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Species composition, seasonal dynamics, and a load of ectoparasites per individual and population of the common shrew Sorex araneus have been examined in coniferous and mixed forests of the Ilmen-Volkhov lowland (a neighbourhood of Oskuy village, Chudovo district, Novgorod Province) during the period 1999—2003. Trapping of mammals was carried monthly, with exception of few accidental gaps. The Gero traps were used for catching micromammalian hosts. The lines of trap were checked 2 times a day, places of lines changed each 3—5 day. Total number of micromammalians collected during the period of study is 3215, including 1115 specimens of the common shrew S. araneus and 246 ones of the pigmy shrew S. minutus. Parasite fauna on the common shrew included 23 ectoparasite species: fleas — 12, ixodid ticks — 2, gamasid mites — 7, and myobiid mites — 2 species. Among recorded species, 9 fleas species and some gamasid species are accidental parasites. These accidental ectoparasite species are common to the bank vole Clethrionomys glareolus in the territory investigated. Species composition, occurrence and abundance indices of parasites changed during the year. In total, about 55% shrew specimens are infected with ectoparasites. The infracommunity of ectoparasites on the common shrew usually consists of 6 species or less. Mean number of all ectoparasite individuals per one host specimens varies from 4 to 83. The greatest number of parasites (50 and 83) was recorded on the shrews, which carried 5 and 4 parasites species, respectively. Biodiversity of parasite species in the ectoparasite community on the common shrew and the load of parasites per one host specimen are lower than those in the bank vole. In forest biotopes explored, the most part of temporary ectoparasite species found on the common shrew was also recorded on other small mammals, which could have contacts with this host. It is possible to conclude that among the parasite supracommunity in the explored ecosystem, the temporary ectoparasites represent a "fond" of temporary parasites, which are common for most small mammal species. A role of different shrew and rodent species as main of additional hosts changes depending on a population density of potential mammalian hosts and other environment factors.

Type series of two species of the genus Hyalomma Koch, 1844 deposited in the Museum of Zoology in Berlin have been examined. Examination of the H. detritum Schulze, 1919 holotype has shown that this name is actually a junior synonym (syn. nov.) of H. marginatum turanicum Pomerantsev, 1946. At the same time it was also found out that the paratypes of H. detritum are conspecific to the syntypes of H. scupense Schulze, 1818, among which the lectotype has been designated. Taxonomic errors of Schulze and other authors, which had led to a worldwide use in acorological literature the name H. detritum instead of the valid name H. scupense, are discussed. It is suggested that the reasons of microevolution within the polymorphic species H. scupense could be explained by unequal climatic conditions. Microevolutionary process in this species is most well expressed in a tendency to reduce the number of contacts with a host during the life cycle. It has resulted in the reformation of the two-host cycle into the one-host cycle.

Study of morphological characters to identify the subspecies of Hyalomma marginatum immature stages is based on material collected throughout all the geographical range of the species. As it was found, the discrimination of subspecies of H. marginatum immature stages needs a complex use of structural and morphometrical characters. Only H. m. marginatum larvae and H. m. isaaci nymphs may be easily differentiated from other subspecies based on the structural (qualitative) characters. Besides, morphometric (quantitative) characters should be used only in combinations for identification of the subspecies. In regard to structural characters of larvae, it was found that the shape and size of coxal spurs of H. marginatum allow differentiating this subspecies from the others (Fig. 3, 5, 6). Based on morphometrical characters of larvae, the following characteristic features of subspecies have been found: in H. m. marginatum, the capitulum is wide, the palpi, hypostome and genua I are short and narrow; in H. m. turanicum, the capitulum is narrow, the palpi are short and narrow, the hypostome is short and wide, the genua I are long and narrow; in H. m. ruflpes, the scutum is large, the capitulum is wide, the palpi are long and narrow, the hypostome and genua I are long and wide; in H. m. isaaci, the scutum is small, the capitulum is narrow, the palpi and hypostome are long and narrow, the genua I are short and narrow. Among structural characters of nymph, several discriminative features of subspecies have been found. The shape of the scutum in H. m. isaaci (Fig. 2, 2) clearly differentiates this subspecies from the others (Fig. 2, 7). In H. m. marginatum, the setae of alloscutum as a rule have bluntly rounded apices (Fig. 1, 2), while in the other subspecies these setae are more tapering apically (Fig. 1, 7). The shape of spiracular plates is rather variable within the species, but in H. m. marginatum and H. m. isaaci (Fig. 1, 3) the plates are larger and more perforated than in H. m. ruflpes and H. m. turanicum (Fig. 1, 4). In H. m. isaaci, the spurs of coxae I are narrower than in other subspecies (Fig. 1, 8). Based on morphometrical characters of nymphs, the following discriminative features of subspecies have been found: in H. m. marginatum, the capitulum is wide, the palpi are short and wide; in H. m. turanicum, the capitulum is narrow, the palpi are long and narrow; in H. m. ruflpes, the scutum is wide, the capitulum is narrow, the palpi are long and narrow, the hypostome is long; in H. m. isaaci, the scutum is long and narrow, the capitulum is wide, the palpi are short and wide, the hypostome is short.

The four species of fleas associated with birds in West Siberian Plain have been recorded. Ceratophyllus styx is a specific parasite of Riparia riparia. Ceratophyllus garei, С. gallinae, and C. tribulis parasitize various setting of birds.

Specific features in the formation of cestode species composition in the common shrew in different biotopes have been analyzed. Four categories of parasites have been recognized depending on a degree of dominance: dominants (Neoskrjabinolepis singularis, Molluscotaenia crassiscolex), subdominants (Ditestolepis diaphana), adominants A (Staphylocystis furcata, Vigisolepis spinulosa), adominants В (Hymenolepis scutigera, Dilepis undula, D. secunda, Taenia mustelae). A significant similarity was discovered between the species diversity and the dominance characteristics of cestodes. It was found that the distribution of mass species of parasites in the host population corresponds to the gamma distribution model. In regard to cestodes examined, a hypothesis considering the spatial structure and size of territory occupied by stable parasitic system is put forward.

A new species of anoplocephalid cestode, Paranoplocephala gubanovi sp. n. (Cyclophyllidea, Anoplocephalidae), from wood lemmings of Eastern Siberia (Myopus schisticolor) is described. The new species differs from other known species of Paranoplocephala associated with Holarctic lemmings by having unique combination of characters as follows: a few-segmented strobila, superficial suckers sticking out of the scolex, ovary covering practically the whole middle part of the segment, relatively little number of testicles situated in the aporal part of the segment, cirrus bursa crossing the poral excretory vessels, and subspherical spermatheca situated in the middle part of the segment. Comparison of P. gubanovi sp. n. and several closest species, P. fellmani Haukisaimi et Henttonen, 2001, P. serrata Haukisaimi et Henttonen, 2000, and P. arctica (Rausch, 1952) has been carried out. Features distinguishing the new species from Aprostatandrya macrocephala and A. microti have also been studied.

Characteristics of final stages of carbohydrate metabolism in a cestode Eubothrium rugosum from the burbot intestine have been studied. It is found out that in the course of in vitro incubation the worms produce lactic acid to the environment with a concomitant acidification of the medium. The rate of pH changes and lactate production eventually fell during the incubation. The medium pH being the result of helminth's metabolism varies within the normal physiological limits of the host intestine pH and pH optima for its basic digestive enzymes.

The activity of five lysosomal hydrolases (acid phosphatase, DNAase, RNAase, β-glucosidase, β-galactosidase), alkaline phosphatase and aldolase have been examined in tissues of the cestode Schistocephalus solidus (Mȕller, 1776) and the three-spined stickleback Gasterosteus aculeatus (L.) forming a stable parasite-host system. As a rule, the activity of enzymes was higher in a cestode body than in fish tissues. The acid and alkaline phosphatases were the exception. The activity and variation of lysosomal nucleases and aldolase in the parasite differed notably from those in both infested and healthy hosts. The paper discusses the role of lysosomal and cytoplasmic enzymes in a cestode adaptation to parasitism, as well as in the mechanisms of the host's chemical and immunological response to infection.

Two new species of nematodes found, in the north of Fergana Plain (Uzbekistan): Raillietnema uzbekistanica sp. n. (Cosmocercidae) from the Horsfields Tortoise Testudo horstfieldi (Testudinidae), and Spironoura govacus sp. n. (Kathlaniidae) from the green toad Bufo viridis (Bufonidae). Data on infection of R. uzbekistanica sp. n. with predatory fungi in different seasons are given.

Approximately 3660 species of Coccidea belonging to 73 genera and 29 families parasitize representatives of the Metazoa kingdom. Coccidea were discovered in 10 of 35 phyla of Metazoa; in the most cases a direct correlation between the number of species in a host group and the number of Coccidea known from that group is clearly traced. Host groups, which are most archaic phylogenetically, are also parasitized by the archaic Coccidea groups. Evo-lutionarily derived hosts are parasitized by groups of Coccidea, which are the youngest phylogenetically. Parallel development of Coccidea and their hosts may be used for an indirect determination the time of origin of different Coccidea groups.

A life longevity of Ixodes ricinus and I. persulcatus have been examined in laboratory conditions. It was found that specimens infected with borreliae live slightly longer than non-infected ones (difference is not reliable); females live 1.5 times longer than males; I. ricinus lives 2—4 times longer than I. persulcatus. It is suggested that I. persulcatus has a higher rate of metabolism than I. ricinus and that the latter species obtains an ability to survive after the last moult two winters and keep an activity in two summer seasons not counting the year of moulting.

Two species of dactylogyrids, Dactylogyrus barbatuli Ermolenko, 1992 and D. tonii Ermolenko, 1992, occuring in the Siberian stone-loah in Primorye are redescribed. These species are distinguished from others monogenean of the genus Dactylogyrus, that are found in fishes of the genus Nemachilus, by the size of anchor structures and complexes of copulatory organs.

The history of the electron microscope investigations in zoology and parasitology in the Zoological Institute of the Russian Academy of Sciences and progress in scanning and transmission electron microscope investigations in this field of biology to the moment are briefly accounted.

Summary is absent.