Abstract:
This research was aimed to study the efficacy of stingless bee as insect pollinator of rambutan var. Sri Thong. The studies done at rambutan orchard in Tambon Wang-cham Amphor Makam Chantaburi province. The research was divided in to 2 experiments as follow: Diversity study of insects visiting inflorescences of rambutan var. Sri Thong was conducted in order to find optimum insect to be use as insect pollinator. Species and numbers of insect visited on inflorescences was observed every 10 minutes from 6.00 a.m. to 5.00 p.m. on 5 inflorescences in each tree for 5 trees. Observation was done for 5 days in January 2014. Efficacy of stingless bee T. laeviceps and T. fuscobalteata as insect pollinator of rambutan var. Sri Thong compare with opened and closed pollinator were conducted with 3 replication during January to June 2014. Experimental design was Completely Randomized Design.
The result of diversity study of insect visiting on rambutan inflorescences revealed that stingless bee was found more than other insects. Visiting time of stingless bee was between 8.00 a.m. - 5.00 p.m. Stingless bee was not found during 6.00 a.m. 7.00 a.m. Highest number of stingless bee was found at 11.00 a.m. and 1.00 p.m. Lower number was found at 2.00 p.m. and 12.00 a.m. respectively. Another insects found on inflorescences of rambutan were fruit fly, butterfly, wasp and carpenter bee which found in a few number. The results of pollination efficacy of stingless bee as insect pollinators revealed that no significant at 95% between all parameters such as numbers of fruit set per inflorescences, numbers of compleat fruit, abnormal fruit, abortive fruit, Total soluble solid (Brix) of fruit pulp, width and length of fruit of each treatment. Only pulp thickness showed highly significant between treatment because there was no pulp in abortive fruit which found in closed pollination treatment. Stinglees bee Tetragonula fuscubalteata showed higher
efficacy as insect pollinator for rambutan var. Sri Thong than T. laeviceps.
It can be concluded that stingless bee visited the rambutan inflorescences at the highest numbers and has the high efficacy as insect pollinators of rambutan var. sri thong. More over T. fuscobalteata showed the higher pollination efficacy than T. laeviceps.