Butterfly diversity and community dynamics in the central Himalayas: Species composition, richness, abundance, and seasonal variation of butterflies (Lepidoptera: Papilionoidea) in Bhorletar, Nepal

Butterflies are among the most effective bioindicators of climate change;
however, their diversity in many rural areas of the Central Himalayas
remains understudied. This study provides an assessment of butterfly
diversity in the foothills of Bhorletar, Madhya Nepal Municipality,
Lamjung District, Nepal, within an elevation range of 420–600 m. Conducted
between July 2019 and January 2021, the survey involved opportunistic
observations and photography of adult butterflies in their natural
habitats, with sampling occurring six times each month. The study aimed to
investigate the species composition, richness, and abundance of
butterflies across the survey period and identify seasonal changes in
species composition and richness. A total of 94,009 individuals across 226
species, 129 genera, and six families were documented. During this study,
Halpe arcuata Evans, 1937 and Hasora taminatus bhavara Fruhstorfer, 1911
were recorded for the first time in Nepal. Additionally, Halpe filda
Evans, 1949 and Ctenoptilum vasava vasava (Moore, [1866]) were recorded
for only the second and third times, respectively, in Nepal, following a
gap of approximately three decades. The most abundant species was Pieris
canidia indica Evans, 1926 (Relative Abundance [RA] 2.55%), followed by
Pseudozizeeria maha maha (Kollar, [1844]) (RA 2.13%). Species richness
showed an annual bimodal distribution, peaking in April (180 species) and
August (161 species), while the lowest richness was observed in January
and February, with 68 and 75 species, respectively. Diversity indices
included a Shannon–Wiener index of 4.71, Pielou's J index of 0.87, an
effective number of species of 111.24, and Margalef's richness index
of 19.65, indicating high species diversity with a well-balanced mix of
species evenness and richness. This study offers the first peer-reviewed
checklist of butterflies from Bhorletar, providing crucial baseline data
for future research and conservation efforts, and highlights the
remarkable seasonal and species diversity within the region.