Diapause in aquatic invertebrates: What's known and what's next in research and medical application?

Dormancy is a profound and ancient adaptation found in a wide spectrum of plants and animals of all habitats. In diapause the switch between active and dormant states is driven by hormonal mechanism that usually includes a photoperiodic pace-maker. Temperature, food limitation and some other stress factors as well are shown as driven by diapause induction in aquatic invertebrates. In the last decade, diapause studies from a wide variety of topics have demonstrated that diapause switch mechanisms may be developed to create novel applications in biotechnology. Resting eggs accumulated in the surface lake sediments represent a "bank" of Zooplankton species that assures their persistence in a community, in spite of periodic harsh conditions. Studies on the vertical distribution of resting eggs in sediment cores yield useful information to opening important perspectives for paleolimnological climate reconstruction and paleoecology. Cultivation of live food, like rotifers, Daphnia, Artemia or marine copepods is an expanding application of practical use of diapause in modern aquaculture. Biotechnologies can now be imagined for maintaining ecosystems outside the Earth's biosphere. Resting stages provide at least two properties highly suitable for such ecosystems. They can be easily transported in space for a long time without special care as compared with an active ecosystem. Also, a storage of seeds and diapausing animals will provide a reserve in case of an unpredictable destruction of the active part of an ecosystem caused, for example, by a meteorite strike. The term alien species takes on a new meaning when one considers another aspect of space biology. By enlarging the distribution area of the species, colonization of new environments could be a safeguard against its extinction. Thus it would also be important to develop technologies to guard against invasions of other species via ship ballast waters and similar means.. We also suggest that molecular genetic insights of diapause in invertebrates provide new ways of looking at carcinogenesis. Tumour cells may have parallels in post-diapause embryonic cells.