scholarly journals Molecular signatures of the rediae, cercariae and adult worm stages in the complex life cycles of parasitic flatworms (Psilostomatidae, Trematoda)

2019 ◽  
Author(s):  
Maksim A. Nesterenko ◽  
Viktor V. Starunov ◽  
Sergei V. Shchenkov ◽  
Anna R. Maslova ◽  
Sofia A. Denisova ◽  
...  
Keyword(s):  
Adult Worm ◽  
Related Species ◽  
Life Histories ◽  
Expression Patterns ◽  
Life Forms ◽  
Life Cycles ◽  
Complex Life Cycle ◽  
Molecular Signatures ◽  
Life Stages ◽  
Complex Life Cycles

AbstractTrematodes are one of the most remarkable animals with complex life cycles with several generations. Life histories of a parasitic flatworms include several stages with disparate morphological and physiological characteristics follow each other and infect hosts ranging from mollusks to higher vertebrates. How does one genome regulate the development of various life forms and how many genes are needed to the functioning of each stages? How similar are molecular signatures of life stages in closely related species of parasitic flatworms? Here we present the comparative analysis of transcriptomic signatures of the rediae, cercaria and adult worm stages in two representatives of the family Psilostomatidae (Echinostomata, Trematoda) -Psilotrema simillimumandSphaeridiotrema pseudoglobulus. Our results indicate that the transitions between the stages of the complex life cycle are associated with massive changes in gene expression with thousands of genes being stage-specific. In terms of expression dynamics, the adult worm is the most similar stage betweenPsilotremaandSpaeridiotrema, while expression patterns of genes in the rediae and cercariae stages are much more different. This study provides transcriptomic evidences not only for similarities and differences between life stages of two related species, but also for cryptic species inSphaeridiotrema.

scholarly journals Robustness of life histories to environmental variability in complex versus simple life cycles

2021 ◽  
Author(s):  
Annie Jonsson
Keyword(s):  
Growth Rate ◽  
Life Histories ◽  
Environmental Variability ◽  
Life Cycles ◽  
Relative Advantage ◽  
Complex Life Cycle ◽  
Life Stages ◽  
Vital Rates ◽  
Habitat Separation ◽  
Simple Life

AbstractMost animal species have a complex life cycle (CLC) with metamorphosis. It is thus of interest to examine possible benefits of such life histories. The prevailing view is that CLC represents an adaptation for genetic decoupling of juvenile and adult traits, thereby allowing life stages to respond independently to different selective forces. Here I propose an additional potential advantage of CLCs that is, decreased variance in population growth rate due to habitat separation of life stages. Habitat separation of pre- and post-metamorphic stages means that the stages will experience different regimes of environmental variability. This is in contrast to species with simple life cycles (SLC) whose life stages often occupy one and the same habitat. The correlation in the fluctuations of the vital rates of life stages is therefore likely to be weaker in complex than in simple life cycles. By a theoretical framework using an analytical approach, I have (1) derived the relative advantage, in terms of long-run growth rate, of CLC over SLC phenotypes for a broad spectrum of life histories, and (2) explored which life histories that benefit most by a CLC, that is avoid correlation in vital rates between life stages. The direction and magnitude of gain depended on life history type and fluctuating vital rate. One implication of our study is that species with CLCs should, on average, be more robust to increased environmental variability caused by global warming than species with SLCs.

Autonomy and integration in complex parasite life cycles

Parasitology ◽  
2016 ◽  
Vol 143 (14) ◽  
pp. 1824-1846 ◽  
Author(s):  
DANIEL P. BENESH
Keyword(s):  
Life Cycle ◽  
Holistic Approach ◽  
Life Cycles ◽  
Complex Life Cycle ◽  
Functional Specialization ◽  
Life Stages ◽  
Free Living ◽  
New Host ◽  
Complex Life Cycles ◽  
Life Cycle Stages

SUMMARYComplex life cycles are common in free-living and parasitic organisms alike. The adaptive decoupling hypothesis postulates that separate life cycle stages have a degree of developmental and genetic autonomy, allowing them to be independently optimized for dissimilar, competing tasks. That is, complex life cycles evolved to facilitate functional specialization. Here, I review the connections between the different stages in parasite life cycles. I first examine evolutionary connections between life stages, such as the genetic coupling of parasite performance in consecutive hosts, the interspecific correlations between traits expressed in different hosts, and the developmental and functional obstacles to stage loss. Then, I evaluate how environmental factors link life stages through carryover effects, where stressful larval conditions impact parasites even after transmission to a new host. There is evidence for both autonomy and integration across stages, so the relevant question becomes how integrated are parasite life cycles and through what mechanisms? By highlighting how genetics, development, selection and the environment can lead to interdependencies among successive life stages, I wish to promote a holistic approach to studying complex life cycle parasites and emphasize that what happens in one stage is potentially highly relevant for later stages.

scholarly journals Do traits separated by metamorphosis evolve independently? Concepts and methods

2019 ◽  
Vol 286 (1900) ◽  
pp. 20190445 ◽  
Author(s):  
Julie Collet ◽  
Simon Fellous
Keyword(s):  
Life Stage ◽  
Genetic Correlations ◽  
Life Cycles ◽  
Complex Life Cycle ◽  
Multivariate Methods ◽  
Life Stages ◽  
Complex Life Cycles ◽  
Quantitative Characters ◽  
Genetic Patterns ◽  
G Matrices

Despite the ubiquity of complex life cycles, we know little of the evolutionary constraints exerted by metamorphosis. Here, we present pitfalls and methods to answer whether animals with a complex life cycle can independently adapt to the environments encountered at each life stage, with a specific focus on the microevolution of quantitative characters. We first discuss challenges associated with study traits and populations. We further emphasize the benefits of using a combination of approaches. We then develop how multivariate methods can limit several issues by revealing genetic patterns that are invisible when only considering trait-by-trait genetic correlations. Finally, we detail how Lande's work on sexual dimorphism can be applied in measuring G matrices across life stages. The methods and tools described here will contribute towards building a predictive framework for trait evolution across life stages.

scholarly journals Does a complex life cycle affect adaptation to environmental change? Genome-informed insights for characterizing selection across complex life cycle

2021 ◽  
Vol 288 (1964) ◽  
Author(s):  
Molly A. Albecker ◽  
Laetitia G. E. Wilkins ◽  
Stacy A. Krueger-Hadfield ◽  
Samuel M. Bashevkin ◽  
Matthew W. Hahn ◽  
...  
Keyword(s):  
Life Cycle ◽  
Empirical Studies ◽  
Life Cycles ◽  
Complex Life Cycle ◽  
Ecological Niches ◽  
Life Stages ◽  
Complex Life Cycles ◽  
High Fecundity ◽  
Trade Offs ◽  
Frequency Changes

Complex life cycles, in which discrete life stages of the same organism differ in form or function and often occupy different ecological niches, are common in nature. Because stages share the same genome, selective effects on one stage may have cascading consequences through the entire life cycle. Theoretical and empirical studies have not yet generated clear predictions about how life cycle complexity will influence patterns of adaptation in response to rapidly changing environments or tested theoretical predictions for fitness trade-offs (or lack thereof) across life stages. We discuss complex life cycle evolution and outline three hypotheses—ontogenetic decoupling, antagonistic ontogenetic pleiotropy and synergistic ontogenetic pleiotropy—for how selection may operate on organisms with complex life cycles. We suggest a within-generation experimental design that promises significant insight into composite selection across life cycle stages. As part of this design, we conducted simulations to determine the power needed to detect selection across a life cycle using a population genetic framework. This analysis demonstrated that recently published studies reporting within-generation selection were underpowered to detect small allele frequency changes (approx. 0.1). The power analysis indicates challenging but attainable sampling requirements for many systems, though plants and marine invertebrates with high fecundity are excellent systems for exploring how organisms with complex life cycles may adapt to climate change.

Japanese Biographies: Life Histories, Life Cycles, Life Stages.

1994 ◽  
Vol 67 (1) ◽  
pp. 128
Author(s):  
Joshua S. Mostow ◽  
Susanne Formanek ◽  
Sepp Linhart
Keyword(s):  
Life Histories ◽  
Life Cycles ◽  
Life Stages

scholarly journals Developmental plasticity and the evolution of animal complex life cycles

2010 ◽  
Vol 365 (1540) ◽  
pp. 631-640 ◽  
Author(s):  
Alessandro Minelli ◽  
Giuseppe Fusco
Keyword(s):  
Life Cycle ◽  
Developmental Plasticity ◽  
Developmental Stages ◽  
Ecological Condition ◽  
Life Cycles ◽  
Complex Life Cycle ◽  
Complex Life Cycles ◽  
Transcription Profiles ◽  
Alternative Phenotypes ◽  
Reproductive Events

Metazoan life cycles can be complex in different ways. A number of diverse phenotypes and reproductive events can sequentially occur along the cycle, and at certain stages a variety of developmental and reproductive options can be available to the animal, the choice among which depends on a combination of organismal and environmental conditions. We hypothesize that a diversity of phenotypes arranged in developmental sequence throughout an animal's life cycle may have evolved by genetic assimilation of alternative phenotypes originally triggered by environmental cues. This is supported by similarities between the developmental mechanisms mediating phenotype change and alternative phenotype determination during ontogeny and the common ecological condition that favour both forms of phenotypic variation. The comparison of transcription profiles from different developmental stages throughout a complex life cycle with those from alternative phenotypes in closely related polyphenic animals is expected to offer critical evidence upon which to evaluate our hypothesis.

scholarly journals Comparative analysis of helminth infectivity: growth in intermediate hosts increases establishment rates in the next host

2021 ◽  
Vol 288 (1947) ◽  
Author(s):  
Spencer Froelick ◽  
Laura Gramolini ◽  
Daniel P. Benesh
Keyword(s):  
Life Cycle ◽  
Life Cycles ◽  
Complex Life Cycle ◽  
Life Stages ◽  
Intermediate Hosts ◽  
Cycle Progression ◽  
Recovery Rates ◽  
High Doses ◽  
Parasitic Worms ◽  
Higher Doses

Parasitic worms (i.e. helminths) commonly infect multiple hosts in succession before reproducing. At each life cycle step, worms may fail to infect the next host, and this risk accumulates as life cycles include more successive hosts. Risk accumulation can be minimized by having high establishment success in the next host, but comparisons of establishment probabilities across parasite life stages are lacking. We compiled recovery rates (i.e. the proportion of parasites recovered from an administered dose) from experimental infections with acanthocephalans, cestodes and nematodes. Our data covered 127 helminth species and 16 913 exposed hosts. Recovery rates increased with life cycle progression (11%, 29% and 46% in first, second and third hosts, respectively), because larger worm larvae had higher recovery, both within and across life stages. Recovery declined in bigger hosts but less than it increased with worm size. Higher doses were used in systems with lower recovery, suggesting that high doses are chosen when few worms are expected to establish infection. Our results indicate that growing in the small and short-lived hosts at the start of a complex life cycle, though dangerous, may substantially improve parasites' chances of completing their life cycles.

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