Unusual nests of red wood ants (Formica, Hymenoptera, Formicidae)

摘要

Some unusual nests of red wood ants are described, and their formation and development are characterized using long-term observation data. One of key factors responsible for the shape and size of a nest is subsidence under its own weight, related tothe mechanical strength of the construction. In large nests, this factor is more significant than the need for microclimatic regulation. In some cases, nest subsidence becomes irreversible and leads to colony fragmentation. For nests with several domes,the critical factor is heat loss, which increases as nest deviates from rounded shape. The structural characteristics of a nest affect such aspects of the colony life as the size limit and fragmentation.