Tuesday, July 27, 2010

Sand (fleas) in your eyes! A living satire of intelligent design

After participating in the European EvoDevo meeting in Paris this month, we took some vacation days and toured some of northern France, including the Normandy coast. Part of that included the invasion beaches and some of the military cemeteries that scatter the countryside to preserve the memory of those who perished in WWI and WWII.

One day, we strolled along a beach just south of Lessay, at the water's edge just as high tide was receding. Our eye was caught by the visual buzz of countless light-tan almost transparent objects, that were clearly alive but were being blown about like grain chaff in the coastal wind -- the photo is not ours (we found it here), but it's much as we remember these animals. What were they?

They were rather elusive, as they would land (or, rather tumble apparently uncontrollably) maybe a foot or more from where they'd taken off. They did scurry about on land, but only briefly before jumping up and again being tossed chaotically by the wind.

When we could look closely at these 'bugs', they had two long protuberant antennae -- or what looked like antennae at their front end, but their oblong bodies seemed weirdly shaped: a long torso, with maybe 6 insect legs only at the rear (though later research made it seem we were wrong about the number), like a huge oil tanker with its abaft engine. How could such a thing walk, much less fly? (so camouflaged was their color, and so rapid and zigzaggy their aerial movement, that we could not see if they had wings or if they did what kind of wings -- on the ground, they looked naked of wings).

After we returned to a WiFi site in our hotel (modern research!), we tried our best to Google these creatures to find out what they were. We're not certain but we think, at least, that they are what are called sand fleas. These tumbling tumblefleas seem to populate beaches around the world. But curiously, they are classed as crustaceans rather than insects (despite what looked to us like only 6 legs).

They seemed nearly transparent, camouflaged, and apparently they act like fleas: they jump and this leaves their fate to the wind, so that they don't, and can't, control where they go or whither they land. If it's true that they burrow when the tide comes in, then perhaps they can do such business as mating then. But they can't have a permanent home location or anything like that. There's no obvious way their antennae could pick up mating pheromones in the windy chaotic beach as when we were there.  From our brief observation it seems an interesting, but bizarre lifestyle.

These creatures are apparently globally distributed, so their 'design' obviously works. But if this is a design of intelligence, the designer must have had a few too many that day. Clearly their evolutionary 'strategy' works, but just as clearly how they got this way is not clear at all.

They are not optimally 'designed' for anything other than surviving, however it is they manage it.


Jennifer said...

I heard a similar story on NPR the other day. An entomologist talked about how many millions of insects are in the air, using the winds to disperse and travel. He mentioned a tiny spider who landed on him from such a breeze, climbed to it's highest point (his finger), lifted its rear end as high as it could and caught the next breeze. It made me think of millions of Mary Poppins!
Cool! I found it! http://www.npr.org/templates/story/story.php?storyId=128389587

Anne Buchanan said...

Thanks, Jennifer. This seeming randomness is an interesting strategy for insects that live in very specific environments, such as the edge of the water, like the sand fleas we're describing. I guess it works because these tiny guys can't actually be blown very far from home.