Why do fire ants stings occur in pairs?

Answer:  I don't know.  I can't find an answer on the internet.

A pretty pair (not) which closely resembles my foot right now, as I just received my first fire ant sting pair of the season:  Many of the single-ant sting photos on the internet do indeed show two closely-spaced wounds like this, but there is no suggestion as to why there are two rather than, say, one or three in close proximity.

Screengrabbed from this Mississippi State University site. 

Given that the characteristic two wounds are separated by a distance roughly equal to the length of the ant's body, I used to assume that one was the bite from the front end of the ant and one was the sting from the back end of the ant.  But apparently the bite is of no medical consequence and is only used to anchor the ant in place so that it can leverage a more effective sting (according to this site, anyway).  So that's not the explanation.

I guess I'll have to do my usual thing and use this as a place-holder post in case the answer becomes apparent later or someone emails me with it.

Meanwhile, I'll leave you with an example of the extraordinary work of Anthill Art, which makes art pieces by using molten aluminum to cast fire ant mounds.

THIS is the way I'd really like to see all red imported fire ant colonies end up.  Especially a certain mound in my own back yard.  

Image courtesy of Anthill Art.  

That's a piece I could display in my home with an abundance of pride.  But as you can imagine, this artist is overrun with business such that he/she/they currently have nothing available for sale.

If you've got two minutes to spare, check out this new video below.  Other entities, including Texas A&M Agrilife, have published illustrations on how to make a fire ant mound cast, but I haven't seen anyone else accomplish it with this kind of skill.

URL:  https://www.youtube.com/watch?v=gmIb2zkMtjQ

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