Stealth bugs

My brother was reading a biography about the development of the F-117, the stealth fighter. According to the author, the first visceral feeling he had that stealth technology actually worked came in the run-up to the first gulf war. Bats lived in the aircraft's storage hangers, and every morning they'd find dead bats littering the floor, from when they'd run into the tail because they couldn't see it with their echo-location.

Its a cool story, but it got me thinking about how often we get engineering ideas from biology--aircraft wings from
birds, velcro from burrs, suction-cups from octopuses, camera lenses from the eye, etc. In fact, we steal ideas from Mother Nature so often that people think that nature does a good job of exploiting the laws of physics to produce some amazing things.

But, I think stealth is an example of an area where nature has fallen down on the job. I can't think of any animals, insects, etc that use the sort of signal deflection and absorption that are used in stealth aircraft. You'd kind of expect those insects which are hunted by bats to have evolved such things, since it seems like it would give them a big advantage.

Then again, I can think of a couple of reasons why it wouldn't have evolved. Stealth is usually useful from only one direction--maybe since bats tend to come from multiple directions its impossible to minimize one's cross-section from all angles without just plain being smaller. Also, I imagine its really tough for nature to produce the sort of flat surfaces that stealth seems to require, although this is less compelling when one considers that the B-2 bomber seems to be mostly curves. One of the biggest reasons, I imagine, are the low thresholds for abnomaities; one hears stories about how just three rivets 1/8th of an inch too high are enough to destroy a F-117's stealth ability. Maybe insects just can't meet those exacting standards consistently across generations.

Even so, though, it seems like some sort of evolutionary motion should have been made in that direction by insect hunted by bats in the last few million years.

Cute

Saw this on a forum.