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Yuliya Y Sokolova – One of the best experts on this subject based on the ideXlab platform.

  • systenostrema alba larsson 1988 microsporidia thelohaniidae in the dragonfly Aeshna viridis odonata aeshnidae from south siberia morphology and molecular characterization
    Journal of Eukaryotic Microbiology, 2006
    Co-Authors: V V Glupov, Yuliya Y Sokolova, Nataliya A Kryukova, James R Fuxa
    Abstract:

    An octospore microsporidium was found in the nymphs of Aeshna viridis, collected in intermittent streams near Novosibirsk, Siberia, Russia in 2003. Spores were uninucleate and measured 6.1+/-0.07 x 3.0+/-0.04 microm on fresh smears. The polar filafilament was anisofilar having 10-11 anterior coils (thicker filament diam.) and 10-11 posterior (thinner filament diam.) coils. Sporophorous vesicles were persistent and measured 12.3+/-0.23 x 11.9+/-0.20 microm. The infection was restricted to the adipose tissue and caused the formation of whitish “cysts” containing mature octospores. Based on ultrastructural similarity we consider this Siberian isolate to be Systenostrema alba, a species described from Aeshna grandis collected in Sweden (Larsson 1988). Maximum likelihood, neighbor joining, and maximum parsimony analyses of the small subunit rDNA all placed Systenostrema alba (Accession no. AY953292) as the sister taxon to a clade consisting of Thelohania solenopsae, Tubulinosema ratisbonensis, and Tubulinosema acridophagus.

James R Fuxa – One of the best experts on this subject based on the ideXlab platform.

  • systenostrema alba larsson 1988 microsporidia thelohaniidae in the dragonfly Aeshna viridis odonata aeshnidae from south siberia morphology and molecular characterization
    Journal of Eukaryotic Microbiology, 2006
    Co-Authors: V V Glupov, Yuliya Y Sokolova, Nataliya A Kryukova, James R Fuxa
    Abstract:

    An octospore microsporidium was found in the nymphs of Aeshna viridis, collected in intermittent streams near Novosibirsk, Siberia, Russia in 2003. Spores were uninucleate and measured 6.1+/-0.07 x 3.0+/-0.04 microm on fresh smears. The polar filament was anisofilar having 10-11 anterior coils (thicker filament diam.) and 10-11 posterior (thinner filament diam.) coils. Sporophorous vesicles were persistent and measured 12.3+/-0.23 x 11.9+/-0.20 microm. The infection was restricted to the adipose tissue and caused the formation of whitish “cysts” containing mature octospores. Based on ultrastructural similarity we consider this Siberian isolate to be Systenostrema alba, a species described from Aeshna grandis collected in Sweden (Larsson 1988). Maximum likelihood, neighbor joining, and maximum parsimony analyses of the small subunit rDNA all placed Systenostrema alba (Accession no. AY953292) as the sister taxon to a clade consisting of Thelohania solenopsae, Tubulinosema ratisbonensis, and Tubulinosema acridophagus.

V V Glupov – One of the best experts on this subject based on the ideXlab platform.

  • Microsporidiosis of the dragonfly Aeshna viridis larvae (Odonata: Aeshnidae) caused by Systenostrema alba Larsson, 1988 (Microsporida: Thelohaniidae)
    Parazitologiia, 2006
    Co-Authors: N A Kriukov, Iu Ia Sokolova, V V Glupov
    Abstract:

    A microsporidian species producing octospores in sporophorous vesicles is found in Aeshna viridis larvae from intermittent streams situated in the vicinity of Novosibirsk City. Size of the spores measured on fresh smears was 6.9 +/- 0.09 microm x 4.1 +/- 0.08 microm (6.0-7.6 x 3.5-4.9). Each spore have single elongated nucleus and an anisofilar polar filafilament composed of 10-11 anterior and 10-11 posterior coils. The infection was restricted to adipose tissue. According to spore morphology the Siberian isolate can be attributed to the species Systenostrema alba described from Aeshna grandis in Sweden (Larsson, 1988). This is the first description of Microsporidia infecting Odonata from Siberia.

  • systenostrema alba larsson 1988 microsporidia thelohaniidae in the dragonfly Aeshna viridis odonata aeshnidae from south siberia morphology and molecular characterization
    Journal of Eukaryotic Microbiology, 2006
    Co-Authors: V V Glupov, Yuliya Y Sokolova, Nataliya A Kryukova, James R Fuxa
    Abstract:

    An octospore microsporidium was found in the nymphs of Aeshna viridis, collected in intermittent streams near Novosibirsk, Siberia, Russia in 2003. Spores were uninucleate and measured 6.1+/-0.07 x 3.0+/-0.04 microm on fresh smears. The polar filament was anisofilar having 10-11 anterior coils (thicker filament diam.) and 10-11 posterior (thinner filament diam.) coils. Sporophorous vesicles were persistent and measured 12.3+/-0.23 x 11.9+/-0.20 microm. The infection was restricted to the adipose tissue and caused the formation of whitish “cysts” containing mature octospores. Based on ultrastructural similarity we consider this Siberian isolate to be Systenostrema alba, a species described from Aeshna grandis collected in Sweden (Larsson 1988). Maximum likelihood, neighbor joining, and maximum parsimony analyses of the small subunit rDNA all placed Systenostrema alba (Accession no. AY953292) as the sister taxon to a clade consisting of Thelohania solenopsae, Tubulinosema ratisbonensis, and Tubulinosema acridophagus.

Robby Stoks – One of the best experts on this subject based on the ideXlab platform.

  • food stress and predator induced stress shape developmental performance in a damselfly
    Oecologia, 2001
    Co-Authors: Robby Stoks
    Abstract:

    I studied effects of stress factors like food shortage, non-lethal predator presence and autotomy on survival and larval performance (growth rate, development rate and developmental stability) of larvae of the damselfly Lestes sponsa. In a laboratory experiment, larvae were raised during their last two instars at two food levels (high or low) crossed with two levels of autotomy (caudal lamellae present or absent). These treatments were nested within three levels of predation risk (Aeshna cyanea absent, Chironomus-fed caged Aeshna or Lestes-fed caged Aeshna). The diet of the predator had no effects. The low food level and the presence of Aeshna independently increased mortality rates of L. sponsa larvae. The low food level, presence of a caged Aeshna and autotomy all independently reduced growth rate (mass and body size at day 40) and wing size at emergence, and the first two stress factors also reduced development rate. Regardless of predator presence and autotomy, all damselfly larvae consumed the food available. This indicated that the predator-induced stress effects were not due to reduced food uptake, but probably reflected lowered assimilation efficiency and/or a higher metabolic rate. Besides a low food level, the presence of caged Aeshna predator larvae and autotomy also increased hind wing asymmetry. This result demonstrated that predator-induced stress may reduce developmental stability in the prey.

  • The influence of predator species and prey age on the immediate survival value of antipredator behaviours in a damselfly
    Fundamental and Applied Limnology, 2000
    Co-Authors: Robby Stoks, Marjan De Block
    Abstract:

    The efficacy of antipredator behaviours may depend on both intrinsic and extrinsic factors. We experimentally studied the effects of predator species and prey age on the immediate survival value of swimming and lamellae loss in larval damsel-flies. Four predators: two invertebrates (the notonectid, Notonecta viridis and the dragonfly larva Aeshna cyanea), and two vertebrates (the three-spined stickleback Gasterosteus aculeatus and the sunfish Lepomis gibbosus) were tested with all combinations of two instars of the damselfly Lestes sponsa (F-0 and F-2). The number of escapes by swimming away were much lower when larvae were attacked by the two fishes than by the two invertebrates. Moreover Lepomis never removed lamellae and killed all larvae. The instars did not differ in the number of escapes by swimming, but F-0 instars were caught more at the lamellae than F-2 instars. All larvae that survived a capture were caught at the lamellae and the majority (90 %) did so by autotomy. The ontogenetic increase in the immediate survival value of this antipredator behaviour was dependent upon the predator species. It was highest in captures by the Notonecta (40 %), and lower when larvae were caught by the Aeshna or Gasterosteus (ca. 17 %). This was probably because the biological relevance of the magnitude of the speed difference between damselfly instars depends upon the predator’s attack performance, We discuss the consequences of these findings for the macrohabitat distribution of the larvae and for the multicomponent antipredator behaviours prey may use.

  • Phenotypic shifts caused by predation: selection or life-history shifts?
    Evolutionary Ecology, 1999
    Co-Authors: Robby Stoks, Marjan De Block, Hans Van Gossum, Luc De Bruyn
    Abstract:

    Predators can impose both selection and life-history shifts in prey populations. Because both processes may affect phenotypic distributions, the estimates of selection differentials may be biased. We carried out two field experiments to disentangle these separate effects. We studied whether dragonfly predation by Aeshna cyanea changes the distributions in body size and lamellae morphology in the damselfly Lestes sponsa. Damselflies have caudal lamellae which are used in escapes by swimming. In a first experiment, we manipulated predator presence (No Aeshna, Encaged Aeshna or Free-ranging Aeshna) and stopped the experiment when all larvae had moulted once. In a second experiment, larvae were confronted with a Free-ranging Aeshna but collected before moulting, and survivors were compared with a control sample taken at the start of the experiment. The presence of Aeshna largely reduced the survival probabilities of the Lestes larvae at a very similar rate in both experiments. Daily survival probabilities did not differ between the No Aeshna and Encaged Aeshna treatments. In the Free-ranging Aeshna treatment of the first experiment, size was reduced compared to the other two treatments, creating a significant apparent selection differential. This was probably mainly due to predator-induced reduced growth because in the second experiment, where growth effects were excluded, size of the survivors did not differ from the control sample. In both experiments there was a significant selection pressure for larger lamellae. Standardized directional selection differentials were similar in both experiments (0.57 and 0.28 phenotypic standard deviation units). No survival selection on lamellae shape was detected. These results are in agreement with previous findings that lamellae size, but not lamellae shape, enhances swimming performance and thereby predator escape in this species.

Nataliya A Kryukova – One of the best experts on this subject based on the ideXlab platform.

  • systenostrema alba larsson 1988 microsporidia thelohaniidae in the dragonfly Aeshna viridis odonata aeshnidae from south siberia morphology and molecular characterization
    Journal of Eukaryotic Microbiology, 2006
    Co-Authors: V V Glupov, Yuliya Y Sokolova, Nataliya A Kryukova, James R Fuxa
    Abstract:

    An octospore microsporidium was found in the nymphs of Aeshna viridis, collected in intermittent streams near Novosibirsk, Siberia, Russia in 2003. Spores were uninucleate and measured 6.1+/-0.07 x 3.0+/-0.04 microm on fresh smears. The polar filament was anisofilar having 10-11 anterior coils (thicker filament diam.) and 10-11 posterior (thinner filament diam.) coils. Sporophorous vesicles were persistent and measured 12.3+/-0.23 x 11.9+/-0.20 microm. The infection was restricted to the adipose tissue and caused the formation of whitish “cysts” containing mature octospores. Based on ultrastructural similarity we consider this Siberian isolate to be Systenostrema alba, a species described from Aeshna grandis collected in Sweden (Larsson 1988). Maximum likelihood, neighbor joining, and maximum parsimony analyses of the small subunit rDNA all placed Systenostrema alba (Accession no. AY953292) as the sister taxon to a clade consisting of Thelohania solenopsae, Tubulinosema ratisbonensis, and Tubulinosema acridophagus.