An ant with a segment identity crisis

Australian ecologist James Schlunke sends in a photo of an Epopostruma trap-jaw ant with a developmental anomaly:

If you’re wondering what’s wrong with this insect, here’s a photo of a “normal” worker:

Epopostruma natalae, courtesy of

The slender, two-segmented waist has been subsumed into the mesosoma as if the cells in those segments had trouble figuring out what they were supposed to do, and the tissues defaulted to a more anterior program.

While it’s tempting to think of these sorts of oddities as genetic mutants, it’s more likely that this ant is genetically normal. Instead, it may have been damaged or parasitized as a larva, disrupting the developmental signals. Most such larvae are terminated before maturing, so the real wonder is how this individual survived to adulthood and how it functions in an ant colony with a rigid, inflexible gaster.

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