Valentin’s rock lizard (
Darevskia valentini
) is suggested to be the parent for several parthenogenetic species (e.g.,
D. armeniaca
,
D. bendimahiensis, D. sapphirina
, and
D. unisexualis
) that evolved through hybridization. Complex evolutionary processes (including reticulate evolution) are occurring within the areas where Valentin’s rock lizard coexists with these and other rock lizards. Hence, a detailed biological specification of this species is important for understanding how vertebrates evolve. Valentin’s rock lizard is a long-lived (up to 9 years), small diurnal lizard with larger females than males, which is unlike other species of the genus. Their relatively large eggs and early reproduction period, which occurs just after emergence from winter shelters, are adaptations for living in a high elevation climate (higher than 2 000 m a.s.l.). Their body temperatures (31–32 °С) are comparable to body temperatures of rock lizards living in milder climates, though female body temperature is more dependent on substrate temperature and basking due to their lower activity than that found in males. Population density fluctuates from several individuals to several hundred per hectare and is not affected by parthenogen coexistence, although hybrids do occur in sexually biased populations where males are more common than females. The male home range is larger than that of females, though these home ranges broadly overlap. Prey is not limited in the mountain meadows and Valentin’s rock lizards feed on a great variety of arthropods. Infanticide occurs in high-density populations.
This paper describes achievements of the All-Russian Scientific Research Institute of Aviation Materials in the field of creating high-temperature heat-shielding, ceramic and metal-ceramic composite materials. The advantages and prospects of applying the developed materials in the manufacturing of structural elements of aircraft and friction joints are discussed. The synthesis features and basic properties of metal-ceramic composite materials based on light alloys, refractory metal matrices, ceramic composite materials for use in heavily loaded structural elements of modern aircraft are presented. The main achievements in the field of heat-shielding materials based on refractory oxide fibres are presented, along with their properties and application in new-generation aircrafts.
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