Introduction

White grubs, the larval stages of scarab beetles (Coleoptera: Scarabaeidae), are soil-dwelling pests characterized by their soft, fleshy, C-shaped bodies, typically white or cream-colored with a darker head capsule1. These larvae belong to multiple subfamilies, including Melolonthinae, Rutelinae, Dynastinae, Cetoniinae, and Aphodiinae, each playing distinct ecological roles. Initially, the term “white grub” was used primarily for Melolonthinae larvae2, but its scope has since expanded to include other subfamilies due to similarities in feeding habits and developmental traits3.

Globally, more than 36,000 scarab beetle species have been identified4, with over 2,000 species recorded in India5. The North-Western Himalayan region, particularly Uttarakhand, serves as a biodiversity hotspot for white grubs due to its diverse altitudinal gradients, soil types, and microclimatic conditions6. However, studies on their diversity, distribution, and population dynamics in this region remain limited, hindering the development of effective pest management strategies.

White grubs play dual roles in agroecosystems and forests. While certain species contribute to ecosystem services such as nutrient cycling3,7 and pollination8, many are significant agricultural pests. The phytophagous larvae of Melolonthinae, Dynastinae, and Rutelinae cause extensive damage to plant roots, leading to wilting, stunted growth, and severe yield losses9. Economic losses due to white grub infestations range from 12 to 100% in various crops, with the most severe damage occurring during the third-instar stage when larvae exhibit peak feeding activity10.

Adult scarab beetles emerging from pupation in the soil play a crucial role in species reproduction. Many species exhibit nocturnal behaviour and are strongly attracted to artificial light sources, a trait exploited in pest management using light traps. The scarab-specific light trap developed by ICAR-Vivekananda Parvatiya Krishi Anusandhan Sansthan, Almora, has demonstrated considerable efficacy in monitoring and reducing adult populations11. Despite such control measures, managing white grubs remains challenging due to their subterranean feeding habits, necessitating precise monitoring and region-specific control strategies.

Comprehensive documentation of species diversity and population fluctuations is crucial for understanding pest outbreaks and implementing targeted management approaches. Identifying species richness, abundance, and seasonal dynamics aids in distinguishing pest and non-pest species, facilitating more effective interventions. Biodiversity indices such as alpha and beta diversity provide essential insights into species composition across different habitats. Alpha diversity, which measures species richness and evenness within a habitat, is commonly assessed using Shannon-Weiner, Simpson’s diversity, and Margalef’s richness indices. Beta diversity, which examines species turnover between locations, is evaluated through Jaccard and Sørensen’s similarity indices12,13. These analytical tools help predict pest outbreaks and develop region-specific pest control strategies14.

Uttarakhand, situated in the Indian Himalayas, is a leading state in organic farming, with a significant proportion of its agricultural land managed under organic practices15. The state’s emphasis on sustainable agriculture has resulted in limited use of synthetic insecticides for white grub management16. Unlike conventional farming systems where chemical pesticides and antiparasitic treatments have been reported to impact beetle diversity17, the minimal application of such chemicals in Uttarakhand likely contributes to its high white grub beetle diversity. However, indirect influences such as livestock dewormers and organic biopesticides should also be considered when assessing beetle population dynamics. Further research is required to evaluate the long-term effects of organic farming practices on white grub diversity and abundance in this region.

This study aims to assess the species diversity, abundance, and population dynamics of white grub beetles across different agroecological zones of Uttarakhand. By analysing seasonal occurrence and species richness, the research will establish baseline data essential for species identification and sustainable pest management. Insights gained from this study will contribute to the development of integrated pest management (IPM) strategies tailored to the unique environmental conditions of the North-Western Himalayan region. Additionally, a deeper understanding of species diversity and habitat preferences will be instrumental in predicting future pest outbreaks under changing climatic conditions, ultimately supporting sustainable agricultural practices in the region.

Materials and methods

Study sites

Selection of study sites

The selection of study sites was done based on the following criteria:

  1. a.

    General history of incidence of white grubs in the study site, based on discussion with the farmers and local people living in that particular area.

  2. b.

    All selected study sites except one were hilly. As the majority of the cropped area in NW Himalayas is under well-drained sandy soil along the hill slopes, which favoured faster multiplication of white grubs.

  3. c.

    The study sites varied in terms of difference in vegetation as well as altitude. It was expected to obtain maximum species variation in the adult white grub beetle species during monitoring.

Thus, a total of seven locations in different agro-ecological regions of Uttarakhand (28° 44’− 31° 28’ North latitude and 77° 35’–81° 01’ East longitude), India were selected for the study (Detailed in Table 1).

Table 1 Description of study sites selected for the white Grub beetle monitoring study.
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Collection of white Grub beetles

The white grub beetles were collected through a light trap i.e., VL white grub beetle trap; IN 290,170. This is a scarab-specific trap which is made of 24 gauge tin sheets and consists of a compact fluorescent lamp assembly, hitting fins, a funnel, and a collection pot (Fig. 1). As trap design play important role in trapping any pest species, thus this trap is designed based on the fact that nocturnal white grub beetles get attracted to the light source and hover around the light; the hitting fins are kept at 120º angle with each other so that the white grub beetles rotating around the light source get hit and collected in the pot by directing through a funnel. The collection pot is half-filled with water so that the beetles trapped will not fly away.

Fig. 1
figure 1

VL white grub beetle trap; IN 290,170 used for monitoring the white grub beetle population dynamics (Image generated by co-author Johnson Stanley (stanley_icar@rediffmail.com)).

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Most of the white grub beetles emerge out of the soil especially after summer showers during May-June at the dusk time for feeding and mating. Considering their activity period, the study was conducted from May-August in 2020 and 2021. Light traps were installed at specific locations viz., Hawalbagh (1,280 m amsl), Chaukhutiya (1,222 m amsl), Mukteshwar (2,250 m amsl), Jeolikote (1,436 m amsl), Pantnagar (219 m amsl), Chinyalisaur (855 m amsl), and Gwaldam (1,960 m amsl) to assess the species diversity and abundance of white grub adults in Uttarakhand (Table 1). In each study location, four light traps with Compact Fluorescent Lamp (15 W) as light source, were positioned at a height of 1.0 m above ground level and at a distance of 500 m to reduce inter-trap interferences. The light traps were operated daily from 6:00 pm to 6:00 am. The sample collections were done fortnightly from May-August in 2020 and 2021.

Identification of white Grub beetles

The white grub beetles were identified based on the reference collection available at ICAR-VPKAS, Almora, and with the help of literature18,19,20,21,22,23,24,25,26. The identified specimens were preserved and maintained at ICAR-VPKAS, Almora (Supplementary file 1).

Data analysis

For quantitative characterization of the white grub beetle community in Uttarakhand, number of diversity indices were used to calculate the alpha diversity and beta diversity.

Alpha diversity

The estimation of the white grub beetle population was done by counting the white grub beetles trapped in the light traps installed at different locations in the study areas. For a complete understanding of the white grub beetle community structure in the selected study area, number of alpha diversity indices were calculated using Past 4.03 software27 (Table 2).

Table 2 Alpha diversity index used to estimate white Grub beetles diversity in selected study locations in Uttarakhand.
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Beta diversity

To have a complete understanding of the white grub beetle community structure between different habitats in Uttarakhand, the Jaccard similarity index and Sorensen’s similarity index were calculated manually.

  1. (i)

    Jaccard similarity index

Jaccard similarity index was calculated by the following formula as stated by Paul Jaccard12.

$${\text{S}} = \frac{{\text{a}}}{{({\text{a}} + {\text{b}} + {\text{c}})}}$$

Where S = Jaccard similarity index, a = Number of shared species between two habitats, b = Number of species present in habitat 1, and c = Number of species present in habitat 2.

  1. (ii)

    Sorensen’s similarity index

Sorensen’s similarity index developed by Thorvald Sørensen13 is used to quantify the similarity between two habitats, statistically by the following formula:

$${\ss} = \frac{{2{\text{C}}}}{{({\text{C + S1 + S2}})}}$$

Where ß= Sorensen’s similarity index, C = Number of shared species between two habitats, S1 = Number of species present in area 1, and. S2 = Number of species present in area 2.

Results

Diversity of white Grub beetles in Uttarakhand

A total of 17,460 and 10,523 white grub beetles were collected from 7 study sites i.e., Chaukhutiya, Chinyalisaur, Gwaldam, Hawalbagh, Jeolikote, Mukteshwar, and Pantnagar in the year 2020 and 2021, respectively. The total white grub beetle fauna represented 34 genera and 101 species during the study period (Table 3). The collected white grub beetle fauna composed of 5 subfamilies (Aphodiinae, Dynastinae, Melolonthinae, Rutelinae, and Scarabaeinae) and 15 tribes (Aphodiini, Dynastini, Oryctini, Pentodontini, Phileurini, Diplotaxini, Melolonthini, Schizonychini, Sericini, Adoretini, Anomalini, Coprini, Oniticellini, Onitini, and Onthophagini). Out of 101 species, 38 species belonged to Melolonthinae in 15 genera, 28 species belonged to Rutelinae in 4 genera, 26 species belonged to Scarabaeinae in 7 genera, 8 species belonged to Dynastinae in 7 genera, and only 1 species belonged to Aphodiinae. Maximum catch belonged to Melolonthinae (50.49% and 48.59% during 2020 and 2021, respectively) followed by Rutelinae (34.04% and 26.63% during 2020 and 2021, respectively), Scarabaeinae (7.87% and 11.05% during 2020 and 2021, respectively), Dynastinae (6.66% and 10.93% during 2020 and 2021, respectively), and Aphodiinae (0.95% and 2.80% during 2020 and 2021, respectively). The subfamily Melolonthinae dominated in terms of species richness (38 species) as well as species abundance (49.77% of total catch). The species belonging to the subfamily Aphodiinae were least abundant in species richness (only 1 species) as well as abundance (1.65% of total catch). Thus, the collected white grub beetle fauna belonged to both groups phytophagous as well as non-phytophagous groups of the family Scarabaeidae.

Table 3 Species diversity and relative abundance of white Grub beetles in Uttarakhand.
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White Grub beetles diversity in seven locations of Uttarakhand

Chaukhutiya (29° 52’ N latitude and 79° 22’ E longitude, 1,222 m amsl)

In Chaukhutiya, 29 species belonging to 4 subfamilies (Dynastinae, Melolonthinae, Rutelinae, and Scarabaeinae) were trapped in the light traps during 2020-21. Out of 29 species, 9 species belonged to Rutelinae, 9 species belonged to Scarabaeinae, 8 species belonged to Melolonthinae, and 3 species belonged to Dynastinae. The maximum catch belonged to Melolonthinae (35.87% and 25.30% during 2020 and 2021, respectively) followed by Rutelinae (24.46% and 33.73% during 2020 and 2021, respectively), Scarabaeinae (23.91% and 27.71% during 2020 and 2021, respectively), and Dynastinae (15.76% and 13.25% during 2020 and 2021, respectively). Xylotrupes gideon (Linnaeus, 1767) (12.00%) was the predominant species followed by Maladera similana (Brenske, 1899) (11.14%), Anomala dimidiata (Hope, 1831) (6.57%), and Onthophagus ramosus (Wiedemann, 1823) (6.29%) (Table 3). Overall, the subfamily Melolonthinae dominated as it contributed 30.86% (8 species) of total abundance.

Chinyalisaur (30° 20’ N latitude and 77° 49’ E longitude, 855 m amsl)

In Chinyalisaur, 28 species belonging to 4 subfamilies (Dynastinae, Melolonthinae, Rutelinae, and Scarabaeinae) were trapped in the light traps during 2020-21. Out of 28 species, 11 species belonged to Melolonthinae, 11 species belonged to Rutelinae, 4 species belonged to Scarabaeinae, and 2 species belonged to Dynastinae. The maximum catch belonged to Melolonthinae (46.17% and 50.20% during 2020 and 2021, respectively) followed by Rutelinae (32.45% and 27.31% during 2020 and 2021, respectively), Dynastinae (17.41% and 17.67% during 2020 and 2021, respectively), and Scarabaeinae (3.96% and 4.82% during 2020 and 2021, respectively). M. similana (11.62%) was the predominant species followed by Anomala rugosa Arrow, 1899 (11.31%), Holotrichia setticollis Moser, 1912 (10.51%), X. gideon (8.92%), and Heteronychus lioderes Redtenbacher, 1868 (8.60%) (Table 3). Overall, the subfamily Melolonthinae dominated in species richness (11 species) as well as abundance (47.77% of total catch).

Gwaldam (30° 00’ N latitude and 79° 33’ E longitude, 1,960 m amsl)

In Gwaldam, 37 species belonging to 4 subfamilies (Dynastinae, Melolonthinae, Rutelinae, and Scarabaeinae) were trapped in the light traps during 2020-21. Out of 37 species, 20 species belonged to Melolonthinae, 7 species belonged to Rutelinae, 6 species belonged to Scarabaeinae, and 4 species belonged to Dynastinae. The maximum catch belonged to Melolonthinae (64.81% and 63.20% during 2020 and 2021, respectively) followed by Dynastinae (15.69% and 17.95% during 2020 and 2021, respectively), Rutelinae (15.05% and 12.21% during 2020 and 2021, respectively), and Scarabaeinae (4.44% and 6.64% during 2020 and 2021, respectively). X. gideon (15.64%) was the predominant species followed by Holotrichia sikkimensis (Brenske, 1892) (14.77%), Hilyotrogus holosericeus Redtenbacher, 1844 (14.57%), and M. similana (10.47%) (Table 3). Overall, the subfamily Melolonthinae dominated in species richness (20 species) as well as abundance (64.11% of total catch).

Hawalbagh (29° 38’ N latitude and 79° 37’ E longitude, 1,280 m amsl)

In Hawalbagh, 71 species belonging to 5 subfamilies (Aphodiinae, Dynastinae, Melolonthinae, Rutelinae, and Scarabaeinae) were trapped in the light traps during 2020-21. Out of 71 species, 29 species belonged to Melolonthinae, 20 species belonged to Scarabaeinae, 16 species belonged to Rutelinae, 5 species belonged to Dynastinae, and only 1 species belonged to Aphodiinae. The maximum catch belonged to Melolonthinae (50.20% and 50.65% during 2020 and 2021, respectively) followed by Rutelinae (39.78% and 28.74% during 2020 and 2021, respectively), Scarabaeinae (5.02% and 8.33% during 2020 and 2021, respectively), Dynastinae (3.66% and 7.45% during 2020 and 2021, respectively), and Aphodiinae (1.35% and 4.83% during 2020 and 2021, respectively). M. similana (14.61%) was the predominant species followed by A. dimidiata (10.29%), Anomala sp. 2 (6.67%), and Holotrichia longipennis (Blanchard, 1850) (5.01%) (Table 3). Overall, the subfamily Melolonthinae dominated in species richness (29 species) as well as abundance (50.35% of total catch).

Jeolikote (29° 20’ N latitude and 79° 28’ E longitude, 1,436 m amsl)

In Jeolikote, 31 species belonging to 4 subfamilies (Dynastinae, Melolonthinae, Rutelinae, and Scarabaeinae) were trapped in the light traps during 2020-21. Out of 31 species, 16 species belonged to Melolonthinae, 9 species belonged to Rutelinae, 5 species belonged to Scarabaeinae, and only 1 species belonged to Dynastinae. The maximum catch belonged to Melolonthinae (56.69% and 55.16% during 2020 and 2021, respectively) followed by Dynastinae (22.05% and 19.28% during 2020 and 2021, respectively), Rutelinae (15.35% and 17.49% during 2020 and 2021, respectively), and Scarabaeinae (5.91% and 8.07% during 2020 and 2021, respectively). X. gideon (20.75%) was the predominant species followed by H. longipennis (12.37%), M. similana (11.95%), and Sophrops sp. 2 (7.76%) (Table 3). Overall, the subfamily Melolonthinae dominated in species richness (16 species) as well as abundance (55.97% of total catch).

Mukteshwar (29° 28’ N latitude and 79° 38’ E longitude, 2,250 m amsl)

In Mukteshwar, 27 species belonging to 4 subfamilies (Dynastinae, Melolonthinae, Rutelinae, and Scarabaeinae) were trapped in the light traps during 2020-21. Out of 27 species, 12 species belonged to Melolonthinae, 7 species belonged to Scarabaeinae, 4 species belonged to Dynastinae, and 4 species belonged to Rutelinae. The maximum catch belonged to Melolonthinae (47.73% and 45.27% during 2020 and 2021, respectively) followed by Rutelinae (27.65% and 8.53% during 2020 and 2021, respectively), Scarabaeinae (16.85% and 22.63% during 2020 and 2021, respectively), and Dynastinae (7.78% and 23.56% during 2020 and 2021, respectively). Anomala sp. 1 (19.32%) was the predominant species followed by H. holosericeus (17.13%), X. gideon (12.01%), and Melolontha nepalensis (Blanchard, 1850) (7.30%) (Table 3). Overall, the subfamily Melolonthinae dominated in species richness (12 species) as well as abundance (46.83% of total catch).

Pantnagar (29° 01’ N latitude and 79° 32’ E longitude, 219 m amsl)

In Pantnagar, 43 species belonging to 4 subfamilies (Dynastinae, Melolonthinae, Rutelinae, and Scarabaeinae) were trapped in the light traps during 2020-21. Out of 43 species, 14 species belonged to Melolonthinae, 14 species belonged to Scarabaeinae, 10 species belonged to Rutelinae and 5 species belonged to Dynastinae. The maximum catch belonged to Rutelinae (21.11% and 40.43% during 2020 and 2021, respectively) followed by Melolonthinae (33.12% and 27.42% during 2020 and 2021, respectively), Scarabaeinae (33.91% and 22.00% during 2020 and 2021, respectively), and Dynastinae (11.85% and 10.14% during 2020 and 2021, respectively). Anomala dorsalis (Fabricius, 1775) (12.56%) was the predominant species followed by Anomala biharensis Arrow, 1917 (10.98%), Digitonthophagus bonasus (Fabricius, 1775) (6.44%), and Onthophagus gazelle (Fabricius, 1775) (6.19%) (Table 3). Overall, the subfamily Rutelinae dominated (31.77% of total catch).

The differences in the species diversity of white grub beetles collected from study sites were apparent. Maximum species richness was recorded in Hawalbagh (71 species), followed by Pantnagar (43 species), Gwaldam (37 species), Jeolikote (31 species), Chaukhutiya (29 species), Chinyalisaur (28 species), and Mukteshwar (27 species). The subfamily Melolonthinae dominated in terms of species richness (38 species) as well as species abundance (49.77% of total catch) (Fig. 2). Maximum diversity was recorded in the genus Anomala with 17 species. Overall, M. similana (12.1%) dominated the collection, followed by A. dimidiata (6.93%), and X. gideon (6.25%) in Uttarakhand (Fig. 3).

Fig. 2
figure 2

Total subfamily-wise relative abundance of white grub beetles trapped in Uttarakhand during the study period (2020–2021).

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Fig. 3
figure 3

Dominant species of white grub beetles in Uttarakhand.

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Diversity analysis

Alpha diversity

The marked difference in species composition was reflected in various alpha diversity indices (Table 4). The highest species richness and diversity was recorded in the mid-altitude region i.e., Hawalbagh. It is reflected in Dominance (0.054), Simpson index (0.946), Shannon index (3.381), Brillouin index (3.370), Menhinick richness index (0.524), Margalef richness index (7.129), Fisher alpha diversity index (9.363), and Chao-1 index (71.75). However, the species distribution was more uniform in the Chaukhutiya region as indicated by Buzas and Gibson’s evenness index (0.712) and Pielou’s evenness index (0.899). The results of the diversity indices revealed that the species diversity was better in Hawalbagh than in the other six regions.

Table 4 Alpha diversity indices calculated using past 4.03 software to estimate white Grub beetles diversity in selected study areas in Uttarakhand.
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Beta diversity

The Jaccard similarity index and Sorensen’s similarity index values calculated between different locations of Uttarakhand are given in Table 5. The beta diversity was observed to be less than 50% between all the study locations except between Gwaldam and Mukteshwar (52.87%). Besides these, Mukteshwar and Pantnagar have poor similarity (10.81%) in terms of species diversity, richness, and abundance index. Although the similarity between different locations was low, the overall results of beta diversity analysis showed that the white grub species diversity changed along the gradient in Uttarakhand. Thus, the values of alpha and beta diversity assessed through various diversity indices revealed the rich diversity of white grub beetles in Uttarakhand.

Table 5 Beta diversity values calculated to measure change in the white Grub beetles diversity along the selected gradients in Uttarakhand.
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Discussion

Biodiversity, or biological diversity, is a concept that often lacks clarity in ecological literature, requiring contextual definition whenever it is mentioned. In some instances, it refers to all species inhabiting a specific area, while in other cases, it pertains to a particular group of organisms. When comparing different environments or regions, the latter definition tends to provide a more accurate estimate38. By quantifying biological diversity as the number of related or similar species, we can better understand how various factors—such as topography, altitude, habitat, soil moisture, temperature, vegetation, and other environmental variables—affect the species present in a given area. White grub beetles, for example, are distributed across different regions of India due to variations in altitude, latitude, and biogeographical zones39. The first thorough study of these beetles in the Indian subcontinent was conducted by Arrow18, whose multi-volume Fauna of British India series18,19,20 reported 72 species from Uttarakhand. By 2017, this number had expanded to 171 species, classified under nine subfamilies and three families within the Scarabaeoidea superfamily40. The species reported include those from the subfamilies Aphodiinae, Dynastinae, Melolonthinae, Rutelinae, and Scarabaeinae, with A. dimidiata, H. longipennis, and H. setticollis being particularly dominant in Uttarakhand41. In recent years, however, the composition and abundance of white grub species have been influenced by various factors such as the introduction of new crops, agricultural intensification, shifts in land use, and climate change3,42,43. Factors like weather, elevation, soil type, and vegetation play significant roles in determining the habitat preferences of white grub species42. As a result, species composition varies across different habitats, reflecting the distinct environmental conditions and selection pressures. The distribution and abundance of these species are key considerations when evaluating the need for pest management interventions in agricultural ecosystems. Thus, this study aims to define and compare the complex white grub species present in various regions of Uttarakhand, which represent diverse elevations, soil types, land use patterns, and ecological conditions.

Uttarakhand is a biodiversity hotspot, supporting a range of environments that sustain diverse taxa, including white grub beetles. To accurately assess species diversity and abundance, reliable and consistent surveying techniques are essential. While a variety of sampling methods exist—ranging from simple pitfall traps to more sophisticated techniques like the Mini-Winkler extractor—pitfall traps remain one of the most commonly used and straightforward methods. Complementary monitoring methods, such as light traps, flight interception traps, and in situ collection, are particularly useful in microhabitats, potentially revealing new species. Other techniques, such as pheromone traps and Mini-Winkler extractors, are less frequently employed. Given the variety of sampling approaches and monitoring efforts, comparing different study sites becomes challenging. Standardizing monitoring techniques is crucial when studying any taxonomic group, including white grub beetles38. In this study, to facilitate comparison across study sites, a single method—a white grub beetle-specific light trap—was chosen for monitoring, ensuring consistency in data collection across spatial and temporal studies38.

In this study, 101 species from 5 subfamilies (Aphodiinae, Dynastinae, Melolonthinae, Rutelinae, and Scarabaeinae) were documented across 7 locations in Uttarakhand: Hawalbagh, Chaukhutiya, Mukteshwar, Jeolikote, Pantnagar, Chinyalisaur, and Gwaldam. The white grub beetle fauna in the region includes both Laparosticti and Pleurosticti species. The Laparosticti species from Aphodiinae are small dung beetles, while those from Scarabaeinae are dung feeders3. These species are further categorized into two groups: dwellers (e.g., Oniticellus) and tunnelers (e.g., Copris, Catharsius, Digitonthophagus, Heliocopris, Onitis, Onthophagus). The Pleurosticti species, which include members of Dynastinae, Melolonthinae, and Rutelinae, are chafers that feed on various plant parts such as leaves, flowers, pollen, and fruits3.

The highest species richness was recorded at Hawalbagh (71 species), likely due to the favourable climatic and ecological conditions of the mid-hills (1,280 m amsl), which support the growth and development of white grubs. The lowest species diversity was found in Mukteshwar (2,250 m amsl), where cooler temperatures at higher altitudes may hinder the development of white grubs22,42,44. This negative correlation between altitude and white grub beetle diversity has been previously noted by Imura45, Pathania et al.46, and Murthy42. Other study sites, including Pantnagar, Gwaldam, Jeolikote, Chaukhutiya, and Chinyalisaur, reported species counts of 43, 37, 31, 29, and 28, respectively. The variation in white grub fauna across these locations is attributed to the rich vegetation that provides feeding and mating grounds for the beetles, a finding also noted by Dhoj et al.47, Pathania et al.46, and Murthy42. The presence of natural vegetation surrounding six of the seven study sites likely contributes to the greater diversity observed22,46,47,48. Furthermore, these sites have a long history of crop cultivation, which helps conserve white grub species, as they are a primary food source for both adults and larvae of phytophagous species46,49. The distribution of white grub species in Uttarakhand is influenced by vegetation, soil type, geographical location, and climatic factors.

The genus Anomala exhibited the greatest species diversity, with 17 species, followed by Onthophagus (11 species), Holotrichia (9 species), Adoretus (7 species), Maladera (6 species), and Onitis (5 species). Other genera included fewer species, with some represented by a single species. Anomala was also identified as the dominant genus in other regions42,46,50. Notable economic species from the genera Anomala, Adoretus, Brahmina, Heteronychus, Holotrichia, Lepidiota, Maladera, Melolontha, Phyllognathus, Sophrops, and Xylotrupes have been reported as pests of various agricultural and horticultural plants and forest trees. In this study, M. similana (12.1%) was the most dominant species, followed by A. dimidiata (6.93%) and X. gideon (6.25%) in Uttarakhand. M. similana damages a wide range of plants, including Carya illinoinensis, Helianthus annuus, Hibiscus rosa-sinensis, Juglans regia, and Solanum tuberosum51. A. dimidiata affects plants such as Lagerstroemia indica, Allium sativum, Brassica oleracea, and Solanum melongena52, while X. gideon damages crops like Abelmoschus esculentus, Bambusa vulgaris, and Musa paradisiaca53,54. Understanding the diversity and predominant species of white grubs is essential for planning effective pest management strategies3.

The subfamily Melolonthinae is recognized as the largest subfamily of white grub beetles, followed by Rutelinae3. However, the distribution of white grub beetles in Uttarakhand remains underexplored. In this study, Melolonthinae (38 species, 49.77% of total catch) was the most dominant subfamily, followed by Rutelinae (28 species, 31.25%), Scarabaeinae (26 species, 9.07%), Dynastinae (8 species, 8.26%), and Aphodiinae (1 species, 1.65%). Similar trends were observed in other states42,46,55,56. Pathania et al.46 recorded 56 species of white grub beetles from Himachal Pradesh, with Melolonthinae constituting 53.23% of the species. Murthy42 found Melolonthinae to be the most dominant subfamily in South India, comprising 38.23% of the species, followed by Rutelinae (20.53%). These findings contrast with those of Kumar et al.50, who reported Rutelinae as the dominant subfamily in Almora, Uttarakhand.

Alpha and beta diversity were calculated to analyze the species composition and distribution of white grub beetles in Uttarakhand. High diversity was recorded in the mid-altitude region of Hawalbagh, reflected in diversity indices such as Fisher’s alpha (9.363) and Margalef’s richness index (7.129). The beta diversity between all study locations was less than 50%, except for Gwaldam and Mukteshwar (52.87%). The similarity between these two locations is likely due to their similar altitudes (Gwaldam: 1,960 m amsl, Mukteshwar: 2,250 m amsl) and cold climatic conditions. In contrast, Mukteshwar and Pantnagar showed poor similarity (10.81%) due to differences in altitude, soil types, vegetation, and climate. Factors such as food, geography, and climate have been shown to influence the diversity and abundance of white grub beetles57,58.

White grub beetles, as bioindicators, provide valuable insights into ecosystem health and quality59. These beetles are increasingly used in ecological studies to monitor biodiversity, environmental disturbances, and habitat quality38,60. The presence of dung beetles, a well-known bioindicator group, reflects the presence of large herbivores, which serve as their food source61. White grub beetles are valuable for assessing management practices, biodiversity, environmental disturbances, habitat classification, and site quality. The current study’s database on white grub beetles in Uttarakhand can serve as a useful tool for future research and monitoring of pest management techniques.

In conclusion, this study provides essential data on the composition, abundance, and diversity of white grub beetles in Uttarakhand. Factors such as soil type, cropping patterns, geographical location, and climate influence their distribution. The location-specific database established here can help develop strategies for the conservation of natural enemies, habitat management, and effective integrated pest management. Additionally, this study lays the groundwork for future research on white grub diversity in Uttarakhand, with the potential for discovering more taxa to further enhance our understanding of this pest group. Continuous monitoring is necessary to address the challenges associated with the economic impact of white grubs.