Valentin Belozerov

• Dr.Sci.
• St Petersburg University

Solifuges (order Solifugae) and pseudoscorpions (order Pseudoscorpiones) united into the superorder Haplocnemata (Shultz, 2007) are nevertheless characterized by essential differences both in morphological and biological characters. Analysis of available information on the biology and life cycles of these arachnids revealed a clear difference betwe...

Analysis of available information on the seasonal features of life cycles in pseudoscorpions (Arachnida, Pseudoscorpiones) shows that in the temperate climate of Europe with distinct seasonality, the development of these peculiar arachnids can be either eurychronous (= homodynamic), with a poorly pronounced seasonal arrangement, or stenochronous (=...

Information on seasonal adaptations in the life cycles of harvestmen (order Opiliones) summarized in this review reveals a great diversity of these arachnids with respect to duration, voltinism, and phenology of their life cycles, as well as to the number and ontogenetic position of the dormant stages required for survival during the winter season...

Data on seasonal adaptations (in particular on distribution of dormant stages) within the life cycles of the Acari (Chelicerata, Arachnida) are reviewed and compared with similar traits in mandibulate arthropods (insects and crustaceans). They all share responses to photoperiod and temperature, but there are some similarities and essential peculiar...

The paper resumes consideration of the problem posed by the Russian ecologist A.M. Emme (1953) on the need for a comparative study of diapause and quiescence (a non-diapause type of dormancy) in insects and other arthropods. The problem has recently become important due to the scarcity of eco-physiological studies of non-diapause dormancy, whose ro...

concerning the problem of life history and such an important its aspect as seasonality of life cycles and their control enabled by dormant stages, the parasitiform mites reveal the obvious similarity with the acariform mites. this concerns the presence of both main kinds of dormancy (diapause and quiescence). The great importance in the seasonal co...

The results of experiments on regeneration of the Haller's sensory organ in the metastriate ixodid tick Haemaphysalis longicornisNeumann in the presence of the juvenoid methoprene and retinoic acid and of studies of its structural changes by SEM confirmed the similarity of prostriate and metastriate ixodids as concerns the juvenalizing effect of th...

The results of experiments on regeneration of the Haller's sensory organ in the metastriate ixodid tick Haemaphysalis longicornis Neumann in the presence of the juvenoid methoprene and retinoic acid and of studies of its structural changes by SEM confirmed the similarity of prostriate and metastriate ixodids as concerns the juvenalizing effect of t...

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 regenerate...

During winter populations of Argas arboreus from heronries of the cattle egret, Bubulcus ibis, in South Africa are composed of adults, with some predominance of males, and II-IV instar nymphs, in a state of diapause. The period of tick activity, including reproduction and development of eggs, larvae and N1 nymphs, is synchronized with the nesting a...

Larvae and nymphae of the tick Ixodes ricinus L. display similar reactions to analogs of the insect juvenile hormones (methopren and pyriproxyfen), which induce at both stages juvenalization of the Haller's sense organ regenerates. Similar effects were also described for retinoic acid. Unlike juvenoids, retinoic acid can affect not only regeneratio...

Larvae and nymphs of the tick Ixodes ricinus L. display similar reactions to analogs of the insect juvenile hormones (methoprene and pyriproxyfen), which induce at both stages juvenalization of the Haller's sense organ regenerates. Similar effects were also described for retinoic acid. Unlike juvenoids, retinoic acid can affect not only regeneratio...

Extrinsic control of developmental diapause in nymphs of prostriate ticks of the subgenus Ixodes sensu stricto (Ixodes ricinus and Ixodes persulcatus from Eurasia and Ixodes scapularis from North America) appears to be based on a complex two-step photoperiodic reaction of a short-day/long-day type. Diapause control in the subgenus Afrixodes (the So...

The set $C^{n^2 + nm} = \{ A:X \to X,B:U \to X\} $ of all linear control systems over the field of complex numbers C with m=dimC U inputs and n=dimC X states is studied from the point of view of algebraic geometry. We give a classification of this set with respect to a simultaneous change of bases of the spaces X and U. We also find a subset $...

It is shown experimentally that the option between developmental diapause and non-diapause development in nymphs of Ixodes scapularis Say, 1821 (Middle Atlantic population) is determined by photoperiodic conditions according to a two-step photoperiodic reaction of short-day long-day type. Diapause arrest of development is induced by an impact of ei...

The Karoo Paralysis tick, Ixodes rubicundus Neumann (Acari: Ixodidae), is a semi-voltine ixodid that survives stressful environmental conditions using morphogenetic diapause (eggs and engorged nymphs) and desiccation resistance. Both photoperiod and temperature influence diapause induction in the engorged nymph. Ixodes rubicundus nymphs are typical...

We present a review of our own and literature data on reparative regeneration in ixodoid ticks (chelicerate arthropods). Ticks have a high potential for reparative regeneration and a close relationship between regeneration and development determined by similar hormonal regulatory mechanisms. These mechanisms depend on ecdysteroid hormones, which pa...

Experiments with Ixodes persulcatus nymphs (Novgorod population) influenced by an alteration of longday (LD 20:04) and shortday (LD 12:12) photoperiods before and after their feeding have shown that development of engorged nymphs (with or without diapause) at 20°C was controlled by a two-step (shortday-longday) photoperiodic reaction. Unfed nymphs...

A study of regeneration in nymphs and adults of the South African tick Ixodes (Afrixodes) rubicundus, from which the forelegs had been amputated during the previous instar, revealed that the structural changes in regenerated Haller''s sensory organs resemble those observed in other ixodid ticks, in particular in another prostriate tick, Ixodes (Ixo...

The sex ratio is an important parameter which characterizes the state and dynamics of natural populations of animals. Although ixodid ticks are specialized ectoparasites, most species are bisexual and are characterized by a 1:1 sex ratio for their progeny. In natural populations and even in laboratory colonies, biased sex ratios are often observed....

Egg batches laid by females of Ixodes persulcatus (maintained under a photoperiod of L:D 20:4 before feeding) contained eggs of two sizes: numerous normal eggs of 0.578 x 0.421 mm and some giant eggs of 0.776 x 0.515 mm. Giant eggs were 32-34% greater in length and 22-24% greater in width than normal eggs. Females maintained under a short-day photo...

Development and diapause in nymphs of Ixodes persulcatus at the age of 12 months are regulated at 18 degrees C by day-length according to the long-day photoperiodic reaction, and regimens of engorged nymphs are of main importance. Long-day photoperiods (LD 20:4) have stimulated non-diapause development in 97-100% specimens (moulting of 50% nymphs i...

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 differen...

Repeated feedings of larval Amblyomma hebraeum ticks on laboratory mice results in strong decrease of engorged tick yield (from 65-73% after primary feeding to 11% after secondary feeding). Laboratory mice differ essentially in this respect from rabbits and sheep which are unable to acquire the resistance (see Norval, 1978) to larvae of this tick.

The oxygen consumption of engorged nymphs of Hyalomma asiaticum was measured at various intervals after drop-off from mice hosts. Duration of nymphal development to the emergence of adults was 25-32 days at 25 degrees C. The oxygen consumption was high immediately after completing the blood meal (193-248 mm3 g-1 h-1 but decreased significantly 18 d...

Amputation of legs in nymphs of ticks, obtained from the first laboratory generation, resulted in regeneration of the legs after moulting to adults. Haller's sensory organ on the upper surface of each foreleg tarsus was significantly modified following regeneration. Haller's organ in non-amputated legs of the experimental ticks remained unchanged,...

This chapter discusses the daily and seasonal rhythms in ticks and their regulation. Ticks have a great diversity of biological rhythms that probably play a significant role in tick adaptation to seasonal and daily cycles as they do among insects. Ticks display circadian rhythms in important activities, such as host seeking, feeding, detachment fro...

Daily rhythm of detachment of engorged larvae of Ixodes ricinus L. and Hyalomma anatolicum Koch is regulated by photoperiod. In photoperiodic conditions (16--20 hours of light p. d.) the maximum of detachment in H. anatolicum occurs at the beginning of photophase (the first 4--8 hours), but in I. ricinus it occurs at the second part of photo-phase...

The polyacrylamide-gel electrophoresis was used to separate the negative charged proteins from adult females of the tick Dermacentor marginatus Sulz. There were separated up to 25 protein bands from haemolymph and up to 19 bands from midgut extracts of the engorged females. The number of protein bands in excreta and eggs was 15 and 18 respectively....

Experiments with Dermactntor silvarum Ol. (ticks from Khabarovsk population) have demonstrated that the competence of unfed adult females to engorge on rabbits depends on temperature and photoperiodic conditions at the prefeeding stage. Ticks from long-day photoperiods reveal the delay in feeding, while ticks after short-day or cold treatment becom...

Seasonal cycles in Arthropods are based on an alternation of periods of active development and dormancy (e.g. diapause). The problem of diapause has been studied for a long time but mainly by entomologists. The problem has now attracted the attention of acarologists dealing with ixodid ticks, although an instance of tick diapause (the seasonal dela...

Characteristic changes in water content and integument permeability of ticks occur during their feeding. Both the permeability and water content are maximal at the stage of slow feeding while both of them decrease simultaneously at the stage of rapid feeding. It is suggested that at the final stage the excessive water is eliminated by means of the...