Calyptostasy: its role in the development and life histories of the parasitengone mites (Acari: Prostigmata: Parasitengona)

Abstract

The paper presents a review of available data on some aspects of calyptostasy, i.e. the alternation of active (normal) and calyptostasic (regressive) stages that is characteristic of the life cycles in the parasitengone mites. There are two different, non-synonymous approaches to ontogenetic and ecological peculiarities of calyptostasy in the evaluation of this phenomenon and its significance for the development and life histories of Parasitengona. The majority of acarologists suggests the analogy between the alternating calyptostasy in Acari and the metamorphic development in holometabolous insects, and considers the calyptostase as a pupa-like stage. This is controversial with the opposite view emphasizing the differences between calyptostases and pupae in regard to peculiarities of moulting events at these stages. However both approaches imply the similar, all-level organismal reorganization at them. The same twofold approach concerns the ecological importance of calyptostasy, i.e. its organizing role in he parasitengone life cycles. The main (parasitological) approach is based on an affirmation of optimizing role of calyptostasy through acceleration of development for synchronization of hatching periods in the parasitic parasitengone larvae and their hosts, while the opposite (ecophysiological) approach considers the calyptostasy as an adaptation to climate seasonality itself through retaining the ability for developmental arrests at special calyptostasic stages evoked from normal active stages as a result of the life cycle oligomerization. Both of these approaches share the understanding of calyptostasy as a tool for synchronization of particular steps in the parasitengone life cycles with seasonal events of physical or biological origin.