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Stanislav N. Gorb - One of the best experts on this subject based on the ideXlab platform.

  • wing wettability gradient in a damselfly lestes sponsa odonata Lestidae reflects the submergence behaviour during underwater oviposition
    Royal Society Open Science, 2020
    Co-Authors: Hana Sigutova, Martin Sigut, Alexander Kovalev, Stanislav N. Gorb
    Abstract:

    The phenomenon of hydrophobicity of insect cuticles has received great attention from technical fields due to its wide applicability to industry or medicine. However, in an ecological/evolutionary ...

  • body temperatures in sympecma paedisca zygoptera Lestidae in the autumn in the central ukraine
    International Journal of Odonatology, 2019
    Co-Authors: Stanislav N. Gorb
    Abstract:

    This short communication reports on the warming ability of the damselfly Sympecma paedisca, which is known for its winter hibernation and tolerance to low temperatures. The data were collected usin...

  • stylus of the odonate endophytic ovipositor a mechanosensory organ controlling egg positioning
    Journal of Insect Physiology, 2002
    Co-Authors: Natalia A. Matushkina, Stanislav N. Gorb
    Abstract:

    Using light and scanning electron microscopy, a sensory field consisting of 15–20 campaniform sensillae is described on the base of the stylus of the endophytic ovipositor of Odonata. It is hypothesised that two symmetric styli equipped with this number of sensillae can function as a mechanosensory organ responsible for control of precise egg positioning in plant stems during oviposition. In laboratory experiments with females of damselflies Lestes sponsa and Lestes barbarus (Lestidae), it was demonstrated that the distance between laid eggs is not dependent on the presence of styli. Removal of styli from both sides did not influence a shift of oviposition to one side. Females with one removed stylus shifted the clutch line in the opposite direction toward the removed stylus. Additionally, removal of styli influenced positions of single eggs in egg sets, and disturbed the capacity for complex oviposition. Thus, both morphological and experimental data support the hypothesis that styli participate in the control of egg line and egg patterning in the clutch.

  • Ultrastructure of the neck membrane in dragonflies (Insecta, Odonata)
    Journal of Zoology, 2000
    Co-Authors: Stanislav N. Gorb
    Abstract:

    This study describes and quantifies the microsculpture and ultrastructural design of the neck membrane of adult Odonata using scanning and transmission electron microscopy. The membranous cuticle has a complex pattern of microfolds, which appear to have a specialized mechanical function. The membrane has two layers of cuticle: the epicuticle and exocuticle. The outermost layer is the electron-opaque epicuticle, which repeats the shapes of the microfolds. The epicuticle has no fibrillar elements. The exocuticle is electron-lucent and rather thin (0.5–1.5 μm) compared with the sclerite cuticle. The cuticle microfibrils in successive lamellae are at angles to each other. The epidermal cells underlying the membrane have an electron-lucent matrix filled with electron-opaque spherical vesicles of 0.1–0.4 μm in diameter. The behaviour of the membrane folds under loading was studied by shock-freezing experiments; these showed that the shape of the folds changed in response to head movements, and stretched under loading. A comparison of the surface patterns of the membrane in 10 odonate species from seven families (Zygoptera: Coenagrionidae, Lestidae, Megapodagrionidae; Anisoptera: Cordulegastridae, Aeshnidae, Corduliidae, Libellulidae) had not revealed any correlation of the measured parameters with the size, sex or systematic position of species studied.

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

  • effect of lamellae autotomy on survival and foraging success of the damselfly lestes sponsa odonata Lestidae
    Oecologia, 1998
    Co-Authors: Robby Stoks
    Abstract:

    Damselfly larvae can autotomize their caudal lamellae to escape predation. Costs of caudal lamellae autotomy were investigated by directly manipulating lamellae condition of Lestes sponsa in laboratory experiments. Larvae without lamellae had higher predation mortality in the presence of Notonecta. Both lamellae loss and larval density increased the probability of being cannibalized. The results suggest that the increased vulnerability after lamellae loss resulted from a reduced escape performance. Larvae were less mobile after lamellae loss or in the presence of a predator, but the decrease was no longer significant when both factors were combined. This indicates that larvae compensate for the increased predation risk with a fixed response. Both lamellae loss and predator presence reduced hunting success, but the decrease after lamellae loss was only significant in the absence of a predator. The fitness consequences of these effects for both the larval and adult stages are discussed. In general, the data strongly suggest that lamellae autotomy plays a role in population regulation of damselflies.

  • Indirect Monitoring of Agonistic Encounters in Larvae of Lestes viridis (Odonata: Lestidae) Using Exuviae Lamellae Status
    Aquatic Insects, 1998
    Co-Authors: Robby Stoks
    Abstract:

    Differences in interference competition between larvae of the damselfly Lestes viridis (Vander Linden) were examined using caudal lamellae status of exuviae. Exuviae from a small temporary fishless pond near Antwerp (Belgium) where L.viridis was the only odonate present were studied. No lamellae loss during emergence was seen. Therefore, the lamellae status of the exuviae reflects the lamellae status of the final instar larvae. The deviations of the distribution of the number of missing lamellae per individual from a binomial distribution suggested that lamellae are not always lost separately or that some animals are more prone to agonistic encounters. I found no difference in agonistic encounters between sexes. In accordance with the hypothesis of Pierce et al. (1985) interference competition was higher in the lestid species inhabiting small, temporary fishless ponds than in the coenagrionid damselfly Ischnura posita inhabiting large permanent fish containing water bodies that was studied by Robinson et ...

Filip Harabiš - One of the best experts on this subject based on the ideXlab platform.

  • Different Oviposition Strategies of Closely Related Damselfly Species as an Effective Defense against Parasitoids.
    Insects, 2019
    Co-Authors: Filip Harabiš, Tereza Ruskova, Ales Dolny
    Abstract:

    Parasitoidism is one of the main causes of insect egg mortality. Parasitoids are often able to detect eggs using semiochemicals released from eggs and disturbed plants. In response, female insects adopt a wide variety of oviposition strategies to reduce the detectability of eggs and subsequent mortality. We evaluated the proportion of parasitized and undeveloped eggs of three common damselfly species from the family Lestidae, the most diverse group of European damselflies, in terms of oviposition strategies, notably clutch patterning and the ability to utilize oviposition substrates with different mechanical properties. We assumed that higher costs associated with some oviposition strategies will be balanced by lower egg mortality. We found that the ability of Chalcolestes viridis to oviposit into very stiff substrates brings benefit in the form of a significantly lower rate of parasitoidism and lower proportion of undeveloped eggs. The fundamentally different phenology of Sympecma fusca and/or their ability to utilize dead plants as oviposition substrate resulted in eggs that were completely free of parasitoids. Our results indicated that ovipositing into substrates that are unsuitable for most damselfly species significantly reduces egg mortality. Notably, none of these oviposition strategies would work unless combined with other adaptations, such as prolonging the duration of the prolarval life stage or the ability to oviposit into stiff tissue.

  • The value of terrestrial ecotones as refuges for winter damselflies (Odonata: Lestidae)
    Journal of Insect Conservation, 2016
    Co-Authors: Filip Harabiš
    Abstract:

    Habitat requirements of many species may vary significantly throughout the lifecycle. Species are often forced to exchange their habitats to meet requirements of different life stages. Due to the effect of human activities, however, there is a loss of habitat complexity and a consequent disappearance of species associated with multiple habitat types. This also applies to freshwater invertebrates occurring in temporary habitats. However, it appears that many species are able to meet their habitat requirements even in a human-altered landscape. The aim of this study was to analyze the habitat preferences of the damselfly Sympecma fusca in an area significantly influenced by human interventions. According to the results of a capture-mark-recapture study and generalized additive models, I found that, during a pre-reproductive period (in the autumn), imagoes utilize predominantly insolated ecotones, which constitute only a small fraction of the available terrestrial habitat. During the reproductive period (in spring), however, imagoes completely change their priorities in favor of reproductive success. At this time, males use ecotones only in adverse weather conditions. Ecotones allow the species to survive a long pre-reproductive period. However, suitable habitat conditions may be lost because of inappropriate interventions (e.g., mowing). These small-scale interventions often resemble natural disturbances and may not necessarily lead to the extinction of an entire population. Imagoes are able to move on to different habitat patches, but only if they have alternative habitats. This outcome indicates that maintaining a high heterogeneity of keystone structures is crucial for maintaining high levels of biodiversity.

  • Do egg parasitoids increase the tendency of Lestes sponsa (Odonata: Lestidae) to oviposit underwater?
    European Journal of Entomology, 2015
    Co-Authors: Filip Harabiš, Ales Dolny, Jana Helebrandova, Tereza Ruskova
    Abstract:

    The selection of oviposition sites by insects can significantly affect egg mortality. Spreadwing damselflies (Odonata: Lestidae) predominantly lay their eggs in parts of plants growing above the surface of water and only occasionally also those parts growing underwater. Factors affecting the choice of oviposition site and decision to lay underwater are still poorly understood. We examined whether localities with different risk of egg parasitism, different oviposition strategies (above or below the water surface) and the depth at which the eggs were laid, affected the total number of eggs laid, the proportion parasitized and egg mortality. In general, a significantly higher proportion of the eggs laid above the surface of water were parasitized but spreadwing damselflies showed significant preference for laying eggs underwater at both of the sites studied. This preference, however, had a different effect on the overall mortality of eggs at the two sites studied. Hence underwater oviposition by damselflies may be seen as a conditional anti-predator strategy, occurring only if the benefits exceed potential risks. Underwater oviposition may provide additional benefits other than protection against egg parasitism.

Tereza Ruskova - One of the best experts on this subject based on the ideXlab platform.

  • Different Oviposition Strategies of Closely Related Damselfly Species as an Effective Defense against Parasitoids.
    Insects, 2019
    Co-Authors: Filip Harabiš, Tereza Ruskova, Ales Dolny
    Abstract:

    Parasitoidism is one of the main causes of insect egg mortality. Parasitoids are often able to detect eggs using semiochemicals released from eggs and disturbed plants. In response, female insects adopt a wide variety of oviposition strategies to reduce the detectability of eggs and subsequent mortality. We evaluated the proportion of parasitized and undeveloped eggs of three common damselfly species from the family Lestidae, the most diverse group of European damselflies, in terms of oviposition strategies, notably clutch patterning and the ability to utilize oviposition substrates with different mechanical properties. We assumed that higher costs associated with some oviposition strategies will be balanced by lower egg mortality. We found that the ability of Chalcolestes viridis to oviposit into very stiff substrates brings benefit in the form of a significantly lower rate of parasitoidism and lower proportion of undeveloped eggs. The fundamentally different phenology of Sympecma fusca and/or their ability to utilize dead plants as oviposition substrate resulted in eggs that were completely free of parasitoids. Our results indicated that ovipositing into substrates that are unsuitable for most damselfly species significantly reduces egg mortality. Notably, none of these oviposition strategies would work unless combined with other adaptations, such as prolonging the duration of the prolarval life stage or the ability to oviposit into stiff tissue.

  • Do egg parasitoids increase the tendency of Lestes sponsa (Odonata: Lestidae) to oviposit underwater?
    European Journal of Entomology, 2015
    Co-Authors: Filip Harabiš, Ales Dolny, Jana Helebrandova, Tereza Ruskova
    Abstract:

    The selection of oviposition sites by insects can significantly affect egg mortality. Spreadwing damselflies (Odonata: Lestidae) predominantly lay their eggs in parts of plants growing above the surface of water and only occasionally also those parts growing underwater. Factors affecting the choice of oviposition site and decision to lay underwater are still poorly understood. We examined whether localities with different risk of egg parasitism, different oviposition strategies (above or below the water surface) and the depth at which the eggs were laid, affected the total number of eggs laid, the proportion parasitized and egg mortality. In general, a significantly higher proportion of the eggs laid above the surface of water were parasitized but spreadwing damselflies showed significant preference for laying eggs underwater at both of the sites studied. This preference, however, had a different effect on the overall mortality of eggs at the two sites studied. Hence underwater oviposition by damselflies may be seen as a conditional anti-predator strategy, occurring only if the benefits exceed potential risks. Underwater oviposition may provide additional benefits other than protection against egg parasitism.

Zhifeng Yang - One of the best experts on this subject based on the ideXlab platform.

  • Spatio-temporal variations of benthic macroinvertebrates and the driving environmental variables in a shallow lake
    Ecological Indicators, 2020
    Co-Authors: Yufeng Yang, Yang Zhou, Xuan Wang, Shanghong Zhang, Zhifeng Yang
    Abstract:

    Abstract Shallow lakes widely distributed in middle and lower reaches of watershed are easily multi-stressed by natural forces and human activities. Here, spatio-temporal variations of macroinvertebrate community and their influential variables in a typical large macrophyte-dominated shallow lake--Baiyangdian Lake were studied, using three-year in-situ observational data of spring, summer, and autumn. In total, ten environmental variables and five biological indices were measured for the six sites from each of the two habitat types, semi-natural habitat and disturbed habitat divided by their different exposures to human activities. Disturbed habitat had deeper mean water depth, lower mean transparency, and higher mean concentrations of DO, TN, NH4-N, NO3-N, and COD than that of semi-natural habitat regardless of seasons. Biological metrics indicate lower family-level richness but higher community tolerance level in disturbed habitat in spring and summer, but the results were close in autumn. The present of Lestidae and Gammaridae was a significant determination of semi-natural habitat. Redundancy analyses showed community temporal distribution was mainly driven by temperature, water depth, and pH that greatly influenced by natural forces, while spatial distribution was mainly driven by TN and transparency that greatly influenced by human activity. Regarding averaged data over the same year, season, and habitat, richness and Shannon-Weiner index had significant Pearson linear correlation with transparency (r = 0.521 and r = 0.541, p