Journal of Threatened Taxa | www.threatenedtaxa.org | 26 April 2021 | 13(5): 18344–18348
ISSN 0974-7907 (Online) | ISSN 0974-7893 (Print)
#4504 | Received 13 October 2019 | Final received 05 August 2020 | Finally accepted 04 April 2021
Report on the stingless bees of Bhutan (Hymenoptera: Apidae: Meliponini)
Associate Lecturer, Department of Environment and Life Sciences, Sherubtse College, Royal University of Bhutan, Trashigang, Bhutan.
Abstract: Two species of stingless bees, Tetragonula gressitti (Sakagami) and Lepidotrigona arcifera (Cockerell), are reported from Bhutan for the first time. The nest description and meliponiculture are described. This is the gross underestimation of Meliponini diversity in Bhutan and summons more study on the diversity, biology, and meliponiculture.
Keywords: Diversity, meliponiculture, Lepidotrigona arcifera, Tetragonula gressitti
Abbreviation: NBCB—National Biodiversity Center, Bhutan.
Stingless bee keeping is known as meliponiculture (Cortopassi-Laurino et al. 2006) and is a rare activity in Bhutan, where it is considered a sin to taste even a tiny drop of honey, from a Buddhist perspective. Perhaps this explains its uncommonness in the country. Although a very few people in southern Bhutan rear stingless bees for domestic consumption nevertheless there is no published record of stingless bee species in Bhutan. Stingless bee honey and propolis are known to have high medicinal value (Choudhari et al. 2012; Vit et al. 2004). Stingless bees not only produce high-priced honey, but also help in pollination of crops, though they are facing various threats at present (Slaa et al. 2006). Therefore, a huge opportunity for meliponiculture exists in Bhutan, with 72% of the country under forest cover with rich and diverse flora, and chemical use in agriculture almost nonexistent, making the country attractive for large-scale organic meliponiculture (Gupta et al. 2014).
There are about 600 species of Meliponini in global tropical and subtropical areas (Cortopassi-Laurino et al. 2006). The Indo-Malayan region has 89 recognized stingless bee species, 43 in Asia and eight in the Indian subcontinent (Michener 2007; Rasmussen 2008; Rasmussen 2013). Two local types (white and black) of stingless bees were collected from different localities of Bhutan. They are locally known as “Putkha” in Nepali (Rasmussen 2013) but they are unambiguously named as “Kalo putka” (=black putka) and Shayto putka (=white putka) in Bhutan. Locally it is said that the honey of the black species has a higher medicinal value than the white (Deo K. Rai pers. comm. 10.xi.2017) though it is yet to be proven.
Specimens were collected with a sweep net. Collected specimens were pinned, dried and stored. Identifications were based on Sakagami (1978), Smith (unpublished), Rasmussen (2013), and Rathor et al. (2013). Measurements were made with digital Vernier caliper under a stereo microscope. The specimens were deposited in the National Biodiversity Centre, Serbithang, Thimphu, Bhutan and a registered reference number is provided for each specimen as provided in the materials examined. Identifications were based on worker specimens collected during the invertebrate inventory project field work in 2014–2017 that focused on Hymenoptera (bees and wasps), Lepidoptera (moths and butterflies), Coleoptera (beetles), Odonata (dragonflies and damselflies), and Mollusca (snails and slugs). The project was funded by the Bhutan Trust Fund for Environmental Conservation (BTFEC) and coordinated by National Biodiversity Center, Bhutan. The surveys were conducted by the experts from Sherubtse College and College of Natural Resources, Royal University of Bhutan, Ugyen Wangchuck Institute for Conservation and Environmental Research (UWICER), National Plant Protection Centre (NPPC) and Naturalis Biodiversity Center, The Netherlands. Distribution within Bhutan is provided with Districts followed by localities in parenthesis.
Results and discussion
Genus Tetragonula Moure, 1961
The genus Tetragonula Moure is differentiated by the combination of the following characters: small size, body smooth, shiny with minute punctation; scutellum projecting backward, over-arching almost the whole propodeum; basal area of propodeum smooth, shiny and hairless; five hammuli per hind wing, hind basitarsus narrower than tibia with large sericeous patch; metasoma narrower than thorax; mesopleural hairs silvery white; clypeus with microscopic appressed silvery-white hairs; malar space not well developed; mandible with 2 teeth; wings uniformly clear.
Tetragonula gressitti (Sakagami, 1978)
(Image 1A,B,C, 2, 3)
Trigona (Tetragonula) gressitti Sakagami 1978: 214–216; Holotype: worker; Type locality: Vietnam, Lâm Đồng province in the central Highlands. Diagnosis: highly melanic; body, scape, alveolus, flagella, hairs, corbicular bristles clypeus, tegula, legs and metasoma black; scape long; mesoscutal hairs do not form distinct bands; mesosoma and metasoma glossy. In Nepali it is known as “kalo putka” corresponding to its melanic body.
Measurements: Seven workers; total body length: 4.39–5.59 mm (mean 5.14mm); Forewing length excluding tegula: 4.31–4.89 mm (mean 4.62mm); Hind tibia length: 1.67–1.78 mm (mean: 1.73mm).
Materials examined: NBCB00282, NBCB00283, NBCB00284, NBCB00285, NBCB00286, NBCB00287, NBCB00288, 29.vii.2016, 7 females, Khengpagang, Sarpang (26.848N & 89.396E, 461m), coll. Deo Kumar Rai & Bishal Rai from a reared colony.
Remark: This species is reported for the first time from Bhutan and known only from a reared colony in Sarpang District and warrants further exploration.
Distribution: Vietnam (Sakagami 1978), India (Rathor et al. 2013), Bhutan.
Genus Lepidotrigona Schwarz, 1939
This genus is distinguished by having six hamuli and dense tesselation on head and thorax; mesonotum with a border of thick, scale-like yellow or whitish hairs. Basitarsis is without sericeous patch on inner face of basitarsus which is rather uniformly setose.
Lepidotrigona arcifera (Cockerell, 1929) (Image 4, A & B; Image 5, 6 & 7)
Trigona arcifera Cockerell 1929: 591–592: Holotype: worker (BMNH 17b.1081); Type locality: India, Sikkim, Teesta bridge.
Diagnosis: Generally black; complete semicircular dark band on the pale first metasomal tergum partly enclosing the basal depression; yellowish apical metasomal terga; densely plumose (“scale-like”) hairs on margin of mesoscutum; body and wing each more than or equal to 4mm in length.
Measurements: 12 workers; total body length: 4–4.60 mm (mean: 4.14mm); forewing length excluding tegula: 3.99–4.91 mm (mean: 4.49mm).
Materials examined: NBCB00268, NBCB00269, NBCB00270, 29.vii.2016, 3 females, Rinchending, Chhukha, (26.848N & 89.396E, 461m), coll. Tshering Nidup; NBCB00271, NBCB00272, NBCB00273, 23.x.2015, 3 females Yongkola, Monggar (27.306N & 91.164E, 1,553m), coll. Phurpa Dorji & Wim Klein; NBCB00274, NBCB00275, NBCB00276, NBCB00277, NBCB00278, NBCB00279, NBCB00280, NBCB00281, 29.vii.2016, 8 females, Khengpagang, Sarpang (26.848N & 89.396E, 461m), coll. Deo Kumar Rai & Bishal Rai.
Remark: This species seems to be widely distributed and recorded at the altitude range of 461–1,553m. It is reported from the seven districts of Chhukha, Dagana, Mongar, Zhemgang, Samdrup Jongkhar, Trashigang, Tsirang and Sarpang however, the nest entrance were examined only in Serzhong (Mongar), Dorona (Dagana), Shumar & Nganglam (Pemagatshel), Mantar & Pemathang (Samdrup Jongkhar), Dovan & Goang (Sarpang), Tsholingkhar (Tsirang), and Panbang (Zhemgang).
Distribution: India (Rasmussen 2008, 2013) Bhutan.
Nest description and meliponiculture
A nest of L. arcifera was observed under natural conditions in the oak forest in Pemagatshel (Image 6). It was nesting in the trunk of an oak tree, ca. 4m above ground on the bulging side of the trunk. The area was sloping and the ground was clear without much undergrowth. The nest entrance varies from broadly funnel-like to round and little narrow at the base but in some the base can be bulging. The color of the entrance is lighter at the tip and darker to reddish-brown at the base. The entrance is bit angled downward and the rim appears as though sliced angularly. It is guarded by 5–12 adults based on a series of the nest photographs. The nest entrance measures about 1.6cm in width (opening), 2cm in length (opening), 7.5cm dorsally from tip to base and 6.5cm ventrally. T. gressitti do not make any nest entrance like L. arcifera; however, it coats the nest tunnel with yellowish substances (likely resin or resin mixed with wax) (Image 2).
According to one informant, honey is extracted in winter and each L. arcifera colony provides approximately 750 ml/year. T. gressitti is thought to produce slightly more than 750 ml/year. Honey of T. gressitti is sold at Nu. 6000 (=100 US Dollars) and honey of L. arcifera at Nu. 3000 (=50 US Dollars), per 750 ml. Currently 20 households rear L. arcifera in Khengpagang village in Sarpang District but only one household rears T. gressitti. The first author also saw one household rearing L. arcifera at Tsholingkhar Village in Tsirang.
These bees are brought to the village from the forest with an undisturbed nest after cutting the trunk of the tree they were nesting in. They are then placed around the house in any position in case of L. arcifera, but in upright position in case of T. gressitti (Image 3). It is said that T. gressitti colony leaves the nest if kept in other positions. They are reared in a natural way and it was never observed that the bees were kept in rational hives or that the keepers knew how to perform divisions of the colonies or artificial feeding.
Choudhari, M.K., S.A. Punekar, R.V. Ranade & K.M. Paknikar (2012). Journal of Ethnopharmacology 141: 363–367.
Cockerell, T.D.A. (1929). Descriptions and records of bees.—CXX. Annals and Magazine of Natural History 10(4): 584–594.
Cortopassi-Laurino, M., V.L. Imperatriz-Fonseca, D.W. Roubik, A. Dollin, T. Heard, I.B. Aguilar, G.C. Venturieri, C. Eardley & P. Nogueira-Neto (2006). Global Meliponiculture: challenges and opportunities. Apidologie 37: 1–18.
Gupta, R.K., W. Raybroeck, J.W. van Veen & A. Gupta (2014). Beekeeping for Poverty Alleviation and Livelihood Security. Springer, London, 665pp.
Michener, C.D. (2007). The Bees of The World. Johns Hopkins University Press, Baltimore, xiv++913pp.
Rasmussen, C. (2008). Catalog of the Indo-Malayan/Australasian stingless bees (Hymenoptera: Apidae: Meliponini). Zootaxa 1935: 1–80.
Rasmussen, C. (2013). Stingless bees (Hymenoptera: Apidae: Meliponini) of the Indian subcontinent: Diversity, taxonomy and current status of knowledge. Zootaxa 3647(3): 401–428.
Rathor, V.S., C. Rasmussen & M.S. Sainai (2013). New record of the stingless bee Tetragonula gressitti from India (Hymenoptera: Apidae: Meliponini). Journal of Melittology 7: 1–5.
Sakagami, S.F. (1978). Tetragonula stingless bees of the continental Asia and Sri Lanka (Hymenoptera, Apidae). Journal of the Faculty of Science, Hokkaido University, Series VI, Zoology 21(2): 165–247.
Slaa, E.J., L.A.S. Cheves, K.S. Malagodi-Braga & F.E. Hofstede (2006). Stingless bees in applied pollination: practice and perspectives. Apidologie 37: 293–315.
Vit, P., M. Medina & M.E. Enríquez (2004). Quality standards for medicinal uses of Meliponinae honey in Guatemala, Mexico and Venezuela. Bee World 85(1): 2–5.