Off-host longevity of the winged dispersal stage ofCarnus hemapterus(Insecta: Diptera) modulated by gender, body size and food provisioning

AbstractHighlighting the dispersal ecology of parasites is important for understanding epidemiological, demographic and coevolutionary aspects of host–parasite interactions. Yet, critical aspects of the dispersal stage of parasites, such as longevity and the factors influencing it, are poorly known. Here we study the lifespan of the dispersal stage of an ectoparasitic dipteran,Carnus hemapterus, and the impact of gender, body size and food provisioning on longevity. We found that freshly emerged imagoes survive at most less than 4 days. Longevity increased with body size and, since this parasite exhibits sexual size dimorphism, the bigger females lived longer than males. However, controlling for body size suggests that males lived relatively longer than females. Furthermore, a humid environment and food provisioning (flowers) significantly increased individual life spans. We discuss the relative importance of spatial and temporal dispersal in relation to the infectious potential of this parasite.

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Host-parasite interactions between the piranha Pygocentrus nattereri (Characiformes: Characidae) and isopods and branchiurans (Crustacea) in the rio Araguaia basin, Brazil

Neotropical Ichthyology ◽

10.1590/s1679-62252004000200006 ◽

2004 ◽

Vol 2 (2) ◽

pp. 93-98 ◽

Cited By ~ 10

Author(s):

Lucélia Nobre Carvalho ◽

Rafael Arruda ◽

Kleber Del-Claro

Keyword(s):

Body Size ◽

Mean Intensity ◽

Feeding Sites ◽

Host Parasite Interactions ◽

Ecological Aspects ◽

Field Samples ◽

Pygocentrus Nattereri ◽

The Tropics ◽

Host Parasite ◽

Ventral Area

In the tropics, studies on the ecology of host-parasite interactions are incipient and generally related to taxonomic aspects. The main objective of the present work was to analyze ecological aspects and identify the metazoan fauna of ectoparasites that infest the piranha, Pygocentrus nattereri. In May 2002, field samples were collected in the rio Araguaia basin, State of Goiás (Brazil). A total of 252 individuals of P. nattereri were caught with fishhooks and 32.14% were infested with ectoparasite crustaceans. The recorded ectoparasites were branchiurans, Argulus sp. and Dolops carvalhoi and the isopods Braga patagonica, Anphira branchialis and Asotana sp. The prevalence and mean intensity of branchiurans (16.6% and 1.5, respectively) and isopods (15.5% and 1.0, respectively) were similar. Isopods were observed in the gills of the host; branchiurans were more frequent where the skin was thinner, and facilitated attachment and feeding. The ventral area, the base of the pectoral fin and the gular area were the most infested areas. The correlations between the standard length of the host and the variables intensity and prevalence of crustaceans parasitism, were significant only for branchiurans (rs = 0.2397, p = 0.0001; chi2 = 7.97; C = 0.19). These results suggest that both feeding sites and body size probably play an important role in the distribution and abundance of ectoparasites.

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Non-linear phenomena in host—parasite interactions

Parasitology ◽

10.1017/s0031182000083426 ◽

1989 ◽

Vol 99 (S1) ◽

pp. S59-S79 ◽

Cited By ~ 108

Author(s):

R. M. Anderson ◽

R. M. May ◽

S. Gupta

Keyword(s):

Control Measure ◽

Chemotherapeutic Agents ◽

Control Measures ◽

Developmental Cycle ◽

Helminth Parasites ◽

Control Effort ◽

Host Parasite Interactions ◽

Non Linear ◽

Host Parasite ◽

The Impact

SUMMARYThe paper examines non-linear dynamical phenomena in host—parasite interactions by reference to a series of different problems ranging from the impact on transmission of control measures based on vaccination and chemotherapy, to the effects of immunological responses targeted at different stages in a parasite's life-cycle. Throughout, simple mathematical models are employed to aid in interpretation. Analyses reveal that the influence of a defined control measure on the prevalence or intensity of infection, whether vaccination or drug treatment, is non-linearly related to the magnitude of control effort (as defined by the proportion of individuals vaccinated or treated with a drug). Consideration of the relative merits of gametocyte and sporozoite vaccines against malarial parasites suggests that very high levels of cohort immunization will be required to block transmission in endemic areas, with the former type of vaccine being more effective in reducing transmission for a defined level of coverage and the latter being better with respect to a reduction in morbidity. The inclusion of genetic elements in analyses of the transmission of helminth parasites reveals complex non-linear patterns of change in the abundance of different parasite genotypes under selection pressures imposed by either the host immunological defences or the application of chemotherapeutic agents. When resistance genes are present in parasite populations, the degree to which abundance can be suppressed by chemotherapy depends critically on the frequency and intensity of application, with intermediate values of the former being optimal. A more detailed consideration of the impact of immunological defences on parasite population growth within an individual host, by reference to the erythrocytic cycle of malaria, suggests that the effectiveness of a given immunological response is inversely related to the life-expectancy of the target stage in the parasite's developmental cycle.

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Critical aspects of phytoalexins in potato

Agricultural and Food Science ◽

10.23986/afsci.72266 ◽

1987 ◽

Vol 59 (3) ◽

pp. 217-230

Author(s):

Sture Brishammer

Keyword(s):

Host Cells ◽

Potato Tubers ◽

Inhibitory Effects ◽

Host Parasite Interactions ◽

Different Types ◽

Endogenous Elicitor ◽

Artificial Inoculations ◽

Host Parasite ◽

Critical Aspects

Phytoalexins in potato are sesquiterpenoid substances produced in response to infections and are believed to help plants resist attack by pathogens. However, these compounds appear in response to compatible as well as incompatible interactions and only accumulate in the tubers. The amounts of phytoalexins produced depend on the physiological condition of the tubers. Young tubers don’t get easily infected with Phytophthora infestans even though they synthesize extremely small amounts of phytoalexins. Furthermore, confusion as to the identity of specific races and the propensity for a given race to produce different effects in the same type of host makes it extremely difficult to predict host-parasite interactions with any acceptable degree of accuracy. It is doubtful that the production of phytoalexins in response to artificial inoculations is representative of that occurring in natural infections. Markedly different types of pathogens induce synthesis of same substances in the host cells. It therefore seems most probable that all the phytoalexins are synthesized in response to stimulation by an endogenous elicitor. Little knowledge is available regarding the biosynthesis of these sesquiterpenes, and many previous determinations have presumably been erroneous. When potato tubers were inoculated with the late blight fungus, secondarily appearing bacteria were not retarded, despite the presence of phytoalexins. There is no generally accepted hypothesis describing the mechanism by which phytoalexins inhibit pathogens and no distinction has been made between the effects on necrotrophs and biotrophs. Adequate bioassays capable of measuring the effects of inhibition have yet to be developed, thus far, no convincing inhibitory effects have been reported. During purification of the phytoalexins there is a high risk for artifact forming, implying that specific compounds cannot be detected with certainty. Moreover, present analytical methods must be improved before we can determine how phytoalexins act in vivo. Probably, phytoalexins are synthesized at a stage in the infection too late to be able to restrict its expansion with the tissues of the host. Phytoalexins are restricted to the attacked parts of the tubers and there is no evidence indicating that these compounds pose any health risks when present in potatoes used for consumption.

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Co-evolution between mosquitoes and microsporidian transmission strategies

10.35662/unine-thesis-2665 ◽

2018 ◽

Author(s):

◽

Giacomo Zilio

Keyword(s):

Evolutionary Dynamics ◽

Horizontal Transmission ◽

Life History Evolution ◽

Induced Response ◽

Ecological Conditions ◽

Transmission Strategy ◽

Host Parasite Interactions ◽

Key Aspects ◽

Host Parasite ◽

The Impact

Parasite and host impose strong selection on each other. The first causes damages and mortality to the host, while the second responds by reducing the detrimental effects and the intensity and/or success of infection. The resulting co-evolutionary dynamics are profoundly affected by the ecological conditions, for these may influence many aspects of host-parasite interactions including life history evolution, virulence and transmission. It is therefore essential to study and incorporate environmental variation in the field of parasitology to gain an exhaustive understanding of how host and parasite evolve. In this thesis, a single generation and an evolutionary experimental approach were used to investigate the impact of the ecological and epidemiological conditions on several aspects of host-parasite interactions, with the main focus on parasite transmission strategies. Firstly, it was examined the effect of the availability of resources for the host, timing of infection, and co-infection on the virulence and transmission success of two parasites with conflicting transmission strategy. Next, it was tested how the environment influenced the trade-off between vertical and horizontal transmission in a parasite with a mixed mode of transmission and it was assessed the genetic contribution of the host to its transmission mode. Whether the vertical and horizontal component of this parasite and the associated virulence responded to restriction opportunities, represented by different availability of resources over several generations, was investigated with an evolutionary experiment. Finally, the presence of a plastically parasite-induced response on the recombination rate of the host as a potential cross-generational defence mechanism was explored. The experiments cover many key aspects of host-parasite interactions and emphasize the role of the ecological conditions on shaping these relationships. The results and their implications are discussed in detail throughout the thesis. Overall, this work highlights the dependence of crucial aspects of host-parasite interactions from the epidemiological and ecological conditions. Disentangling the various forces surrounding these interactions may help us to acquire a better knowledge of how a changing environment may drive the evolution of both host and parasite.

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Noise pollution: acute noise exposure increases susceptibility to disease and chronic exposure reduces host survival

Royal Society Open Science ◽

10.1098/rsos.200172 ◽

2020 ◽

Vol 7 (9) ◽

pp. 200172

Author(s):

Numair Masud ◽

Laura Hayes ◽

Davide Crivelli ◽

Stephen Grigg ◽

Jo Cable

Keyword(s):

Noise Exposure ◽

Animal Health ◽

Parasite Burden ◽

Aquatic Organisms ◽

Noise Pollution ◽

Parasitic Infections ◽

Terrestrial Vertebrates ◽

Host Parasite Interactions ◽

Host Parasite ◽

The Impact

Anthropogenic noise is a pervasive global pollutant that has been detected in every major habitat on the planet. Detrimental impacts of noise pollution on physiology, immunology and behaviour have been shown in terrestrial vertebrates and invertebrates. Equivalent research on aquatic organisms has until recently been stunted by the misnomer of a silent underwater world. In fish, however, noise pollution can lead to stress, hearing loss, behavioural changes and impacted immunity. But, the functional effects of this impacted immunity on disease resistance due to noise exposure have remained neglected. Parasites that cause transmissible disease are key drivers of ecosystem biodiversity and a significant factor limiting the sustainable expansion of the animal trade. Therefore, understanding how a pervasive stressor is impacting host–parasite interactions will have far-reaching implications for global animal health. Here, we investigated the impact of acute and chronic noise on vertebrate susceptibility to parasitic infections, using a model host–parasite system (guppy– Gyrodactylus turnbulli ). Hosts experiencing acute noise suffered significantly increased parasite burden compared with those in no noise treatments. By contrast, fish experiencing chronic noise had the lowest parasite burden. However, these hosts died significantly earlier compared with those exposed to acute and no noise treatments. By revealing the detrimental impacts of acute and chronic noise on host–parasite interactions, we add to the growing body of evidence demonstrating a link between noise pollution and reduced animal health.

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Evolution of transgenerational immunity in invertebrates

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2016.1136 ◽

2016 ◽

Vol 283 (1839) ◽

pp. 20161136 ◽

Cited By ~ 22

Author(s):

R. Pigeault ◽

R. Garnier ◽

A. Rivero ◽

S. Gandon

Keyword(s):

Experimental Studies ◽

Ecological Factors ◽

Immune Protection ◽

Vertebrate Species ◽

Invertebrate Species ◽

Host Parasite Interactions ◽

Expected Longevity ◽

Host Parasite ◽

The Impact ◽

Evolution Of Immunity

Over a decade ago, the discovery of transgenerational immunity in invertebrates shifted existing paradigms on the lack of sophistication of their immune system. Nonetheless, the prevalence of this trait and the ecological factors driving its evolution in invertebrates remain poorly understood. Here, we develop a theoretical host–parasite model and predict that long lifespan and low dispersal should promote the evolution of transgenerational immunity. We also predict that in species that produce both philopatric and dispersing individuals, it may pay to have a plastic allocation strategy with a higher transgenerational immunity investment in philopatric offspring because they are more likely to encounter locally adapted pathogens. We review all experimental studies published to date, comprising 21 invertebrate species in nine different orders, and we show that, as expected, longevity and dispersal correlate with the transfer of immunity to offspring. The validity of our prediction regarding the plasticity of investment in transgenerational immunity remains to be tested in invertebrates, but also in vertebrate species. We discuss the implications of our work for the study of the evolution of immunity, and we suggest further avenues of research to expand our knowledge of the impact of transgenerational immune protection in host–parasite interactions.

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Impact of eutrophication on wood frog, Rana sylvatica, tadpoles infected with Echinostoma trivolvis cercariae

Canadian Journal of Zoology ◽

10.1139/z06-119 ◽

2006 ◽

Vol 84 (9) ◽

pp. 1315-1321 ◽

Cited By ~ 23

Author(s):

L.K. Belden

Keyword(s):

Environmental Changes ◽

Rana Sylvatica ◽

Infection Level ◽

Wood Frogs ◽

Host Parasite Interactions ◽

Infection Treatment ◽

Second Intermediate Host ◽

Host Parasite ◽

The Impact ◽

Echinostoma Trivolvis

In freshwater systems, environmental changes, such as eutrophication, are occurring that could impact the outcome of host–parasite interactions. Using tadpole infection with trematode cercariae as a host–parasite system, this study examined (i) growth, development, and maintenance of trematode ( Echinostoma trivolvis (Cort, 1914)) infection levels in second intermediate host larval wood frogs ( Rana sylvatica LeConte, 1825) and (ii) post-infection impacts of eutrophication on R. sylvatica tadpoles infected to varying degrees with E. trivolvis cercariae. Results from the first experiment suggest no impact of infection with 50 cercariae on R. sylvatica growth and development compared with uninfected controls. Results from the second experiment, investigating the impact of eutrophication on infected tadpoles, showed that survival to metamorphosis of the individuals in the highest infection treatment (80 cercariae) was reduced regardless of eutrophication treatment. However, for individuals surviving infection with 80 cercariae and for individuals infected with only 20 cercariae, no impact of infection on mass at metamorphosis was documented, although individuals were larger at metamorphosis in the eutrophic tanks. These data demonstrate that infection with E. trivolvis can impact R. sylvatica survivorship, at least above some threshold infection level, and that eutrophication may have minimal impacts on tadpole hosts once infection has occurred.

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Host–parasite interactions: resist or tolerate but never stop running

Biology Letters ◽

10.1098/rsbl.2009.0444 ◽

2009 ◽

Vol 5 (6) ◽

pp. 721-722

Author(s):

Jay D. Evans

Keyword(s):

Immune Response ◽

Immune Responses ◽

Common Ground ◽

European Science Foundation ◽

Immune Systems ◽

Host Parasite Interactions ◽

European Science ◽

Host Parasite ◽

The Impact ◽

Over Time

A conference exploring ‘The impact of the environment on innate immunity: the threat of diseases’ was held on 4–9 May 2009 in Obergurgl, Austria, thanks to the support from the European Science Foundation, Innsbruck University and the Austrian Science Foundation. The goals of the conference were to explore how the outcomes of host–parasite interactions depend on variation across individuals, their parasites and the environment in which they both find themselves. Central themes were the inherent costs of mounting an immune response, the ability of some organisms to pre-empt infection by ‘priming’ their immune systems, the fact that parasites learn to evade immune responses over time and the use of theory to predict when diseases will get out of hand. Many of the systems presented had clear impacts on human health, agriculture or the maintenance of complex ecosystems. There was common ground throughout in developing methodologies and embracing what one of the organizers termed the ‘interactome’ between hosts and those which would exploit them.

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Host-parasite interactions and global climate oscillations

Parasitology ◽

10.1017/s0031182011000655 ◽

2011 ◽

Vol 138 (8) ◽

pp. 1022-1028 ◽

Cited By ~ 3

Author(s):

HIDEYUKI DOI ◽

NATALIA I. YURLOVA

Keyword(s):

Linear Models ◽

Lymnaea Stagnalis ◽

Global Climate ◽

Host Snail ◽

Climatic Oscillations ◽

The North ◽

Host Parasite Interactions ◽

The North Atlantic Oscillation ◽

Host Parasite ◽

The Impact

SUMMARYIt is suspected that host-parasite interactions are influenced by climatic oscillations such as the North Atlantic Oscillation (NAO). However, the effects of climatic oscillations on host-parasite interactions have never been investigated. A long-term (1982–1999) dataset of the host snail Lymnaea stagnalis and trematode metacercariae infection has been collected for Lake Chany in Western Siberia. Using this dataset, we estimated the impact of the NAO on the population dynamics of hosts and parasites as well as their interactions. The results of general linear models showed that the abundance of dominant parasite species and the total parasite abundance significantly increased with NAO, with the exception of Moliniella anceps. Other climatic and biological factors were relatively weak to explain the abundance. There was no significant relationship between NAO and the population density of host snails. The prevalence of infection was related to the total abundance of parasites, but not to the NAO. Thus, the responses to the NAO differed between the host and parasites, indicating mismatching in host-parasite interactions. Therefore, climatic oscillations, such as the NAO, influence common parasitism.

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Mesoscale spatiotemporal variability in a complex host-parasite system influenced by intermediate host body size

PeerJ ◽

10.7717/peerj.3675 ◽

2017 ◽

Vol 5 ◽

pp. e3675 ◽

Cited By ~ 3

Author(s):

Sara M. Rodríguez ◽

Nelson Valdivia

Keyword(s):

Body Size ◽

Parasite Burden ◽

Spatiotemporal Variability ◽

Intermediate Hosts ◽

Host Body ◽

Host Parasite Interactions ◽

Essential Components ◽

Host Parasite ◽

Parasite Exposure ◽

Host Body Size

Background Parasites are essential components of natural communities, but the factors that generate skewed distributions of parasite occurrences and abundances across host populations are not well understood. Methods Here, we analyse at a seascape scale the spatiotemporal relationships of parasite exposure and host body-size with the proportion of infected hosts (i.e., prevalence) and aggregation of parasite burden across ca. 150 km of the coast and over 22 months. We predicted that the effects of parasite exposure on prevalence and aggregation are dependent on host body-sizes. We used an indirect host-parasite interaction in which migratory seagulls, sandy-shore molecrabs, and an acanthocephalan worm constitute the definitive hosts, intermediate hosts, and endoparasite, respectively. In such complex systems, increments in the abundance of definitive hosts imply increments in intermediate hosts’ exposure to the parasite’s dispersive stages. Results Linear mixed-effects models showed a significant, albeit highly variable, positive relationship between seagull density and prevalence. This relationship was stronger for small (cephalothorax length >15 mm) than large molecrabs (<15 mm). Independently of seagull density, large molecrabs carried significantly more parasites than small molecrabs. The analysis of the variance-to-mean ratio of per capita parasite burden showed no relationship between seagull density and mean parasite aggregation across host populations. However, the amount of unexplained variability in aggregation was strikingly higher in larger than smaller intermediate hosts. This unexplained variability was driven by a decrease in the mean-variance scaling in heavily infected large molecrabs. Conclusions These results show complex interdependencies between extrinsic and intrinsic population attributes on the structure of host-parasite interactions. We suggest that parasite accumulation—a characteristic of indirect host-parasite interactions—and subsequent increasing mortality rates over ontogeny underpin size-dependent host-parasite dynamics.

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