Bactrocera dorsalis, the Oriental fruit fly, is one of the world's most destructive agricultural insect pests and a major impediment to international fresh commodity trade. The genetic structuring of the species across its entire geographic range has never been undertaken, because under a former taxonomy B. dorsalis was divided into four distinct taxonomic entities, each with their own, largely non‐overlapping, distributions. Based on the extensive sampling of six a priori groups from 63 locations, genetic and geometric morphometric datasets were generated to detect macrogeographic population structure, and to determine prior and current invasion pathways of this species. Weak population structure and high genetic diversity were detected among Asian populations. Invasive populations in Africa and Hawaii are inferred to be the result of separate, single invasions from South Asia, while South Asia is also the likely source of other Asian populations. The current northward invasion of B. dorsalis into Central China is the result of multiple, repeated dispersal events, most likely related to fruit trade. Results are discussed in the context of global quarantine, trade, and management of this pest. The recent expansion of the fly into temperate China, with very few associated genetic changes, clearly demonstrates the threat posed by this pest to ecologically similar areas in Europe and North America.

The changing global climate has significantly impacted the spread of plant pests. The cassava mealybug (Phenacoccus manihoti) is among the most dangerous quarantine pests affecting cassavas worldwide, causing substantial losses in agricultural production and food security across several regions. Although China is currently free of the cassava mealybug, its proximity to affected countries and extensive trade with these regions necessitate a detailed understanding of the pest’s distribution pattern and dynamic ecological niche changes. Using the Biomod2 model, we selected two historical climate scenarios and two future climate scenarios (SSP1-2.6 and SSP5-8.5) to investigate the distribution patterns, potential habitats, distribution centers, and dynamic ecological niches of cassava mealybugs in China. Key environmental variables influencing the distribution were identified, including bio4, bio8, bio12, bio18, and bio19. The potential habitat of cassava mealybugs is mainly located in several provinces in southern China. In the future, the suitable habitat is projected to expand slightly under the influence of climate change, maintaining the overall trend, but the distribution center of suitable areas will shift northward. Dynamic ecological niche prediction results indicate the potential for further expansion; however, the ecological niches may be unequal and dissimilar in the invaded areas. The predictions could serve as a valuable reference for early warning systems and management strategies to control the introduction of cassava mealybugs.

Introduction: Erigeron philadelphicus and Erigeron annuus are two ecologically destructive invasive plants from the Asteraceae family. Predicting the potential distribution pattern of two invasive alien Erigeron weeds can provide a scientific basis for prevent the further spread of these two weeds in China under climate change.Methods: Based on historical occurrence datasets and environmental variables, we optimized a MaxEnt model to predict the potential suitable habitats of E. philadelphicus and E. annuus. We also analyzed the shifts of distribution centroids and patterns under climate change scenarios.Results: The key variables that affect the potential geographical distribution of E. annuus and E. philadelphicus, respectively, are temperature seasonality and precipitation of the driest month. Moreover, topsoil sodicity and topsoil salinity also influence the distribution of E. philadelphicus. Under climate change, the overall suitable habitats for both invasive alien Erigeron weeds are expected to expand. The potential geographical distribution of E. annuus exhibited the highest expansion under the SSP245 climate scenario (medium forcing scenarios), whereas E. philadelphicus had the highest expansion under the SSP126 climate scenario (lower forcing scenarios) globally. The future centroid of E. annuus is projected to shift to higher latitudes specifically from Hubei to Hebei, whereas E. philadelphicus remains concentrated primarily in Hubei Province. The overlapping suitable areas of the two invasive alien Erigeron plants mainly occur in Jiangsu, Zhejiang, Fujian, Jiangxi, Hunan, Guizhou, and Chongqing, within China.Discussion: Climate change will enable E. annuus to expand into northeastern region and invade Yunnan Province whereas E. philadelphicus was historically the only suitable species. E. annuus demonstrates a greater potential for invasion and expansion under climate change, as it exhibits higher environmental tolerance. The predictive results obtained in this study can serve as a valuable reference for early warning systems and management strategies aimed at controlling the spread of these two invasive plants.

Tephritidae fruit flies (Diptera: Tephritidae) are regarded as important damage-causing species due to their ability to cause great economic losses in fruit and vegetable crops. Bactrocera minax and Bactrocera tsuneonis are two sibling species of the subgenus Tetradacus of Bactrocera that are distributed across a limited area of China, but have caused serious impacts. They share similar morphological characteristics. These characteristics can only be observed in the female adult individuals. The differences between them cannot be observed in preimaginal stages. Thus, it is difficult to distinguish them in preimaginal stages morphologically. In this study, we used molecular diagnostic methods based on cytochrome c oxidase subunit I and species-specific markers to identify these two species and improve upon the false-positive results of previous species-detection primers. DNA barcode sequences were obtained from 900 individuals of B. minax and 63 individuals of B. tsuneonis. Based on these 658 bp DNA barcode sequences of the cytochrome c oxidase subunit I gene, we successfully designed the species-specific primers for B. minax and B. tsuneonis. The size of the B. minax specific fragment was 422 bp and the size of the B. tsuneonis specific fragment was 456 bp. A series of PCR trials ensured the specificity of these two pairs of primers. Sensitivity assay results demonstrated that the detection limit for the DNA template concentration was 0.1~1 ng/μL for these two species. In this study, we established a more reliable, rapid, and low-cost molecular identification method for all life stages of B. minax and B. tsuneonis. Species-specific PCR can be applied in plant quarantine, monitoring and control of B. minax and B. tsuneonis.