Impact of soil contamination on the growth and shape of ant nests.

As entomopathogens are detrimental to the development or even survival of insect societies, ant colonies should avoid digging into a substrate that is contaminated by fungal spores. Here, we test the hypotheses that ant workers (i) detect and avoid fungus-infected substrates and (ii) excavate nest patterns that minimize their exposure to entomopathogenic spores. Small groups of workers were allowed to dig their nest in a two-dimensional sand plate of which one half of the substrate contained fungal spores of , while the other half was spore-free.