Ants turn carbon dioxide into 'armor'

Ants often surprise us, but this news is about chemistry rather than behavior. Sericomyrmex amabilis, a relative of leaf-cutter ants from Central and South America, releases part of its carbon dioxide from the nest through its ventilation and turns another part into a mineral layer on its exoskeleton.

Something similar has been seen before. In 2020, Cameron Currie of the University of Wisconsin-Madison and colleagues described a biomineral armor in Acromyrmex echinatior and linked it to bacteria of the genus Pseudonocardia. This new work reports that no symbiotic bacteria have yet been found in Sericomyrmex amabilis. If that is confirmed, the species would be the first known animal to turn gas into mineral without the help of bacteria.

The researchers used carbon stable isotope tracing, nanoscale secondary ion mass spectrometry and carbon-13 solid-state NMR. They found that the layer contains dolomite, a mineral that is hard to produce in the laboratory. To synthesize well-ordered dolomite usually requires pressures and temperatures in the range of hundreds of degrees, and in nature it forms over thousands to millions of years.

The ants, by contrast, create partially ordered dolomite quickly and at low temperatures. The mechanism is still unknown. This biomineralization solves two problems at once: it strengthens the armor and removes excess CO₂ from the nest.

An important caveat: the work has been posted on the bioRxiv preprint server and has not yet undergone peer review, so the results are preliminary. That makes it all the more interesting to follow what comes next.

Source: Naked Science