[The quill mite Syringophilopsis fringilla (Fritsch) (Acari: Trombidiformes: Syringophilidae): The structure of receptor organs providing feeding of the parasite inside the feather quill].

The structure of sensory organs situated on palps and inside the cheliceral stylet of the quill mite Sringophilopsis fringilla (Fritsch, 1958) was examined in scanning and transmitting electron microscopes. Eight sensilla of 3 types were revealed on palptarsus, including two contact chemo-mechanosensory sensilla, a single distant chemosensory (probably olfactory) sensillum, and 5 tactile mechanosensitive sensilla. All other sensilla situated on basas parts of the palp and on the outer surface of gnathosoma are represented by tactile mechanoreceptors. A proprioceptor sensillum was revealed in the movable digit of the chelicera; modified cilia of dendrites of 5 sensory neurons run in the inner non-sclerotized core of the stylet, ending at different levels as electron-dense rods connected with the sclerotized wall of the stylet. The authors assume that the proprioceptor sensillum of the stylet detects the pressing force of the movable digit on the inner wall of the quill during piercing process, while papal sensilla determine the optimal place for piercing.

[QUESTING BEHAVIOR OF HARD TICKS (IXODIDAE) IN ONTOGENESIS].

Literary and own data on questing behavior of larvae, nymphs, and adults in main genera of hard ticks are analyzed. Evolutionary patterns of this behavior and the role of different life stages in this process are discussed.

[Fine structure of glands forming porous areas (area porosa) in the European forest tick Ixodes rucinus (L.) (Ixodidae, Ixodinae)].

The use of scanning and electron microscopy methods has shown that porous areas (area porosa) on the gnathosoma of Ixodes ricinus are formed of cuticular orifices of bicellular glands. Each gland is formed of a duct cell and a glandular cell, characterized by high degree of secretory activity. No difference in the gland structure between females and males were revealed. Questions associated with a probable function of these glands are discussed.

[In memory of Yuri Sergeevich Balashov (25.XII.1931-28.IX.2012)].

Biographical notes describe the life and scientific activities of Yuri Balashov, an outstanding Russian parasitologist, the Chief Editor of Parazitologiya.

[The main evolutionary trends in sensory organs and questing behavior of parasitiform ticks and mites (Parasitiformes)].

Studies of sensory organs in parasitiform mites by methods of scanning and transmitting electron microscopy and electrophysiology in Russia were initiated by Yu. S. Balashov. A review of the material accumulated since that time allows revealing the main trends in evolution of the morphology the main complicated sense organs (the Haller's organ, palpal and tarsal organs, and eyes). Tight correlation between the evolution of the questing behavior and of sensory organs was demonstrated.

[Sense organs on palps and fore tarsi of gamasid mites (Parasitiformes, Rhinonyssidae), parasites of the nasal cavity of the great tit, the rock dove, and the Eurasian coot].

The main sensory organs (the palpal organ and the tarsal sensory complex) were examined by scanning electron microscopy method in parasites of the nasal cavity of the great tit Parus major (Ptilonyssus sairae, Ptilonyssus pari), the rock dove Columba livia (Mesonyssus melloi), and the Eurasian coot Fulica atra (Rallinyssus caudistigmus). It was shown that differences in the topography of sensilla within the tarsal complex correspond to the taxonomic relations between species and genera, whereas differences in the structure of the palpal organ are not associated with the taxonomy and, probably, reflect ecological peculiarities of parasitism.

[Tarsal gland of the ticks Ixodes persulcatus and Ixodes ricinus (Ixodidae)].

A complicated multicellular gland is situated in tarsi of all the legs, occupying one third to half of the segment. Glandular cells form a single-layer sack; inner surface of the sack (gland cavity) is enveloped by a multilayer membrane. Cuticular rods connecting muscles with the claw pass inside this cavity. Glandular cells are characterized by the presence of numerous apical microvilli associated with accumulations of mitochondria, and secretory vacuoles enclosed in cellular membranes. The basal part of each cell contains lipid vacuoles and glycogen granules. The possibility of the track contact pheromone's production by the tarsal gland is discussed.

[Fine structural features of the sensory system in the ixodid tick Dermacentor niveus (Parasitiformes, Ixodidae)].

The main sensory organs (eyes, Haller's organ, and palpal organ) of Dermacentor niveus were examined in scanning and transmitting electron microscopes. The Haller's organ consists of a capsule with five porous SW-WP olfactory sensilla and pleomorphs; anterior pit with porous SW-WP, two grooved DW-WP, two thin NP-SW, and one conical DW-NP sensilla; four posterior DW-WP sensilla; and anterior group of SW-WP and DW-UP sensilla. Duct orifices of two dermal glands are situated near the capsule. Contact chemosensory sensilla of palps are represented by 4 DW-UP and 6 SW-UP sensilla. Eyes possess flattened lenses without the system of radial channels typical of eyes of other ixodid ticks examined. Unipolar photoreceptor cells with microvilli of rhabdomeres running in parallel to longitudinal cells axis contain basal bodies treated as rudiments of the cilia. On the whole, sensory system of D. niveus, dweller of semi-exposed habitats (floodland meadows, tugai forests, and shrub thickets of arid zones) is characterized by combination of features typical of species dwelling in exposed (deserts) and concealed (forests) habitats.

[Estimation of the biological age in females of the taiga tick Ixodes persulcatus by changes in the body shape and surface of cuticle].

A method of visual estimation of the biological age of living hungry tick females by visible changes in the depth of marginal groove and the structure of the alloscutum cuticle during natural ageing is developed. In recently activated individuals, the body is convex and the marginal groove is exposed, demonstrating distinctly visible cuticular microfolds (Figs 1-4). In attenuated ticks, the body is flattened and marginal fold overlays the marginal groove, concealing cuticular microfolds (Figs 5-8).

[Adaptation of sensory systems of gamasid mites (Parasitiformes, Gamasina) to dwelling in different environment].

The main complication sensory organs (the palpal organ and the tarsal sensory complex) of several species of gamasid mites were studied in scanning electron microscope. The species examined included permanent ectoparasites (Laelaps agilis, Laelaptidae), parasites of the nasal cavity and respiratory tract of birds (Sternostoma tracheocolum and Ptilonyssus reguli, Rhinonyssidae), dwellers of the sea littoral zone (Parasitus kempersi, Parasitus immanis, Parasitidae), and mites found on soil and on plants (Amblyseius barkeri, Parasitidae). Similar sensillar types, including olfactory SW-WP sensilla, contact chemo-mechanosensory (SW-UP and DW-UP) sensilla, termo-chemo-mechanosensitive (DW-WP) sensilla of two types, and tactile (NP) sensilla were found in all these species, excluding endoparasites, where some sensillar types (in particular, DW-WP sensilla with slit-like pores) are absent. It was shown that the topography of olfactory SW-WP sensilla of the tarsal complex reflects taxonomic position and phylogenetic history of mite genera, whereas the number of certain sensillar types and the degree of their development reflect ecological specialization of species. The palpal organ is characterized by rather uniform structure in mites of different families, dwellers of different environments, except for the endoparasites of the family Rhinonyssidae, where this organ is strongly reduced.

[Palpal sensory organ in the chicken mite Dermanyssus gallinae (Acari: Dermanyssidae)].

Palptarsus of the chicken mite bears 5 single-wall upper-pore (SW-UP) chemo-mechanoreceptor sensilla (type A); 4 double-wall upper-pore (DW-UP) chemosensitive sensilla (type B), and 6 no-pore (NP) mechanoreceptor sensilla (type M). The author assumes that sensilla of the type A participate in perception of the aggregation pheromone; of the type B, in perception of trophic stimuli; and of the type M, in determination of mechanical properties of the substrate.

[Tarsal sensory complex of the red chicken mite Dermanyssus gallinae (Acari: Dermanyssidae)].

The tarsal sensory complex of the red chicken mite Dermanyssus gallinae is situated on dorsal surface of each fore leg near the claw. It comprises 28 sensilla of 5 morphological types: 4 SW-UP (single-wall upper-pore) (gustatory organs), 8 SW-WP (single-wall wall-pore) (olfactory organs), 8 DW-WP (double-wall wall-pore) of two subtypes (thermo-chemoreceptory organs), 6 NP-TB (no pore--tubular body) (tactile organs), and 2 reduced sensilla. No sex or stage dimorphism was revealed. Morphological data point to the fact that tarsal sensory complex of the red chicken mite is mainly an organ detecting temperature changes and olfactory stimula.

[Fine structure of tarsal sensilla in the taiga tick Ixodes persulcatus (Ixodinae)]. / Tonkoe stroenie tarzal'nykh sensill taezhnogo kleshcha Ixodes persulcatus (Ixodidae).

The first tarsal segment of the taiga tick bears 4 general types of sensilla (except for sensilla forming the Haller's sensory organ on the dorsal surface of the tarsus): tactile mechanoreceptor sensilla of 3 types, contact chemo-mechanoreceptor sensilla of 2 types, and double-walled pore sensilla. One of these types, the chemo-mechanoreceptor upper-pore sensilla, was found only in the Ixodinae, and not found in the examined representatives of the Amblyomminae. This type of sensilla was also found in the palpal receptor organ of the ixodid and argasid ticks.

Regeneration of Haller's sensory organ in two species of hard ticks of the genus Haemaphysalis (Acari: Ixodidae).

A study of Haller's organ regeneration in nymphs and adults of Haemaphysalis turturis and parthenogenetic females of H. longicornis, from which the forelegs had been amputated during the previous instar, revealed structural changes in regenerated organs. The adult regenerates reestablished atavistic structural features, while the nymphal regenerates retained larval features, which is typical of regenerates of two other genera examined previously (Ixodes and Hyalomma). Data on regeneration of Haller's sensory organ testify to an ancient character of the genus, standing closely to the base of the phylogenetic tree of hard ticks.

Phenol and lactone receptors in the distal sensilla of the Haller's organ in Ixodes ricinus ticks and their possible role in host perception.

Extract of steer wool odor was found to excite olfactory receptor(s) in a wall-pore olfactory sensillum on the distal knoll of the Haller's organ. Three active volatile compounds were revealed in this odor by gas chromatography. Electrophysiological experiments revealed two types of receptors (sensory neurons) within the sensilla examined. One type of receptor responded only to phenolic derivatives, such as o-chlorophenol, o-bromophenol, o-methylphenol, 2,6-dichlorophenol, 2,6-dibromophenol, 2,4,6-trichlorophenol, but not to o-nithrophenol, p-methylphenol, 2,5-dichlorophenol, 3,5-dichlorophenol, 2,6-dinithrophenol, 2,6-dimethylphenol, and pentachlorophenol. The other type of receptor responded only to gamma-valerolactone. It is assumed that these cells play an important role in perception of a host from long distances (10-15 m), which is typical of Ixodes ricinus ticks.

[Comparative study of the sensory system in gamasid mites Rhinonyssus rhinolethrum, Rh. subrhinolethrum and Ptilonyssus motacillae (Mesostigmata: Gamasina: Rhinonyssidae), parasites in the nasal cavity of birds]. / Sravnitel'noe issledovanie sensornoi sistemy gamazovykh kleshchei Rhinoyssus rhinolethrum, Rh. subrhinolethrum i Ptilonyssus motacillae (Mesostigmata: Gamasina: Rhinonyssidae), parazitov nosovoi polosti ptits.

Sensillae of the tarsal receptor complex, palpal organ, and body chaetom were examined by means of scanning electron microscopy in three endoparasitic gamasid mites: Rhinonyssus rhinolethrum, Rh. subrhinolethrum and Ptilonyssus motacillae, the parasites of Anser albifrons, Anas crecca, and Motacilla alba, respectively. In the tarsal sensory complex, the scale of reduction of the olfactory sensilla reflects the adaptation of gamasid mites to cavernous parasitism. The topography of this sensilla is specific at generic and species taxonomic levels. In the palpal sensory organ, the number and scale of reduction of two main sensilla types depend on peculiarities of places of blood-sucking.

[Structure of eyes in trombidioid mites (Acariformes: Trombidioidea)]. / Stroenie glaz krasnotelkovykh kleshchei (Acariformes: Trombidioidea).

The eyes or ocelli of trombidioid mite larvae of Euschoengastia rotundata, Hirszutiella zachvatkini and Camerotrombidium pexatum, and larvae and adults of Platytrombidium fasciatum were studied by means of transmission electron microscopy. These species together with larvae of Odontacarus efferus, Ericotrombidium hasgelum, Walchia chinensis and adult E. rotundata and H. zachvatkini were also studied under scanning electron microscope. The eyes of larvae are not inverted and characterized by an epicuticular lamellar lens. The group of phoreceptor cells with rhabdomeres arranged typically of Chelicerata is underlaid by a pigment cup. The eyes of adult mites are inverted, perikarions of photoreceptor cells are situated between the lens and rhabdomeres; tapetum occupies the space between the pigment cup and rhabdomeres. Sensitivity of eyes to light is similar to that of primary eyes of spiders dwelling on soil surface.

[Toxicity of mercaptoethanol to mutant strains of the yeast Pichia methanolica growing on different carbon sources]. / Toksichnost' merkaptoétanola dlia mutantnykh linii drozhzhei Pichia methanolica, rastushchikh na razlichnykh istochnikakh ugleroda.

Addition of beta-mercaptoethanol at a concentration of 2-3 mM to media containing methanol, glucose, or yeast extract caused a 50% inhibition of the growth of wild-type yeast Pichia methanolica; mercaptoethanol at a concentration of 0.7 to 25 mM inhibited the growth of the mutant strain ecr1. The mutation mth1 of P. methanolica repressed its ability to consume methanol and was accompanied by the loss of alcohol oxidase (EC 1.1.3.13) activity. beta-Mercaptoethanol restored the ability of mth1 mutant cells to grow on methanol and stimulated their growth under derepression conditions. The growth effect of beta-mercaptoethanol during derepression was accompanied by partial restoration of alcohol oxidase activity.

[The palpal receptor organ of gamasid mites (Mesostigmata: Gamasina)]. / Pal'pal'nyi retseptornyi organ gamazovykh kleshchei (Mesostigmata: Gamasina).

Three types of sensilla were distinguished during scanning electron microscope investigations of the palpal sensory organ, one of the main organs in food suitability detection, in 8 species of mites belonging to the genera Gamasellus, Macrocheles, Euryparasitus, Eulaelaps, Myonyssus, Raillietia, Spinturnix, and Pneumonyssus. Two types (A and B) are chemo-mechanoreceptor single-walled and double-walled sensilla (SW-UP and DW-UP) and one type (M) is represented by mechanoreceptor (NP) sensilla. It is shown, that no type of feeding influences the structure of palpal organ, whereas a character of host-parasite relationship (transition to constant parasitism and parasitism in cavities of inner organs) leads to oligomerization and reduction of chemoreceptor sensilla.

Pathways of regeneration of Haller's sensory organ during the life cycle of the tick Hyalomma asiaticum.

A study of regeneration in nymphs and adults of the Asiatic desert tick, Hyalomma asiaticum, from which forelegs had been amputated during the previous instar, revealed that regenerated Haller's sensory organs exhibited significant changes in structure. Adult regenerates possessed atavistic features in terms of the number and topography of different sensillar types. Regularity in these changes was similar to that demonstrated in regenerates of Ixodes ricinus (Leonovich and Belozerov [1992] Exp. Appl. Acarol., 15:59-79). Nymphal regenerates, by contrast, had larval features of the parent species. An hypothesis is presented about the ontogenesis of the complete, peripheral, polymodal sensory organ as a process in which the initial cell differentiation of cells begins at different starting points.