DIVERSITY AND DISTRIBUTION OF SCARAB BEETLES (COLEOPTERA: SCARABIDAEIDAE) IN MALAKAND DIVISION, PAKISTAN

Abstract

Dung beetles (Coleoptera: Scarabaeidae) play important roles in terrestrial ecosystems by cycling nutrients, aerating soil, dispersing seeds, and controlling parasites. In this context, we examined the diversity and distribution of dung beetles in the Malakand Division of Khyber Pakhtunkhwa, Pakistan, from 2019 to 2021. We aimed to identify species, understand their ecological roles, and determine how environmental factors affect their populations. Over three years, we identified 42 species from 27 genera and collected 2,698 beetles using baited pitfall traps, hand-picking, sweeping, and beating vegetation.

Malakand Division includes a range of habitats, such as forests, farms, and rangelands, which support dung beetle populations that rely on organic matter, especially mammal dung. Building on this, researchers conducted the study in 10 locations across the region, including Swat, Buner, Chitral, Dir Upper, Dir Lower, Shangla, and Malakand, each with different altitudes and climates. They sampled beetles during peak activity from May to September. To measure species diversity, abundance, and distribution, the researchers used the Shannon Index, Inverse Simpson Index, and Fisher Alpha Index. These tools assessed species richness, evenness, dominance, and the overall health of beetle communities.

The results revealed a high level of diversity in the Scarabaeidae populations, with 42 species identified across the study period. Notably, 17 species, including Xylotrupes ulysses, Phyllognathus dionysius, Anomala dimidiata, and Oniticellus cinctus, were recorded in Pakistan for the first time. Shannon Index values ranged from 2.89 to 3.17, showing moderate to high diversity and a stable community across all three years. Simpson Index values remained between 0.94 and 0.96 each year, meaning no single species dominated, which points to a healthy balance. The Fisher Alpha Index averaged 4.93, indicating high species richness overall. However, the Inverse Simpson Index detected notable yearly variation: in 2019, the mean was 0.96, indicating low diversity and possible species dominance; in 2020, this mean jumped to 23.50, suggesting a sudden increase in diversity or more balanced abundances; in 2021, it decreased to 3.17, indicating declining diversity from the 2020 peak but still above the 2019 baseline. These changes in the Inverse Simpson Index suggest shifts in which species were most common, potentially due to environmental changes affecting food sources or beetle movement each year. In 2020, changes in vegetation or climate may have reduced dung availability and affected mammal behavior, leading to a temporary peak in diversity. Despite fluctuations in which species were abundant, the Shannon and Fisher Alpha Indices showed that overall diversity and species richness stayed relatively stable year to year. This suggests that while the balance of dominant species shifted, the diversity and number of species remained fairly constant.

In summary, this research provides important information about dung beetle diversity and distribution in the Malakand Division and highlights their key role in maintaining ecosystem health. Although a high number of species persists and the community remains stable, shifts in dominant species indicate that dung beetles respond to environmental changes. We must continue monitoring and enact focused conservation to protect their essential ecological roles in the region.