Trap nesting bees of genus Megachile and nesting biology of three species of subgenus Callomegachile (Hymenoptera; Megachilidae) from North India

Studies conducted on the fitness of types of trap nests for Megachile bees showed that six species, viz. Megachile (Callomegachile) cephalotes, Megachile (Callomegachile) disjuncta, Megachile (Pseudomegachile) lanata, Megachile (Callomegachile) relata, Megachile (Eutricharaea) studiosella and Megachile (Callomegachile) umbripennis nested in tunnels (5-10 mm diameter), provided in different forms (drilled tunnels in bee nesting posts and wooden logs, and hollowed tunnels in bamboo sticks and reed stems). Nesting biology studies for three callomegachid bees, M. cephalotes, M. disjuncta and M. umbripennis, revealed that they nest in tunnels of similar length (; ) and diameter (; ). The cell walls and cell partitions were significantly different among the three species. The M. cephalotes females used resin to build their brood cells leaving an empty space. Megachile disjuncta females constructed their brood cells without leaving any basal space using resin as well as other materials in different combinations. In M. umbripennis, we recognized two distinct types of nests. One, similar to those of the two other resin bees usually having cylindrical or tubiform brood cells, and a second having only oval cells scattered all over in the nesting tunnel. The structural details of their nests exhibited several common features but also showed intraspecific and interspecific variations. This study provides new information on nesting details for these bees including their nest structure, brood development and adult emergence pattern for two different generations, which would be valuable in understanding the ecology of the diverse group of Megachile bees.