Victor R. Alekseev

Diapause in Aquatic Invertebrates Theory and Human Use

PART I: Strategies and Mechanisms of Diapause in Aquatic Invertebrates 1. INTRODUCTION TO DIAPAUSE, Victor R. Alekseev, Oscar Ravera & Bart T. De Stasio 1. Diagnosis of diapause, 1.2 Ecological causes of diapause in aquatic organisms, 1.3 Terminology on dormancy 2. TIMING OF DIAPAUSE IN MONOGONONT ROTIFERS: MECHANISMS AND STRATEGIES, John J. Gilbert 2.1 Introduction, 2.2 Female types and the fertilized resting egg, 2.3 The timing of sex: environmental controls, 2.4 The Timing of sex: endogenous controls, 2.5 General mechanistic models for the control of mixis, 2.6 Theoretical models for maximizing resting-egg production, 2.7 Diapausing parthenogenetic eggs, 2.8 Acknowledgments 3. DIAPAUSE IN CRUSTACEANS: Peculiarities of Induction, Victor R. Alekseev 3.1 Introduction, 3.2 Diapause in crustacean life cycles, 3.3 Presence of diapause among crustaceans, 3.4 Evolution of points of view on inducing factors, 3.5 Diapause as a photoperiodic response, 3.6 Light as the source of information about the season, 3.7 Role of temperature and photoperiod in diapause induction, 3.8 Population density and manifestations of photoperiodic reactions, 3.9 Food quality and diapause induction in Crustacea, 3.10 Population polymorphism and inheritance of photoperiodic responses, 3.11 Heredity of photoperiodic responses, 3.12 Acknowledgments 4. REACTIVATION OF DIAPAUSING CRUSTACEANS, Victor R. Alekseev 4.1 Introduction, 4.2 Patterns of reactivation processes for different types of diapause, 4.3 Endogenous phase of diapause, 4.4 Reactivation action of oxygen, 4.5 Participation of carbon dioxide in reactivation, 4.6 Hormonal basis of diapause, 4.7 Acknowledgments 5. DIAPAUSE IN AQUATIC INSECTS, WITH EMPHASIS ON MOSQUITOES, Elena B. Vinogradova 5.1 Introduction, 5.2Mosquitoes (Culicidae), 5.3 Other groups of aquatic insects, 5.4 Acknowledgments 6. A BRIEF PERSPECTIVE ON MOLECULAR MECHANISMS OF DIAPAUSE IN AQUATIC INVERTEBRATES, Victor R. Alekseev 6.1 Introduction, 6.2. Molecular mechanism of diapause in nematode Caenorhabditis elegans, 6.3 Acknowledgments PART 2: The Role of Diapause in Science and Human Uses 7. EGG BANK FORMATION BY AQUATIC INVERTEBRATES: A BRIDGE ACROSS DISCIPLINARY BOUNDARIES, Bart T. De Stasio 7.1 Introduction, 7.2 Dormancy processes, 7.3 Egg bank size and dynamics, 7.4 Creating an egg bank, 7.5 Conclusion, 7.6 Acknowledgements 8. USE OF CLADOCERAN RESTING EGGS TO TRACE CLIMATE-DRIVEN AND ANTHROPOGENIC CHANGES IN AQUATIC ECOSYSTEMS, Susanne L. Amsinck, Erik Jeppesen & Dirk Verschuren 8.1 Introduction, 8.2 Tracing acidification, 8.3 Tracing eutrophication, 8.4 Tracing fish introductions and biomanipulation, 8.5 Tracing heavy metal pollution, 8.6 Tracing climate change, 8.7 Discussion and conclusion: limitations, concerns and future potentials, 8.8 Acknowledgements 9. RECONSTRUCTING MICRO-EVOLUTIONARY DYNAMICS FROM LAYERED EGG BANKS, Luc De Meester, Joachim Mergeay, Helen Michels & Ellen Decaestecker 9.1 Introduction: dormant stages and the study of micro-evolution, 9.2 A short survey of recent success stories, 9.3 Pitfalls, 9.4 Conclusion and future directions, 9.5 Acknowledgments 10. DOES TIMING OF EMERGENCE WITHIN A SEASON AFFECT THE EVOLUTION OF POST-DIAPAUSE TRAITS? Post-diapause and directly developing phenotypes of Daphnia, Kestutis Arbaciauskas 10.1 Introduction, 10.2 Daphnia life cycle, 10.3 Neonates: biochemical quality and body size, 10.4 Physiology: respiration and starvation resistance, 10.5 Life-history: growth, allocation and relative fitness, 10.6 Descendents of post-diapause and d

Types of diapause in Crustacea: definitions, distribution, evolution

Definitions of diapause and of the three types of diapause (embryonal, larval and imaginal) as they apply to the Crustacea are given and the distribution of the types among different orders of crustaceans is discussed. A special role of diapause as a way to escape competition among ecologically similar species is noted and the significance of photoperiod responses as a pace-maker of the biorhythmical function of diapause for a wide range of species is demonstrated. A common unspecific regression for the description of oxygen consumption with duration of diapause in crustaceans of different sizes, different orders and different types of diapause is suggested. A special significance of embryonal diapause for the adaptation of palaeo-, meso- and neolimnic species of crustaceans that migrated from the sea into inland waterbodies is postulated.

Cryptic or pseudocryptic: can morphological methods inform copepod taxonomy? An analysis of publications and a case study of the Eurytemora affinis species complex

Interest in cryptic species has increased significantly with current progress in genetic methods. The large number of cryptic species suggests that the resolution of traditional morphological techniques may be insufficient for taxonomical research. However, some species now considered to be cryptic may, in fact, be designated pseudocryptic after close morphological examination. Thus the “cryptic or pseudocryptic” dilemma speaks to the resolution of morphological analysis and its utility for identifying species. We address this dilemma first by systematically reviewing data published from 1980 to 2013 on cryptic species of Copepoda and then by performing an in-depth morphological study of the former Eurytemora affinis complex of cryptic species. Analyzing the published data showed that, in 5 of 24 revisions eligible for systematic review, cryptic species assignment was based solely on the genetic variation of forms without detailed morphological analysis to confirm the assignment. Therefore, some newly described cryptic species might be designated pseudocryptic under more detailed morphological analysis as happened with Eurytemora affinis complex. Recent genetic analyses of the complex found high levels of heterogeneity without morphological differences; it is argued to be cryptic. However, next detailed morphological analyses allowed to describe a number of valid species. Our study, using deep statistical analyses usually not applied for new species describing, of this species complex confirmed considerable differences between former cryptic species. In particular, fluctuating asymmetry (FA), the random variation of left and right structures, was significantly different between forms and provided independent information about their status. Our work showed that multivariate statistical approaches, such as principal component analysis, can be powerful techniques for the morphological discrimination of cryptic taxons. Despite increasing cryptic species designations, morphological techniques have great potential in determining copepod taxonomy.

Molecular-genetic-based contribution to the taxonomy of the Acanthocyclops robustus group

Long-standing taxonomic problems involving the Acanthocyclops robustus–vernalis complex of freshwater cyclopoids have not been resolved. After Kiefers designation of A. robustus Sars as an older synonym of Acanthocycops americanus Marsh, a lot of data indicating their differentiation have been accumulated. To handle this taxonomical problem, representative populations from type localities of the respective taxa and from other European and US sites were analyzed morphologically and genetically using mitochondrial COI and 12S rRNA. Molecular-genetic analysis revealed that the three species described at the end of the nineteenth century: A. robustus, A. americanus and A. vernalis are well-separated species with genetic distances between them of around 20% for both genes. Within A. vernalis we also found substantial genetic variability (5–10%). The recently described species A. trajani corresponds to A. americanus, and A. einslei to A. robustus. A. americanus is re-described and its re-establishment as a valid species is suggested. http://www.zoobank.org/urn:lsid:zoobank.org:pub:68FC2C52-54FF-417D-9057-7B822BC7F15A

Invasion of Eurytemora sibling species (Copepoda: Temoridae) from north America into the Baltic Sea and European Atlantic coast estuaries

The Baltic Sea is one of the worlds most intensive centres for maritime traffic. This sea has become an important recipient of alien species transported with ballast water from all over the world. Sibling species are a special group of invasive animals that are hardly distinguishable from relative but often ecologically different local species. In this study, a molecular genetic diagnosis was performed, based on the analysis of DNA nucleotide sequences (barcoding) in the populations of a dominant circumpolar species Eurytemora affinis (Poppe, 1880) from the Gulf of Finland and the Atlantic coast of European estuaries and of Eurytemora carolleeae Alekseev and Souissi, 2011, a new North American suspected invasive form. The results of the diagnosis were completed by morphological analyses. Considering the key role of E. affinis in the Baltic Sea zooplankton community, the invasion of E. carolleeae might have consequences for biodiversity, biogeography, conservation and ecosystem management in this area.

Components of morphological variation in Baikalian endemial cyclopid Acanthocyclops signifer complex from different localities

Use of traditional methods for morphological studies only permits the analysis of a small part of the information embodied in morphological structures. Besides comparing populations using the mean values of characters which allows one to estimate their morphological similarity, analysis of variation among individuals within a population can be informative. Variation among individuals consists of factorial and stochastic components. The factorial component is an upper estimate of genetic heterogeneity and thus permits one to evaluate the populations adaptability. The stochastic component (estimated by fluctuating asymmetry, i.e. random deviations from perfect bilateral symmetry), being a measure of developmental stability, is an indicator of a populations fitness. Assessment of measurement error is necessary for assessment of the true value of the stochastic component and for selection of the most informative characters. Such analysis allows one to extract additional information from morphological data in comparison with methods traditionally used on copepods. This approach was applied to an analysis of morphological variation in the study of the Baikalian endemic cyclopoid Acanthocyclops signifer (Mazepova) from three different isolated localities. Characters typically used in studies of taxonomy of this group are considered here. Measurement error was rather high (more than 50% of the stochastic component), which can be explained by technical difficulties of measuring the characters. All populations differ in the mean values of the characters. This shows the taxonomic heterogeneity of this group and reveals the necessity of its taxonomic revision. Populations also differ in the level of stochastic and factorial components of the total variance. The data are interpreted from the point of view of taxonomy and the possible evolution of the group.

Feeding and digestive activity of cyclopoid copepods in active diapause

Three different methods were used to compare the feeding patterns of active cyclopoids and cyclopoids in active diapause from different habitats. First, we offered 14C- labeled algal detritus to stage III, stage IV (two different physiological groups), and adult females of Acanthocyclops vernalis from temporary water-bodies of the Volga Delta. Second, we compared the functional responses of active and actively diapausing cyclopoids preying on copepod nauplii. Stage III, stage IV (various physiological groups), stage V, adult males and females of Acanthocyclops viridis, Cyclops kolensis, C. abyssorum sevani from the Volga Delta, Lake Sevan (Armenia), and Mozhaisk Reservoir (Moscow District) were tested. Finally, we examined the activity of digestive enzymes (proteases) of CIV of C. kolensis from Mozhaisk Reservoir at different temperatures and temperature acclimation regimes. All three approaches used have led to similar conclusions. Actively diapausing cyclopoids were capable of feeding on both plant and animal prey; however, their feeding rates and digestive enzyme activity were 2–8 times lower than those of active cyclopoids of similar size. At the initial stage of active diapause the feeding rates were comparable with those of active cyclopoids then declined to a low level during approximately two weeks. Transfer of cyclopoids undergoing winter diapause from ambient temperature (4 °C) to warmer water (20 °C) resulted in dramatic increase of proteases activity only if the acclimation period was relatively long (two weeks).

Does the survivorship of activated resting stages in toxic environments provide cues for ballast water treatment

The toxic effects of three inorganic metals (Cu, Cr, Hg), three organic (phenol, formalin, ammonium) chemicals, ozone-enriched water and peroxides (H2O2) on embryonic development were tested in 8 species from the Porifera, Bryozoa and Crustacea. Toxicants with lower molecular weight showed stronger negative impacts on post-diapause embryos than chemicals with higher molecular weight if related to the toxicity of the chemicals to active adult stages. Only few embryos of the cladoceran Moina macrocopa and none of the cladoceran Wlassicsia pannonica treated with peroxides at concentration 0.3% developed further. Ozone-enriched water had no significant effect on post-diapause embryonic development in cladocerans. Ammonium (the product of NH4OH dissociation) in concentration 100 mg/l and higher killed all embryos of M. macrocopa inside protective membranes. Peroxides and ammonium are suggested for the purification of ship ballast waters as effective, non-expensive and non-persistent toxic chemicals. Resting stages of invertebrates including at least Crustaceans, Porifera and Bryozoa seem to allow not only dispersal among toxic industrial environments such as ship ballast compartments, but may also endure serious pollution events common in seaports and estuaries. Artemia cysts due to their strong protection against different toxic substances are recommended as a model for studies of toxic effects in diapausing stages in polluted estuaries and marine environments.

Eucyclops dumonti sp.nov. from Central Mongolia

Eucyclops dumonti sp.nov. is described from a shallow spring-fed lake in Central Mongolia. Data on its morphological variability are given, a comparison with the type population of Eucyclops serrulatus (Fischer, 1853) from St. Petersburg area is made, and its position relative to some closely related congeners is discussed.

Studying the Phenomenon of Dormancy: Why it is Important for Space Exploration

Investigations to forward the use of animal and plant anabiosis, e.g. cryptobiosis and some other forms of dormancy, in space exploration highlight five notable programs on exobiology. The authors give an outline of each program and list the biological species from bacteria to vertebrates and higher plants that have a resting phase within the life cycle and have been selected for in-space studies. Biomedical support of humans in the absence of factors important to sustenance and development of every living thing is one of the indisputable aspects of space exploration. A critical aspect of the biomedical support framework is creation of the central ecological life support systems (CELSS) and, therefore, investigations in this area are no less important than designing space vehicles. Development of life support systems (LSS), including systems incorporating the biological cycle, has been pursued since the initial space flights of cosmonauts. The ground-based test experiment with CELSS performed in the USSR in the period from the early 1960s to 1980s demonstrated that, though simple in design, these systems were capable of regenerating atmosphere, water, and food and thus adequately provided the necessities of human subjects (Gitelson et al. 1975; Shepelev 1975; Meleshko & Shepelev 1996; Sychev et al. 2002, 2003). Implementation of CELSS for space crews requires prior all-around tests and studies in order to: ● Determine the biological impacts of the space flight factors on the life of individual organisms, as well as communities (populations and biocenoses) ● Develop technologies for cultivating highly productive populations of autotrophs and heterotrophs in the zero-gravity environment ● Design hardware to sustain the vital functions of autotrophs and heterotrophs as members of space crew CELSS ● Search for methods to preserve the gene pool aboard the space vehicle and on the planetary outposts ● Optimize CELSS with consideration for microgravity and constant radiation exposure According to the results of CELSS-related investigations in space flight, microgravity impedes tremendously both functioning of the biological systems components and their integration into a uniform system. There are some hardware and technologies that can make up for the lack of gravity; yet, some problems cannot be resolved technically. Modeling of even simplified ecosystems for remote planetary outposts, e.g. on Mars, instantly raises the issue of long-term transportation of the whole