Diversity, richness, and species composition of fruit flies with new and first records from Meghalaya, India.

Fruit flies are cosmopolitan insects affecting almost all the fruit growing regions of the world. This insect is of significant economic importance as they can cause serious damage to fruit, sometimes resulting in almost total crop failure. This study investigates the diversity and species composition of fruit flies in relation to host availability with the aim of identifying and recording new species of fruit fly in Meghalaya and across the Indian sub-continent. For this, a three-year survey (October 2020-September 2023) was conducted across three ecosystems, forest, fruit tree and vegetable ecosystems in the Ri-bhoi district of Meghalaya. Influence of host plants, seasons, trap types and attractants on the fruit fly abundance was assessed. Diversity indices, including species richness (S), Shannon-Wiener index (H'), Simpson's D (dominance), and Pielou's evenness (J'), were calculated monthly for the three ecosystems. The study recorded 37 fruit fly species across several genera and tribes. These included Bactrocera, Dacus, and Zeugodacus (Dacini, Dacinae); Acroceratitis, Acrotaeniostola, and Paraxarnuta (Gastrozonini, Dacinae); and Rioxoptilona, Themara, Erectovena, and Phorelliosoma (Acanthonevrini, Phytalminae). A total of 16 subgenera were identified, with Bactrocera being the most dominant in Meghalaya. Two new species, Zeugodacus umiam and Z. nasivittatus, were recorded from Khasi mandarin and sweet orange, respectively; the former was attracted to cue-lure, while the latter responded to protein and yeast baits. Additionally, several rare species - Bactrocera abbreviata, Erectovena desperata, and Phorelliosoma hilaratum-were recorded for the first time in the Indian subcontinent. Acroceratitis bimacula and Acrotaeniostola spiralis were exclusively collected from bamboo using yeast-based baits, while P. hilaratum was found on forest trees and attracted to yeast- and protein-based baits. Sample-size and coverage-based rarefaction/extrapolation curves revealed that net traps and Zingerone lures captured the highest fruit fly, indicating effective sampling across sites. Zeta diversity analysis demonstrated higher initial species sharing in forest ecosystems compared with vegetables and fruit tree ecosystems. Principal Component Analysis (PCA) revealed clear differentiation of fruit fly assemblages across ecosystems and lure types, highlighting the influence of habitat and bait preference on community structure. Together, these findings establish a baseline for fruit fly diversity, seasonal patterns, and bait preferences in the region, while also highlighting its rich fauna through the discovery of several new species and first reports across the Indian subcontinent.