Dynamics of the Italian locust <Emphasis Type="Italic">Calliptamus italicus</Emphasis> L. population in the southeast of the West Siberian Plain

Seasonal dynamics and changes in the general condition of the Italian locust population in the southeast of the West Siberian Plain that were observed throughout the 20th century are characterized in this paper. It was demonstrated that during the last outbreaks of mass reproduction of this species, dominant were individuals transitional from typical gregarious to typical solitary ones. A complicated undulating picture of long-term spatial redistribution of maximum and minimum densities of the Italian locust is detected for the first time, and drastic dynamic differences between neighboring groups of its local populations are shown. The regularities found are in discrepancy with the traditionally accepted unidirectional character of long-term changes in the species numbers within one physiographic region.