Ethnobotanical study on plants used for traditional beekeeping by Dulong people in Yunnan, China

Dulongjiang Township, the only settlement of the Dulong (Drung) people in China, is located in the west of Gongshan Dulong and Nu Autonomous County, Nujiang Lisu Autonomous Prefecture, Yunnan Province, China (Fig. 1). Dulongjiang Township (27° 40′ ~ 28° 50′ N, 97° 45′ ~ 98° 30′ E) borders Bingzhongluo and Cikai townships to the east, Chayu County of Tibet Autonomous Region to the north, and Kachin State of the Federation of Myanmar to the west and south [25]. Dulongjiang Township has a typical alpine-gorge landscape with a large altitude gradient ranging from 222 to 3400 meters above sea level. The average rainfall is 3672.8 mm per year. Dulongjiang Township is one of the core areas of the Gaoligongshan National Nature Reserve and the World Natural Heritage of Three Rivers Parallel. It is one of the highest biodiversity areas of China, with 275 species in 41 families of ferns and 2003 species in 158 families of seed plants [25‐28].

Dulong is one of the 55 ethnic groups in China and is the smallest ethnic group by population in Yunnan Province. The 6930 Dulong people living in Dulongjiang Township account for 99% of the total population. Most people speak the Dulong language. Only young people can speak Mandarin Chinese. These indigenous people have minimal income, most of which is generated from plantations of spices and herbs [29‐31].

During August and November 2019, we conducted ethnobotanical surveys in Dulongjiang Township covering villages of Xiongdang, Dizhengdang, Longyuan, Xianjiudang, Kongdang, Bapo, and Miaku (Fig. 1, Fig. 2).

Ethnobotanical methods including free listing, semi-structured interviews, participatory investigation, and key informant interviews were used in the field investigations. A total of 42 informants were selected using snowball sampling. In the first stage, participants were invited to freely list all plants used in beekeeping. Then, semi-structured interviews were conducted. Interviews (Table 1) were conducted in Mandarin Chinese and translated into Dulong language with the assistance of our Dulong guide. Informed consent was obtained verbally from all participants prior to the study. After obtaining permission, photos were taken of the main steps in the beekeeping process.

In the second stage of field surveys, researchers accompanied by local villagers conducted a field walk to collect plant species used in beekeeping and to observe the beehives. Some plant species used to make log beehives were not found during the field survey. Pictures from the Plant Photo Bank of China (http://​ppbc.​iplant.​cn/​) of these plants were shown to informants to confirm species identification and other relevant information. The nomenclature of all vascular plants reported in our study follows the Flora of China [32]. Prof. Chunlin Long identified the plant species, and the voucher specimens were deposited at the herbarium in College of Life and Environmental Sciences, Minzu University of China, in Beijing.

A total of 42 Dulong respondents (7 from Bapo, 8 from Kongdang, 8 from Xianjiudang, 6 from Longyuan, 7 from Maku, and 6 from Dizhengdang) were selected for interviews. The study found that activities related to traditional beekeeping are generally performed by men; thirty-eight of the respondents were male, and only four were female. The respondents’ ages ranged from 25 to 73 years old, and the average age was 41. Most beekeepers were farmers. The overall level of education was low. Young people had higher levels of education than the elders (Table 2).

To identify plant resources used for log beehive materials that are “easier to obtain” and “more popular,” we used questions 1, 4, and 5 in Table 1 to determine citation frequency (how many times the informants mentioned each plant), abundance, and preference ranking (PR) of log beehive plants [33]. Frequency of citation was the key factor in prioritizing log beehive materials. Abundance of log beehive species can represent the resource and accessibility of plants, and frequency of citation was calculated based on the work of Zhang et al. [34]. Preference ranking was used with ten selected informants—regarded as professional beekeepers in their village—to rank the most popular log beehive plant species in the study area. All informants were asked to score the seven plant species with the highest citation frequency, with a score of 5 meaning highly preferred and a score of 1 meaning highly undesirable [35, 36].

There are two general forms of traditional Dulong beekeeping in the study area: living tree beekeeping and log beehive beekeeping (Fig. 3a, b). Living tree beekeeping is relatively rare because of the complexity of the process, which requires more time and effort to construct the beehives. Generally, it is only done in the trunks of Pinus yunnanensis and Alnus nepalensis. The Dulong people use a tree with holes or chisel a rectangular hole about 1.5 m above the ground, cover the nest door, and leave a few small holes next to it. They then burn the inside of beehives with fire, and finally coat the inside with mud. The advantage of living tree beekeeping is that it stimulates the natural environment and avoids destruction by wild animals such as black bear (Ursus thibetanus).

The process of log beehive beekeeping generally includes construction, applying various pre-treatments, and installation (Fig. 4b–d). Log beehives are mostly made of round wood 70 to 100 cm in length and 30 to 50 cm in diameter. They are made from dead trunks or wood salvaged from the river.

There are two ways to make nest doors to log beehives: hollowed from the side or hollowed on both ends. If the log is hollowed from the side (Fig. 4b), the hole is covered with a 20 cm × 10 cm rectangular wooden board. If the log is hollowed from both ends (Fig. 4c), one end is sealed with a circular wooden board whose diameter is close to that of the hole. There are various ways of constructing the nest door on the other end of the log to allow bees to move in and out of the hive. For example, holes can be opened up on the nest door, or a small gap can be left between the nest door and the log, which allows 4–5 bees at a time to pass through. After the preparation, various pre-treatments, such as drying and removing worms from the log beehive, are required. Some beekeepers bake the inside of log beehives with fire. Others use chopsticks to form a cross shape inside the beehive, making it easier to cut honey.

Most beekeepers install their hives on the leeward side of a structure. Log beehives are placed behind houses or on cliffs and cannot be reached from the ground. To prevent the log beehives from getting wet, the Dulong build a shelter made of bamboo and rattan, cover the hive with leaves of Caryota obtusa and Magnolia rostrata, or put a wooden board on top of the log beehives (Fig. 4a). With modernization, more artificial materials, such as rope and iron plates, are being used in log beehive construction. However, these modern materials are not as effective as the traditional materials. To prevent damage from wild animals and natural disasters, beekeepers use natural barriers to shield the hives. They also concentrate beehives on cliffs, which forms a beautiful landscape (Fig. 5).

Thirty-eight species—including 30 tree species—belonging to 19 plant families were documented through interviews of 42 informants from six villages (Fig. 6) (Table 3). Different plant parts were reported by beekeepers for constructing shelters and log beehives, for driving swarms away during honey collection, for affixing hives to their bases, and for attracting swarms. All tree species, except Magnolia officinalis, Caryota obtusa, and Luculia yunnanensis, are used for making log beehives. Leaves of Magnolia officinalis and Caryota obtusa are used for shelter construction, and flowers of Luculia yunnanensis are used to attract swarms. All bamboo species are used to make shelters, while Chimonobambusa armata, Fargesia pleniculmis, and Fargesia praecipua are also used for affixing hives. One herb (Urtica laetevirens) is processed into twine for affixing while the other (Imperata cylindrica) is used for making shelters and driving swarms away. Dulong people burn the whole plant of I. cylindrica when collecting honey to drive swarms away. Only one liana (Holboellia angustifolia) is used in traditional beekeeping, for affixing.

A total of 27 tree species are used for making log beehives. In terms of plant families, Pinaceae and Fagaceae have the greatest representation of species with 6 and 5 species, respectively, while other families are only represented by one or two species (Fig. 7). In our survey, seven most cited plants (mentioned by more than 75% of respondents) were Pinus yunnanensis, Cinnamomum camphora, Juglans regia, Alnus nepalensis, Quercus lamellosa, Toxicodendron vernicifluum, and Toona sinensis. The most abundant plants were Pinus yunnanensis, Quercus lamellosa, Alnus nepalensis, and Juglans regia.

Six plants used in beekeeping are included in the national list of protected species. For example, the trunks of Taxus wallichiana, Taiwania cryptomerioide, Picea brachytyla var. complanata, and Cinnamomum camphora are used to make log beehive, and the leaves of Houpoea rostrata and Caryota obtusa are used to make shelters. The Dulong do not cut down these endangered plants. The materials used for making log beehives are generally sourced from dead trunks or wood salvaged from the river, which are easy to process. This also avoids cutting living trees.

The survey results show that among the most commonly used materials, the beekeepers’ favorite materials are Alnus nepalensis, Pinus yunnanensis, Juglans regia, Cinnamomum camphora, Toxicodendron vernicifluum, Toona sinensis, and Cyclobalanopsis glauca. During the investigation, we found that beekeepers generally choose log beehive materials based on four criteria: abundance, ease of processing, durability, and smell. Different tree species have pros and cons in various aspects. For example, Pinus yunnanensis, Alnus nepalensis, Quercus lamellosa, and Juglans regia are very common and easy to obtain. In terms of durability, Pinus yunnanensis, Quercus glauca, and Cinnamomum camphora are the best, because they are excellent materials for buildings. However, materials that are more durable are also more challenging to process. Alnus nepalensis, Juglans regia, and Toona sinensis are easier to process. In terms of smell, Toxicodendron vernicifluum, Toona sinensis, and Cinnamomum camphora have strong odors while the odor of Pinus yunnanensis is faint. Some beekeepers prefer constructing bee barrels from plants with strong odors because the odor discourages pests and disease, while others believe that strong odors are bad because bees avoid or dislike the smell. Based on abundance, ease of processing, durability, and smell, the tree species most highly valued by beekeepers for log beehives are Alnus nepalensis, Pinus yunnanensis, and Juglans regia (Table 4).

Dulong people use traditional beekeeping methods to keep native bees (A. cerana). The scale of traditional Dulong beekeeping in Dulongjiang area continues to grow. Except for Dizhengdang Village, the number of beehives in the other five villages has been increasing in the past three years (Fig. 8). The unique geography, weather conditions, and rich biodiversity of the Dulongjiang area provide abundant nectariferous plants for native bees, which provides a solid ecological basis for maintaining traditional beekeeping. In addition, the unique beekeeping methods and rich TEK provide a better chance of survival for native bees (Fig. 9). There has been a growing interest in the development of bee products and their medical, health, diet, and beauty benefits, but little attention has been paid to the crucial role of beekeeping in maintaining ecological balance. Traditional beekeeping is the main income of the Dulong, and it also protects the native bee species and promotes the pollination of nectariferous plants. In addition, it plays an irreplaceable role in maintaining ecosystem stability and promoting ecosystem services of the Dulongjiang area. Over time, traditional beekeeping promotes a sustainable, eco-agricultural economy while increasing income for local residents (Fig. 9).