The Other Wasmannia

The cerrado site at Carrancas, Minas Gerais, where we encountered Wasmannia sulcaticeps. (Photographic aside: the deep blue sky results from using a polarizing filter on the lens. If you want to get into landscape photography, you'll definitely need one of these!)

Over the weekend I blogged about a store in the business of selling Wasmannia auropunctata, one of the world’s most damaging pest ants. Much has been written about this species and its trail of ecological destruction. Google scholar, to illustrate my point, returns over 1500 papers mentioning this ant.

Wasmannia holds several other species, however. The graph above mentions a few of the better-studied congeners, and as you can see, most receive a pale shadow of the scientific attention accorded their cosmopolitan cousin.

I had the pleasure of meeting one of the relative unknowns, W. sulcaticeps, in a small cerrado fragment in Minas Gerais. They were tiny, only a couple millimeters long, and painfully shy. This ant, unlike W. auropunctata, did not leave an impression of impending pestilence.

Wasmannia sulcaticeps workers in the nest.

The nest was small. It contained, under a rock, a few dozen workers and pupae. I don’t know whether the depauperate nature of the discovery was due to our locating just a fragment of the full colony, or whether these ants naturally live in small groups.

A worker carries a pupa to safety.

Why has Wasmannia auropunctata transformed into a global pest while the outwardly similar W. sulcaticeps remains a quaint and unobtrusive element of native South American habitats? Until someone takes the time to really study the behavior and biology of the non-famous species, we can only speculate.

(note: thanks to Bob Solar & Julio Chaul for assistance in the field, and to Jack Longino for taxonomic support.)

4 thoughts on “The Other Wasmannia”

  1. This paper “Clonal reproduction by males and females in the little fire ant” by Fournier et al. (2005) could mean a small propagule can become invasive because there is no inbreeding and sisters could mate with brothers. No clue if other Wasmannia sp can do this. Thoughts?

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