Study area

This study was conducted in five Dzongkhags (districts) and eight Gewogs (blocks) in Bhutan: Chhukha (Logchina) from western region, Sarpang (Chhundzom, Jigmecholing, Samteling, and Singye), and Zhemgang (Shingkhar) from south central, Mongar (Jurmey) from eastern region, and Wangdue Phodrang (Athang) from west central region as shown in Fig. 1 and Table 1.

Fig. 1

Map of Bhutan showing the study area, Gewogs (blocks) under Chhukha, Wangdue Phodrang, Sarpang, Zhemgang, and Mongar Dzongkhags (districts)

Table 1 Geographical information of the study areaEthno-zoological information collection

Bhutan is multi-ethnic and multi-lingual kingdom [35]. The primary ethnic groups in Bhutan include the Ngalops, of Tibetan descent, and the Sharchops, who are descendants of indigenous Tibetan people closely linked to the Monpas [36]. Another distinctive ethnic group in southern Bhutan is the Lhotshampas, descended from Nepalese origins (Fig. 2), and they inhabit the lowlands. This ethnic group is further divided into five sub-ethnic categories: the Bhawan, the Gurung, the Tamang, the Monger, the Rai. Each of them speaks their own dialects and has their own unique culture [36]. Likewise, the Khengpas are another distinct group from the south-central region of the country [37, 38].

Fig. 2

A Domestication of stingless bee in Chhudzom Gewog. B–E. Destructive extraction of stingless bees’ hive products from wild colonies. F Wax and propolis collected for traditional use Senior author (right). G Interviewing with the Bhawan communities of Bhutan in Chhudzom Gewog

The field survey for this study was conducted during the spring and summer months of 2022. Semi-structured interviews were conducted with 55 informants from five districts and eight blocks described in the study area. We followed all procedures and the code of ethics published in International Society of Ethnobiology Code of Ethics [39]. The criteria for selection of the informants were that they should have knowledge of the stingless bees in terms of types, uses, the location or ecology of the stingless bees in the wild, nesting behavior and the management practices. Therefore, the network of informants was built by the recommendations of Gups (Head of the block), Mangmis (Gup assistant), and the informants themselves by using the snowball-sampling method [40, 41]. They belong to eight ethnic communities consisting of the Bhawan, the Gurung, the Tamang, the Monger, the Rai belonging to the larger category of the Lhotshampas and the Ngalop, the Sharchop, and the Khengpa (Table 2). The informants vary among the blocks, districts, and ethnicities indicating the prevalence of ethno-biological knowledge among different ethnicities. Informants consist of 50 males (90.9%) and 5 females (9.1%). Their age ranges from 21 to 74 years, and the majority (49%) of the informants were of the age 51–65 years. All those informants who could just read and write were considered literate (2.7%) and 67.3% were illiterate. The majority (70.9%) of the informants practice Hinduism followed by Buddhism and Christianity (Table 3). All the informants (100%) are farmers, mostly practicing integrated farming constituting crop and livestock production. Our informants either domesticated stingless bees in their backyard or collected stingless bee honey and honey products from wild colonies from their natural habitat. Interviews were recorded by using a Sony ICD-UX570 voice recorder in native languages, were later translated, and transcribed for the data analysis. Data analysis was done using computer-assisted software like Microsoft Excel and SPSS.

Table 2 Ethnicity of the informantsTable 3 Demographic profile of the informants

The first author (TG) who is a native of Bhutan adopted a participant observation method [42], where he facilitated the interviews with informal conversations. The first author has good command over the national language of Bhutan, Dzongkha which is used to interview Dzongkha speaking Ngalops of Wangdue Phodrang. Lhotshampa (Nepali language) was used in all the blocks of Sarpang and Logchina of Chhukha. Sharchopkha dialect was used in the Mongar district. The fourth author was involved in an interview in Shingkhar, Zhemgang in local dialect Khengkha. Each interview lasted for a maximum of 30 min.

The National Biodiversity Centre, the national focal agency for inventory and documentation of traditional knowledge associated with biological resources reviewed this study and provided approval both for field research and publication.

Ecological and socio-economic features of the study site

Logchina block in the Chhukha district has an area of 70.4 sq. km., 12 small villages, 430 households, and a population of 2500. The Ngalops and the Lhotshampas are the two major ethnic groups inhabited in this block. The livelihood in this block is supported by cash crops such as cardamom, ginger, areca nut, mandarin, and organic vegetables [43]. The elevation of this block ranges from 600 to 1200 m. above sea level and has subtropical climatic conditions [44]. Stingless bees are domesticated as one of the sources of income by some of the Lhotshampas farmers in this block.

Athang is one of the remotest blocks in the Wangdue Phodrang district. It lies at an elevation ranging from 700 to 3500 m. above sea level and characterized by dry subtropical climate. It has an area of 746 sq. km., 198 households, and a population of 793. The Ngalops constitute the major ethnic community residing in this block. This place is best known for its smoked fish (locally known as Nga dosem). Paddy, maize, wheat, barley, buckwheat, potato, and organic vegetables are the major cash crops in the area to support their livelihoods [45]. Jurmey block in the Mongar district is characterized by the subtropical climate. It has an area of 55 sq.km., 304 households, and a population of 2646. The Sharchops constitute the major ethnic community residing in this block. Maize is the main crop in this block, and it faces acute shortage of water as most of the settlements are on hilltops and the water sources are in the valley [46]. Shingkhar block is located at a higher altitude in a remote part of the Zhemgang district and well characterized by cooler climatic conditions. It has an area of 309 sq.km., 244 households, and a population of 960. The Khengpas people are the major inhabitants in this block and mostly dependent on livestock for their livelihood. This block is very rich in biodiversity and cultural heritage with numerous traditional and religious festivals [47]. The Ngalops, the Sharchops, and the Khengpas people follow Buddhism as their religion. They practice extracting stingless bees’ hive products from natural wild nests and use them for medicinal purposes, yet they do not undertake domestication.

Chhudzom, Jigmecholing, Singye, and Samtenling blocks in the Sarpang district are inhabited by the Lhotshampas including the Bhawan, the Gurung, the Tamang, the Mongar, the Rai people. The Lhotshampas ethnic communities follow Hinduism as their religion. Chhudzom has a humid and wet subtropical climate. It covers an area of 222 sq. km., 637 households, and a population of 4422. Jigmecholing has an area of 501 sq.km., 698 households, and a population of 5716. It lies at an altitude of 1200–1500 m. above sea level. Singye has an area of 232 sq. km., 287 households, and a population of 1824. It lies at an elevation of 249–900 m. above sea level. Similarly, Samtenling has an area of 55 sq.km, 467 households, and a population of 3068. It lies at an elevation of 190–380 m. above sea level [48]. Agriculture is a significant economic sector in the Sarpang district to support the livelihoods of the Lhotshampas people. The Lhotshampas community in the above-mentioned blocks collects the natural nests of stingless bees, brings them to their homes in the form of log hives, and domesticates them in their backyards. They also practice destructive harvesting hive products from natural nests and utilize them in many ways.

Quantitative evaluation of ethno-zoological data

We analyzed the ethno-medicinal uses and cultural importance of stingless bees and their hive products used by the different ethnic communities in Bhutan by grouping all the mentioned uses into several categories (#C) such as food, medicine, veterinary medicine, crafts, beliefs, and religious uses. Within those categories, specific uses (#U) of stingless bees and their hive products are sub-grouped (Table 5).

A “researcher tally” method as described by Philip [49] was employed to group specific uses of stingless bees and their hive products into several categories. In calculating the relative cultural importance (RCI) index, we adhered to the methodology outlined by Gonzalez et al. [50], employing a modified index derived from Bennett & Prance [51], which is commonly used to assess the RCI of medicinal plants. The index is calculated based on the sum of the proportion of the number of use categories (C) and the proportion of the number of specific uses (U) multiplied by 50 ([C + U] × 50). The output of the index is expressed on a scale from 0 to 100. Kruskal–Wallis test and Dunn’s multiple comparison tests were used to assess the relative differences in the RCI among different ethnic communities [8]. Additionally, we employed the mention index to evaluate different categories of uses, determining the proportion of mentions for a specific category divided by the total number of interviews [52].

Collection and preservation of sample

Fifteen worker bee specimens were collected from each nest we encountered both in the forest and under domestication. Bee specimens were collected by using a sweep net [53]. The collected bee specimens were kept in vials containing ethanol in the field. Bee specimens were picked up by pointed forceps and pinned in the meso-scutum on the thorax with the help of the pinning block in the laboratory setting. After pinning, each bee specimen was dried and kept inside the specimen box for further morphometric measurement and identification process. Photographs and morphometric measurements were taken in the National Biodiversity Centre laboratory in Serbithang, Bhutan. After the identification of bee specimens, the identification label, the locality label, and the collector label were provided to each specimen.

Morphometric measurements

Key features for identification are based on Sakagami [54] as cited in Rasmussen [21]. All morphological measurements were recorded in micrometer (mm). The measurements were taken with an image acquisition-programmed zoom-stereo microscope. Terminology and measurements follow as explained in Michener [7] and Ruttner [55]. The indices and their abbreviations used are: (1) total body length (BL), (2) head length (HL), (3) head width (HW), (4) length of clypeus (LC), (5) length of scape (LS), (6) length of mandible (LM), (7) length of forewing (LF), (8) width of forewing (WF), (9) length of hind wing (LH), (10) width of hind wing (WH), (11) width of tibia (WT), (12) length of basitarsus (LB), (13) length of meso-scutum (LM), (14)length of tibia (LT), and (15) width of basitarsus (WB). The observations pertaining to the bilateral body parts such as eyes, antennae, legs, and wings were taken on the right side of the body part. Using forceps, a bee sample from specimen box was picked and was placed under stereomicroscope for measurement of total body length and width. After recording, the sample was mounted under image acquisition-programmed zoom-stereo microscope for further morphometric measurement. After morphological characterization, the photographs were taken for further identification and documentation.