scholarly journals A meta-analysis reveals temperature, dose, life stage, and taxonomy influence host susceptibility to a fungal parasite

2019 ◽  
Author(s):  
Erin L. Sauer ◽  
Jeremy M. Cohen ◽  
Marc J. Lajeunesse ◽  
Taegan A. McMahon ◽  
David J. Civitello ◽  
...  
Keyword(s):  
Host Species ◽  
Species Interactions ◽  
Pathogenic Fungus ◽  
Meta Analysis ◽  
Life Stage ◽  
Host Susceptibility ◽  
Average Dose ◽  
Infection Dose ◽  
Host Mortality ◽  
Host Life

AbstractComplex ecological relationships, such as host-parasite interactions, are often modeled with laboratory experiments. However, some experimental laboratory conditions, such as temperature or infection dose, are regularly chosen based on convenience or convention and it is unclear how these decisions systematically affect experimental outcomes. Here, we conducted a meta-analysis of 58 laboratory studies that exposed amphibians to the pathogenic fungus Batrachochytrium dendrobatidis (Bd) to better understand how laboratory temperature, host life stage, infection dose, and host species affect host mortality. We found that host mortality was driven by thermal mismatches: hosts native to cooler environments experienced greater Bd-induced mortality at relatively warm experimental temperatures and vice versa. We also found that Bd dose positively predicted Bd-induced host mortality and that the superfamilies Bufonoidea and Hyloidea were especially susceptible to Bd. Finally, the effect of Bd on host mortality varied across host life stages, with larval amphibians experiencing lower risk of Bd-induced mortality than adults or metamorphs. Metamorphs were especially susceptible and experienced mortality when inoculated with much smaller Bd doses than the average dose used by researchers. Our results suggest that when designing experiments on species interactions, researchers should carefully consider the experimental temperature, and inoculum dose, and life stage and taxonomy of the host species.

scholarly journals A meta‐analysis reveals temperature, dose, life stage, and taxonomy influence host susceptibility to a fungal parasite

Ecology ◽  
2020 ◽  
Vol 101 (4) ◽  
Author(s):  
Erin L. Sauer ◽  
Jeremy M. Cohen ◽  
Marc J. Lajeunesse ◽  
Taegan A. McMahon ◽  
David J. Civitello ◽  
...  
Keyword(s):  
Meta Analysis ◽  
Life Stage ◽  
Host Susceptibility ◽  
Fungal Parasite

scholarly journals Between virus correlations in the outcome of infection across host species: Evidence of virus by host species interactions

2021 ◽  
Author(s):  
Ryan M. Imrie ◽  
Katherine E. Roberts ◽  
Ben Longdon
Keyword(s):  
Host Species ◽  
Species Interactions

Seasonal growth and duration of the parasitic life stage of the landlocked sea lamprey (Petromyzon marinus)

1995 ◽  
Vol 52 (6) ◽  
pp. 1257-1264 ◽  
Author(s):  
Roger A. Bergstedt ◽  
William D. Swink
Keyword(s):  
Seasonal Pattern ◽  
Life Stage ◽  
Petromyzon Marinus ◽  
Biomass Accumulation ◽  
Sea Lamprey ◽  
Gonadal Development ◽  
Adult Size ◽  
Sea Lampreys ◽  
Mean Size ◽  
Host Mortality

We used lengths and weights of 2367 live parasitic-phase sea lampreys (Petromyzon marinus) collected from Lake Huron, 1984–1990, to calculate their mean size at half-month intervals. Growth in weight was linear during June through September; increments averaged 11.1 g per half month. Growth increased sharply in October to several times the summer rate. We speculate that the increase in growth in October is explained partly by water temperature and partly by an increase in appetite related to the onset of gonadal development. The greater compression of biomass accumulation in autumn than has been previously demonstrated better explains the autumn pulse of sea lamprey induced host mortality. Based on the seasonal pattern of growth and on recaptures of marked sea lampreys, we conclude that landlocked individuals grow to adult size and mature in one parasitic growth year. Regressions of weight (grams) on total length (millimetres) differed significantly among months, and the season of collection must be considered in predicting weight from length.

Composition patterns and network structure of epiphyte–host interactions in Chilean and New Zealand temperate forests

2021 ◽  
Author(s):  
A Taylor ◽  
A Saldaña ◽  
G Zotz ◽  
C Kirby ◽  
I Díaz ◽  
...  
Keyword(s):  
New Zealand ◽  
Host Species ◽  
Species Interactions ◽  
Temperate Forests ◽  
Null Model ◽  
Host Interactions ◽  
Host Trees ◽  
Specific Host ◽  
Random Patterns ◽  
Epiphyte Species

Ecological networks are becoming increasingly used as a framework to study epiphyte–host interactions. However, efforts to quantify the properties of epiphyte–host networks have produced inconsistent results. Epiphyte–host interactions in New Zealand and Chilean temperate forests were quantified to test for non-random patterns in nestedness, negative co-occurrences, number of links, and network specialisation. Results showed that three out of five New Zealand networks were significantly more nested than null model expectations, compared with just one out of four Chilean networks. Epiphytes co-occurred more often than null model expectations in one New Zealand network and one in Chile. In all cases, the number of links maintained by each epiphyte and host species was consistent with null model expectations. Lastly, two New Zealand networks and one in southern Chile were significantly less specialised than null model expectations, with all remaining networks returning low specialisation scores. As such, aside from the tendency for greater nestedness in New Zealand networks, most epiphyte species were distributed on their host trees at random. We attribute the result of nestedness in New Zealand to the abundance of large nest epiphytes (Astelia spp. in particular), which may facilitate the sequential colonisation of epiphyte species on developing host trees. The lack of negative co-occurrences suggests that negative species interactions are not an important determinant of species assemblage structure. Low network specialisation scores suggest that epiphytes are selecting for specific host traits, rather than specific host species for colonisation.

scholarly journals A Meta-Analysis of Stressors from the Total Environment Associated with Children’s General Cognitive Ability

2020 ◽  
Vol 17 (15) ◽  
pp. 5451
Author(s):  
Frances M. Nilsen ◽  
Jazmin D.C. Ruiz ◽  
Nicolle S. Tulve
Keyword(s):  
Early Childhood ◽  
Cognitive Development ◽  
Cognitive Ability ◽  
Meta Analysis ◽  
Life Stage ◽  
Early Life Stage ◽  
Toxic Substances ◽  
General Cognitive Ability ◽  
Childhood Cognitive Ability ◽  
Total Environment

General cognitive ability, often referred to as ‘general intelligence’, comprises a variety of correlated abilities. Childhood general cognitive ability is a well-studied area of research and can be used to predict social outcomes and perceived success. Early life stage (e.g., prenatal, postnatal, toddler) exposures to stressors (i.e., chemical and non-chemical stressors from the total (built, natural, social) environment) can impact the development of childhood cognitive ability. Building from our systematic scoping review (Ruiz et al., 2016), we conducted a meta-analysis to evaluate more than 100 stressors related to cognitive development. Our meta-analysis identified 23 stressors with a significant increase in their likelihood to influence childhood cognitive ability by 10% or more, and 80 stressors were observed to have a statistically significant effect on cognitive ability. Stressors most impactful to cognition during the prenatal period were related to maternal health and the mother’s ability to access information relevant to a healthy pregnancy (e.g., diet, lifestyle). Stressors most impactful to cognition during the early childhood period were dietary nutrients (infancy), quality of social interaction (toddler), and exposure to toxic substances (throughout early childhood). In conducting this analysis, we examined the relative impact of real-world exposures on cognitive development to attempt to understand the inter-relationships between exposures to both chemical and non-chemical stressors and early developmental life stages. Our findings suggest that the stressors observed to be the most influential to childhood cognitive ability are not permanent and can be broadly categorized as activities/behaviors which can be modified to improve childhood cognition. This meta-analysis supports the idea that there are complex relationships between a child’s total environment and early cognitive development.

scholarly journals The influence of pesticide use on amphibian chytrid fungal infections varies with host life stage across broad spatial scales

2018 ◽  
Vol 27 (11) ◽  
pp. 1277-1287 ◽  
Author(s):  
Samantha L. Rumschlag ◽  
Jason R. Rohr
Keyword(s):  
Fungal Infections ◽  
Spatial Scales ◽  
Life Stage ◽  
Pesticide Use ◽  
Host Life

scholarly journals Effects of Life Stage, Site, and Species on the Dragonfly Gut Microbiome

2020 ◽  
Vol 8 (2) ◽  
pp. 183 ◽  
Author(s):  
Sarah Nobles ◽  
Colin R. Jackson
Keyword(s):  
Gut Microbiome ◽  
Host Species ◽  
Life Stage ◽  
Rrna Gene ◽  
Life Stages ◽  
Aquatic Habitats ◽  
Surrounding Environment ◽  
Different Levels ◽  
Generation Sequencing ◽  
Bacterial 16S Rrna Gene

Insects that undergo metamorphosis from juveniles to adults provide an intriguing opportunity to examine the effects of life stage, species, and the environment on their gut microbiome. In this study, we surveyed the gut microbiomes of 13 species of dragonfly collected from five different locations subject to different levels of human impact. Juveniles were collected as nymphs from aquatic habitats while airborne adults were caught at the same locations. The gut microbiome was characterized by next generation sequencing of the bacterial 16S rRNA gene. Life stage was an important factor, with the gut microbiomes of dragonfly nymphs differing from those of adult dragonflies. Gut microbiomes of nymphs were influenced by sample site and, to a lesser extent, host species. Neither sample location nor host species had a strong effect on the gut microbiome of dragonfly adults. Regardless of life stage, gut microbiomes were dominated by members of the Proteobacteria, with members of the Bacteroidetes (especially in adults), Firmicutes, and Acidobacteria (especially in nymphs) also being proportionally abundant. These results demonstrate that different life stages of metamorphosing insects can harbor very different gut microbiomes and differ in how this microbiome is influenced by the surrounding environment.

Natural stressors and disease risk: does the threat of predation increase amphibian susceptibility to ranavirus?

2012 ◽  
Vol 90 (7) ◽  
pp. 893-902 ◽  
Author(s):  
N.A. Haislip ◽  
J.T. Hoverman ◽  
D.L. Miller ◽  
M.J. Gray
Keyword(s):  
Predation Risk ◽  
Stress Responses ◽  
Species Interactions ◽  
Disease Risk ◽  
Natural Populations ◽  
Emerging Infectious Diseases ◽  
Host Susceptibility ◽  
Continuous Exposure ◽  
Amphibian Species ◽  
Predator Cues

Emerging infectious diseases have been identified as threats to biodiversity, yet our understanding of the factors contributing to host susceptibility to pathogens within natural populations remains limited. It has been proposed that species interactions within communities affect host susceptibility to pathogens, thereby contributing to disease emergence. In particular, predation risk is a common natural stressor that has been hypothesized to compromise immune function of prey through chronic stress responses possibly leading to increased susceptibility to pathogens. We examined whether predation risk experienced during the development of four larval anuran species increases susceptibility (mortality and infection) to ranaviruses, a group of viruses responsible for amphibian die-offs. Using controlled laboratory experiments, we exposed each species to a factorial combination of two virus treatments (no virus or virus) crossed with three predator-cue treatments (no predators, larval dragonflies, or adult water bugs). All four amphibian species reduced activity by 22%–48% following continuous exposure to predator cues. In addition, virus exposure significantly reduced survival by 17%–100% across all species. However, exposure to predator cues did not interact with the virus treatments to elevate mortality or viral load. Our results suggest that the expression of predator-induced plasticity in anuran larvae does not increase ranaviral disease risk.

scholarly journals Evolution and Diversity of Inherited Spiroplasma Symbionts in Myrmica Ants

2017 ◽  
Vol 84 (4) ◽  
Author(s):  
Matthew J. Ballinger ◽  
Logan D. Moore ◽  
Steve J. Perlman
Keyword(s):  
Time Scales ◽  
Genome Sequencing ◽  
Host Species ◽  
Species Interactions ◽  
Bacterial Symbiont ◽  
Evolutionary Time ◽  
Content Type ◽  
Myrmica Ants ◽  
Microbial Symbionts ◽  
Nutrient Provisioning

ABSTRACT Microbial partners play important roles in the biology and ecology of animals. In insects, maternally transmitted symbionts are especially common and can have host effects ranging from reproductive manipulation to nutrient provisioning and defense against natural enemies. In this study, we report a genus-wide association of Myrmica ants with the inherited bacterial symbiont Spiroplasma . We screen Myrmica ants collected from the wild, including the invasive European fire ant, Myrmica rubra , and find an extraordinarily high prevalence of this symbiont—8 of 9 species, 42 of 43 colonies, and 250 of 276 individual workers harbored Spiroplasma —only one host species was uninfected. In our screens, each host species carried a distinct Spiroplasma strain, and none were infected with more than one strain. All symbionts belong to the citri clade, allied most closely with pathogenic strains of Spiroplasma infecting corn crops and honeybees, and there is strong evidence of host-symbiont persistence across evolutionary time scales. Genome sequencing of two Spiroplasma symbionts revealed candidate genes that may play a part in the symbiosis, a nutrient transporter absent from other Spiroplasma strains, and a ribosome-inactivating protein previously implicated in parasite defense. These results together suggest long-term, likely mutualistic, relationships atypical of Spiroplasma -insect associations with potential significance for broad ecological interactions with Myrmica . IMPORTANCE Animal-associated microbial symbionts can dramatically affect the biology of their hosts. The identification and characterization of these intimate partnerships remain an essential component of describing and predicting species interactions, especially for invasive host species. Ants perform crucial ecological functions as ecosystem engineers, scavengers, and predators, and ants in the genus Myrmica can be aggressive resource competitors and reach high densities in their native and invaded habitats. In this study, a novel symbiosis is identified between Myrmica ants and the facultative bacterial symbiont Spiroplasma . Broad host distribution, high frequencies of infection, and host-symbiont codivergence over evolutionary time scales, an uncommon feature of Spiroplasma associations, suggest an important likely mutualistic interaction. Genome sequencing identified highly divergent gene candidates that may contribute to Spiroplasma 's role as a possible defensive or nutritional partner in Myrmica .

The relation between the number of parasites/host and host age: population dynamic causes and maximum likelihood estimation

Parasitology ◽  
1988 ◽  
Vol 96 (1) ◽  
pp. 197-210 ◽  
Author(s):  
S. W. Pacala ◽  
A. P. Dobson
Keyword(s):  
Maximum Likelihood ◽  
Arctic Charr ◽  
Likelihood Estimation ◽  
Host Susceptibility ◽  
Host Age ◽  
Parasite Distribution ◽  
Age Dependent ◽  
Host Mortality ◽  
Varying Environments ◽  
Theoretical Results

SUMMARYWe examined dynamical factors that shape the distribution of the number of parasites/host in constant or temporally varying environments, and with or without host-age dependent variation in host susceptibility and parasite mortality. We predict properties of the parasite distribution in the absence of density-dependent factors such as densitydependent mortality or recruitment and parasite-induced host mortality. These properties provide a criterion for the detection of density dependence in temporally variable systems with host-age dependent interactions. We have then introduced methods to estimate and statistically evaluate the effects of host age or size on the distribution of parasites/host. The methods are based on a maximum likelihood protocol for linear and non-linear regression when data are negatively binomially distributed. We have illustrated the use of the theoretical results and statistical methods by re-analysing the data of Halvorsen & Andersen (1984) on cestode infections in Norwegian arctic charr and by analysing new data on nematode infections in Caribbean Anolis lizards.

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