The diversity of stingless bee (Apidae: Meliponini) in Batusangkar, West Sumatra: the current meliponiculture status

The study on the diversity of stingless bees (Apidae: Meliponini) in Batusangkar was conducted from September until December 2020. This study aimed to inventory stingless bee species at meliponicultures in three subdistricts of Batusangkar City in Tanah Datar Regency, West Sumatra. The study surveyed the meliponiculture sites by purposive sampling and directly collecting, by hand, the workers of the stingless bee at their colony entrances. A total of 5 species of stingless bees from 44 colonies were collected. The species with the most abundant population observed was Heterotrigona itama (23 colonies). Other four species shortly followed i.e., Geniotrigona thoracica (10 colonies), Tetragonula laeviceps (seven colonies), Tetragonula fuscobalteata (three colonies), and Homotrigona fimbriata (one colony). The diversity of stingless bees in this study was thought to be influenced by species’ productivity and behavior that work in their favor to be included by the farmers in their meliponiculture. This study presents the most suitable species of stingless bees to breed in the meliponiculture environment in Batusangkar.


Introduction
One of the most dominant pollinator insects is the bee [1].Bees are social insects that live in colonies.Based on the position of taxa, bees are divided into two major groups, stinging bees (Apinae) and stingless bees (Meliponinae).The most widely distributed sting bees are Apis mellifera Linnaeus and Apis cerana Linnaeus.Both species have been long domesticated and widely known as honey bees [2].
Similar to the honey bees, stingless bees have also been common among beekeepers, and bred for their honey and propolis in the system termed as meliponiculture [3].The distribution of stingless bees ranges from tropical to subtropical regions [4], with the most common species found in Southeast Asia being Tetragonula laeviceps [5].Indonesia as a tropical country possesses the most diversity of stingless bees [6].
The products of stingless bees have been integrated into the socio-cultural customs of many societies, including food, medicinal substance, ritualistic component, and commercial commodity [7].Considering the amounts of honey and pollen in their hives, in addition to the large quantity of bee wax produced, stingless bees become an essential or additional source of income for people [8].Recently, the meliponiculture has increased due to the significant benefits of honey and propolis that are considered beneficial for humans' medical and health aspects.In Batusangkar, meliponiculture was recently introduced two years ago with a handful of farmers involved in it.Consequently, insufficient information is available to describe the extent of stingless bee diversity bred in meliponiculture in Batusangkar.Hence, this study aimed to do the inventory of stingless bee species of meliponiculture in Batusangkar which provides an important baseline regarding the future direction of this activity.This study was conducted from September to December 2020 using the purposive sampling method at five meliponiculture sites spread in three subdistricts in Batusangkar, West Sumatra, Indonesia.Two sites were Lima Kaum Subdistrict, two in Tanjung Emas Subdistrict, and one in Sungai Tarab (Figure 1); all sites were characterized by hilly plateau topography (ca.450-550 elevation).The observation was implemented through a direct sampling method of the stingless bee inventory from stingless beekeeping sites.For identifying stingless bee species, a handful of workers were collected at the colony entrance and stored in vials containing 70% ethanol.The identification process was performed at the Laboratory of Animal Taxonomy, Biology Department, Faculty of Mathematics and Natural Sciences, Universitas Andalas, Padang.

Data Analysis
The stingless bee samples were sorted, photographed, and identified.Morphological characters supported identification, following the reference for the region [9].The data was then tabulated with specific concerns given to species inventory and their distribution across the study sites.The results were then thoroughly discussed.

Results and Discussion
There were four genera and five species of stingless bees recorded in Batusangkar.They, from the most common species found to the least one, were Heterotrigona itama Cockerell (24 colonies), Geniotrigona thoracica Smith (10 colonies), Tetragonula laeviceps Smith (seven colonies), Tetragonula fuscobalteata Cameron (three colonies), and Homotrigona fimbriata Smith (one colony) (Table 1).These five species were five out of 18 total stingless bee species recorded for the West Sumatra region [10].H. itama was the most common stingless bee species observed in this study.Aside from being bred in the beekeeping sites, its natural colonies were also found in the surrounding vegetation.G. thoracica was also found to be common at meliponiculteres, while H. fimbriata was the rarest.The commonness of H. itama and G. thoracica in the beekeeping environment is presumably derived from their specific features, which are favorable for the beekeepers [9].Both stingless bee species possess stouter bodies, hence constructing larger honey pots that increase the volume of honey produced in a colony per month [11].High productivity, supported by a bigger body that helps collect more nectar and pollen from various plants, became the reason that made H. itama such as popular beekeeping species [12].
In this study, the measured body length of H. itama was between 4.6-5.2mm, while the total body length (including wings) reached 7 mm.This body length was relatively shorter than the specimen from Malaysia, with 4.78 mm body length and 7.85 mm total body length [7].H. itama was found to have a completely black head, thorax, and abdomen (Figure 3).Its head was covered with short setae, large compound eyes, and geniculate-type antennae.Its thorax with mesoscutum is clear and covered with long setae.Three pairs of legs attach to the thorax, with the posterior basitarsus being 2/3 of the size of the hind tibia.This description was following the morphology of Heterotrigona itama observed in Yogyakarta [13].Its wings were black with weak venation, with the fore-and the hind wings connected by seven hooks (hamuli) [13].Heterotrigona is the only genus of stingless bees that has one tooth in the lower jaw and is found in Indonesia archipelago, Malaysia, and Singapore [14] Figure 2. Total number of colonies per species from several beekeeping (meliponiculture) in Batusangkar.
The second most common stingless bee at meliponiculture in Batusangkar was G. thoracica (Figure 2).This species was also widely bred in Malaysia [12,15].It was characterized by a large head covered with sparse short setae and with geniculate-type antennae.On the thorax, its mesoscutum is punctate

Species
and large, which typical character of this species.The mesoscutum was bicolor and seemed to be segmented by the dye arrangement; this is typical for this species [7].G. thoracica had a smooth and shiny abdomen with a dark brown tint.This was the following morphological description for this species mentioned to be shiny and triangular [13].The hindquarters of the tibia are long, pear-shaped, and clearly defined, completely covered with long setae that became much shorter around the base of the legs.Hind basitarsi are short and sparse, overgrown with short setae.The size of Geniotrigona thoracica observed in this study was a bit larger than what was reported for this species.Its body length ranged from 6.8 to 7.9 mm, while the total body length (including wings) exceeded 8 mm.In Malaysia Peninsular, its total body length was an average of 8.39 mm [13].Two members of the genus Tetragonula were recorded in this study, Tetragonula laeviceps and Tetragonula fuscobalteata.The workers of Tetragonula laeviceps were black with metasoma brown.It had rounded brown tegulae, semi-transparent wings, and dark brown wing venation.The hind tibia was entirely black.Basitarsi was entirely black; some individuals might have blackish brown for this part.Abdomen dark brown to black.The head and chest of Tetragonula laeviceps in Indomalaya were black [7].Apical edge of testaceous clypeus blackish, testaceous-type antennae, mandible with brownishblack tegula; coxae and prothorax brownish; the front tarsus and other small segments of tarsi light brown.Metasoma blackish brown, scutum and scutellum hairs blackish, anterior corbicular margin mostly brown but some hairs blackish; ribbon-shaped scutum.Its body length was recorded as 3.8-4.1 mm in this study, which was smaller than what was reported from Malaysia that ranging from 4.24 to 4.37 mm [15].Mesoscutum is finely spotted, surrounded by short setae, and with a length equal to its width.
The other Tetragonula member, T. fuscobalteata, became the smallest stingless bee in this study.The average body length was measured to be 3.14 mm.Its head is black with blackish brown clypeus.The compound eyes as well as the ocelli black.Mesoscutum was black and the abdomen was blackish brown.The wing veins were blackish.Its workers were blackish-brown, mesoscutum consisting of six longitudinal hairs and each separated by six conspicuous glabrous, pale clypeus.Hind anterior limbs with silvery gray fringe hairs; pale abdomen and dark brown teeth [16].
Homotrigona fimbriata was recorded in the least number.It was found in a single colony in an agricultural area in Lima Kaum Subdistrict, Batusangkar.This species had a reddish body, strikingly different from other species.Its morphological characteristics included a large head, geniculate antennae, and large compound eyes.The front of the head with light brown clypeus.The compound eyes and ocelli were blackish.Mesoscutum and scutellum reddish.It was previously reported that the entire body of Homotrigona fimbriata was brick red [14].In Thailand, Homotrigona fimbriata only exists in bamboo forests [17].The entrance of Homotrigona fimbriata colony looked very different from the entrances of other species colonies.While others' entrances with a funnel shape, the entrance of Homotrigona fimbriata colony is shaped like a hole in the wall of rearing boxes (Figure 4).In addition to its colony entrance, Homotrigona fimbriata colony produced honey scattered.It might indicate the possibility of a higher volume of honey production.The beekeepers, however, admitted the difficulties in propagating their colonies due toits timid behavior.

4.Conclusion
A total of five stingless bee species were recorded from Batusangkar: Geniotrigona thoracica,Tetragonula laeviceps, Tetragonula fuscobalteata, Homotrigona fimbriata.These five species were thought to be the most suitable species for stingless beekeeping in this region.Beekeepers prefer stingless bee species with high productivity.This study observed that two to four stingless bee species can be bred in the same beekeeping site.

Figure 4 .
Figure 4.The stingless beekeeping in Batusangkar.a. Stingless bee colonies reared inside roofed wood boxes, b.A colony in a box with a small hole, c.The entrance of Geniotrigona thoracica colony, d.The entrance of Homotrigona fimbriata colony, e.The entrance of Heterotrigona itama colony, f. the entrance of Tetragonula laeviceps colony.

Table 1 .
A number of stingless bee colonies per study site in Batusangkar.