In a study on sanitary behaviour in ants, a new study in the journal PLOS ONE has shown that ants appear to designate the corners of their nests as ‘toilets’. The study comes from Tomer Czaczkes and colleagues from University of Regensburg, Germany.



Research on sanitary behaviour in social living, for example in social insects, is not extensive. Studies that do exist on other social insects have shown different mechanisms for dealing with potentially dangerous faecal waste. For example, even very young honeybees that would not otherwise leave the nest go on ‘defecation flights’ to avoid such matter in their hives. Other social animals appear to use their faeces for particular purposes, suggesting that it is not always a dangerous source of pathogens. For example, termites construct their nests using faecal material and leaf cutter ants fertilise their fungal food source gardens with faeces.

The current study concerned colonies of Lasius niger ants kept in plaster nests in a foraging box. The ants were provided with sucrose dyed one colour and protein jelly dyed a different colour. Pictures were taken of the nests and foraging boxes weekly over a two month period. At this point the ants were removed and an observer blinded to the experimental conditions observed the locations of coloured patches in the nests.



The results indicated that between 1-4 patches of the same colour as the sucrose solution were found in all the 21 nests. No trace of the protein colour was found in these patches; protein is barely required by worker ants and can be harmful to them. The coloured patches were almost always located in the corners of the nests. They did not contain other potentially hazardous waste such as dead ants, nest debris or fragments of the protein food source; this type of material was dumped outside the nest.



The research team termed the patches in the corners of the nest ‘toilets’. The reasons why the ants created these toilets are not yet entirely clear. It appears they do not regard the faecal matter as hazardous as they did not appear to avoid the toilet area, nor did they use unoccupied chambers in the nest when they were available to locate their toilets. Thus, as with some other social insects, it appears the faecal matter may have an as yet unknown use for these ants. Dr. Czaczkes concluded: “Some insects use faeces for defence, as building materials, as manure for their crops, and as markings. Perhaps these toilets are also gardens for crops, or even stores for valuable nutrients.”