As I am developing the new update to my Lucid key to invasive ants, I realized it might be a good idea to post some of the illustrations I’m working on as little vignettes of the larger project. When I’m not quite sure about an ant ID, I find myself using the ‘comparison chart’ tab on PIAkey more often than the actual Lucid key. It’s like a quick-access cheat sheet for when you already know the genus and just need a little refresher for distinguishing among a few species.
This chart shows how to tell the very commonly encountered Argentine ant (Linepithema humile) from its less well known, but occasionally intercepted congener L. iniquum. The characters are adapted from Alex Wild’s treatise of the genus (Wild, 2007).
| L. humile | L. iniquum | |
|---|---|---|
| Profile |  |  |
| Erect hairs on cephalic dorsum (above eye level) + gastral tergites 1 & 2 |  No |  Yes |
| Dense pubescence covering mesopleura |  Yes |  No |
| number of convexities on profile of mesosomal dorsum |  Two |  Yes |
| propodeal shape |  Angular |  Globular |
| propodeal spiracle bordering posterior margin of propodeal profile |  Yes |  No |
