Stingless bees (Hymenoptera: Apidae) in South and West Sulawesi, Indonesia: morphology, nest structure, and molecular characteristics

Abstract

Being part of the Wallacea region, Sulawesi has many endemic fauna, including five species of stingless bees. However, their morphology, nest structure, and molecular characteristics have not been documented fully. Therefore, this study aimed to examine the morphology, nest structure, and molecular characteristics of stingless bees in South and West Sulawesi. Samples were collected from seven sampling sites and identified based on ten morphological features supported by morphometric analysis and the cytochrome c-oxidase I (COI) gene from mitochondrial DNA. We identified five stingless bee species based on morphological features: Tetragonula sapiens, T. clypearis, T. fuscobalteata, Lepidotrigona terminata, and Wallacetrigona incisa. Furthermore, we observed the shape, diameter, length, ornamentation, and color of the nest entrance and the arrangement, cells, and color of brood cells. We provide the first report of high variations in the type of entrance opening (irregular, round, oval, ellipse, and triangle) and three different brood cells arrangements (semi-cluster, cluster, and semi-comb) for Tetragonula sapiens, which occurs abundantly in Sulawesi. In addition, for the first time, we documented the nest structure of the endemic stingless bee W. incisa, which had a slit longitudinal entrance with lamellate pillar structures in a 2-m cavity of a tree trunk. We also found that the COI gene sequence can be used to distinguish the five stingless bee species in Sulawesi, and it is especially accurate at separating the species in the genus of Tetragonula.

Keywords:

• Wallacetrigona incisa
• stingless bee
• nest structure
• COI gene
• Wallacea

Acknowledgments

We acknowledge to stingless bee farmers: Paimin and Sulastri (North Luwu, South Sulawesi), Ridha (West Sulawesi) for allowing the authors to collect the stingless bees and to take the nest photograph for current research. We also thank Prof. Dr. Michael S. Engel from Kansas University for the species confirmation.

Disclosure statement

No potential conflict of interest was reported by the author.

Supplementary material

Supplementary Tables S1–S3 and Figure S1 are available via the ‘Supplementary’ tab on the article’s online page (http://dx.doi.org/10.1080/00218839.2020.1816272).

Additional information

Funding

This work was supported by the Indonesian Ministry of Research Technology and Higher Education, under the scheme of Competitive Research Grant (Hibah Kompetensi) on behalf of Rika Raffiudin [Grant number 011/SP2H/LT/DRPM/IV/2017]. The first author was supported by LPDP (Indonesia Endowment Fund for Education) for Master Scholarship [PRJ-2849/LPDP.3/2016].