare.
This presents
two problems. Why this here and just how
does natural evolution wish to explain this?
One would almost prefer to posit a keen young grad student engineering
this variation in order to acquire his Phd about thirty thousand years ago. Other protocols do exist and I cannot see the
benefit of this been particularly advantageous.
With this
surprise item we would be hard put to discover much not done first by living
organisms.
Insect
Mechanical Gears: Scientists ‘Totally Dumbfounded’ by New Discovery
The Issus, insects
also known as planthoppers, use structures in their legs that are like
mechanical gears to propel them, scientists discovered.
The finding came
after Malcolm Burrows, a zoologist at the University of Cambridge in the
United Kingdom, and his colleague Gregory Sutton were studying how insects jump
so quickly.
They started
studying the Issus coleoptratus, or planthopper, and found that these insects
have protruding structures on their hind-leg joints that are like teeth.
The teeth, upon
closer examination, were found to lock together neatly to propel the creatures’
leaps and bounds.
“You could see
these gear wheels moving past each other, just like a man-made gear wheel. It
was extraordinary.”
The gears enable
the creatures to jump at speeds as high as 8.7 miles per hour, with each back
leg moving within 30 microseconds (30 millionths of a second) of the other.
This is
the ”first observation of mechanical gearing in a biological structure”
the researchers said in a statement.
“We usually think
of gears as something that we see in human designed machinery, but we’ve found
that that is only because we didn’t look hard enough,” said Sutton, now at the
University of Bristol. ”These gears are not designed; they are evolved –
representing high speed and precision machinery evolved for synchronisation in
the animal world.”
Curiously enough,
adult planthoppers don’t have the same gears. They’re gone when the young
insects, or nymphs, transition to adulthood and cast off rigid skin.
It’s unclear why
this is but the scientists say it could be because the gear system is wholly
damaged when one tooth on the gear breaks. Nymphs can repair the damage through
molting, but adults couldn’t repair it because molting stops.
“If you damage
your cogwheel on your first day as an adult, then you’re a very unlucky
planthopper,” Burrows said.
The adults also
have something similar to thigh bones that appears to enable them to jump at
the similar speeds and heights without needing the gears.
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