Foraging activity and role of stingless bee Tetragonula iridipennis Smith (Hymenoptera: Apidae) in bitter gourd

In the bitter gourd cropping system, honey bees were the primary pollinators. In the Coimbatore district, a field study was conducted to record the foraging activity and pollination efficiency of the stingless bee Tetragonula iridipennis in bitter gourd. Bee foraging activity was recorded separately in male and female flowers, with the number of foragers/flower/min recorded. Fruit set and yield were assessed under three different conditions: pollinator exclusion, bee pollination, and open pollination. Abundance of Pollinators and foraging rate of stingless bees observed on male flower 1.71 bees/ flower/ minute and flower handling time in seconds was (37.86 sec) was higher than female flowers 1.22 bees / flower/ minute and (25.73 sec) respectively. The peak foraging activity of stingless bees was observed between 08:00-10:00 hours with 3.30 bees/ 5 mins. The pollination efficiency index of stingless bees in bitter gourd flowers was 41600. The foraging activity of bees at the hive entrance was at its peak at 08:00 to 10:00 hours. T. Iridipennis colony growth parameters show increased honey sealed area 1464.5 g and brood development. The experiment results show that yield was higher in the managed bee-pollinated condition in terms of number of fruits/plant was (18.2 fruits) and fruit yield per hectare (44.08 t/ha) than in the open pollinated condition (16.5 fruits) and (38.30 t/ha), and with pollinators excluded, no fruit set was recorded.