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Robby Stoks - One of the best experts on this subject based on the ideXlab platform.
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Reinforcing effects of non-pathogenic bacteria and predation risk: from physiology to life history
Oecologia, 2014Co-Authors: Lizanne Janssens, Robby StoksAbstract:The important ecological role of predation risk in shaping populations, communities and ecosystems is becoming increasingly clear. In this context, synergistic effects between predation risk and other natural stressors on prey organisms are gaining attention. Although non-pathogenic bacteria can be widespread in aquatic ecosystems, their role in mediating effects of predation risk has been ignored. We here address the hypothesis that non-pathogenic bacteria may reinforce the negative effects of predation risk in larvae of the Damselfly Coenagrion puella . We found synergistic effects for all three life history variables studied: mortality increased, growth reductions were magnified and bacterial load was higher when both non-lethal stressors were combined. The combined exposure to the bacterium and predation risk considerably impaired the two key antipredator mechanisms of the Damselfly larvae: they no longer reduced their food intake under predation risk and showed a synergistic reduction in escape swimming speed. The reinforcing negative effects on the fitness-related traits could be explained by the observed synergistic effects on food intake, swimming muscle mass, immune function and oxidative damage. These are likely widespread consequences of energetic constraints and increased metabolic rates associated with the fight-or-flight response. We therefore hypothesize that the here documented synergistic interactions with non-pathogenic bacteria may be widespread. Our results highlight the ignored ecological role of non-pathogenic bacteria in reinforcing the negative effects of predation risk on prey organisms.
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temperature and latitude specific individual growth rates shape the vulnerability of Damselfly larvae to a widespread pesticide
Journal of Applied Ecology, 2014Co-Authors: Lizanne Janssens, Khuong Dinh Van, Sara Debecker, Robby StoksAbstract:Summary Freshwater ecosystems are especially vulnerable to climate change and pollution. One key challenge for aquatic toxicology is to determine and manage the combined effects of temperature increase and contaminants across species' ranges. We tested how thermal adaptation and life-history evolution along a natural temperature gradient influence the vulnerability of an aquatic insect to a pesticide under global warming. We applied a space-for-time substitution approach to study the effect of warming on the vulnerability of Ischnura elegans Damselfly larvae to the pesticide chlorpyrifos in a common garden warming experiment (20 and 24 °C) with replicated populations from three latitudes spanning >1500 km in Europe. Chlorpyrifos was more toxic to Damselfly larvae at the higher temperature: mortality only occurred at 24 °C and the reductions in growth rate were stronger at 24 °C. This could partly be explained by parallel reductions in food intake but not by the activities of two widespread enzymatic biomarkers, glutathione S-transferase (GST) and acetylcholinesterase (AChE). There was some evidence that the increased toxicity of the high chlorpyrifos concentration at 24 °C was stronger in terms of growth reduction in the faster-growing larvae from the low-latitude populations. This is consistent with energy allocation trade-offs between growth rate and pesticide tolerance, but suggests that local thermal adaptation does not play a role in coping with pesticide stress. Synthesis and applications. Damselfly larvae from populations in lower latitudes were more vulnerable to a common pesticide at higher temperatures and pesticide concentrations, whereas evidence for the influence of local thermal adaptation on the vulnerability of larvae was weak. These results emphasize the need for spatially explicit bioassessment and conservation tools. Management practices aimed at mitigating pesticide run-off into aquatic ecosystems are particularly important in agricultural areas at low latitudes.
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behavioural physiological and biochemical markers in Damselfly larvae ischnura elegans to assess effects of accumulated metal mixtures
Science of The Total Environment, 2014Co-Authors: Nander Van Praet, Robby Stoks, Maarten De Jonge, Ronny Blust, Lieven BervoetsAbstract:Currently it is not known at which organismal level effects of metal mixtures in nature can best be detected, which is relevant to develop accurate monitoring schemes and quality standards. The present study investigated relationships between accumulated metals with different levels of biological organisation in the aquatic larval stage of the Damselfly Ischnura elegans. Larvae were collected in seven Flemish ponds differing in metal load. In each field-collected larva we quantified concentrations of accumulated metals and a set of biochemical markers (acetylcholinesterase (AChE) and glutathione-S-transferase (GST)), physiological endpoints (energy storage), and behavioural responses (locomotory activity and the feeding rate). Accumulated metal levels and the measured endpoints significantly differed among ponds, however, a large variation in metal load index was observed within individuals of the same population. Only GST and energy availability could be partly predicted by the observed variation in metal load index on individual Damselfly level. However, no single endpoint could be used to detect the observed variation in metal load index among populations. In conclusion, the sublethal endpoints cannot be used as reliable biomarkers to monitor the toxicity of accumulated metal mixtures in natural populations of I. elegans.
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food stress and predator induced stress shape developmental performance in a Damselfly
Oecologia, 2001Co-Authors: Robby StoksAbstract: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.
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Indirect Monitoring of Agonistic Encounters in Larvae of Lestes viridis (Odonata: Lestidae) Using Exuviae Lamellae Status
Aquatic Insects, 1998Co-Authors: Robby StoksAbstract: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 ...
Mark R. Forbes - One of the best experts on this subject based on the ideXlab platform.
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Threats from the air: Damselfly predation on diverse prey taxa.
The Journal of animal ecology, 2020Co-Authors: Kari M. Kaunisto, Mark R. Forbes, Tomas Roslin, André Morrill, Ilari E. Sääksjärvi, Anna I. E. Puisto, Thomas M. Lilley, Eero J. VesterinenAbstract:To understand the diversity and strength of predation in natural communities, researchers must quantify the total amount of prey species in the diet of predators. Metabarcoding approaches have allowed widespread characterization of predator diets with high taxonomic resolution. To determine the wider impacts of predators, researchers should combine DNA techniques with estimates of population size of predators using mark-release-recapture (MRR) methods, and with accurate metrics of food consumption by individuals. Herein, we estimate the scale of predation exerted by four Damselfly species on diverse prey taxa within a well-defined 12-ha study area, resolving the prey species of individual damselflies, to what extent the diets of predatory species overlap, and which fraction of the main prey populations are consumed. We identify the taxonomic composition of diets using DNA metabarcoding and quantify Damselfly population sizes by MRR. We also use predator-specific estimates of consumption rates, and independent data on prey emergence rates to estimate the collective predation pressure summed over all prey taxa and specific to their main prey (non-biting midges or chironomids) of the four Damselfly species. The four Damselfly species collectively consumed a prey mass equivalent to roughly 870 (95% CL 410-1,800) g, over 2 months. Each individual consumed 29%-66% (95% CL 9.4-123) of its body weight during its relatively short life span (2.1-4.7 days; 95% CL 0.74-7.9) in the focal population. This predation pressure was widely distributed across the local invertebrate prey community, including 4 classes, 19 orders and c. 140 genera. Different predator species showed extensive overlap in diets, with an average of 30% of prey shared by at least two predator species. Of the available prey individuals in the widely consumed family Chironomidae, only a relatively small proportion (0.76%; 95% CL 0.35%-1.61%) were consumed. Our synthesis of population sizes, per-capita consumption rates and taxonomic distribution of diets identifies damselflies as a comparatively minor predator group of aerial insects. As the next step, we should add estimates of predation by larger odonate species, and experimental removal of odonates, thereby establishing the full impact of odonate predation on prey communities.
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Seasonality of gregarine parasitism in the Damselfly, Nehalennia irene: understanding unimodal patterns
Parasitology research, 2011Co-Authors: Mark R. Forbes, Julia J. Mlynarek, Jane E. Allison, Kerry R. HeckerAbstract:We studied parasitism by gut protozoans (Apicomplexa: Eugregarinidae) in the Damselfly, Nehalennia irene (Hagen) (Odonata: Coenagrionidae). We tested whether there was any seasonal pattern, as has been found for other parasites of damselflies and which has implications for selection on emergence and breeding. Using aggregate data from 12 date-by-site comparisons involving five sites, we found that both prevalence and intensity of gregarine parasitism were seasonally unimodal. Parasitism first increased and then declined seasonally after peaking mid-season. This Damselfly species has shown seasonal increases in density followed by declines at several sites including a site sampled in this study. Therefore, similar seasonal changes in a directly transmitted parasite were expected and are now confirmed. Other factors that might account for seasonal changes in parasitism by gregarines are either unlikely or can be discounted including sampling of older damselflies mid-season but not late in the season, or sex biases in parasitism and overrepresentation of the more parasitized sex mid-season.
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Inter-annual variation in prevalence and intensity of mite parasitism relates to appearance and expression of Damselfly resistance
BMC ecology, 2010Co-Authors: Laura Nagel, Tonia Robb, Mark R. ForbesAbstract:Insects can resist parasites using the costly process of melanotic encapsulation. This form of physiological resistance has been studied under laboratory conditions, but the abiotic and biotic factors affecting resistance in natural insect populations are not well understood. Mite parasitism of damselflies was studied in a temperate Damselfly population over seven seasons to determine if melanotic encapsulation of mite feeding tubes was related to degree of parasitism, host sex, host size, emergence timing, duration of the emergence period, and average daily air temperature. Although parasite prevalence in newly emerged damselflies was > 77% each year, hosts did not resist mites in the early years of study. Resistance began the year that there was a dramatic increase in the number of mites on newly emerged damselflies. Resistance continued to be correlated with mite prevalence and intensity throughout the seven-year study. However, the percentage of hosts resisting only ranged from 0-13% among years and resistance was not sex-biased and was not correlated with host size. Resistance also was not correlated with air temperature or with timing or duration of Damselfly emergence. Resistance in host damselflies was weakly and variably expressed over the study period. Factors such as temperature, which have been identified in laboratory studies as contributing to resistance by similar hosts, can be irrelevant in natural populations. This lack of temperature effect may be due to the narrow range in temperatures observed at host emergence among years. Degree of mite parasitism predicted both the appearance and continued expression of resistance among parasitized damselflies.
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Nutritional stress and behavioural immunity of damselflies
Animal Behaviour, 2001Co-Authors: Brian Leung, Mark R. Forbes, Robert L. BakerAbstract:Increased mortality in the presence of stress may result from stress-reduced availability of energy for immune function, coupled with the presence of pathogens or parasites. We tested the hypothesis that stress reduces antiparasite responses of damselflies Ischnuraverticalis (Hagen) to their ectoparasitic mitesArrenuruspseudosuperior (Marshall). Numbers of colonizing mites did not differ between nutritionally stressed and unstressed damselflies. However, unstressed damselflies successfully removed more attached mites than nutritionally stressed host larvae. Furthermore, certain Damselfly behaviours increased in the presence of nonfeeding mite larvae. Some of these behaviours were effective in defending against mites, but were reduced by nutritional stress. These results are sufficient to explain inverse relations found between Damselfly condition and intensity of mite parasitism seen in nature, and are likely to be applicable to other host–ectoparasite associations.
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Female morphs of the Damselfly Enallagma boreale Selys (Odonata: Coenagrionidae): a benefit for androchromatypes
Canadian Journal of Zoology, 1991Co-Authors: Mark R. ForbesAbstract:Females of the coenagrionid Damselfly Enallagma boreale Selys occur as three distinct colour morphs at a study site in eastern Ontario, Canada; > 65% are blue (termed androchromatypes) like the conspecific male, ca. 30% are green, and < 5% have both blue and green on their abdomen. I provide experimental evidence which suggests that one advantage of androchromatypism is avoidance of harassment from heterospecific males of the congeneric Damselfly Enallagma ebrium (Hagen).
Shucun Sun - One of the best experts on this subject based on the ideXlab platform.
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effect of norfloxacin on algae cladoceran grazer larval Damselfly food chains algal morphology mediated trophic cascades
Chemosphere, 2020Co-Authors: Lingling Wan, Yaoyue Long, Jin Hui, Hao Zhang, Zhiyong Hou, Jiexin Tan, Ying Pan, Shucun SunAbstract:Abstract Antibiotic norfloxacin (NOR) has recently been demonstrated to affect the swimming behavior of zooplankton species and phytoplankton-zooplankton interactions, which may further affect trophic cascades. To test this hypothesis, two food chains (Scenedesmus quadricauda–Daphnia magna–larval Damselfly and Chlorella vulgaris–D. magna–larval Damselfly) were used to examine the effect of NOR concentrations (0, 0.5, 5, and 25 mg L−1) on trophic cascades. In the absence of NOR, larval damselflies reduced grazer density and increased algal density, regardless of algal species. In the presence of NOR, increasing NOR concentration strengthened the positive effect of larval damselflies on the growth of C. vulgaris because larval damselflies suppressed grazer density more efficiently resulting from reduced swimming ability in the grazers. Conversely, increasing NOR concentration reduced the positive effect on the growth of S. quadricauda due to inhibited grazer-induced colony formation in S. quadricauda. Therefore, exposure to NOR altered the direction and strength of trophic cascades and showed species-specific differences, depending on algal morphology-mediated indirect interactions. These findings provide novel insights into how NOR affects aquatic food chains and reveal the importance of algal traits in determining trophic cascades.
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Effect of norfloxacin on algae–cladoceran grazer–larval Damselfly food chains: Algal morphology-mediated trophic cascades
Chemosphere, 2020Co-Authors: Lingling Wan, Yaoyue Long, Jin Hui, Hao Zhang, Zhiyong Hou, Jiexin Tan, Ying Pan, Shucun SunAbstract:Antibiotic norfloxacin (NOR) has recently been demonstrated to affect the swimming behavior of zooplankton species and phytoplankton-zooplankton interactions, which may further affect trophic cascades. To test this hypothesis, two food chains (Scenedesmus quadricauda-Daphnia magna-larval Damselfly and Chlorella vulgaris-D. magna-larval Damselfly) were used to examine the effect of NOR concentrations (0, 0.5, 5, and 25 mg L-1) on trophic cascades. In the absence of NOR, larval damselflies reduced grazer density and increased algal density, regardless of algal species. In the presence of NOR, increasing NOR concentration strengthened the positive effect of larval damselflies on the growth of C. vulgaris because larval damselflies suppressed grazer density more efficiently resulting from reduced swimming ability in the grazers. Conversely, increasing NOR concentration reduced the positive effect on the growth of S. quadricauda due to inhibited grazer-induced colony formation in S. quadricauda. Therefore, exposure to NOR altered the direction and strength of trophic cascades and showed species-specific differences, depending on algal morphology-mediated indirect interactions. These findings provide novel insights into how NOR affects aquatic food chains and reveal the importance of algal traits in determining trophic cascades.
Robert L. Baker - One of the best experts on this subject based on the ideXlab platform.
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Nutritional stress and behavioural immunity of damselflies
Animal Behaviour, 2001Co-Authors: Brian Leung, Mark R. Forbes, Robert L. BakerAbstract:Increased mortality in the presence of stress may result from stress-reduced availability of energy for immune function, coupled with the presence of pathogens or parasites. We tested the hypothesis that stress reduces antiparasite responses of damselflies Ischnuraverticalis (Hagen) to their ectoparasitic mitesArrenuruspseudosuperior (Marshall). Numbers of colonizing mites did not differ between nutritionally stressed and unstressed damselflies. However, unstressed damselflies successfully removed more attached mites than nutritionally stressed host larvae. Furthermore, certain Damselfly behaviours increased in the presence of nonfeeding mite larvae. Some of these behaviours were effective in defending against mites, but were reduced by nutritional stress. These results are sufficient to explain inverse relations found between Damselfly condition and intensity of mite parasitism seen in nature, and are likely to be applicable to other host–ectoparasite associations.
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Condition and fecundity of the Damselfly, Enallagma ebrium (Hagen): the importance of ectoparasites
Oecologia, 1991Co-Authors: Mark R. L. Forbes, Robert L. BakerAbstract:The extent, magnitude, and cause of natural covariation between degree of parasitism and other variables known or suspected of influencing host fitness (such as host age or body size) has been understudied. We demonstrate that degree of parasitism by larval water mites ( Arrenurus spp.) was associated with reduced condition of males and with lowered fecundity of young females of the Damselfly, Enallagma ebrium (Hagen) (Odonata: Coenagrionidae). We also demonstrate that degree of parasitism can covary with both age and size of host damselflies. We explain the putative causes of such natural covariation, and we suggest that degree of parasitism, host age, and host size can all interact to determine Damselfly fitness. We expect that natural covariation between the host's phenotype and degree of parasitism will be frequently observed. Studies of such natural covariation will help researchers to assess better the importance of several variables on host reproductive success and to understand better the dynamics of host-parasite interactions.
Andre Nel - One of the best experts on this subject based on the ideXlab platform.
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Extreme adaptations for probable visual courtship behaviour in a Cretaceous dancing Damselfly.
Scientific reports, 2017Co-Authors: Daran Zheng, Suchin Chang, Edmund A Jarzembowski, Haichun Zhang, Andre Nel, Fangyuan Xia, Haoying Liu, Bo WangAbstract:Courtship behaviours, frequent among modern insects, have left extremely rare fossil traces. None are known previously for fossil odonatans. Fossil traces of such behaviours are better known among the vertebrates, e.g. the hypertelic antlers of the Pleistocene giant deer Megaloceros giganteus. Here we describe spectacular extremely expanded, pod-like tibiae in males of a platycnemidid Damselfly from mid-Cretaceous Burmese amber. Such structures in modern damselflies, help to fend off other suitors as well as attract mating females, increasing the chances of successful mating. Modern Platycnemidinae and Chlorocyphidae convergently acquired similar but less developed structures. The new findings provide suggestive evidence of Damselfly courtship behaviour as far back as the mid-Cretaceous. These data show an unexpected morphological disparity in dancing Damselfly leg structure, and shed new light on mechanisms of sexual selection involving intra- and intersex reproductive competition during the Cretaceous.
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The oldest ‘amphipterygid’ Damselfly of tropical affinities in the Paleocene of Menat (Zygoptera: Eucaloptera)
Historical Biology, 2017Co-Authors: Romain Garrouste, Jean-marc Pouillon, Sonja Wedmann, Andre NelAbstract:The new Damselfly genus and species Valerea multicellulata is described from the Paleocene of Menat (France), a Lagerstatte with many fossil insects, plants and vertebrates with high paleontological value. Aquatic insects are very scarce in this outcrop, this Damselfly being the fourth described Odonata. Its closest modern relatives belong to the Amphipterygidae or the Devadattidae, families with very narrow tropical extant distributions. This new fossil allows us to confirm the tropical affinities of the odonatan fauna of the Menat paleolake communities. It also shows that the amphipterygids were clearly more widespread during the Paleogene than today, probably in relation to the worldwide warm and equable climate in the Paleocene.
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A new Early Jurassic Damselfly from the Grand Duchy of Luxembourg (Odonata: Campterophlebiidae)
Alcheringa, 2017Co-Authors: Andre Nel, Robert WeisAbstract:Gallodorsettia kronzi gen. et sp. nov., the first representative of the Damselfly family Campterophlebiidae from the Toarcian of Grand Duchy of Luxembourg, is described herein. Its closest relative is the genus Dorsettia, known from the early Lower Jurassic of UK and China. The Campterophlebiidae seem to be rare in the Early Jurassic of Western Europe, despite being one of the most diverse odonatan families at that time, especially in Asia.
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The oldest ‘amphipterygid’ Damselfly of tropical affinities in the Paleocene of Menat (Zygoptera: Eucaloptera)
Historical Biology, 2016Co-Authors: Romain Garrouste, Jean-marc Pouillon, Sonja Wedmann, Andre NelAbstract:International audienceThe new Damselfly genus and species Valerea multicellulata is described from the Paleocene of Menat (France), a Lagerstatte with many fossil insects, plants and vertebrates with high paleontological value. Aquatic insects are very scarce in this outcrop, this Damselfly being the fourth described Odonata. Its closest modern relatives belong to the Amphipterygidae or the Devadattidae, families with very narrow tropical extant distributions. This new fossil allows us to confirm the tropical affinities of the odonatan fauna of the Menat paleolake communities. It also shows that the amphipterygids were clearly more widespread during the Paleogene than today, probably in relation to the worldwide warm and equable climate in the Paleocene
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Elektroeuphaea gen.n., the oldest representative of the modern Epallaginae from Eocene Baltic amber (Odonata: Zygoptera: Epallagidae)
Insect Systematics & Evolution, 2013Co-Authors: Andre Nel, Wiesław Krzeminski, Jacek SzwedoAbstract:Elektroeuphaea flecki gen.n. sp.n., the oldest representative of the modern Damselfly subfamily Epallaginae, is described from the Middle Eocene Baltic amber. This study confirms a Palaeocene age (or older) for the Epallagidae, previously supported by the presence of representatives of Eodichrominae from the Palaeocene-Eocene Mo-clay Formation of Denmark and from Baltic amber.
