Stingless bee Tetragonula iridipennis Smith for pollination of greenhouse cucumber
Kishan Tej M, Srinivasan MR, Rajashree V and Thakur RK
The present studies were carried out to know the activity and effect of stingless bee Tetragonula iridipennis in pollination of cucumber cultivated greenhouses located in Orchard, Tamil Nadu Agricultural University, Coimbatore (11.01oN 76.93oE, 427m above MSL) and Srivilliputhur (9°30N 77°38, 137m above MSL) of southern India. Two stingless bee colonies with an approximate population of 2000 bees each were placed at the middle of experimental area of 500 m2 greenhouse (treatment plot). Greenhouse without stingless bee colonies served as control. A Multistar hybrid of cucumber was chosen for treatment. Foraging activity of stingless bee in the cucumber greenhouse of TNAU orchard started at 07:00 hrs and continued up to 18:00 hrs. At Srivilliputhur, foraging activity of bees started much earlier at 06.00 hrs and continued up to 18:00 hrs. Among the foragers, the floral handling time varied between the foragers which collected nectar (7.8 ± 1.6 sec in TNAU orchard and 7.4 ± 1.7 in Srivilliputhur) and pollen (3.9 ± 0.5 sec in TNAU orchard and 3.5 ± 0.3 in Srivilliputhur). A significant increase was seen in the yield attributes such as fruit length, fruit girth, fruit weight, number of fruits per plant and yield/plant among treated and control plots. Stingless bee pollinated plots in TNAU orchard had an average fruit length of 19.1 cm compared to 17.6 cm in control while the pollinated plots in Srivilliputhur had an average fruit length of 18.8 cm compared to 17.3 cm in control. Prominent increases were also observed in the fruit girth, and yield attribute in the pollinated plots which was 11.4 cm (in pollinated) compared to 10.7 cm (in control) in TNAU orchard and 9.5 cm compared to 9.0 cm in Srivilliputhur. It is concluded that keeping stingless bees in greenhouse cucumber can improve its pollination and thus fruit weight and yield. However, additional studies with respect to the suitable microclimate inside greenhouses for stingless bees under tropical conditions are essential to utilize the bees for pollination.