Miniature Trap-jaw Ants

Strumigenys louisianae stalking a springtail
Tucson, Arizona

Non-native species should make a naturalist’s skin crawl, but these ornate little trap-jaw ants are a guilty pleasure. Strumigenys louisianae is among the most widespread of the miniature trap-jaw ants, occurring naturally from the southeastern U.S. to northern Argentina. The desert climate in Tucson is too dry for Strumigenys, but they persist in lawns, gardens, and other places in town where irrigation raises the moisture levels. No one knows when or how they arrived, but it is likely the founding colonies stowed away in someone’s potted plants.

The affinity these tiny insects have for humidity provides a handy trick for photography. As anyone who has photographed ants knows, these frantic little insects just don’t sit still, especially when there’s a lens pointed at them.  I spent twenty minutes chasing them about before finding a solution: give them a comfort zone.

A droplet of water soaked into an otherwise dry rock created a small humid refuge.  Once they settled down over the wet spot, I could shoot leisurely. They were happy, I was happy, and we got some nice pictures.


photo details: Canon MP-E 65mm 1-5x macro lens on a Canon 20D
f/13, 1/250 sec, ISO 100
illuminated with MT-24-EX twin flash diffused through tracing paper


2 thoughts on “Miniature Trap-jaw Ants”

  1. What a beautym and a very attractive carrot coloring. Looks like there are even hairs on the mandibles. Can you tell us what size these are? Great shots, good use of tracing paper.

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