The Bug Geek

Insects. Doing Science. Other awesome, geeky stuff.

Tag Archives: Heteroptera

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.

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Nosy

Check out the schnozz on this guy:

Euschistus sp.

Ok, ok, it’s not a nose proper; it’s a “beak” or, more accurately, a rostrum.   And it’s not for sniffing, it’s for feeding (which our friend may in fact be doing). 

Another “true bug” here…BUG BUG BU… ah, well, you get the idea.  This one is a Stink Bug (Pentatomidae); the rather unfortunate moniker is the result of the smelly defensive chemical they secrete from thoracic glands when they’re handled or disturbed.   It’s not harmful to humans, though…just smelly.   (Personally, I don’t find it all that offensive, only distinctive.)

The Stink Bug family is a mixed bag of herbivores and carnivores; some sup happily on plant juices while others prefer the innards of other insects.   Pentatomids overwinter as adults under leaf litter and other insulated nooks and emerge in the spring.  In my experience, this is a little early to find a stink bug out and about, but then, this has been an unseasonably early and warm April so far.   

On that note, may I just say that April has a crappy sense of humour?

Like, really?  Was this really necessary today?  (I’d like to state for the record that  just yesterday I was overheating in shorts and t-shirt and getting sunburned).   This is the scene after only an hour of precipitation, and it’s coming down in droves.  Ridonculous, I say.  Utterly ridonculous.

Edited to add:

Thirty minutes later, and this:

Blech.

BUG!

I’ve confessed here on this blog to my blatant disregard of proper nomenclature with respect to my overuse of the term “bug” to describe anything with six (or 8 or many) legs.   Just yesterday my wife was once again scolding me about it: “Don’t say ‘bug’ if you mean something else!”   Yeesh.  I’ve trained her too well.

Today I throw caution to the wind:  HEY, DARLING WIFE, LISTEN TO THIS:  I found a bug!  BUG BUG BUG BUG BUG BUG BUG BUG BUG!!!!!!!!  HA!

The only reason I won’t have to sleep on the couch tonight is that this IS a bug…a “true bug” of the order Hemiptera (suborder Heteroptera).  It’s a juvenile (nymph)…if you look closely at the region of the thorax you can see the little wing buds that will, after several moults, form the full-length semi-membranous wings typical of this suborder.   The needle-like, segmented beak is also visible: this is the “straw” used to slurp up food.

This particular bug belongs to the family Reduviidae, or Assassin Bugs, so named because of their nasty habit of lying quietly in wait then pouncing upon their unsuspecting prey.  The subfamily, Harpactorinae, is the largest of the assassins.  I believe this to be a nymph of the genus Zelus…possibly Z. luridus, which is the most common species in my area.

The Zelus spp. are a pretty nifty bunch – they possess a unique hunting strategy that their other Reduviid cousins lack: a so-called “sticky trap”.  The front tibiae possess unique dermal glands that produce a sticky secretion; this secretion is smeared onto setae (hairs).  The long, predatory legs thus become even more efficient at snaring prey.   Only more mature nymphs have the ability to produce the secretion; newly hatched nymphs cleverly collect the sticky coating from their own egg and use it in a similar manner until they’re able to make their own sticky trap.

 (Still love me, DW?) 😛

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Reference:

Heteropteran systematics lab at UCR

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