Predation risk affects egg mortality and carry over effects in the larval stages in damselflies

2019 ◽  
Author(s):  
Szymon Sniegula ◽  
Jean d'Amour Nsanzimana ◽  
Frank Johansson
Keyword(s):  
Predation Risk ◽  
Egg Mortality ◽  
Larval Stages ◽  
Carry Over

scholarly journals Thermal tolerance of the zoea I stage of four Neotropical crab species (Crustacea: Decapoda)

2018 ◽  
Vol 35 ◽  
pp. 1-5
Author(s):  
Adriana P. Rebolledo ◽  
Rachel Collin
Keyword(s):  
Thermal Tolerance ◽  
Elevated Temperatures ◽  
Marine Invertebrates ◽  
Negative Impact ◽  
Larval Survival ◽  
Crab Species ◽  
Marine Habitat ◽  
Mangrove Species ◽  
Larval Stages ◽  
Carry Over

. Although larval stages are often considered particularly vulnerable to stressors, for many marine invertebrates studies of thermal tolerance have focused on adults. Here we determined the upper thermal limit (LT50) of the zoea I of four Caribbean crab species (Macrocoelomatrispinosum, Aratuspisonii, Armasesricordi, and Minucarapax) and compared their thermal tolerance over time and among species. The zoea from the subtidal species M.trispinosum and tree climbing mangrove species A.pisonii had a lower thermal tolerance, 35 and 38.5 °C respectively, than did the semiterrestrial A.ricordi and M.rapax. In all four species tested, the estimates of thermal tolerance depend on the duration of exposure to elevated temperatures. Longer exposures to thermal stress produce lower estimates of LT50, which decreased by ~1 °C from a two- to a six-hour exposure. Crab embryos develop on the abdomen of the mother until the larvae are ready to hatch. Therefore, the thermal tolerances of the embryos which need to coincide with the environmental conditions experienced by the adult stage, may carry over into the early zoea stage. Our results suggest that semiterrestrial species, in which embryos may need to withstand higher temperatures than embryos of subtidal species also produce larvae with higher thermal tolerances. Over the short term, the larvae of these tropical crab species can withstand significantly higher temperatures than those experienced in their marine habitat. Longer term rearing studies are necessary to determine the temperature at which chronic exposure has a negative impact on embryonic and larval survival.

scholarly journals Effects of Environmental Stressors on the Early Development of Intertidal and Subtidal Gastropod Embryos

2021 ◽  
Author(s):  
◽  
Jeannine Fischer
Keyword(s):  
Embryonic Development ◽  
Early Development ◽  
Multiple Stressors ◽  
Environmental Stressors ◽  
Embryonic Mortality ◽  
Egg Mass ◽  
Egg Masses ◽  
Larval Stages ◽  
Carry Over ◽  
Species Specific

<p>Salinity, temperature and ultraviolet-B (UV-B) radiation are common environmental stressors in coastal habitats. These stressors are likely to increase in intensity due to the effects of climate change and can have important impacts on population and community dynamics for early development in gastropods that deposit egg masses on rocky shores. The aim of this study was to identify the effects of single and multiple stressors on the development of intertidal and shallow subtidal gastropods with encapsulated embryos. In manipulative experiments I exposed egg masses of the gastropod species Siphonaria australis, Ercolania felina, Pleurobranchaea maculata, Aplysia juliana and Doris wellingtonensis to realistic levels of either salinity, temperature or UV-B radiation, or to a combination of stressors, for different lengths of time. Embryos were then subjected to the most stressful levels of each stressor at either early or late stages of development and at different days of embryonic development. Further, egg masses were exposed to sublethal salinity, temperature and UV-B radiation stress simultaneously, simulating tide pool conditions on a warm sunny summer day. Larvae hatching from stressed and unstressed egg masses were subsequently periodically subjected to increased temperature and UV-B radiation and examined over 10 days to detect possible carry-over effects of exposure to stress in the egg mass. The results revealed that for individual stressors, low salinity (20‰), high temperature (25°C) and high UV-B (1.7 W m ⁻ ² s ⁻ ¹, i.e. a level similar to a sunny NZ summer day) all caused the highest embryonic mortality. The response to stressors was species-specific but overall the intertidal species had lower embryonic mortality than the subtidal species. Generally, chronic exposure had higher impacts on the development of embryos than periodic exposure and early embryonic development stages were most vulnerable to stress. UV-B radiation had particularly damaging effects on embryonic and larval stages for the intertidal pulmonate limpet Siphonaria australis. Further, multiple stressors had synergistic effects and caused high embryonic mortality in the egg mass as well as impacting on the vulnerability of larvae to stressors. This study revealed that stress experienced during embryonic stages can result in sub-lethal damage that increases vulnerability to temperature and decreases vulnerability to UV-B radiation experienced in the larval stage. In total, my results suggest that (1) the effects of different environmental stressors on early development of intertidal and subtidal gastropods are complex and depend on the intensity, duration and time of stress, and are generally species-specific; (2) multiple stressors can act synergistically to affect early development and (3) sublethal exposure to stress in the egg mass can have negative carry-over effects on later larval stages.</p>

scholarly journals Effects of Environmental Stressors on the Early Development of Intertidal and Subtidal Gastropod Embryos

2021 ◽  
Author(s):  
◽  
Jeannine Fischer
Keyword(s):  
Embryonic Development ◽  
Early Development ◽  
Multiple Stressors ◽  
Environmental Stressors ◽  
Embryonic Mortality ◽  
Egg Mass ◽  
Egg Masses ◽  
Larval Stages ◽  
Carry Over ◽  
Species Specific

<p>Salinity, temperature and ultraviolet-B (UV-B) radiation are common environmental stressors in coastal habitats. These stressors are likely to increase in intensity due to the effects of climate change and can have important impacts on population and community dynamics for early development in gastropods that deposit egg masses on rocky shores. The aim of this study was to identify the effects of single and multiple stressors on the development of intertidal and shallow subtidal gastropods with encapsulated embryos. In manipulative experiments I exposed egg masses of the gastropod species Siphonaria australis, Ercolania felina, Pleurobranchaea maculata, Aplysia juliana and Doris wellingtonensis to realistic levels of either salinity, temperature or UV-B radiation, or to a combination of stressors, for different lengths of time. Embryos were then subjected to the most stressful levels of each stressor at either early or late stages of development and at different days of embryonic development. Further, egg masses were exposed to sublethal salinity, temperature and UV-B radiation stress simultaneously, simulating tide pool conditions on a warm sunny summer day. Larvae hatching from stressed and unstressed egg masses were subsequently periodically subjected to increased temperature and UV-B radiation and examined over 10 days to detect possible carry-over effects of exposure to stress in the egg mass. The results revealed that for individual stressors, low salinity (20‰), high temperature (25°C) and high UV-B (1.7 W m ⁻ ² s ⁻ ¹, i.e. a level similar to a sunny NZ summer day) all caused the highest embryonic mortality. The response to stressors was species-specific but overall the intertidal species had lower embryonic mortality than the subtidal species. Generally, chronic exposure had higher impacts on the development of embryos than periodic exposure and early embryonic development stages were most vulnerable to stress. UV-B radiation had particularly damaging effects on embryonic and larval stages for the intertidal pulmonate limpet Siphonaria australis. Further, multiple stressors had synergistic effects and caused high embryonic mortality in the egg mass as well as impacting on the vulnerability of larvae to stressors. This study revealed that stress experienced during embryonic stages can result in sub-lethal damage that increases vulnerability to temperature and decreases vulnerability to UV-B radiation experienced in the larval stage. In total, my results suggest that (1) the effects of different environmental stressors on early development of intertidal and subtidal gastropods are complex and depend on the intensity, duration and time of stress, and are generally species-specific; (2) multiple stressors can act synergistically to affect early development and (3) sublethal exposure to stress in the egg mass can have negative carry-over effects on later larval stages.</p>

scholarly journals Immediate and carry-over effects of perceived predation risk on communication behavior in wild birds

2015 ◽  
Vol 27 (3) ◽  
pp. 708-716 ◽  
Author(s):  
Robin N. Abbey-Lee ◽  
Aurélien Kaiser ◽  
Alexia Mouchet ◽  
Niels J. Dingemanse
Keyword(s):  
Predation Risk ◽  
Wild Birds ◽  
Communication Behavior ◽  
Carry Over ◽  
Perceived Predation Risk

scholarly journals Welcome to the Dark Side: Partial Nighttime Illumination Affects Night-and Daytime Foraging Behavior of a Small Mammal

2022 ◽  
Vol 9 ◽  
Author(s):  
Julia Hoffmann ◽  
Franz Hölker ◽  
Jana A. Eccard
Keyword(s):  
Predation Risk ◽  
Foraging Behavior ◽  
Small Mammal ◽  
Interspecific Interactions ◽  
Dark Side ◽  
Natural Light ◽  
Giving Up Density ◽  
Night And Day ◽  
Carry Over ◽  
Perceived Predation Risk

Differences in natural light conditions caused by changes in moonlight are known to affect perceived predation risk in many nocturnal prey species. As artificial light at night (ALAN) is steadily increasing in space and intensity, it has the potential to change movement and foraging behavior of many species as it might increase perceived predation risk and mask natural light cycles. We investigated if partial nighttime illumination leads to changes in foraging behavior during the night and the subsequent day in a small mammal and whether these changes are related to animal personalities. We subjected bank voles to partial nighttime illumination in a foraging landscape under laboratory conditions and in large grassland enclosures under near natural conditions. We measured giving-up density of food in illuminated and dark artificial seed patches and video recorded the movement of animals. While animals reduced number of visits to illuminated seed patches at night, they increased visits to these patches at the following day compared to dark seed patches. Overall, bold individuals had lower giving-up densities than shy individuals but this difference increased at day in formerly illuminated seed patches. Small mammals thus showed carry-over effects on daytime foraging behavior due to ALAN, i.e., nocturnal illumination has the potential to affect intra- and interspecific interactions during both night and day with possible changes in personality structure within populations and altered predator-prey dynamics.

scholarly journals Egg mortality of northeast Arctic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus)†

2013 ◽  
Vol 71 (5) ◽  
pp. 1129-1136 ◽  
Author(s):  
Øystein Langangen ◽  
Leif C. Stige ◽  
Natalia A. Yaragina ◽  
Frode B. Vikebø ◽  
Bjarte Bogstad ◽  
...  
Keyword(s):  
Interannual Variability ◽  
Gadus Morhua ◽  
Developmental Stages ◽  
Synthetic Data ◽  
Quantitative Information ◽  
Melanogrammus Aeglefinus ◽  
Arctic Cod ◽  
Egg Mortality ◽  
Larval Stages ◽  
Haddock Melanogrammus Aeglefinus

Abstract High and variable mortality during the egg and larval stages is thought to be an important source of interannual variability in stock size in many marine fish. However, quantitative information about the mortality during these life stages, especially interannual variability, is sparse. Here, we used a time-series covering 35 years (1959–1993) of survey data to estimate mortality during the egg stages of northeast Arctic cod (Gadus morhua) and Northeast Arctic haddock (Melanogrammus aeglefinus). Using a regression approach based on the numbers of eggs in different developmental stages, we calculated the mean instantaneous mortality rate of cod eggs to be 0.17 d−1 (95% CI: 0.15–0.19), which is significantly higher than that for haddock, 0.09 d−1 (95% CI: 0.07–0.12). Interannual variability in egg mortality ranges from ∼0.12 to ∼0.22 d−1 for cod and from ∼0.04 to ∼0.12 d−1 for haddock. The accuracy of these estimates was evaluated by the analysis of synthetic data constructed from a coupled physical–biological model, suggesting that mean mortality and the magnitude of interannual variability were estimated reliably, but not mortality for any given year.

scholarly journals Does the spatial sorting of dispersal traits affect the phenotype of the non-dispersing stages of the invasive frog Xenopus laevis through coupling?

2020 ◽  
Author(s):  
Natasha Kruger ◽  
John Measey ◽  
Giovanni Vimercati ◽  
Anthony Herrel ◽  
Jean Secondi
Keyword(s):  
Xenopus Laevis ◽  
Common Garden ◽  
Phenotypic Traits ◽  
Larval Stages ◽  
The Core ◽  
Trade Offs ◽  
Spatial Sorting ◽  
Dispersal Traits ◽  
Morphology Development ◽  
Carry Over

Abstract In amphibians, spatial sorting progressively enhances the dispersal capacities of dispersing stages in expanding populations but may enhance or limit the performance of the earlier non-dispersing stages. Phenotypic traits of non-dispersing tadpoles and metamorphs can be coupled, through carry-over effects and trade-offs, or decoupled to dispersal traits in adults. We used the globally invasive amphibian, Xenopus laevis, to examine whether spatial sorting of adult phenotypes affects the phenotype of larval stages to metamorphosis in the core and at the periphery of an invasive population in France. We combined common garden laboratory and outdoor experiments to test the effect of parental pond location (core or periphery) on morphology, development and survival to metamorphosis and found no differences between tadpoles. After metamorphosis, the only difference observed in either of the experiments was the larger body size of metamorphs from the periphery, and then only when reared in the laboratory. Differences in metamorph size may indicate that a shift of dispersal traits occur after metamorphosis in X. laevis. Thus, our findings illustrate that decoupled evolution through spatial sorting can lead to changes of X. laevis adult phenotypes that would enhance dispersal without affecting the phenotype of tadpoles before metamorphosis.

A scanning electron microscopic study of the veliger larvae of the scallop argopecten purpuratus

1988 ◽  
Vol 46 ◽  
pp. 284-285
Author(s):  
G.C. Bellolio ◽  
K.S. Lohrmann ◽  
E.M. Dupré
Keyword(s):  
Morphological Description ◽  
Electron Microscopic ◽  
Larval Stages ◽  
Scanning Electron Microscopic Study ◽  
The Pacific ◽  
Argopecten Purpuratus ◽  
Veliger Larvae ◽  
20 Nm ◽  
Ethanol Series ◽  
Scanning Electron

Argopecten purpuratus is a scallop distributed in the Pacific coast of Chile and Peru. Although this species is mass cultured in both countries there is no morphological description available of the development of this bivalve except for few characterizations of some larval stages described for culture purposes. In this work veliger larvae (app. 140 pm length) were examined by the scanning electron microscope (SEM) in order to study some aspects of the organogenesis of this species.Veliger larvae were obtained from hatchery cultures, relaxed with a solution of MgCl2 and killed by slow addition of 21 glutaraldehyde (GA) in seawater (SW). They were fixed in 2% GA in calcium free artificial SW (pH 8.3), rinsed 3 times in calcium free SW, and dehydrated in a graded ethanol series. The larvae were critical point dried and mounted on double scotch tape (DST). To permit internal view, some valves were removed by slightly pressing and lifting the tip of a cactus spine wrapped with DST, The samples were coated with 20 nm gold and examined with a JEOL JSM T-300 operated at 15 KV.

Minimizing Carry-Over Effects After Treatment Failure and Maximizing Therapeutic Outcome

2014 ◽  
Vol 222 (3) ◽  
pp. 171-178 ◽  
Author(s):  
Mareile Hofmann ◽  
Nathalie Wrobel ◽  
Simon Kessner ◽  
Ulrike Bingel
Keyword(s):  
Treatment Failure ◽  
Human Subjects ◽  
Subsequent Treatment ◽  
Clinical Samples ◽  
Administration Route ◽  
Healthy Human ◽  
Negative Experiences ◽  
Analgesic Treatment ◽  
Balanced Design ◽  
Carry Over

According to experimental and clinical evidence, the experiences of previous treatments are carried over to different therapeutic approaches and impair the outcome of subsequent treatments. In this behavioral pilot study we used a change in administration route to investigate whether the effect of prior treatment experience on a subsequent treatment depends on the similarity of both treatments. We experimentally induced positive or negative experiences with a topical analgesic treatment in two groups of healthy human subjects. Subsequently, we compared responses to a second, unrelated and systemic analgesic treatment between both the positive and negative group. We found that there was no difference in the analgesic response to the second treatment between the two groups. Our data indicate that a change in administration route might reduce the influence of treatment history and therefore be a way to reduce negative carry-over effects after treatment failure. Future studies will have to validate these findings in a fully balanced design including larger, clinical samples.

Does CBT for Psychosis Have an Impact on Delusions by Improving Reasoning Biases and Negative Self-Schemas?

2018 ◽  
Vol 226 (3) ◽  
pp. 152-163 ◽  
Author(s):  
Stephanie Mehl ◽  
Björn Schlier ◽  
Tania M. Lincoln
Keyword(s):  
Behavioral Therapy ◽  
Theoretical Models ◽  
Self Esteem ◽  
Secondary Outcome ◽  
Intervention Effect ◽  
Produce Change ◽  
Attribution Biases ◽  
Carry Over ◽  
Implicit And Explicit ◽  
Reasoning Biases

Abstract. Cognitive-behavioral therapy for psychosis (CBTp) builds on theoretical models that postulate reasoning biases and negative self-schemas to be involved in the formation and maintenance of delusions. However, it is unclear whether CBTp induces change in delusions by improving these proposed causal mechanisms. This study reports on a mediation analysis of a CBTp effectiveness trial in which delusions were a secondary outcome. Patients with psychosis were randomized to individualized CBTp (n = 36) or a waiting list condition (WL; n = 34). Reasoning biases (jumping to conclusions, theory of mind, attribution biases) and self-schemas (implicit and explicit self-esteem; self-schemas related to different domains) were assessed pre- and post-therapy/WL. The results reveal an intervention effect on two of four measures of delusions and on implicit self-esteem. Nevertheless, the intervention effect on delusions was not mediated by implicit self-esteem. Changes in explicit self-schemas and reasoning biases did also not mediate the intervention effects on delusions. More focused interventions may be required to produce change in reasoning and self-schemas that have the potential to carry over to delusions.

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