Preliminary Exploration of the Species, Distribution, and Nest Ecology of Stingless Bees Along the Krueng Woyla River, Sumatra, Indonesia

Abstract

Stingless bees (Meliponini) are important pollinators in tropical ecosystems; however, information on their species diversity, distribution, and nesting ecology along the river of Sumatra remains limited. This study was conducted from October to November 2025 along the Krueng Woyla River in West Aceh Regency, Aceh Province, Indonesia. An exploratory survey, combined with local ecological knowledge, was conducted to document stingless bee colonies and describe their nesting characteristics. The study identified a single species, Tetragonula fuscobalteata, characterized by a bicolored body (black with a yellowish abdomen) and small morphometric size, with a total body length of 3.35-3.61 mm, head width of 1.40-1.47 mm, and forewing length of 3.68-3.91 mm. A total of 47 nests were recorded across three sub-districts, all located in settlement areas and constructed on four types of nesting substrates. Nest entrances, which were generally small, varied in dimensions, color, shape, texture, pore presence, and resin occurrence. Nests were found at heights of 40-302 cm above ground level and within 5 km of the river. Overall, T. fuscobalteata demonstrated high adaptability to riverine environments, indicating that these areas provide suitable nesting substrates and food resources. This finding indicates that semi-natural environments along river corridors are important ecosystems that should be conserved, while also underscoring their role as potential habitats for stingless bees.