The Little Architect with Its Marvellous Creation: A Study on the Nest Architecture of Tropical Hornet, Vespa affinis 

Abstract

Knowingly or unknowingly, we are surrounded by many creatures that are specialized in building amazing structures with great finesse. It is really wonderful to see how such tiny brains coordinate with each other to create perfect structures, which is perhaps impossible for humans. On similar lines, the present study describes the nest architecture of tropical hornet, Vespa affinis, built across several locations in Jalpaiguri district of West Bengal, India. Mature nests are roughly pear shaped, broadening from the top to the truncate base. The architecture of the nest is in the pattern of a spiral staircase with a central and several auxiliary petioles supporting each of the comb layers. Two large usually round entrance holes along with 6-7 small holes were also seen on the walls of the nest. Strikingly, the hypertrophy of the nest envelope above the combs into a prominent roof cone with cellular structure is observed. The hardening of the nest texture and the extensive papering over of the cells in the initial comb layers, thereby reducing their reutilization, form an essential feature of the nest. Several morpho-metric measurements of a typical nest (with seven comb layers) from the study site was conducted. Each comb layer of the nests showed a rough bimodality of cell diameter, with peaks at about 0.85 and 1.0 mm. The maximum number of occupied cells in the centremost stages of the nest (i.e., comb layer 3) probably support the maximum number of brood members. The highest number of auxiliary petioles along with the tree branch provide the greatest protection to the brood in this layer. Besides the highest number of petioles, the maximum number of unoccupied cells in comb layers 2 and 4 also provide extra protection to the developing brood in the comb layer 3. A decrease in the rate of nest building in the final stages (i.e., comb layers 6 and 7) is evident by the decrease in the number of cells in these layers.