Bee diversity and pollination dynamics on Ankol (Alangium salvifolium) in the foothills of Mount Abu, Rajasthan

Introduction

Pollination is a crucial environmental process that has evolved over millions of years, benefiting both flowering plants and their pollinators. Pollinators visit flowers for various reasons, including for food, pollen gathering, and warmth. During these visits, pollen rubs off or falls onto their bodies, facilitating the transfer of genetic material between flowers. This process is essential for the life cycle of all flowering plants, as it triggers seed and fruit formation. The superfamily Apoidea, which includes bees, is a vast group with over 20,000 species worldwide, playing a vital role in pollination across ecosystems. Bees are among the most diversified taxa, largely due to their apicultural importance and effectiveness as pollinators (Michener, 2007) [6] . They play a critical ecological role by pollinating both natural and managed ecosystems (Gallai et al., 2009) [3] . In India, the distribution of bee families includes Stenotritidae (0 species), Melittidae (4 species), Colletidae (31 species), Andrenidae (20 species), Halictidae (214 species), Megachilidae (237 species), and Apidae (218 species). In total, 724 bee species have been recorded in India, compared to 20,077 species globally (Makkar and Chhuneja, 2015) [5] . Chaudhary et al. (2018) [2] evaluated the pollination of mustard crops (Brassica campestris) in Jhunjhunu district, Rajasthan, and found that a total of 80 insect species were involved in pollination, 19 of which belonged to the order Hymenoptera. Saini et al. (2016) [10] recorded 8 bee species for the first time in Rajasthan, including Amegilla cingulata, A. confusa, A. dizona, A. fallax, A. mucorea, A. niveocincta, A. violacea, and A. zonata. Pollination is crucial for biodiversity conservation, ecosystem stability, cultural practices, food security, and agricultural productivity. However, factors such as urbanization, climate change, pesticide use, genetically engineered plants, and invasive species pose significant threats to pollinators, as reported by Potts et al. (2016) [9] . Imran et al. (2018) [4] observed that 16 bee species from three families (Halictidae, Apidae, and Megachilidae) contributed to the pollination of onion crops in Western Rajasthan, enhancing both the quality and quantity of production. Pollinators play a crucial role in biodiversity, ecosystem services, crop production, and human health. However, their decline is attributed to factors such as habitat loss, habitat degradation, pesticide use, pathogens, climate change, and the presence of exotic species (Potts et al., 2010) [8] . Bhardwaj et al. (2012) [1] documented 13 hymenopteran species involved in the pollination of various cultivated crops in an agro-ecosystem in Bikaner, Rajasthan. The diversity of plant species in and around agricultural landscapes plays a crucial role in sustaining pollinator populations by providing essential food resources and habitats for both domestic and solitary bee species, along with other beneficial insects. This increased biodiversity directly enhances pollination efficiency and overall ecosystem services within agro-ecosystems (Nicholls and Altieri, 2012) [7] . Alangium salvifolium, a plant of significant ecological and medicinal value, has long been utilized in traditional healing systems such as Ayurveda and Siddha. Its various parts-including the roots, leaves, stems, and bark-are employed in treating a wide range of ailments. Recent scientific research has increasingly affirmed its therapeutic potential, demonstrating efficacy in managing conditions such as diabetes, peptic ulcers, arthritis, inflammation, and anthelmintic activity, highlighting its promising role in modern pharmacological applications. The Ankol plant (Alangium salvifolium) is a highly underutilized shrub with significant potential in the food industry for its bioactive compounds, including anthocyanins, flavonoids, and phenols. Found widely across Asia and Africa, this plant offers functional food applications due to its therapeutic properties such as antidiabetic, anti-cancer, and cardio-protective effects. Molecular research suggests the presence of novel phytochemicals, positioning A. salvifolium as a valuable resource for both functional foods and pharmaceutical advancements Alangium salvifolium is known to contain a range of physiologically active phytochemicals, including alangine, ankorine, tubulosine, alangicine, and salsoline, among others. This plant is widely distributed across Southeast Asia, including regions such as India, China, Thailand, the Philippines, Indonesia, and Papua New Guinea, as well as Africa, Madagascar, southern and eastern Asia, tropical Australia, the western Pacific Ocean islands, and New Caledonia (Shravya et al., 2017) [11] . Pollinators are not only critical for sustaining natural ecosystems, but they also play an essential role in maintaining healthy and productive agricultural systems by ensuring the development of high-quality fruits and viable seed sets in many crops. The present study focuses on examining the diversity of bees and their association with A. salvifolium. It aims to explore the importance of bee conservation in relation to human health and ecosystem services, such as maintaining plant diversity in forest ecosystems, enhancing agricultural productivity, ensuring food quality, and supporting economically beneficial bee species. The study will contribute valuable insights into the vital role of bees in promoting biodiversity and sustaining the health of both natural and agricultural environments.

Materials and Methods Study Area:

The survey areas are located on one side in agricultural regions and on the other side in forest regions, near Abu Road in the Sirohi District of Rajasthan, India. The study site was visited weekly for bee collection and observation during the flowering seasons, which spanned from March to May in both 2021 and 2022. The bees were collected during the daytime, typically between 8:00 AM and 2:00 PM. The bees were collected twice from the area using a simple hand net with a sweeping method, ensuring collection occurred only when the wind speed did not exceed 2.5 m/s. Bees were captured using an aerial insect net. The following collection; the insects were immediately transferred into a killing bottle, constructed from a cylindrical glass jar. After being transferred to the killing bottle, the bees were carefully spread and pinned on a spreading board to facilitate detailed morphological studies and precise species identification. The specimens were subsequently pinned using entomological steel pins and allowed to undergo proper desiccation. Some Collected specimens were kept in vials with 70% alcohols. The deceased specimens were then placed in storage boxes for preservation. To prevent fungal and other pest contamination, naphthalene balls were placed within the storage boxes. Photographs of Bees are taken in lab with a Camera Nikon D5600 and AF-S Micro NIKKOR 60 mm 1.2.8.G ED lens. Initial identification to the genus level was conducted in field. Identifications were further approved and identified to species level by experts Dr. Jagdish Saini, Assistant Professor, Department Zoology, University of Allahabad, Prayagraj, Uttar Pradesh, India-211002.

Result

A total of 155 individuals representing 19 bee species were collected and examined, belonging to the families Apidae, Halictidae, and Megachilidae. These families fall under the superfamily Apoidea, suborder Apocrita, within the order Hymenoptera. Among the identified species, 13 belonged to the family Apidae, 3 to the family Halictidae, and 3 to the family Megachilidae. The detailed list of identified species has been organized in a tabular format (Table 1). The total number of bees collected was 155, with various species showing different levels of abundance. The most dominant species was A. florea, making up 16.12% of the total population. The second most abundant species was A. dorsata at 10.32%, followed by Tetragonula iridipennis (8.38%), C. smaragdula (7.74%), and Apis cerana (7.09%). Other species in the sample include Amegilla cingulata (5.80%), A. dizona (5.16%), A. violacea (5.16%), A. zonata (4.51%), Xylocopa fenestrata (4.51%), X. latipes (3.87%), M. bicolor (3.22%), Thryeus remosus (1.29%), Nomia crassipes (1.29%), Pseudapis oxybeloides (1.29%), Megachile cephalotes (1.29%), M. gathela (1.29%), and the least abundant species, N. elliotii (0.64%). The limited number of species reported in the present study may be attributed to the relatively short sampling period. A longer sampling duration could have resulted in the identification of additional species. The diversity revealed the abundance, and distribution of bee taxa in study area, emphasizing the role of these spaces as viable ecological habitats for diverse bee fauna. However, information on the ecological significance of bee, with most research concentrated on their pollination efficiency in ecosystems. Relative Abundance: Bee abundance was calculated as the total number of bees collected at site, summed across all sampling events. Bee diversity was calculated by summing the number of unique species across all sampling periods and then applying Shannon's Diversity Index. Total 155 individuals are captured and 19 species were recorded. The Average population size is 8.158 recorded.

1. Simpson Index: (∑ i n i (n i -1)/N (N-1): 0.07734 2. Margalef Richness Index: S-1/ln N: 3.569 Note: Alpha indices are for a single sample of a single region. These indices are calculated with all data provided to the calculator as a single sample. A total ten sweeps of the hand insect net were made on the study plant.

Conclusion

This study highlights the diversity and abundance of bee species visiting Ankol (Alangium salvifolium), a medicinally important plant, in the semi-arid foothills of Mount Abu, Rajasthan. The findings underscore the crucial ecological role of bees in the pollination and reproductive success of A. salvifolium, which is vital for its sustainability and the broader biodiversity of the region. The medicinal significance of A. salvifolium, due to its diverse pharmacological properties, further emphasizes the importance of conserving bee populations to support its propagation and the associated benefits for traditional medicine and pharmaceutical research. Protecting these pollinators is essential for maintaining ecological balance and ensuring the continuation of valuable plant-pollinator interactions.

References

1. A. dizona (Engel, 2009)
2. A. violacea (Lepeletier, 1841)
3. Ceratina bighami (Cockerell, 1908)
4. Tetragonula iridipennis (Smith, 1854)
5. Thyreus ramosus (Lepeletier, 1841)
6. N. elliotii (Latreille, 1804) References
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