On the efficiency of introduction of American insects feeding on the common ragweed (Ambrosia artemisiifolia L.) in the south of Russia

The explosive spread of the common ragweed induced by disturbance of the natural habitats in the postwar years created an ideal vacant niche for acclimation of North American phytophagous insects introduced to the South of Russia in the 1960–70s. The propagation of these species resulted in restoration of natural succession periodicity and promoted the subsequent acclimation of the predatory stink bug Perillus bioculatus, an extremely important agent of biological control of the Colorado potato beetle. Besides the economic effect, the studies of these introduction events were significant from the theoretical viewpoint, revealing the phenomenon of a solitary population wave (SPW) of the ragweed leaf beetle. The theoretical concept of an SPW as the key factor of efficiency of the biological control of weeds underlies the method of suppression of the common ragweed which consists in inducing SPWs by establishing local refuges for the initial buildup of the beetle population.     

On the taxonomic position of Miocene valvatiform gastropods and their ecological features

The assignment of tiny valvatiform gastropods from the Early Meotian and Early Chokrakian to Skenea Fleming, 1825, a genus of marine gastropods of the superfamily Trochoidea is substantiated. It is emphasized that Miocene Skenea belongs to an ecosystem connected with bryozoan bioherm buildups.