Published online July 11, 2022
Journal of Ecology and Environment (2022) 46:15
1Meliponini and Apini Research Laboratory, Department of Entomology and Plant Pathology, Faculty of Agriculture, Chiang Mai University, Chiang Mai 50200, Thailand
2Department of Plant and Soil Science, Faculty of Agriculture, Chiang Mai University, Chiang Mai 50200, Thailand
3Science and Technology Research Institute, Chiang Mai University, Chiang Mai 50200, Thailand
4Department of Plant Medicals, Andong National University, Andong 36729, Republic of Korea
5Department of Horticulture, Oregon State University, Corvallis, OR 97331, USA
Correspondence to:Bajaree Chuttong
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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.
Keywords: Apis mellifera, foraging, mango, pollination, stingless bee
The mango (
Pollen transmission from stamens to pistils, a vital stage in most flowering plants’ seed reproduction, depends on the behavior of various animals, from insects to birds and mammals. Bee pollination is essential for the world’s most important commercial crops, including mango (Tanda 2021). Studies in India and Israel examined the characteristics and biology of mango pollination and discovered that insects of the orders Diptera such as
In a study on mango pollinators in northern Australia, Anderson et al. (1982) reported that insects of the order of Diptera and stingless bees of the genus
The honey bee colonies had approximately 8,000 bees/hive. We used Nucleus hives (Nuc-hives), which contained four combs per hive. Each hive had about 80% of the adult bee population. We applied the Burgett and Burikam (1985) method to evaluate the adult honey bee population used in the experiment.
There is no standard or published method to estimate the population size of the stingless bee (
Two locations of the Nam Dokmai mango cultivar in Chiang Mai province were studied to examine the efficacy of insect pollination. The initial location was a Nam Dokmai mango cultivation plot in Pa Tum Subdistrict, Phrao District, Chiang Mai Province, with latitude and longitude coordinates of 19°22’32” N, 99°14’22” E and an elevation of 330 m above sea level. Another location was the Nam Dokmai mango cultivation plot in Khie Lek Subdistrict, Mae Taeng District, Chiang Mai Province, with 19°6’37” N, 98°52’34” E coordinates, at a height of 450 m above sea level.
The mango trees were randomly selected from each location. A total of four experimental plots were identified in each research location. Mango trees with a height of around 3.5 m, a similar age (three years old), and an identical growing cycle from flowering period to fruiting period were chosen for each plot. There were four different experimental treatments. Treatment 1 (T1) was caged with honey bees (
During the flowering period, colonies of honey bees (
Ten inflorescences were randomly selected and tagged from each mango tree at the early inflorescence stage, for a total of 160 bunches per tree. During the harvesting phase, data on the amount and quality of mango fruit were obtained. In addition, the results from the tagged branches were examined for: 1) the average number of mango fruit per tree, 2) the average weight of fruit per tree, and 3) the average fruit size per tree (length, width and thickness).
The data regarding four different treatments (open plot, honey bee cage, stingless bee cage, and without pollinators/closed cage) were compared. The number of fruits per tree, the weight of fruit and fruit size were subjected to statistical analysis using analysis of variance. At
At the Phrao location (Fig. 1), the foraging activity of
At the Mae Taeng location (Fig. 2), the foraging activity of
The number of flowers visited by bees in a 1-minute period was counted at the Phrao location.
At the Mae Taeng location, the number of flowers visited by bees in a 1-minute period was observed.
The average number of mango fruit set was recorded in both research locations. There was no statistically significant difference between treatment 1 (T1), which employed honey bees as pollinators, and treatment 2 (T2), which used stingless bees as pollinators. However, there was a significant difference between treatment 3 (T3) (open plot) and treatment 4 (T4) (closed plot) (
Our results indicated the peak foraging times of honey bees and stingless bees were different. In both locations we studied,
Bees with larger wings are expected to be able to fly for a longer period than those with smaller wings (Mostajeran et al. 2006). Furthermore, the adaptation of honey bee subspecies to various climatic circumstances may influence foraging behavior (Alqarni et al. 2006). This study indicates that the honey bee had a more extended foraging period than the stingless bee. The results revealed that the average number of bees that flew out of the hive within one minute in Phrao was greater than in Mae Taeng. This difference could be due to microclimatic factors such as temperature and relative humidity (Amin et al. 2015). Honey bee foraging rates tended to be positively correlated with air temperature, while relative humidity had less effect on flight activity (Gebremedhn et al. 2014; Joshi and Joshi 2010). This is not correlated to our findings on the foraging behavior of the honey bee and stingless bee. The number of food plants, the degree of nectar and pollen demands inside the colony, and the interior environment of the plot all influence bee foraging activities (Abou-Shaara 2014). Maia-Silva et al. (2014) stated the stingless bee (
The number of flowers visited by bees per one minute is consistent with the Gadhiya and Pastagia (2019) study of the time
Puangjik (2000) stated that using pollinators, such as honey bees and stingless bees, to support the pollination of Nam Dokmai mango flowers and enable natural insect pollination increased the fruiting efficiency of mango trees. However, pollinator-free treatments (closed plots) produced no fruit set. Our results demonstrated the number of fruits per tree with a pollinator trial (
According to our results on bees’ foraging activity, stingless bees spend more time on flowers than honey bees. This behavior can assist in pollen transfer, which is necessary for fruit development. The most active time of the stingless bee foraging is comparable to the maximum flowering time of mango between 9:30 and 10:30 a.m., while the peak number of forager honey bees flying was in the afternoon. By combining our results, pollinators significantly affect the number of fruit sets where the yield can be significantly increased by insect pollinators. This highlights the significance of bees in mango pollination. However, pollinator species of either honey bee or stingless bee did not differ in pollination services, resulting in similar quality of mango, i.e., fruit weight and size, but showed superior service over both open pollination and exclusion treatments.
The management of insect pollination services in mango is significant, and the utilization of insect pollinators and conservation of natural pollinators is also very important to increase the mango yield.
The authors would like to thank the Thai Mango Growers Association members in Phrao and Mae Taeng Districts, Chiang Mai province, for supporting the mango planting plots.
BC and LP conducted the laboratory and field research, analyzed the data, and wrote the manuscript. The field investigation was conducted by CT and PL, who also edited the manuscript. The manuscript was reviewed and edited by WP, PC, CJ, and MB. The authors read and approved the final version.
This research was supported by National Research Council of Thailand (NRCT). CJ was supproted by agenda project and National Research Foundation of Korea (NRF), MoE. (NRF-2018R1A6A1A03024862).
The datasets generated and/or analyzed during the current study are available from the corresponding author on reasonable request.
The authors declare that they have no competing interests.
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Daniel Bisrat1,2* and Chuleui Jung1,3