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common name: Himalayan giant honey bee, cliff honey bee (suggested common names)
scientific name: Apis laboriosa Smith (Insecta: Hymenoptera: Apidae)

Introduction - Distribution - Description - Life Cycle - Biology - Economic Impact - Management - Selected References



Introduction (Back to Top)

Although the Himalayan giant honey bee Apis laboriosa Smith (Figure 1), is the largest honey bee species in the world, it is also one of the least studied. It has a distribution mostly concentrated in the Hindu Kush Himalayan region of southern Asia. This species is a member of the subgenus Megapis, along with Apis dorsata. Apis laboriosa was long considered to be a subspecies of Apis dorsata (Koeniger et al. 2011) until 1980 when Sakagami described Apis laboriosa as a separate species (Engel 1999; Sakagami et al. 1980), which was later supported by genetic sequencing (Cao et al. 2012). Apis laboriosa builds a large open nest with a single comb, usually on rocky cliffsides. Here, we highlight the unique characteristics of Apis laboriosa and compare it to other honey bee species, particularly the other giant honey bee, Apis dorsata.


Figure 1. An Apis laboriosa worker (non-reproductive female) in Trongsa Dzongkhag, Trongsa District, Bhutan with an elevation of approximately 6,759 ft (2,060 m) above sea level. Photograph by pemthrinlai https://www.inaturalist.org/observations/18594655, (CC BY-NC-ND 4.0) https://creativecommons.org/licenses/by-nc-nd/4.0/.

Figure 1. An Apis laboriosa worker (non-reproductive female) in Trongsa Dzongkhag, Trongsa District, Bhutan with an elevation of approximately 6,759 ft (2,060 m) above sea level. Photograph by pemthrinlai https://www.inaturalist.org/observations/18594655, (CC BY-NC-ND 4.0) https://creativecommons.org/licenses/by-nc-nd/4.0/.



Distribution (Back to Top)

While Apis dorsata is widely distributed from the Indian subcontinent to Southeast Asia, the distribution of Apis laboriosa is primarily found in the Hindu Kush Himalayan (HKH) region of southern Asia (Figure 2). It has a westernmost border of western Nepal and a southeast border that expands through the northern borders of Laos and Vietnam. It can be found as far north as the northern border of India into southern China (Otis 1996; Roubik et al. 1985).


Figure 2. Global distribution of Apis laboriosa in southern Asia which shows some overlap with the related species Apis dorsata. Map designed by The Polistes Corporation created by Discover Life https://tinyurl.com/34z94799.

Figure 2. Global distribution of Apis laboriosa in southern Asia which shows some overlap with the related species Apis dorsata. Map designed by The Polistes Corporation created by Discover Life https://tinyurl.com/34z94799.



Description (Back to Top)

Apis laboriosa is the largest extant honey bee species in the world with a body length slightly larger than Apis dorsata (Figure 3). Apis laboriosa workers average just over 1.2 in (3 cm) in length. The scutellum (dorsal side of thorax) is dark brown to black with long yellowish hairs. All segments of the abdomen are dark (Kitnya et al, 2020) (Figure 4).


Figure 1. Typical hook-like galls on rice roots infected byFigure 3. Apis laboriosa (left) and Apis dorsata (right) workers for comparison. Scale bar: 0.4 in (1 cm). From "Geographical distribution of the giant honey bee Apis laboriosa Smith (Hymenoptera, Apidae)" by Kitnya et al, 2020. Meloidogyne graminicola. Photograph by Hung Xuan Bui.

Figure 3. Apis laboriosa (left) and Apis dorsata (right) workers for comparison. Scale bar: 0.4 in (1 cm). From “Geographical distribution of the giant honey bee Apis laboriosa Smith (Hymenoptera, Apidae)” by Kitnya et al, 2020.




Figure 4. Apis laboriosa, worker (non-reproductive female) lateral view. Photograph by Chelsey Ritner chelsey.ritner@usda.gov, Exotic Bee ID, USDA APHIS PPQ, Bugwood.org, (CC BY-NC 3.0) https://creativecommons.org/licenses/by-nc/3.0/.

Figure 4. Apis laboriosa, worker (non-reproductive female) lateral view. Photograph by Chelsey Ritner chelsey.ritner@usda.gov, Exotic Bee ID, USDA APHIS PPQ, Bugwood.org, (CC BY-NC 3.0) https://creativecommons.org/licenses/by-nc/3.0/.



Life Cycle (Back to Top)

Like all other honey bee species, Apis laboriosa are holometabolous insects that undergo a complete metamorphosis with the following stages: egg, larva, pupa, and adult. Details regarding Apis laboriosa development are largely unknown, most likely because the nests are difficult to access for study. However, inferences can be made based on the development of Apis dorsata (Tan 2007).

Egg: The life of a honey bee starts when an egg laid by the queen in a wax cell. The larva will eclose (emerge) from the egg after three days.

Larva: As the larva ecloses from its egg, it is now dependent on the workers (its sisters) for food and care. A healthy larva takes on a plump C shape on its side in the cell that has liquid food in the bottom of the cell. As the larva matures, it will send a chemical cue to the workers that the cell is ready to be capped with wax after nearly six days.

Pupa: This is a non-feeding growth phase where the pupa will remain undisturbed for 11 days. Each day the pupa loses larval characteristic and gains more adult features.

Adult: When the pupa is a fully formed adult, it emerges from the capped cell, crawls out, and joins its sisters in colony work.

In smaller honey bee species like Apis mellifera, the workers make longer cells for drone brood on the periphery of the nest. Apis laboriosa and Apis dorsata workers are very large, therefore the sizes of workers and drones are indistinguishable in the nest (Koeniger et al. 2011). Currently, almost no information is available regarding Apis laboriosa queens. In Figure 5, an adult worker crawls over a comb with various stages of larvae and pupae visible. For reference, the cells are approximately 0.25 in (0.6 cm) across and 0.8 in (2.0 cm) long (Valli and Summers 1988).



Figure 5. The remains of an Apis laboriosa nest, destroyed during a honey hunt in Nepal. Photograph from “The Honey Hunters” by © Eric Valli http://www.ericvalli.org/honey-hunters-eric-valli-photos/, used with permission.

Figure 5. The remains of an Apis laboriosa nest, destroyed during a honey hunt in Nepal. Photograph from “The Honey Hunters” by © Eric Valli http://www.ericvalli.org/honey-hunters-eric-valli-photos/, used with permission.



Biology (Back to Top)

Apis laboriosa are similar to other honey bees in that they are considered eusocial or truly social insects. They meet these requirements for several reasons, one being that there is a reproductive division of labor among two female castes, the queens and workers. The queen is the only female within the colony to lay eggs and the workers collectively care for the brood, even though they do not normally produce any themselves (Mortensen et al. 2015). Apis laboriosa queens can produce many generations of workers per year, with some overlap; thus, meeting all the requirements of classifying organisms as eusocial.

In a single Apis laboriosa colony there may be thousands of workers (non-reproductive females) that complete all the tasks that keep the colony functioning (Corlett 2011). They tend to the brood and the queen as she cannot feed herself. They produce wax to build and maintain the single comb nest (Figure 6). They forage for pollen and nectar that is brought back to the colony to prepare food products. With their large body size and wing span, they are known to forage up to 2.5 mi (4,100 m) (Thapa et al. 2018).


Figure 6. Phylogenetic analysis within populations and species of the genus Meloidogyne as inferred from maximum likelihood analysis using the D2-D3 of 28S rRNA gene sequence dataset with T92+G model. Newly obtained sequences are indicated in bold and the others were obtained from the GeneBank database.

Figure 6. Apis laboriosa workers (non-reproductive females) building a nest in Omba, Trashiyangtse Dzongkhag, Trashiyangtse District, Bhutan with an elevation of approximately 7,129 ft (2,173 m) above sea level. Photograph by tandinwangchuk1 https://www.inaturalist.org/observations/10593425, (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/.


The nest is designed as a large, single comb that is exposed on all sides, which is similar to Apis dorsata. Apis laboriosa colonies aggregate close together with their nests typically found in steep, rocky cliffs attached to the underside of an overhanging ledge for protection from the elements (Figure 7). Nests can easily reach 4.9 ft (1.5 m) long by 3.3 ft (1 m) wide (or larger) and are often located on a southwest or southeast facing sheer rock cliff at elevations from 3,937 - 12,123 ft (1,200 - 4000 m) above sea level (Ahmad et al. 2003; Otis 1996; Trung et al. 1996; Allen 1995; Valli and Summers 1988; Roubik et al. 1985). In areas of distribution that overlap with Apis dorsata, the nesting elevation separates the two species as Apis dorsata typically nests at altitudes below 4,921 ft (1,500 m) (Allen 1995; Roubik et al. 1985).


Figure 8. Rice root-knot nematode gall index for evaluating the infection severity caused by Meloidogyne graminicola. Adapted from Bridge et al. (2005).

Figure 7. A nesting site of Apis laboriosa in Zhemgang, Bhutan with an elevation of approximately 2,121 m above sea level. Photograph by CheongWeei Gan https://www.inaturalist.org/photos/44194596, (CC BY-NC 4.0) https://creativecommons.org/licenses/by-nc/4.0/.


Apis laboriosa seasonally migrates to different altitudes to avoid harsh environmental conditions. From May to October the bees migrate upward to previous nesting sites 8,202 - 11,483 ft (2,500 - 3,500 m) above sea level. As temperatures begin to cool the bees migrate down to previous nesting sites 3937 ft (1,200 m) above sea level. Before the coldest temperatures of late November to early January the bees migrate once again to the forest ground and shelter at the base of trees or under rocks. The bees will not have a nest, but cluster together to keep warm until early spring. In late January the bees will return to their mid-level nesting site where they will stay until summer (Thapa et al. 2018; Woyke et al. 2012a; Hepburn 2011).

Woyke et al. (2012b) studied the specific placement of each Apis laboriosa nest on a cliff and noticed that Apis laboriosa were more likely to nest on lighter colored rocks, as it is often an indication of being better protected from the elements (Figure 8). Additionally, Apis laboriosa nesting sites are likely to only be 65 - 656 ft (20 - 200 m) away from major sources of water (Figure 9) (Ahmad et al. 2003).


Figure 8. Rice root-knot nematode gall index for evaluating the infection severity caused by Meloidogyne graminicola. Adapted from Bridge et al. (2005).

Figure 8. A Himalayan cliff displaying different colors of rock from which Apis laboriosa chooses to build its nest. Location: Nepal. Photograph by © Ganesh Sharma, used with permission.


Figure 9. Mountain valley in the Himalayan region. Photograph by unknown / public domain https://pxhere.com/en/photo/687060, (CC0 1.0) https://creativecommons.org/publicdomain/zero/1.0/.

Figure 9. Mountain valley in the Himalayan region. Photograph by unknown / public domain https://pxhere.com/en/photo/687060, (CC0 1.0) https://creativecommons.org/publicdomain/zero/1.0/.



An interesting defense behavior used by members of the subgenus Megapis is called shimmering (Figure 10). This defense method involves bees raising their abdomens in sequential order, sending waves across the surface of the nest. Watching honey bees move this way is thought to intimidate and possibly confuse the predator, making it difficult to single out one bee to attack (Woyke et al. 2008).


Figure 10. Overlapping layers of Apis laboriosa workers (non-reproductive females) forming a curtain on a large, single honeycomb, that hangs exposed. Located in Themnangbi, Mongar Dzongkhag, Mongar District, Bhutan at an elevation of approximately 7,382 ft (2,250 m) above sea level. Photograph by Markus Lilje https://www.inaturalist.org/observations/6899529, (CC BY-NC-ND 4.0) https://creativecommons.org/licenses/by-nc-nd/4.0/.

Figure 10. Overlapping layers of Apis laboriosa workers (non-reproductive females) forming a curtain on a large, single honeycomb, that hangs exposed. Located in Themnangbi, Mongar Dzongkhag, Mongar District, Bhutan at an elevation of approximately 7,382 ft (2,250 m) above sea level. Photograph by Markus Lilje https://www.inaturalist.org/observations/6899529, (CC BY-NC-ND 4.0) https://creativecommons.org/licenses/by-nc-nd/4.0/.



Economic Impact (Back to Top)

Apis laboriosa in Nepal produce an average yield of 55 - 132 lbs (25 - 60 kg) of honey per colony, per year (Thapa et al. 2018; Aryal et al. 2015), producing different types of honey depending on the season. Honey produced by Apis laboriosa has a high moisture content and ferments fast (Thapa et al. 2018). As Apis laboriosa nest at high elevations, collecting honey can be challenging. A tribal tradition called honey hunting has taken place for thousands of years in Nepal and the HKH region. Men of the tribe build ladders of rope and wooden rungs that are secured to land above the nests (Figure 11). From below, a fire is set to smoke the honey bees away from their nests (Figure 12). A man will climb the ladder to cut the nests down, collecting them in a basket. Figure 13 is a closer image that indicates the nest size by the ladder.


Figure 11. Nepalese men of the Gurung tribe fashion ladders out of braided bamboo ropes and wooden rungs before each hunt. Photograph by © David Caprara http://www.davidcaprara.com/the-honey-hunters-of-nepal/, used with permission.

Figure 11. Nepalese men of the Gurung tribe fashion ladders out of braided bamboo ropes and wooden rungs before each hunt. Photograph by © David Caprara http://www.davidcaprara.com/the-honey-hunters-of-nepal/, used with permission.


Figure 11. Nepalese men of the Gurung tribe fashion ladders out of braided bamboo ropes and wooden rungs before each hunt. Photograph by © David Caprara http://www.davidcaprara.com/the-honey-hunters-of-nepal/, used with permission.

Figure 12. Nepalese men of the Gurung tribe have lit a fire at the bottom of the cliff. The smoke rises upwards to the nest to act as a deterrent against the Apis laboriosa nest defenders. Photograph by © David Caprara http://www.davidcaprara.com/the-honey-hunters-of-nepal/, used with permission.


Honey hunters bring in more than 50% of the annual honey yield in the region (Ahmad et al. 2003). This destructive hunting practice has directly contributed to the rapid decline of the Apis laboriosa population in recent decades (Thapa et al. 2018; Joshi et al. 2004). Other possible contributors to the alarming decline may include land loss from deforestation and landslides, (Thapa et al. 2018; Aryal et al. 2015; Joshi et al. 2004; Ahmad et al. 2003) or parasites and diseases (Chantawannakul et al. 2016; Anderson & Morgan 2007; Allen et al. 1990).


Figure 13. For Apis laboriosa nest size reference, look at the ladder next to the men in Figure 11. Photograph by © David Caprara http://www.davidcaprara.com/the-honey-hunters-of-nepal/, used with permission.

Figure 13. For Apis laboriosa nest size reference, look at the ladder next to the men in Figure 11. Photograph by © David Caprara http://www.davidcaprara.com/the-honey-hunters-of-nepal/, used with permission.


The most valuable honey is known as red, psychedelic, or mad honey and is produced in the spring when plants of the Ericaceae family are in bloom. The nectar and pollen are collected at high altitude between 8202 - 12,795 ft (2500 - 3900 m) above sea level, from several Rhododendron (Figure 14), PierisAgarista and Kalmia genera that contain grayanotoxins which appear to be harmless to the bees that collect and produce the honey (Roubik et al. 1985). While rarely fatal to humans, some have appeared dead or felt close to death in the days following consumption of mad honey.


Figure 14. Rhododendron Forest in the Sagarmatha National Park, Himalaya, Nepal. Apis laboriosa workers visit rhododendron flowers during the spring to create what is known as mad honey. Photograph by Peter Prokosch https://www.grida.no/resources/1598, (CC BY-NC-SA 2.0) https://creativecommons.org/licenses/by-nc-sa/2.0/.

Figure 14. Rhododendron Forest in the Sagarmatha National Park, Himalaya, Nepal. Apis laboriosa workers visit rhododendron flowers during the spring to create what is known as mad honey. Photograph by Peter Prokosch https://www.grida.no/resources/1598, (CC BY-NC-SA 2.0) https://creativecommons.org/licenses/by-nc-sa/2.0/.


Some try mad honey hoping to experience the claims of euphoria or relaxation. Others consume it for it is believed therapeutic properties which have been rumored to treat or even cure conditions such as hypertension, diabetes, and sexual dysfunction. Depending on the amount of mad honey consumed, the reactions to grayanotoxin poisoning could result in acute onset of: nausea, vomiting, diarrhea, prolific sweating, double or blurred vision, extreme physical weakness (or emotional exhaustion), along with low blood pressure, slow heart rate, unresponsiveness to stimuli, symptoms that resemble cardiac events, and in severe cases loss of consciousness, seizures, or even death. The poisoning and list of symptoms are collectively known as mad honey disease (Broscaru et al. 2018).


Figure 15. Harvested Apis laboriosa comb with honey squeezed from the comb. Photograph by © David Caprara http://www.davidcaprara.com/the-honey-hunters-of-nepal/, used with permission.

Figure 15. Harvested Apis laboriosa comb with honey squeezed from the comb. Photograph by © David Caprara http://www.davidcaprara.com/the-honey-hunters-of-nepal/, used with permission.



Management (Back to Top)

Nepalese honey hunting practices require modification to promote honey bee sustainability. Without intervention, the Gurung tradition passed down for thousands of years will likely die as well. Programs by the International Centre for Integrated Mountain Development promote beekeeping to generate income through a sustainable practice so they can continue their traditions of collecting honey and beeswax (Ahmad et al. 2007).

As Apis laboriosa has a limited distribution, there is little evidence to suggest that this bee might become an invasive species in the United States. Nevertheless, its presence, along with all other honey bee species, is monitored by the Florida Department of Agriculture and Consumer Services Apiary Inspection service to ensure early detection were it ever to arrive in Florida, USA.



Selected References (Back to Top)