Vol 97, No 7 (2017)

In field experiments, honeybees learned to discriminate between rewarded and unrewarded feeders differing in color. After learning, familiar feeders were presented against a different background or the place of presentation was shifted several meters away. Both innovations decreased the average percentage of correct choices. This decrease is considered to be evidence of “contextual isolation.” This isolation was partial because the discrimination of learned colors was partially retained under the new conditions. This appears to be the first known example of partial contextual isolation. Significant individual differences were revealed. Some bees demonstrated spontaneous color preferences while the others did not. Four out of 34 bees failed to learn the rewarded color even after 30–40 visits.

A total of 139 collembolan species from 55 genera were found in coastal tundra near the settlement of Lavrentiya in the eastern part of the Chukchi Peninsula. The local fauna of the region is quite “Beringian” in species composition but its structure appears to be in full agreement with the known characteristics of southern tundra faunas of other sectors in the Arctic. The specificity of collembolan complexes of the main plant associations in the studied area is not very high because the predominant collembolan species usually inhabit a wide range of communities. The performed study on Collembola fails to confirm the conventional view of a significantly higher diversity of northeastern Palaearctic faunas. Despite the rather southern position of the studied coastal tundra, the species richness of its collembolan fauna seems to be the same as or only slightly higher than that of analogous landscapes in the other Arctic sectors. The apparent discrepancy between relatively low diversity of Collembola at the local level as shown herein and its rich regional fauna may be the result of increased differentiation of the collembolan fauna of the region characterized by very complex orography and extremely contrasting climatic conditions.

The composition of the genus Parendacustes Chop. and of its two subgenera is briefly discussed. Nine new taxa of the nominotypical subgenus are described: P. berezini sp. n., P. arachne sp. n., P. pahangi borealis subsp. n., P. sylvestris sp. n., P. tkatshevae sp. n., P. tawau sp. n., P. tiomani sp. n., P. ectoparameralis sp. n., and P. magnispeculum sp. n. New data on the distribution of P. p. pahangi Gor. and considerations on the generic position of P. latifrons Chop. and P. lifouensis Desutter-Grandcolas are also provided.

The merkli group of the weevil genus Plinthus is revised. Plinthus navarsati Davidian et Savitsky, sp. n. is described from Northeastern Turkey. New data on the morphology and geographical distribution of P. merkli Frivaldszki, 1894, P. cavazzutii Meregalli, 1985, and P. latipennis Meregalli, 1985 are given, with a key to all the four species of the merkli group.

The problem of urban ticks has arisen from the increased rate of urbanization since WWII. Expansion of municipal boundaries encompasses adjacent territories, so that large areas of wilderness together with all their inhabitants get incorporated into city limits. Current strategies of biodiversity conservation include the creation of green corridors and other forms of connectivity between wilderness and urban areas as well as between green patches within cities. All this allows various mammals and birds to migrate from their native habitats into and between various parts of the cities and to establish permanent urban populations. Medium-sized and larger animals provide adult ticks with blood meal, thus creating suitable conditions for the establishment and persistence of tick populations. Independent tick populations can exist in urban forests, parks, private properties, old cemeteries, etc. Over the last decades, the tick populations that originated from those in natural habitats around the cities have become a permanent component of urban fauna. Among such ticks, the castor bean tick Ixodes ricinus is the most important species for European cities, while the deer tick I. scapularis is of great significance for the East Coast of the United States. The taiga tick I. persulcatus is the most important species for the Russian cities and towns within its range. All these and some other ticks aggressively attack humans and their pets inside cities. The tick species especially well adapted to urban life are those which can live and reproduce in buildings. The brown dog tick Rhipicephalus sanguineus (family Ixodidae), the pigeon ticks from the reflexus group of the genus Argas, and Ornithodoros ticks (family Argasidae), which form urban and semi-urban populations, are the main urban tick pests and vectors. House infestation by ticks can lead to human infection with tick-borne pathogens or severe allergic reactions. Some tick hosts, mammals as well as birds, maintain tick-transmitted pathogens and serve as competent reservoir hosts. Urban populations of these animals can participate in the circulation of some pathogens within cities. Thus, the enlargement of urban green areas followed by their population by wild mammals and birds create good opportunities for the establishment of urban populations of tick vectors with the resulting threat to the health of urban dwellers and their pets. At the same time, our understanding of the real scope and complexity of the problem of urban ticks is far from being sufficient. Finding the ways of protecting the environment without increasing the risk to human health in modern cities is a pressing and challenging problem of our time.

Ground beetles were captured in a mixed southern taiga forest near the city of Vologda, Russia, from March to September 2014 using different collection techniques. Of the 250 specimens of ground beetles belonging to 22 species, 109 beetles representing 11 species yielded 326 specimens of mites of the cohorts Gamasina (4 species), Astigmatina (5), and Heterostigmatina (1). Two mite species, Antennoseius pseudospinosus Eidelberg, 1990, a common species in the steppes of southeastern Europe, and Halodarcia incideta Karg, 1969, a polyzonal European hydrophile, are recorded in the taiga zone for the first time. Dorsipes dorsipes Regenfuss, 1968, a specialized parasite of beetles of the genus Carabus Linnaeus, 1758, is new to the fauna of Eastern Europe. An adult mite of the genus Stylochirus G. Canestrini et R. Canestrini, 1882 was found for the first time in a natural hibernating chamber in close contact with an overwintering ground beetle, in particular, a male of S. fimetarius (Müller, 1859) on Carabus granulatus Linnaeus, 1785. The most common mite to occur on ground beetles was Antennoseius bullitus Karg, 1969, which was found on 7 carabid species with the mean occurrence of 41% and comprised 68% of the total mite sample. Joint phoresy of 2–3 mite species was recorded on 12 specimens of ground beetles; in 5 cases the co-occurring mites were Antennoseius bullitus and Stylochirus fimetarius. Three dominant mite species (85% of the total mite sample) were mainly collected off three dominant carabid species (70% of the beetle sample), but individual mite species preferred different hosts.

Cold-hardiness of soil-dwelling invertebrates (37 species of insect and 27 species from other taxa) was studied in the continental parts of Northeast Asia, which represent a region with winter temperatures extreme for the Northern Hemisphere. Insects belonging to 34 species overwinter in the supercooled state, whereby they withstand temperatures of–12...–35°C. Thirteen species (insects, myriapods, slugs, earthworms, and an amphipod) spend winter in the frozen state and survive temperatures from–5 to–45°C. Cryoprotective dehydration is typical of slug eggs, earthworm cocoons, and certain click beetle larvae, which survive temperatures ranging from–20 to–40°C, down to the record value of–196°C. The majority of the studied organisms tolerate cooling to–25...–30°C, which corresponds to average temperature minima in the upper soil horizons of most biotopes in the continental parts of the Asian Northeast.