Diversity and Foraging Behaviour of Different Insect Pollinators on Sunflower, Helianthus annuus Lin

Present investigation was carried out to assess diversity and foraging behaviour of different insect pollinators visiting on sunflower, Helianthus annuus Lin. Fourteen insect species belonging to five families and two orders Hymenoptera and Diptera were observed visiting the blossom of sunflower. The activity of flower visiting insects was recorded o highest (3.80 foragers/head/5min) at 1200 h when average temperature and relative humidity were 39.2 °C and 40.1 per cent respectively. Among the insect visitors, average relative abundance was observed highest with Apis mellifera (4.50 foragers/head/5min; 28.57% of total pollinators). The overall mean of foraging rate and mean foraging speed of pollinators was observed highest (10.13 flower head/foragers/min and 6.43 sec/flower, respectively) at 1000 h when o average temperature and relative humidity were 36.9°C and 49.6 per cent. Amongst the foragers, foraging rate was highest of Apis mellifera (10.83 flowers head/foragers/min); constituting 25.63 per cent of the total pollinators observed and the average time spent by single forager per flower was maximum with Apis mellifera 6.90 sec/flower.