Development of Heterotrigona itama (Cockerell, 1918) queens by in vitro culture for conservation purposes

Abstract

An eco-friendly technique for rapid multiplication of the stingless bee colonies, species Heterotrigona itama from Malaysia, to achieve the most effective in vitro queen production is highly needed. In this study, there were significant differences in the volumes of the queen larval food collected from different wild combs (114 µL,127 µL, and 138 µL) at the various sampling sites (F 2,44 = 4.85, p < 0.05). While there was no significant difference (i.e. more consistent) in the humidity and temperature readings within the hives, at 68.2%–73.8% (F 9,449 = 0.27, p > 0.05) and 24.5 °C–32 °C (F 9,449 = 1.73 p > 0.05), respectively. For the rearing process, the optimum parameters were set up based on the optimised data for the first 10 days of the larval food, with the relative humidity (%) of 72 ± 2 and temperature (°C) 27 ± 5, similar to the inside hive values obtained in the field. Several modifications had been made by trial and error due to several reasons. A total of five replicated experiments conducted with three amounts of larval food on the ELISA plates showed that 127 µL and 138 µL gave the best results in the frequency of the hatched queens, with 75% to 77.5% survival. The Kaplan-Meier survival analysis showed significant differences between the amounts of larval food given (χ2 = 10.385, df = 2, p < 0.05) in survival probability, with 138 µL showing the highest. These novel findings specifically obtained for the H. itama species with their optimum food supply, relative humidity, and temperature for in vitro rearing are very valuable for conservation purposes.