Buzzing for Broccoli (Brassica oleracea var. italica): Exploring Insect Pollinators, Their Behaviour, Single-Visit Efficiency and the Significance of Honey Bees in Yield Enhancement

Entomophily plays an important role in optimum seed set of self-incompatible Brassica oleracea var. italica. In the present study, a total of 27 insect species belonging to three orders Hymenoptera (64.88%), Diptera (33.15%) and Lepidoptera (1.97%) visited broccoli flowers, among which the Indian bee (Apis cerana indica) was the dominant pollinator (49.21%). The peak activity of A. c. indica and A. mellifera mellifera was recorded at 13.00 h during all the flowering stages. Pollen foragers of A. c. indica (61.14%) were more frequently observed than nectar foragers (38.86%), whereas A. m. mellifera recruited a higher number of nectar foragers (63.67%). The pollen foragers of A. m. mellifera were swift flyers visiting significantly a higher number of flowers (12.35 flowers/minute) and spending least time per flower (3.32 s/flower). The pollination efficiency of A. c. indica and A. m. mellifera was found to be 0.50 and 0.64, respectively. The foragers of A. c. indica and A. m. mellifera were estimated to pollinate 6838 and 7935 flowers a day and required 2.00 and 1.56 visits per flower for optimum seed set. Yield enhancement studies through entomophily showed that flowers receiving unrestricted visit from pollinators (open control) recorded 286.38% higher yield followed by interaction of two pollinators (A. c. indica + A. m. mellifera) 234.71%, A. m. mellifera (197.43%) and A. c. indica (178.3%) with respect to control close treatment.