title: [Resting nymphal stages and the nature of individual development in trombiculid mites (Acariformes: Trombiculidae)].
abstract: A morphological expression of quiescent nymphal instars (calyptostases) in trombiculid mites (Trombiculidae) is analysed. The analysis takes into consideration ontogenetic functions of different instars during the individual development of these mites, which includes an alternation of active and regressive quiescent instars. Cyclic start and blocking of different integumental differentiation programs in Trombiculidae is caused by the cyclic reduction and renewal of particular functions of respective instars, whereas internal organs of these mites do not transform significantly during the life cycle. The reduction of some functions, particularly the locomotion and feeding, in the quiescent nymphal instars with changed integumental function has an inevitable result in a complication and prolongation of the moulting process. The moulting of these instars begins at once after finishing the previous moulting cycle, i.e. it is realized in "automatic pattern" without the intermoult phase. In general, the organization of both quiescent proto- and tritonymph is the same, because it expresses concordant morphological correlations and synchronous reductions of certain functions and structures in these instars during the evolutionary process. At the same time, the trombiculid mites and, perhaps, other representatives of Parasitengona reveal the most generalized type of ontogenesis in Acariformes within the "alternating calyptostasy" phenomenon.
authors.forename: A B
authors.initials: AB
authors.lastname: Shatrov
mesh_terms: D000818:Animals; D008018:Life Cycle Stages; D009758:Nymph / Q000254:growth & development; D013997:Time Factors; D014324:Trombiculidae / Q000254:growth & development*
vernacular_title: Pokoiashchiesia nimfal'nye stadii i kharakter individual'nogo razvitiia krasnotelkovykh kleshcheĭ (Acariformes: Trombiculidae).