Is the mound ofFormica polyctena foerst. in orgin a simulation of a rock

The red wood antFormica polyctena builds a mound of dead vegetable material which is accumulated into a sort of loose thatch. Some taxonomic relatives ofFormica nest beneath rocks and the two nest types are closely related in a physical sense. Possibly this similarity is more than just coincidental. The hypothesis is suggested that the mound ofFormica polyctena has evolved as a simulation of a rock.