Global Color Variation in Giant Hornet Vespa mandarinia Smith (Hymenoptera: Vespidae) and Potential Threat of Spread of the Commercially Reared "Hongniang" Phenotype.

The largest giant hornet Vespa mandarinia (VM) as a notorious "murder hornet" exhibits a complex color polymorphism and has been reared and directly released into the wild for commercial purposes in China, raising concerns that it may become an anthropogenic invasion disaster. Compiling the collections, as well as the global data online, a comprehensive description, modeling, and analysis on color variations and distribution patterns were conducted. A total of 42 images are presented firstly to represent all identified color phenotypes, which are categorized into four main color varieties, including a new variety, Vespa mandarinia var. pseudomagnifica (VMP). Prediction models show that VM is mainly native in Asia; the "400 mm isohyet" in China is a major biogeographic barrier limiting the northwestward expansion. Over the past decade, the distribution area of Vespa mandarinia var. magnifica (VMF) has probably expanded significantly (from 121.25 × 104 km2 to 260.29 × 104 km2), particularly in China. The potential distribution of VMF and Vespa mandarinia var. mandarinia (VMM) shaped the typical asymmetry of biogeographic pattern and highlight the west Palaearctic-Oriental boundary. These findings provide a scientific basis for risk assessment, inform monitoring, and management decisions related to the commercial rearing and population control of expanding hornet populations.