"Tags: creepy raft made of bugs, nature, ants"

April 29, 2011 9:01 AM

"You've seen ants. Thousands of them. And most of the time, you've seen them in colonies, living as a group. But have you seen them float as a group? Apparently a single fire ant will struggle in water, but a cluster of them can bob happily for months. A new study has used time lapse photography to figure out why — and how — that is."
posted by ocherdraco (40 comments total)

And now let's go to the shuttle's live video feed, where– GAHH!
posted by AugieAugustus at 9:05 AM on April 29, 2011 [4 favorites]

How do you tell if they're happy?
posted by ODiV at 9:08 AM on April 29, 2011

"These findings may contribute to future technologies for floating devices and waterproof materials."

I love that; every human construction is but an inefficient facsimile of the natural world.
posted by Turkey Glue at 9:14 AM on April 29, 2011 [5 favorites]

Well, there goes ever sleeping again.
posted by Kitteh at 9:14 AM on April 29, 2011 [2 favorites]

I for one welcome ... ah, fuck it. This is cool.
posted by bayani at 9:15 AM on April 29, 2011 [1 favorite]

This is nothing short of amazing. How long until they are able to build themselves into ant-machines of mass destruction?
posted by owtytrof at 9:16 AM on April 29, 2011

How do you tell if they're happy?

Are they all together? Do they look like they want to eat you? If so, they're happy.
posted by quin at 9:18 AM on April 29, 2011 [1 favorite]

I know I'm supposed to find this fascinating, and I do. But also, I'm creeped out. I don't want the ants to be that smart and cooperative. Next thing you know, they're going to be driving my car around town in the middle of the night.
posted by fyrebelley at 9:18 AM on April 29, 2011 [3 favorites]

fyrebelley: "I know I'm supposed to find this fascinating, and I do. But also, I'm creeped out. I don't want the ants to be that smart and cooperative. Next thing you know, they're going to be driving my car around town in the middle of the night."

*cough* How often do you check your odometer?
posted by workerant at 9:20 AM on April 29, 2011 [8 favorites]

Next thing you know, they're going to be driving my car around town in the middle of the night.

Nah, there's no style in that. Instead, they'd take a look at your car, and make a better version of it, out of themselves, to drive around town.
posted by quin at 9:21 AM on April 29, 2011 [17 favorites]

The first photo in the story has the correct solution. Poke them with a stick and push them underwater. Fire ants are evil, and need to die.
posted by Lokheed at 9:23 AM on April 29, 2011 [3 favorites]

For anyone who read and re-read Godel, Escher, Back in his misspent youth, the emergent intelligence of this is awesome.
posted by shothotbot at 9:24 AM on April 29, 2011 [1 favorite]

FTFA: In short: by joining this way the ants are able to decrease their mean density as a whole and become a buoyant raft; if left alone they would sink.

Bullshit. The video clearly shows single ants walking around the raft. Many of us have seen the same on our own: ants are too light to break water's surface tension.

It's not even a density issue; it's a weight/area issue. Highly dense, but widely spread, material will float (think paper, which is clearly dense enough to sink: drop a ream of it sometime in a bath tub).
posted by IAmBroom at 9:30 AM on April 29, 2011 [2 favorites]

I think the ants just stole IAmBroom's car and dropped it into a bathtub.
posted by fyrebelley at 9:39 AM on April 29, 2011 [1 favorite]

BBC video in the wild (including hungry fish!); similar videos from Georgia Tech: floating fire-ant-raft, and a fire ant ball is pushed underwater; their capturing air is similarly fascinating.
posted by progosk at 9:41 AM on April 29, 2011 [1 favorite]

Oh man, where's my railgun?
posted by reverend cuttle at 9:43 AM on April 29, 2011

also, as already noted by IAmBroom, the science - it is faint: "The above fire ants, or Solenopsis invicta, have evolved so remarkably, that they can self-assemble into structural tools" - IANYEB, but surely evolution is hardly the issue here.
posted by progosk at 9:49 AM on April 29, 2011

I don't want the ants to be that smart and cooperative.

If it helps, ants have been shown in experimentation to have zero problem-solving skills. I forget the exact circumstances of the study but it was something like a species of ants that has been observed to build huge mounds of dirt at the entrance to their colonies, and then a bunch of ants were put in an environment with food elevated just out of their reach, and with plenty of dirt to build a mound to use for reaching the food. The ants could clearly smell the stuff and knew it was there but just milled around, unhappy that they had no means to get to it.
posted by shakespeherian at 9:54 AM on April 29, 2011 [2 favorites]

think paper, which is clearly dense enough to sink: drop a ream of it sometime in a bath tub

Have you tried this before? I'm not sure you're correct. I have an unopened ream of 20 lb paper right here. It's 8.5"x11"x1 15/16" and weighs five pounds, which is 0.028 pounds per cubic inch. Water at room temperature is 0.036 pounds per cubic inch. I think your ream of paper will float (until it gets waterlogged).

(And, by the way, density in Imperial units is measured in slugs/cubic foot. Pounds per volume is specific weight.)
posted by backseatpilot at 9:57 AM on April 29, 2011 [1 favorite]

Go, you unstoppable little fuckers, go! I admire you bitey tenacity and refusal to die!
posted by troublewithwolves at 10:07 AM on April 29, 2011

If it helps, ants have been shown in experimentation to have zero problem-solving skills

Until you put them into Hex.

There's a reason the sticker says "Anthill Inside".
posted by quin at 10:11 AM on April 29, 2011 [1 favorite]

Now I wanna watch Enthiran again except with a giant snake made out of ROBOANTS. (Also it would be rad if Aishwarya Rai did a dance number with a guy in an ant suit, but it is not vital to my enjoyment of the proposed film.)
posted by elizardbits at 10:45 AM on April 29, 2011

Have you tried this before? I'm not sure you're correct. I have an unopened ream of 20 lb paper right here. It's 8.5"x11"x1 15/16" and weighs five pounds, which is 0.028 pounds per cubic inch. Water at room temperature is 0.036 pounds per cubic inch. I think your ream of paper will float (until it gets waterlogged).

backseatpilot: You forgot a factor of 2 somewhere:

5 lb / 8.5"x11"x1 15/16" = 0.057 pounds per cubic inch
>
water density = 0.036 pounds per cubic inch

(But the rest of my criticisms still stand, regardless.)
posted by IAmBroom at 10:57 AM on April 29, 2011

Previously
posted by Brodiggitty at 11:10 AM on April 29, 2011

5 lb / 8.5"x11"x1 15/16" = 0.057 pounds per cubic inch

I double checked it, and I still think i'm right. 8.5*11*2 = 187 cubic inches, 5/187 = .027 pounds/cubic inch.

Funny enough, I looked at the abstract mentioned in the NPR piece and nowhere does it mention density. It just looks at "water repellency".
posted by backseatpilot at 11:51 AM on April 29, 2011

WILL SOMEONE PLEASE JUST DROP A REAM OF PAPER IN A TUB ALREADY
posted by brain_drain at 12:13 PM on April 29, 2011 [6 favorites]

Thank you, MetafilterScience!. Between this and the stinkbug post, I won't be sleeping well any time soon.
posted by Sweetdefenestration at 12:15 PM on April 29, 2011

These findings may contribute to future technologies for floating devices and waterproof materials.

Flight Attendant: In the event of a water landing, millions of fire ants will drop from the overhead compartment...
posted by Splunge at 12:16 PM on April 29, 2011 [13 favorites]

Splunge wins.
posted by shakespeherian at 12:23 PM on April 29, 2011

This was my greatest fear in pre-Katrina New Orelans -- that if the bowl ever flooded, we'd be beset by floating balls of fire ants. Now my greatest fear is that another Bush might become president.
posted by Astro Zombie at 1:22 PM on April 29, 2011

Ok, from the abstract:

We find that ants can considerably enhance their water repellency by linking their bodies together, a process analogous to the weaving of a waterproof fabric (emphasis added)

Glancing at the article, they measure the density of the ant rafts at 0.2 (density water = 1.0; single ant = 1.1), and give this edification about the water repellency and buoyancy of the ant rafts:

An advantage of being hydrophobic is the ability of ants and semiaquatic insects to trap a plastron layer of air around their bodies, without which they would sink. We verified the necessity of the plastron by measuring the volume displacement of ant rafts. We find that clean water permits plastron retention, whereas soapy water prevents it. [ . . . ] The presence of the plastron also explains why ants in rafts rarely drown: Their plastron enables them to breathe even when they are at the bottom of the raft.

An ant raft has a surface tension 10x that of water, although that's mentioned in the context of modeling ant rafts as fluids, rather than water repellency:

Given that ants are significantly more viscous than water, the physical picture of an ant raft is that of a viscous lens (a large pancake-shaped drop) floating on an immiscible nonviscous liquid.

Other stuff: They worked with raft populations of 1,000-7,000 ants, but speculate that a raft could have a population of millions. Oh, and yeah, these are the invasive fire ants first discovered by E.O. Wilson in Mobile, AL, and now infesting most of the southeast US (and Australia, the Philippians , China and Taiwan). Evidently, even noxious pests can be interesting.
posted by Tuesday After Lunch at 1:34 PM on April 29, 2011 [1 favorite]

WILL SOMEONE PLEASE JUST DROP A REAM OF PAPER IN A TUB ALREADY

Why bother? We already know the answer!

(Theoretical) Science!
posted by backseatpilot at 2:45 PM on April 29, 2011

But what happens if the tub of water is on a conveyor belt?
posted by shakespeherian at 2:48 PM on April 29, 2011 [1 favorite]

You don't fool me. It's ants all the way down.
posted by Splunge at 3:28 PM on April 29, 2011

5 lb / 8.5"x11"x1 15/16" = 0.057 pounds per cubic inch
I double checked it, and I still think i'm right.

Missed the 1 in "1-15/16", backseatpilot.

Your math is correct. My other points stand.
posted by IAmBroom at 3:41 PM on April 29, 2011

DAMN YOU BACKSEATPILOT!

now who's gonna get me a grant to buy dry paper? braindrain? anyone?
posted by IAmBroom at 4:33 PM on April 29, 2011 [3 favorites]

So what happens when you add a single drop of dish soap? Do they just sink? Where's the video of this?
posted by cman at 5:10 PM on April 29, 2011 [1 favorite]

If it wasn't for those damn kids and their bottle of Fairy Liquid, I'd have gotten away with it too.
posted by arcticseal at 5:52 PM on April 29, 2011

cman : So what happens when you add a single drop of dish soap? Do they just sink? Where's the video of this?

For anyone curious, this has a truly awesome (in the literal sense) effect for quite a good distance downstream.

And after you all run out and try it, mourn for the billions of poor critters you just killed as the physics of their world suddenly and inexplicably (to them) fail. Imagine if suddenly the ground appeared to liquify beneath you, swallowing you whole and depriving you of access to air.
posted by pla at 8:13 PM on April 29, 2011 [2 favorites]

I hate to make such a dry followup to pla's awesome description, but there's a pubicly available Supporting Information link which has a pdf and 5 mov files. From the pdf:

Experiments of Ant Rafts in Soap Solutions. We find that even trace amounts will cause the ants to radically change their behavior, as shown in the images of a raft on water with traces of soap (Fig. S1). As soon as ants become even slightly soapy, they immediately release their grip with each other, which is shown by the disintegration of the raft and its submergence underwater. This is in contrast to the closely packed ants in the buoyant raft, as shown in Figs. 1 and 2 in the main text.

None of the movies show the effect of surfactants, but there's a set of 4 pictures (figure S1, on page 2of4).
posted by Tuesday After Lunch at 8:34 PM on April 29, 2011