The Handsome Cross Grasshopper Oedaleus decorus (Germar) (Orthoptera: Acrididae) in the Asian Part of Its Range

The handsome cross grasshopper Oedaleusdecorus (Germar), which was a minor pest in the 19th and first half of the 20th century, in the late 20th and early 21st centuries, became one of the emerging regional pests in the Asian part of its range, especially across the intermountain basins of the mountains of South Siberia, Mongolia and North and Northeast China. This is why it is necessary to identify the main trends of possible changes in its distribution. Several sets of data on the species distribution (1895–1960, 1961–2023, and all data) are analysed and several various approaches to modelling (graphic, maximum entropy and multidimensional ellipsoid) are utilised. The models produced for modern conditions describe well the known geographical and ecological distributions of the species in the Asian part of its range. Graphic models characterising the species’ distribution within a system of life zones and major ecosystem types show its general preference for dry steppes and semideserts. The models demonstrate apparent opportunities for this species to pierce northwards (at least up to 58° N in West Siberia, 62–63° N in East Siberia) in the future. This means that in the future, there is a certain probability that some individuals will migrate to these more northern regions. In the context of global warming, further northwards and northeastward shifts in the range boundaries of O. decorus can be predicted. In addition, there have been some changes in its population distribution and abundance, especially in the optimal parts of its population system where O. decorus normally colonises all applicable habitats; its average abundance is relatively high and it is common even during depressions. These shifts may be justified by both climatic changes (especially northwards) and some transformations of human activities (mainly for eastwards relocation).