Utilization of the Stingless Bee (Trigona sp.) as a Natural Pollinator in Rubber (Hevea brasiliensis) Agroforestry Program of PT Pertamina EP Sangatta Field, East Kalimantan, Indonesia
Abstract
Rubber (Hevea brasiliensis) is an agroforestry commodity that provides ecological services, such as carbon uptake, erosion control, and habitat provision. However, its small, densely clustered flowers limit effective pollination by wild insects, so seed set and latex productivity often remain below their potential levels. This study reports a biodiversity conservation program carried out by PT Pertamina EP Sangatta Field, East Kalimantan, Indonesia, which introduced stingless bee (Trigona sp.) colonies in collaboration with partner farmer group, Trigona Reborn Group, as a natural pollinator for rubber trees grown under an agroforestry system together with citrus, mango, and papaya as companion crops. A suction-based honey-harvesting tool (Bee-Sap) was introduced to collect honey without damaging the comb, thereby allowing the colony to function as a pollinator. Monitoring conducted from January to June 2025 recorded the conservation of 250 rubber trees, an estimated colony population of 13,000 Trigona sp. individuals, and a program biodiversity index (H') of 0.90. The results indicate that the small body size and floral constancy behavior of Trigona sp. allow it to effectively reach the small rubber flowers, supporting cross-pollination, while the partnership also provides an additional income source for the farmer group through honey and propolis production.
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Introduction
PT Pertamina EP Sangatta Field is a company engaged in oil and gas exploration and production that is committed to environmental conservation and community empowerment in its operational area. As part of this commitment, the company manages a conservation area for rubber (Hevea brasiliensis) developed under an agroforestry system, in which forestry species are combined with agricultural crops on the same land unit to increase land productivity, maintain ecosystem sustainability, and generate economic, ecological, and social benefits. Rubber-based agroforestry provides broader ecosystem services than rubber monoculture, including higher carbon storage and stronger support for biodiversity indicators (Perdomo Diaz et al., 2025).
Globally, Hevea brasiliensis is listed as Least Concern on the IUCN Red List (Fabriani & Hills, 2020). However, this status does not automatically guarantee the long-term sustainability of rubber populations, as regeneration still depends on the quality of the surrounding ecosystem, including the availability of effective pollinators. As a long-lived tree species, rubber also provides important ecological functions, such as carbon absorption, reduction of greenhouse gas emissions, prevention of soil erosion, maintenance of microclimate humidity, and provision of habitat for various flora and fauna (Singh et al., 2021; Liu et al., 2016).
Rubber is a cross-pollinated plant, and fruit and seed formation depend strongly on the presence of an effective pollinator (Li et al., 2022). In practice, however, natural pollination of Hevea brasiliensis by wild insects tends to be nonoptimal because the flowers are small, densely arranged, and clustered, which limits the ability of larger insects to reach the stigma. A study on insect pollinators in oil palm, rubber, and jungle-rubber land uses in Sumatra also found that pollinator communities in rubber plantations are commonly dominated by small carpenter bees rather than large-bodied bees, and that a Trigona sp. nest was found inside a rubber tree trunk (Siregar et al., 2016). Nonoptimal pollination reduces the number of seeds available for generative propagation and constrains natural regeneration, which increases the risk that a rubber stand becomes dominated by older, less productive trees.
At the same time, the company's CSR partner group in Sangkima Selatan Village, Trigona Reborn Group, maintains stingless bee (Trigona sp.) colonies, but has faced declining colony productivity because the number and variety of flowers available around the settlement area are limited. Honey harvesting that is still performed manually also tends to damage the comb, which disturbs the colony and reduces its long-term sustainability (Md Zaki & Abd Razak, 2018).
Pollinators play an important economic and ecological role. Approximately 75% of global food crops depend at least partly on animal pollination (Potts et al., 2016). Among insect pollinators, stingless bees have been reported as effective pollinators for various crops because of their small body size and floral constancy behavior, which increases the efficiency of cross-pollination and improves fruit and seed formation (Atmowidi et al., 2022; Wongsa et al., 2023). Due to these conditions, PT Pertamina EP Sangatta Field has proposed a solution by employing Trigona sp. colonies from the partner group as natural pollinators for rubber flowers. The program design was complemented by a honey-harvesting device that was specifically engineered to maintain the sustainability of the colonies. This study aims to evaluate the effectiveness of the stingless bee (Trigona sp.) colonies as natural pollinators within rubber (Hevea brasiliensis) agroforestry systems, assessed based on: (1) the number of rubber trees and bee colonies successfully conserved, (2) the biodiversity index of the conservation area, and (3) a comparison of pollination conditions before and after the intervention.
Conclusion
The integration of Trigona sp. stingless bee colonies as natural pollinators, proposed by the PT Pertamina EP Sangatta Field conservation program in collaboration with Trigona Reborn Group, supported the conservation of 250 rubber trees and an estimated colony of 13,000 individuals, with a program biodiversity index of 0.90. The small body size and floral constancy behavior of Trigona sp. allowed it to effectively access the small, clustered rubber flowers, while the non-destructive harvesting tool helped maintain colony sustainability. The program also generated economic benefits for the partner farmer group through increased honey and propolis production. As this program was implemented as an applied field intervention rather than a controlled experiment, further systematic monitoring, such as direct measurement of seed set, latex yield, colony population dynamics, and a multi-species fauna survey to complement the current flora-based index, is recommended to strengthen the quantitative evidence for the pollination effect reported here.
References
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