Entomophages of spruce bud scales (Hemiptera: Coccidae) in the Ukrainian eastern forest-steppe

Abstract

The population number of spruce bud scales within localities can be regulated by a complex of predators and parasitoids, of the predatory species, the most massive is Antribus nebulosus Forster – Anthribus nebulosus. Apart from Antribus nebulosus Forster, numerous representatives of incheumonids from the Encertidae family develop, among which representatives of the Microterys genus are most commonly spread on spruce bud scales. In the course of our research, we have found that in spruce plantations inhabited by spruce bud scales entomophages populate females. Beyond the city limits, spruce plantations are more populated by entomophages than within the city limits. Both species of entomophages populated females in the dendrological park of Kharkiv National Agrarian University named after V.V. Dokuchaiev (49°90'N, 36°45'E) and Feldman Ecopark (50°66'N, 36°16'E). The highest inhabiting percentage of phytophages by entomophages was observed in the dendrological park of KhAU – 65 % of the examined females, of which 65 % were inhabited by Anthribus nebulosus and 45 % by Microterys lunatus. On the territory of Feldman Ecopark, 50% of the examined females were inhabited by entomophages, of which 25% were inhabited by Anthribus nebulosus and 75% by Microterys lunatus. In the nursery garden of ornamental plants (75 Siverska St.) (49°99'N, 36°36'E), only beetles of Anthribus nebulosus were found in 55 % of the studied female specimens. In the village of Vysoke (49°53'N, 36°07'E), Kharkiv district, in 80% of the studied females of spruce bud scales we have found only Microterys lunatus incheumonids. The lowest inhabiting percentage of phytophages by entomophages was observed in areas with severe man-caused air pollution. In the street plantations of Kharkiv Tractor Plant neighborhood (49°95'N, 36°40'E), 15 % of the studied females of spruce bud scales were inhabited by incheumonids of Microterys lunatus. Near the plant “Turboatom” (3 Energetychna St.) (49°97'N, 36°30'E) – 10 % of entomophages. Entomophages are collected in different places of the city and region, and in laboratory conditions we have once again convinced that the number of useful insects depends on the location of spruce plantations. The more spruce trees are negatively affected by cities and people, the fewer entomophages were recorded. Our research has shown that of the two entomophage species that are most sensitive to air pollution, beetles of Anhtribus nebulosus species, their number within the city limits is minimal or completely absent.