Nest architecture of stingless bee, Tetragonula gressitti Sakagami from Nagaland, India

Abstract

Tetragonula gressitti Sakagami is the new species of stingless bee discovered in Nagaland (2020). It was earlier found in Arunachal Pradesh (2013), South West China (2019) and Vietnam in 1978. The nest architecture of this particular species was never studied although there had been regular reports of its presence in forest areas by the local populace and all earlier reports were simply documented on the basis of collected samples from forests. This is the first detailed report on nesting characteristics of the stingless bee, T. gressitti, which were found located in the forest and village areas of Phek district in Nagaland during the early winters of 2019. The natural nests were found in tropical to sub-tropical evergreen forests on tree cavities, commonly at a height of 2.91 m ± 0.21 with a single entrance for each colony. The colonies were naturally active as seen and recorded from the activity of bees at their entrance gates during day time. The nests were extracted carefully with appropriate tools and transported to the experimental site. A total of seven natural nests were located for the study. Out of them, three nests were opened to observe the internal nest structure while the remaining nests were kept intact for further development and pollination studies. The observations revealed that the nest entrance on the external region was free from any wax or cerumen funnel/ tube and was meticulously kept clean by the bees. The nest entrances of all the colonies varied in size and shape. Internally, the entrance was connected to the brood through a waxy passage of 11.42 cm ± 0.73 length till it reached the involucrum. The brood was covered in a partial involucrum of 2.15 cm ± 0.23 thickness. The honey pots and pollen pots were found separated from the brood area and were connected through numerous small openings in the involucrum. The adult bees were observed to be deep black in colour. The required data on size of different cells and castes were also recorded accordingly.