Flight range colony characteristics and pollination efficacy of stingless bee tetragonnula travancorica in chilli (Capsicum annuum L.)

Abstract

The study entitled “Flight range, colony characteristics and pollination efficacy of stingless bee Tetragonula travancorica in chilli (Capsicum annuum L.).” was conducted at Department of Agricultural Entomology, College of Agriculture, Vellayani, during the year 2018- 2020 with an objective to study the flight range, colony characteristics and pollination efficacy of stingless bee Tetragonula travancorica in chilli. To determine the flight range of stingless bees, artificial food bait was standardized and the standardized food bait was used as attractant in order to calculate the foraging distance. Colony composition of ten well maintained stingless bee hives were determined by counting the population of queen and workers and also, the internal nest characteristics like brood area and storage pots were determined. The brood area temperature was recorded from four well maintained stingless bee colonies with the help of data loggers. Stingless bee hives made out of four different wood types were exposed to 40ºC inside hot air oven for 3hrs in order to evaluate their temperature variation. Pollination efficacy of stingless bees in chilli was determined by comparing yield from self- pollination, open pollination and stingless bee pollination respectively. The study on standardization of food bait for determining flight range revealed that, 35 % sugar concentration was the food bait preferred by stingless bees, which is on par with 35 % honey concentration. The maximum foraging distance of stingless bee was found to be 378m and an inverse relation between distance travelled by the bees and their numbers were observed. Observations on brood area inside the hive revealed that, length, breadth and height of brood area varied between 6cm to 16cm, 4cm to 12cm and 4cm to 12cm respectively. Brood volume varied from 96 cm3 to 1147.5 cm3. Volume of pollen pots varied from 21cm3 to 105 cm3. Volume of honey pots varied from 0.021L to 0.250L. The population of queen was similar in all 10 hives i.e. one in number and population of workers varied between seven hundred to three thousand two hundred and fifty-five numbers. The brood area temperature and RH of stingless bee hives varied between 22.9ºC to 33ºC and 71.7 % to 93.3 % respectively. The temperature and relative humidity inside empty hive varied between 24.1ºC to 33.4 ºC and 73.1 % to 98.1 % respectively. It was inferred that the stingless bees have the ability to control humidity and temperature inside the hive. Bridelia was the best wood type for making stingless bee hives, which control temperature control inside the hive effectively. Bridelia wood exhibited an average temperature control of 39.56ºC followed by Terminalia with 38.2ºC and the lowest temperature control was recorded in jack wood (31.86ºC). The time trend followed by the wood types to reach 40ºC was least in Bridalia followed by Terminalia, Teak and Jack. Pollination efficiency was maximum in stingless bee pollination followed by open and self-pollination with average fruit set percentage of 82.74%, 69.69% and 62.41% respectively. Number of fruits /plant, yield/ plant, weight of the fruit and percentage fruit set was highest in stingless bee pollination. The percentage increase in yield was 42% over control and percentage increase in fruit number and fruit weight was 18% over the control.