Faunal Diversity and Abundance of Syrphids in Litchi and Guava Ecosystems, Including a New Record of Scaeva latimaculata (Brunetti, 1923) from the Shivalik Hills, Himachal Pradesh, India

Abstract

Aims: Himachal Pradesh is situated in the western Himalayas. Kangra district of the state, especially Shivalik hills are known to retain a rich treasure of climatic variability, favourable for diversified vegetation and insect fauna. This study assessed the abundance and diversity of syrphids (Diptera) in litchi and guava ecosystems. Study Design: Orchards were randomly divided into three replicates without a fixed design. Place and Duration of Study: Total six different locations in the Kangra district were surveyed from the year 2019 to 2020. Surveys on litchi were conducted during the year 2019 at Palampur, Nagrota Bagwan, Sulah and Saliana while on guava during 2020 at Palampur, Bharwar and Nurpur. Methodology: Sweep net collections were preserved and identified. Species richness, relative abundance, diversity indices, and per cent contribution of syrphid fauna were calculated. Results: Ten species across seven genera in two subfamilies (Eristalinae, Syrphinae) were recorded. In addition, Scaeva latimaculata (Brunetti, 1923) was reported for the first time from Kangra in litchi. Litchi exhibited greater diversity than guava, with higher species richness and diversity indices (Simpson, Shannon-Weiner: 1.98 vs 1.28; Pielou’s Evenness: 0.95 vs 0.92), indicating uniform species distribution and absence of dominance. Overall, Eristalini syrphids comprised 48.89% of specimens. Litchi attracted more Eristalini members, while guava attracted more Syrphini. Among locations, Nagrota Bagwan had the highest visitation (28.89%), while Saliana documented the lowest (5.56%). These records of syrphid flies from different sites will enrich the prevailing data on syrphid fauna and their spatial arrangement during their blooming periods within the two selected ecosystems i.e. litchi and guava. Conclusion: Syrphids formed one of the major insect visitor groups and were anticipated to enhance pollination in the region. Litchi ecosystem was more diverse when compared to guava and indicated more uniform distribution of syrphid population. Eristalini outnumbered overall, though crop-specific trends emerged differently. Eristalini members dominated litchi, while Syrphini dominated guava. Spatial records from this study enhance baseline data on syrphid fauna and distribution patterns during bloom, though extended monitoring is recommended for validation.