Colony Reproduction and Arboreal Life in the Ponerine Ant Gnamptogenys Menadensis (Hymenoptera: Formicidae)

Gnamptogenys menadensis is an Indonesian ponerine ant that is exclusively arboreal. Foragers hunt for prey and sweet secretions on the branches and leaves of shrubs and trees, but never walk on the ground. It nests in pre-existing tree cavities which are sealed with a lining of organic material. Several factors facilitate colony reproduction by fragmentation: available nest sites are plentiful, nest structure represents only a minor investment of labour, and nests cannot be enlarged, inducing nest emigration or polydomy as colonies grow in size. A mechanism of colony fragmentation is one of the preadaptations to enable the replacement of queens by worker reproductives. We found that the majority of colonies (95%) in the studied population (Sulawesi) are queenless, and reproduce through gamergates (mated workers laying reproductive eggs). Nevertheless, queens can occasionally be produced, and 5% of nests contained a single reproductive queen. Due to obligate arboreal life, alate queen production seems to remain an infrequent strategy in addition to budding, since only independent founding queens can colonise new patches of vegetation.