Ants built toilets in their nests and use the lavatories instead of randomly dropping waste, new research has discovered. The insects may also utilize their manure as a type of fertilizer, as well as building material.

Black garden ants were provided with a sugary food containing a dye, which allowed researchers to track deposits of feces within nests. They found the insects kept certain areas of their nests set aside for use as lavatories. Within two months of the start of the experiment, distinct colored marks were seen in corners of the artificial nests created by researchers.

Food waste and corpses are removed from the nests by black ants on a regular basis. However, feces is left behind, which suggests to researchers that the material could be used for useful purposes, perhaps to assist the tiny animals in growing their own food. This behavior would also seem to suggest that the ants are not endangered by the presence of pathogens in the droppings. Protein jelly, which is toxic to worker ants, was also provided to the community, but was brought outside the nests, along with dead insects and food waste.

Unlike human beings, it is unlikely that ants have a sense of disgust at walking through feces, which would suggest that confining droppings to one or two locations in the nest serves some beneficial purpose.

Social insects are known to utilize their scat for specific purposes. Leaf cutter ants use the material to help grow fungus, which they then consume for food, and termites use the substance for building their nests. Some termite droppings even possess antimicrobial properties, which could help maintain the health of the community. Unlike those insects, honeybees go for flights to release their manure outside their hives, and spider mites also drop their waste far from their home.

No fungus was observed growing on regions marked by ant droppings while the insects were in the nest, but it did grow when the tiny creatures were removed from the complex. The tiny insects were also observed as they avoided walking through areas covered in droppings.

"The growth of micro-organisms on the toilets may be actively inhibited by the ants, perhaps by the application of formic acid or antibiotic secretions. Alternatively, the ants may be using the toilets as a garden, and eating the resulting fruiting bodies, as a way of accessing otherwise inaccessible nutrients from their waste," Tomer Czackzkes, a biologist from the University of Regensburg in Germany, said.

Examination of behavior of black ants and their feces was published in the journal Plos One.