Urban mango and jackfruit favor the proliferation of invasive fruit flies

Between January 2023 and March 2024, we collected fallen and overripe fruits from mango (Mangifera indica) and jackfruit (Artocarpus heterophyllus) trees in various urban locations throughout the Federal District (Table S1; Figure 1), including public green spaces and residential backyards. Fruits were transported to the laboratory, weighed, and placed in containers covered with fine mesh lids and containing vermiculite at 25°C (12/12 h photoperiod). Adult flies emerging over 21 days were collected and preserved in 70% ethanol (Ribeiro et al., 2023; Viana et al., 2024). To characterize community structure, adults were identified to species level whenever possible, using external morphology and taxonomic key (Yuzuki & Tidon, 2020). Identified species were assigned a biogeographic origin (Neotropical, Oriental, Afrotropical) using published records. Neotropical species were then classified as native, while introduced species sustaining self-propagating populations were classified as invasive non-native, following the nomenclature proposed by Soto et al., (2024). To estimate infestation pressure, we calculated drosophilid density as the number of individuals per gram of fruit (ind/g) for both mango and jackfruit. To estimate the contribution of each drosophilid species to the community, we calculated its relative abundance for each fruit species based on Viana et al., (2024): RAi = (TAi/TAd) × 100 where RAi represents the relative abundance of drosophilid species i, TAi is the total number of individuals of that species, and TAd is the total number of drosophilids (all species combined).本研究于2023年1月至2024年3月期间，从联邦特区境内多处城市区域的芒果（Mangifera indica）与波罗蜜（Artocarpus heterophyllus）树上采集掉落及过熟果实（见表S1、图1），采样范围涵盖公共绿地与住宅后院。将果实转运至实验室，经称重后置于铺有细网盖的容器内，容器中铺有蛭石（vermiculite），饲养环境设置为25℃、12/12小时光周期（photoperiod）。21天内羽化的成虫被收集并以70%乙醇保存（Ribeiro et al., 2023; Viana et al., 2024）。 为表征群落结构，本研究尽可能通过外部形态学特征与分类检索表（taxonomic key，Yuzuki & Tidon, 2020）将成虫鉴定至物种水平。基于已发表的文献记录，为鉴定得到的物种标注其生物地理起源（biogeographic origin），划分为新热带区、东洋区与非洲热带区。随后参照Soto等人（2024）提出的命名规范，将新热带区物种归类为本土物种；而能够维持自我繁殖种群（self-propagating populations）的引入物种，则划分为外来入侵物种。 为估算侵染压力，本研究以每克果实的个体数（ind/g）为指标，计算芒果与波罗蜜样本中的果蝇科（Drosophilidae）密度。为评估各果蝇物种对群落的贡献度，基于Viana等人（2024）的方法，针对每种果实物种计算对应果蝇物种的相对丰度（relative abundance）： RAi = (TAi/TAd) × 100 其中RAi代表果蝇物种i的相对丰度，TAi为该物种的总个体数，TAd为所有果蝇物种的总个体数。