Why Bugs Are Not Huge

http://news.yahoo.com/s/livescience/...bugsarenothuge

Dragonflies with hawk-sized wing spans and millipedes longer than a human leg lived more than 250 million years ago. Scientists have long wondered why sci-fi bugs don't exist today.

The reason has to do with a bottleneck that occurs in insects' air pipes as they become humongous, new research shows. In the Paleozoic Era, insects were able to overcome the bottleneck due to a high-oxygen atmosphere.

Unlike animals with backbones, like us, insects deliver oxygen to their tissues directly and bloodlessly through a network of dead-end tracheal tubes. In bigger insects, this mode of oxygen transport becomes less efficient, but no one has been exactly sure why.

Alex Kaiser of Midwestern University and his colleagues at Argonne National Laboratory and Arizona State University delved deeper by shining X-rays on four living beetle species , ranging in body mass by a factor of 1,000. This allowed the team to measure the exact dimensions of the beetles' tracheal tubes.

Kaiser found that bigger beetle species devote a larger portion of their bodies, proportionately, to airways than do smaller species.

And the air passageways that lead from the body core to the legs turn out to be bottlenecks that limit how much oxygen can be delivered to the extremities, Kaiser said. The team also examined the passageways that lead from the body core to the head.

"We were surprised to find that the effect is most pronounced in the orifices leading to the legs, where more and more of the space is taken up by tracheal tubes in larger species," he said.

Kaiser and Argonne biologist Jake Socha also used the results to predict the largest size of currently living beetles. If data on the air passageways to the head were used as a limiting factor, they predicted a crazy-large, foot-long beetle, while the leg data predicted a beetle that matches the size of today's largest living beetle, Titaneus giganteus. The research is detailed in the Aug. 7 issue of the journal Proceedings of the National Academy of Sciences.

"This study is the first step toward understanding what controls body size in insects," Socha said. "It's the legs that count in the beetles studied here, but what matters for the hundreds of thousands of beetle species and millions of insect species overall is still an open question.

The research was funded by the National Science Foundation.


:)

Awww, no super-bugs

I always thought it was because bugs have no bones, so if they get too big they won't be sustain their weight.

yeah, I always thought the reason we dont see humongous land animals anymore is because their huge mass and girth was impractical to sustain, requiring enormous amounts of food. I thought that extended to big insects as well, smaller is simply better and more efficient...

Or so i thought anyway.

Well, I once saw a documentary about the past with dinos and superbugs. That was a couple of years ago and they already said the insects were so big cause of the high amount of oxygen ... so whats new about that?

hmm interesting...

I also thought that Insects couldn't grow big cause they're bodies couldn't support the weight.

shouldn't this be in the athenaeum?

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Originally Posted by Modern Life is Rubbish

hmm interesting...

I also thought that Insects couldn't grow big cause they're bodies couldn't support the weight.

shouldn't this be in the athenaeum?

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No, because if you imagine if you Had to fight Hordes of foot-long cockroaches just to be able to get to your kitchen then it'd be Thema Devia material. *pulls out a can of Raid* If I'm not back in Five minutes, then wait longer.

Starship Troopers

Them 1954

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Originally Posted by Juggernaut

I always thought it was because bugs have no bones, so if they get too big they won't be sustain their weight.

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Bugs have an exoskeleton which keeps their size down. 250 million years ago the atmosphere must have been able to support bigger exoskeletons... or something.

175th Post! :gnight:

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Originally Posted by Bernard L Black

Bugs have an exoskeleton which keeps their size down. 250 million years ago the atmosphere must have been able to support bigger exoskeletons... or something.

175th Post! :gnight:

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Well, I always thought that they have only exoskeletons so if they want to become large, they'd have to make their exoskeleton thicker.
But if they make it too thick it becomes too heavy and it would be crushed by it's own weight.

there were some pretty large bugs, one of the bigger ones was like a giant centipede that was 5 ft tall when it stood up.

Quote:

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Originally Posted by Juggernaut

Well, I always thought that they have only exoskeletons so if they want to become large, they'd have to make their exoskeleton thicker.
But if they make it too thick it becomes too heavy and it would be crushed by it's own weight.

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Exactly.