Changes in the Population Phenetic Structure of the Lacebug Dictyla humuli (Fabr.) (Heteroptera, Tingidae) in the Usman' Forest (Voronezh Oblast) in 1999-2001

摘要

Analysis of the population phenetic structure of a species and its spatial and temporal variation is an important line of research in microevolution. The choice of the object (model species) and its characteristics to be estimated, as well as the determination of their quantitative and qualitative variations, plays an important role in these studies. The variant frequencies reflect the pattern of phenotypic and genotypic changes at the population level (Timofeeff-Ressovsky et al., 1973; Yablokov, 1980). Although this field of research is of primary importance, few studies have dealt with variations in insect populations with time. In some insect species, the phenotypic characteristics of the populations have been found to remain stable during the study period. These are Trichius fasciatus (Novozhenov, 1977, 1989), Brachyta interrogationis, Pachyta quadrimaculata (Novozhenov, 1980, 1989), Melolontha hippocastani (Novozhenov, 1982), Leptinotarsa decemlineata (Kokhmanyuk, 1982), and Philaenus spumarius (Novozhenov, 1989). Specific, stable phenotypic characteristics are typical of the populations of some moths, such as Argynnis paphia and Pararge aegeria, notwithstanding their migrations (Novozhenov, 1989). Other insects, e.g., some Meloidae, are characterized by long-term variations in phenotypic characteristics from year to year (Bakirova, 1985). Lacebugs (Heteroptera, Tingidae), a peculiar family of phytophagous insects, seem to be a promising model for phenetic studies. Their integuments have an areolate structure whose variation is clearly discrete and may be easily formalized based on the number of cells in the pattern. The geographic range of the lacebug Dictyla humuli (Fabr.) encompasses almost all of central Europe and a considerable part of southern Europe and spreads to Siberia as far east as the Angara River; the species is also abundant in Transcaucasia and has been found in Turkey and northern Iran (Pericart, 1983; Pericart and Golub, 1996; Golub, 1997). Dictyla humuli inhabits wet biotopes (floodplains, depressions, and waterlogged spots in forests, forest edges, and open places), where it lives on some representatives of the family Boraginaceae (Bator, 1953; Puchkov, 1974; Pericart, 1983). Symphytum officinale L. is its main food plant in eastern European forest-steppe. The species is characterized by high abundance, low mobility, and confinement to specific food plants.