More gliding ants

Dear Antboy,

I tried to make a gliding ant out of paper like you said. I think I got the face more or less right, but I’m not so sure about the rest of it. His name is Gerald, but he doesn’t glide very well. Could you please give me some pointers on how to make him better? Here’s a picture so you can see what he looks like now:

Thanks!
Jose Jones

Dear Jose –

That’s a great looking start you’ve got there, and I agree, the face is looking pretty tops. I think I’ve got a few suggestions that might help out with Gerald’s aerodynamics, but there’s a change Gerald is going to have to go through before we work on any structural issues. You may wish to ask Gerald how he feels about the name Geraldine, as he’s going to have to become a she.

You see, all gliding Cephalotes worker ants are girls. And if you’re wondering how one tells a boy ant from a girl ant, it’s actually pretty easy in practice – generally, if you’re holding it, it’s a girl. For most of the lifetime of an ant colony, there are no male ants around. There is (usually) a single queen ant whose job it is to lay all the eggs that become workers, and then there are lots of worker ants who are all female and usually sterile. Then, at certain times during the life cycle of the colony, the colony of ants goes into a reproductive phase and some of the eggs laid by the queen become reproductive males and others become reproductive females. The males are not particularly helpful members of the colony, and exist only to engage in large mating swarms with the reproductive females. Once they’ve mated, they die soon after.

Yes, yes, now would be an excellent time to collect all of those awesome joke ideas you just thought of and write them all down. It’s okay, I’ll still be here when you get back. For the rest of you, here’s your basic worker ant, that does all the hard work around the colony:

IMG_7255

This is a pretty common species of ant here in the tropics, named Ectatomma tuberculatum.

Now, you may be wondering what these useless males look like, and the short answer is: weird. Colloquially referred to as ‘flying sperm missiles’, male ants tend to have pretty minimal equipment besides gonads and a set of wings. Here’s a male Ectatomma tuberculatum for comparison to the worker above:

Ectatomma tuberculatum male

And here’s a shot from the side:

Ectatomma tuberculatum male

Few things to notice here:
1) Wings. If you weren’t previously aware that male ants had wings, don’t worry, you’re not alone.
2) Big old abdomen (or ‘gaster’, to use the correct term that no-one who doesn’t study Hymenoptera knows).
3) Teeny little head with wimpy little mandibles.

So let’s start with the big one, i.e. the wings. Now, those of you who spent a few minutes earlier drawing parallels between your own life experiences and the differing roles of males and females in ant colonies might now be having a hard time with this, in that the males are not only completely useless and do no work, but also get sweet wings. But it’s okay, the reproductive female ants get wings too. Here’s a picture of a Pheidole female reproductive ant that landed on me in the dining hall the other day:

Pheidole alate

But aha, you may be saying, this ant clearly has no wings. Here’s the cool part: she did have wings at one point, and you can see where they used to be attached on her thorax there if you look closely. The reproductive alate females (alate being a fancy word for ‘with wings’) leave the colony, find a bunch of males, mate, and then try to find a nice place to start a new colony. At that point, she’ll drop her wings off and internally digest her flight muscles, using that energy to raise the first brood of workers that will help her set up her new colony. Or at least, that’s how it’s supposed to work; most of the time things don’t really work out and the young queen ant ends up getting eaten.

Anyway, so that was a long-winded digression to help explain why your ant Gerald isn’t really a boy, but we haven’t really helped out with Geraldina’s aerodynamics yet. Now, as I mentioned earlier, the facial detailing is top notch, but one of the things you’re missing at the moment is legs, which turn out to be pretty important if you’re a gliding ant. Now, recall from last time that your basic gliding ant looks a little like this:

C. atratus

Pretty, yes, but it’s not immediately obvious how something like this ends up being a glider. That is, she doesn’t have any obvious wings or wing-like things sticking out of her that look like they might be useful for gliding. So, in an effort to try and learn a little about how these ants glide, I’ve been doing experiments where I toss them into a wind tunnel and see what they do. It turns out that their standard gliding posture looks a little like this:

Gliding C. atratus

See how she’s holding her legs outstretched and above her body? What she’s doing there is basically making a little parachute out of her body, by putting the parts of herself that have little mass but lots of surface area (i.e. her legs) above her heavier parts that have more mass per unit of area (i.e. her abdomen). I’ll go into how all of this works in a future post on the aerodynamics of stability and control in human parachutists and gliding ants, but for now you should have a few more ideas on how to help Geraldine be a better glider. Try adding some legs, and bending those legs up and outward from the body. Now when you drop Geraldine, she should at least always fall right side up when she falls. To see how important leg position is, try bending her legs in the opposite direction and see what happens. Then, just for kicks, try bending them up on one side and down on the other. It’s fun, trust me.

Also, for those still having fun with the whole bugs vs insects thing, here’s a couple cool bugs I found running around. This guy here my friend Steve found for me up in the canopy – he’s actually a gliding wingless bug, and hopefully I’ll get some time to throw him in the wind tunnel:

Bug

And then here’s another Reduviid bug (that is, one that preys on other insects), this one being a thread-legged bug. When I found this guy, I thought it was a mantis due to the way it was holding its forelegs, but under the macro lens it revealed itself to be a bug. Any ideas on how you can tell this guy’s not a mantis?

Thread-legged Bug

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