The Bug Geek

Insects. Doing Science. Other awesome, geeky stuff.

Tag Archives: Formicidae

Ants do the “waggle dance” (or something!)

I was out in the yard with the dogs this afternoon, gazing at the wildflowers (weeds?  no, wildflowers) growing on the periphery of the property, along the fence line.  I spotted the white berries of a small red-twigged osier dogwood (Cornus sericea), but my eye was quickly drawn from the snowy fruit to the movement on the dark green leaves, many of which were oddly gnarled and curled.

Ants!  Lots of them!  Large black ones, but only partly black: the thorax was a deep shade of red.   The ants seemed to be moving over these deformed leaves and their accompanying stems rather randomly, and without purpose.  My first thought, given the numbers, was that they were tending aphid colonies, but no such colonies seemed to exist. 

Neither did they appear to be foraging or actively feeding; their random ramblings simply took them across a leaf, then over then under again.

Their mandibles were, for the most part, open and looking like they would be rather pinchy should they make contact with silly human fingertips (so I kept mine at a safe distance).

Then I noticed this weird (in my experience anyways) behaviour:

(Sorry about all the heavy breathing, but it’s not mine…the small mugsly one was waiting – rather impatiently I might add – for her next frisbee toss).

Anyways.  Did you see it?  Look at the ant on middle of the leaf in the centre of the shot at about 0:15 for a pretty good example…although there are at least a dozen or so examples of the behaviour in the clip.   It immediately brought to mind the “waggle dance” of their hymenopteran cousins, the bees.  I have never seen this before, and I can’t find any good information about it other than a vague reference to a chapter in a book about communication in social insects.  It seems to be a scraping-type of communication, where the tip of the abdomen is scraped on the substrate (in this case, the leaf) to create vibrations that can be picked up by other nearby ants. I have seen this in some caterpillars, but never in ants (if that’s even what it was).

Exactly WHAT these guys were trying to communicate, however, is beyond me.  I’m hoping someone who knows a little about ants and stuff (or anybody else for that matter) might be able to chime in on this one…because it was pretty wicked-cool to watch.

UPDATE: 

So I went out yesterday morning, while it was still cool, to have a closer look at the dogwood plant.  The ants were nowhere to be seen…until I started to handle the gnarled leaves.  Then they emerged from within the protective coils and folds – cold, slow and sleepy – but armed with open mandibles at at the ready.  I tapped one leaf sharply to dislodge the ants, then quickly plucked it from the stem.  There had to be something more to this story…and there was:

Hidden on the underside of the leaf were numerous teeny-tiny aphids.  Ah-ha!  So now I understand the ants’ presence as well as their roamings over the leaves.  I still am unsure how to interpret their communications, however.  A few of my ideas: a “call to arms”, summoning other ants to a protective position in response to my presence and pokings; a friendly  “hey, there’s some decent food over here”; or something being said to the aphids themselves perhaps?  Something to stimulate their feeding and subsequent secretion of delectable honeydew?  The plot thickens….

UPDATE 2:

My fave antologist, Alex Wild, has provided some excellent information on both the identity and behaviour of these ants:

I can’t say I know for sure what the ants are doing. But I can tell you who they are: Camponotus noveboracensis, a carpenter ant species found in north temperate/boreal habitats across the northern tier of our continent.

Carpenter ants can communicate through substrate vibrations. One thing they do is spread an alarm signal by drumming their heads against the ground. They also do a simple vibration-type dance to recruit nestmates to food. You could be seeing either of both of those behaviors here.

!!!Ant Update!!!

I came across another colony of my Little-Orange-Non-stingies under another rock this afternoon, and what I witnessed confirms my suspicion that these are indeed Citronella Little-Orange-Non-stingy ants of the genus Lasius (Ok, so I had nothing to do with it.  Thanks, Alex!!!).  Here’s how the scene unfolded:

An aphid...under a rock?

Yes, that’s what it looks like: a plump, pale green aphid under a rock.  There were several, actually, all supping on a slender white root.   

The aphid starts to leave...but wait! Who's this?

It finally dawns on the aphid that something is amiss…er, missing (its rock).  It starts to lumber off in search of a shadier nook.  But wait!  Someone is in hot pursuit!  Why, it’s our friend Little-Orange-Non-stingy!  What’s SHE up to?
Ups-a-daisy!

How rude!  The little aphid is hoisted in the air by careful mandibles! 

Interestingly, the aphid doesn’t seem all that concerned: it tucks in its legs and antennae, becoming a streamlined little package (well, as streamlined as an aphid can reasonably hope to become).    A few minor adjustments, and LON-s quickly squirrels its bundle down an entrance hole. 

What is our little aphid’s fate?  Will it become food these hungry ants?   Hardly! 

What we have here is a REALLY COOL example of the mutually beneficial arrangements between many species of ants and aphids.  This is just the first time I’ve seen it happen UNDERGROUND.   These ants actually farm these root aphids; in exchange for their protection from predators (and unforeseen disasters like Geeks Who Lift Rocks), they are granted delicious meals of sweet honeydew, which the aphid secretes during feeding.  Mutualism FTW!

In which I LOL at an old-school National Geographic article and talk briefly about sexism.

One of my Xmas prezzies was a digital compilation of every National Geographic issue since 1888.  Très cool.   This little gem consists of 6 disks of full-colour issues whose articles are fully searchable by topic, author, year, etc.   Although I dearly loved the sight of yellow row upon yellow row adorning my old bookshelf, I eventually donated my own hard copies to an elementary school because a) they took up too much space and b) they were simply not practical.  The searchable index of this electronic version is a godsend, not to mention user-friendly and visually appealing.

So I plug “insects”  into the search engine, and find an article from May 1959 entitled “GIANT INSECTS OF THE AMAZON” (bah-bah-baaaaaah!) by Paul A. Zahl, a NG naturalist and senior editor at the time.   Sounds like a goodie, so I click.

It is, overall, an interesting article peppered with good photographs, mainly centered on the authour’s quest to get his hands on specimens of the impressive and elusive Titan beetle, Titanus giganteus (now I know what to ask for next Christmas).  But what struck me most, almost to the point of distraction, was the archaic and overly anthropomorphic writing style.

The article begins with the authour’s harassment of giant ants, Dinoponera gigantea (and I’m not using “harass” in the sarcastic sense, he literally smashes up their colony with a pick, axe, shovel, then comments on how “sorrowful” and “frustrated” the evicted ants appeared the next day.  How nice of him to notice).  

Zalh refers to individual ants, which are almost exclusively female, as “ladies”, “huntresses”, “sisters”.  Those he collected in a jar as they returned to the colony from foraging become part of  “his harem”.     He places a large number of them in a cage with soil for observation.  Later that day he spots a number of them clustered in a circle around a newly-deposited clutch of eggs, a scene which he describes thusly:

 The sisters were gathering around to honour the event, perhaps to act as midwives, certainly to serve as nurses to this brand-new ant life.

Excuse me a moment while I BWAAAAAHAHAHAHAHAHA!!!!  *sniff*  I’m sorry, but this is some funny stuff.  I’m as guilty as the next entomophile of assigning personalities to my tiny charges, just for funsies, but this stuff is RICH.   “Huntress“?  Who says that?*  “Harem”?  “Midwives”?  OMG!!!

It’s interesting to observe how writing styles and the acceptability of certain phrases/terms change with time.  I suppose that this type of narrative would have been considered colourful and amusing, and, really, socially relevant at the time.  Considering that “sexism” was not a widely used term until a decade after Zahl’s article was published, and the use of gender-neutral language was largely scoffed at prior to, oh, the early-to-mid 90s or so, I suppose I should read the article with this in mind.   It’s very hard not to “OMG” my way through it though.  

Very rarely have I come across this kind of language as a student/researcher of the 21st century, with the notable exception of one caricature of a professor (he wore tweed, received his degrees from Haaaaaahvard and insisted on being called “Professor” So-and-so, no exceptions).  Some of the crap that spilled out his mouth was so maddening, it would throw me off my game for entire lectures.  Days later,  I would find myself staring at lecture notes I couldn’t remember taking – my hand must have been dutifully working on auto-pilot while my brain was seething over Professor So-and-so’s latest sexist brain fart.**   This exception duly noted, I must acknowledge that while my chosen field is traditionally considered “male-dominated”, I have never felt demeaned, overlooked, patronized or otherwise oppressed in any way because of my gender.   It’s encouraging to see such a stark contrast between the attitudes and beliefs that cultivated Zahl’s report of his ant “harem” and the current reality for female scientists***. 

And on that positive note, enjoy this fun clip of researchers bagging a Titanus specimen in the field, complete with happy dance.

* even my WordPress spell-checker doesn’t recognize this word!

**the most maddening one involved his description of insect exoskeletons.  Exoskeletons are in part composed of overlapping layers of chitin; these layers are oriented in different directions, like plywood; this arrangement strengthens the structure.  The plywood analogy is a good one, but  Professor So-and-so started describing it like this: “So you girls in the room will probably not get this, but you men will: exoskeletons are blah blah blah”.  WHAT???  Three giant fails here: 1. assuming women don’t know what plywood is; 2. forging ahead with the analogy anyways, despite the (however erroneous) belief that half of  the audience won’t understand the explanation, and; 3. referring to the females using a noun usually reserved for children while referring to the males using adult terminology.  AUGH!!!

***while I recognize that there will always be exceptions, as well as ignorant a-holes, I think it’s safe to say that, for the most part, the playing field has leveled

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