Eucalyptus is one of the most planted tree genera across the world, but is heavily challenged by invasive insect pests originating from the native range of these trees. The rate of introduction of non-native Eucalyptus-feeding insects has increased globally, including in sub-Saharan Africa where Eucalyptus trees have an important socio-economic role. In this study, we mapped the distribution and examined the genetic diversity of non-native Eucalyptus insect pests in 14 countries across sub-Saharan Africa. We focused on five foliage-feeding insect pests of Eucalyptus which are known to be present in the region, namely the bluegum chalcid wasp, Leptocybe invasa; the redgum lerp psyllid, Glycaspis brimblecombei; the bronze bug, Thaumastocoris peregrinus; the Eucalyptus weevil, Gonipterus sp.n.2; and the Eucalyptus gall wasp, Ophelimus maskelli. Insect samples were collected through structured surveys and small-scale sampling which were both combined with published literature to determine the distribution of these insect pests. Genetic diversity of each of these insect pests was estimated/assessed based on mitochondrial cytochrome oxidase I (COI) or cytochrome b (Cyt b) sequence data. Except O. maskelli, which is a relatively recent arrival, the other insect pests were found broadly distributed across the sampled countries, with first reports in many countries. Analysis of genetic diversity confirmed a common origin of geographically distant populations for G. brimblecombei and O. maskelli, moderate diversity for T. peregrinus and Gonipterus sp.n.2 and at least two distinct lineages for L. invasa. Two divergent haplogroups of L. invasa, with overlapping geographic range were confirmed in Ghana, Malawi, Sierra Leone, South Africa and Zimbabwe. Compared to published literature, new haplotypes were detected for T. peregrinus, Gonipterus sp.n.2 and L. invasa, suggesting multiple introduction of those pests in the region. Results of this study will have implications for quarantine, management and future research of Eucalyptus insect pests in the region and beyond.

桉树是世界上种植最多的树属之一，但受到来自这些树种的原生范围的入侵性害虫的严重挑战。在全球范围内，以非天然桉树为食的昆虫的引进速度有所提高，包括在撒哈拉以南非洲，桉树在其中扮演着重要的社会经济角色。在这项研究中，我们绘制了分布图，并检查了撒哈拉以南非洲14个国家/地区的非本地桉树害虫的遗传多样性。我们集中研究了已知在该地区存在的五种以树叶为食的桉树害虫，即蓝桉叶蜂，Leptocybe invasa；赤ler木虱，甘草; 青铜虫，Thaumastocoris peregrinus；桉树象鼻虫Gonipterus sp.n.2; 还有桉树黄蜂，Ophelimus maskelli。通过结构化调查和小规模采样收集昆虫样本，将它们与已发表的文献相结合以确定这些害虫的分布。根据线粒体细胞色素氧化酶I（COI）或细胞色素b（Cyt b）序列数据估算/评估每种害虫的遗传多样性。除了O. maskelli，这是一个相对较新的到来，其他害虫被广泛分布在抽样国家中，许多国家都首次报告。遗传多样性的分析证实地理上远离人群的一个共同的起源G. brimblecombei和O. maskelli，对中度多样性T.游隼和Gonipterus sp.n.2和至少两种不同谱系L. invasa。在加纳，马拉维，塞拉利昂，南非和津巴布韦确认了地理分布重叠的L. invasa两个不同的单倍群。与已发表的文献相比，百日草（T. peregrinus），Gonipterus被发现了新的单倍型sp.n.2和L. invasa，表明该区域多次引入了这些有害生物。这项研究的结果将对该地区及其他地区的桉树害虫进行检疫，管理和未来研究。