Foraging behavior and pollination efficiency of honey bees (Apis mellifera L.) and stingless bees (Tetragonula laeviceps species complex) on mango (Mangifera indica L., cv. Nam Dokmai) in Northern Thailand

Background: The mango is one of the essential fruit trees for the economy of Thailand. Mango pollination relies primarily on insects. Other external forces, such as wind, are less efficient since pollen is sticky and aggregating. There is only one report from Thailand on the use of bees as mango pollinators. The study of the behavior and pollination efficiency of honey bees (Apis mellifera) and stingless bees (Tetragonula laeviceps species complex) was conducted in Nam Dokmai mango plantings in Phrao and Mae Taeng districts, Chiang Mai province, between February and March 2019. Results: Our results reveal that the honey bees commenced foraging earlier than the stingless bee. The number of flowers visited within 1 minute by honey bees was higher than that visited by stingless bees. The average numbers of honey bees and stingless bees that flew out of the hive per minute from 7 a.m. and 6 p.m. in the Phrao district were 4.21 ± 1.62 and 9.88 ± 7.63 bees/min, respectively, i.e., higher than those observed in Mae Taeng, which were 3.46 ± 1.13 and 1.23 ± 1.20 bees/min, respectively. The numbers of fruits per tree were significantly higher in the honey bee and stingless bee treatments (T1 and T2) than in the open pollination treatment (T3). The number of fruits between T1 and T2 treatments was not different. In the pollinator exclusion treatment (T4), no fruit was produced. Fruit size factors were not significantly different among T1, T2, and T3 treatments. Conclusions: Our results showed that insect pollination is crucial for mango production, especially with the Nam Dokmai variety in Northern Thailand. As pollinator exclusion treatment showed no fruit set, and pollinator treatment significantly increased the fruit sets compared to open access plots, a managed pollinator program would benefit the mango growers for better productivity. Both the honey bee and the stingless bee were shown to be effective as pollinators.