Abstract
Based on the study of photographs posted on three Internet sites, as well as field collections, the representation of four colour forms of the grasshopper Omocestus viridulus in different parts of its distribution area from Western Europe to Altai and Tien Shan was analyzed. A conclusion was made about a regular decrease in the representation of the green form (viridis) from west to east up to its complete disappearance. It is shown that within the studied part of the distribution area, O. viridulus populations can be grouped into three clusters: British-Scandinavian (the largest proportion of representatives of the viridis form), East Eurasian (a very weak representation of the viridis form up to its complete absence), and Western European (intermediate position). In addition, the rarity of males of the hyalosuperficies form (green top and gray or brown sides), females of the rubiginosa form (gray or brown sides and top) and females of the purpurata form (purplish-red flanks and a green top) is shown throughout the entire studied part of the distribution area of O. viridulus. A close connection between the representation of the viridis form among both sexes and the rubiginosa form among O. viridulus females with the degree of climate continentality was proved. Increasing climate continentality (in particular, the greater the annual temperature range) is correlated with a decrease in the proportion of the viridis form and increase in the proportion of females of the rubiginosa form.