Dormant plasticity of rotifer diapausing eggs in response to predator kairomones

2021 ◽  
Vol 17 (11) ◽  
Author(s):  
Xuwang Yin ◽  
Yuecen Zhao ◽  
Shuang Tian ◽  
Xiaochun Li
Keyword(s):  
Life Cycles ◽  
Freshwater Ecosystems ◽  
Sexual Life ◽  
Hatching Rate ◽  
Ecological Implication ◽  
Maternal Environment ◽  
Predator Prey ◽  
Diapausing Eggs ◽  
Embryonic Exposure ◽  
Phenotypic Responses

In freshwater ecosystems, hatching strategy of diapausing eggs (DEs) under predation risk has important ecological implication for zooplankters. Although kairomones released by predators can induce phenotypic responses of prey, hatching patterns of DEs in response to kairomones have received contradictory conclusions in zooplankters. Maternal environment may also affect hatching strategy of DEs during predator–prey interactions. We used classical Brachionus calyciflorus – Asplanchna models to determine the timing and proportion of DE hatching in association with parental and embryonic exposure to kairomones. Results obtained from two Brachionus clones supported the hypothesis that DEs could detect Asplanchna kairomones and adjust hatching patterns. DEs showed early and synchronous hatching patterns in the environment with kairomones. Data also supported the prediction that DEs could gain information about predators from maternal environments and adjusted their hatching pattern in response to the presence of kairomones. Compared with DEs from Brachionus mothers not exposed to kairomones, DEs produced by mothers that were experienced with kairomones attained a higher hatching rate when both of them hatched in the environment either with or without kairomones. Our results suggest that DEs of B . calyciflorus possess dormant plasticity to defend against predation from Asplanchna , which may be regulated by maternal environmental effects during sexual life cycles.

scholarly journals Diversity of echinostomes (Digenea: Echinostomatidae) in their snail hosts at high latitudes

Parasite ◽  
2021 ◽  
Vol 28 ◽  
pp. 59
Author(s):  
Camila Pantoja ◽  
Anna Faltýnková ◽  
Katie O’Dwyer ◽  
Damien Jouet ◽  
Karl Skírnisson ◽  
...  
Keyword(s):  
North America ◽  
Dna Sequences ◽  
Sequence Data ◽  
Molecular Data ◽  
Migratory Bird ◽  
Parasite Fauna ◽  
Life Cycles ◽  
Freshwater Ecosystems ◽  
Trematode Species ◽  
Host Life

The biodiversity of freshwater ecosystems globally still leaves much to be discovered, not least in the trematode parasite fauna they support. Echinostome trematode parasites have complex, multiple-host life-cycles, often involving migratory bird definitive hosts, thus leading to widespread distributions. Here, we examined the echinostome diversity in freshwater ecosystems at high latitude locations in Iceland, Finland, Ireland and Alaska (USA). We report 14 echinostome species identified morphologically and molecularly from analyses of nad1 and 28S rDNA sequence data. We found echinostomes parasitising snails of 11 species from the families Lymnaeidae, Planorbidae, Physidae and Valvatidae. The number of echinostome species in different hosts did not vary greatly and ranged from one to three species. Of these 14 trematode species, we discovered four species (Echinoparyphium sp. 1, Echinoparyphium sp. 2, Neopetasiger sp. 5, and Echinostomatidae gen. sp.) as novel in Europe; we provide descriptions for the newly recorded species and those not previously associated with DNA sequences. Two species from Iceland (Neopetasiger islandicus and Echinoparyphium sp. 2) were recorded in both Iceland and North America. All species found in Ireland are new records for this country. Via an integrative taxonomic approach taken, both morphological and molecular data are provided for comparison with future studies to elucidate many of the unknown parasite life cycles and transmission routes. Our reports of species distributions spanning Europe and North America highlight the need for parasite biodiversity assessments across large geographical areas.

scholarly journals Universal Evolutionary Model for Periodical Species

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Eric Goles ◽  
Ivan Slapničar ◽  
Marco A. Lardies
Keyword(s):  
Fitness Function ◽  
Evolutionary Model ◽  
Prime Numbers ◽  
Life Cycles ◽  
The Other ◽  
Exclusion Principle ◽  
Greatest Common Divisor ◽  
Predator Prey ◽  
Integer Multiple ◽  
New Period

Real-world examples of periodical species range from cicadas, whose life cycles are large prime numbers, like 13 or 17, to bamboos, whose periods are large multiples of small primes, like 40 or even 120. The periodicity is caused by interaction of species, be it a predator-prey relationship, symbiosis, commensalism, or competition exclusion principle. We propose a simple mathematical model, which explains and models all those principles, including listed extremal cases. This rather universal, qualitative model is based on the concept of a local fitness function, where a randomly chosen new period is selected if the value of the global fitness function of the species increases. Arithmetically speaking, the different interactions are related to only four principles: given a couple of integer periods either (1) their greatest common divisor is one, (2) one of the periods is prime, (3) both periods are equal, or (4) one period is an integer multiple of the other.

Life cycle of the southern cattle tick, Rhipicephalus (Boophilus) microplus Canestrini 1888 (Acari: Ixodidae) under laboratory conditions

2018 ◽  
Vol 23 (6) ◽  
pp. 1169 ◽  
Author(s):  
Haytham Senbill ◽  
Lakshmi Kanta Hazarika ◽  
Aiswarya Baruah ◽  
Deepak Kumar Borah ◽  
Badal Bhattacharyya ◽  
...  
Keyword(s):  
Life Cycle ◽  
Efficiency Index ◽  
Life Cycles ◽  
Boophilus Microplus ◽  
Cattle Tick ◽  
Hatching Rate ◽  
Egg Masses ◽  
Laboratory Conditions ◽  
Adult Feeding ◽  
Southern Cattle Tick

The southern cattle tick, Rhipicephalus (Boophilus) microplus is one of the most important tick species affecting bovine wealth worldwide. Three uninterrupted generations of this species were observed under laboratory conditions (28±3 oC and 80±5% R.H.) using rabbit hosts. The average life cycle was determined as 65±8 days. Adult feeding period averaged 7.1±1.24 days. Pre-oviposition and oviposition periods averaged 4.1±1.3 days and 8.6±0.85 days, respectively. Pre-hatching periods averaged 21.03±2.99 days. Larval free-living and feeding to moulting periods averaged 3.5±0.75 days and 7.9±0.69 days, respectively. Nymphal feeding to moulting periods averaged 10.9±1.38 days. Weights of unfed and fed females averaged 1.26±0.29 mg and 120.32±45.6 mg, respectively and produced egg masses with average weights of 29.5±9.03 mg. Number of eggs per female averaged 1455.3±434.5 eggs with peak oviposition on the 3rd day. Average hatching rate was 83.5±2.94%, and the reproduction efficiency index averaged at 12.79±2.85. The conversion efficiency index averaged at 0.26±0.05 and the reproduction fitness index averaged at 10.68±2.4. Tick recovery rate averaged at 4.7%. A strong linear relationship was found between weights of engorged females and weights of egg masses (r = 0.83) and also between weights of engorged females and number of eggs laid (r = 0.82). This work aims to describe temporal and quantitative biological facts of R. (B.) microplus life cycles. Few studies have discussed R. (B.) microplus biology in quantitative terms, and these data can be useful in designing control plans or in epidemiological studies under laboratory conditions.

scholarly journals Noble Crayfish Are More Sensitive to Terbuthylazine than Parthenogenetic Marbled Crayfish

2020 ◽  
Vol 231 (11) ◽  
Author(s):  
Jan Laurenz ◽  
Lena Lietz ◽  
Heinz Brendelberger ◽  
Kai Lehmann ◽  
Arne Georg
Keyword(s):  
Survival Rate ◽  
Embryonic Development ◽  
Freshwater Ecosystems ◽  
Model Organisms ◽  
Hatching Rate ◽  
Freshwater Crayfish ◽  
Toxicological Studies ◽  
Noble Crayfish ◽  
Marbled Crayfish ◽  
Median Effective Concentration

AbstractWe investigated the sensitivity of two freshwater crayfish species (Astacus astacus and Procambarus virginalis) during embryonic development to chronic exposure to the herbicide terbuthylazine under laboratory conditions. The assessed parameters included time of embryonic development, survival rate, hatching weight and histopathology of hepatopancreas. LC50 (median lethal concentration) and ED50 (median effective concentration) were estimated. We were able to determine effects of terbuthylazine for every investigated parameter. For noble crayfish, the LC50 value after 45 days was 0.11 mg/L, and the histology of the hepatopancreas showed effects starting from 0.025 mg/L. Other parameters revealed effects starting at concentrations of 1.6 mg/L for weight and 6.4 mg /L for embryonic development time and hatching rate. Marbled crayfish only showed effects concerning the hatching rate and survival rate at concentrations without a clear dose-effects curve. As a conclusion, our data shows the risk of terbuthylazine in existing concentrations in freshwater ecosystems to non-target organisms and also the need of toxicological studies on directly affected species in addition to the use of model organisms.

scholarly journals Sexual conflict and the evolution of asexuality at low population densities

2016 ◽  
Vol 283 (1841) ◽  
pp. 20161280 ◽  
Author(s):  
Nina Gerber ◽  
Hanna Kokko
Keyword(s):  
Sexual Harassment ◽  
Sexual Reproduction ◽  
Sexual Conflict ◽  
Life Cycles ◽  
Sexual Life ◽  
Relative Advantage ◽  
Male Mating ◽  
Population Densities ◽  
Asexual Populations ◽  
Sexual Life Cycle

Theories for the evolution of sex rarely include facultatively sexual reproduction. Sexual harassment by males is an underappreciated factor: it should at first sight increase the relative advantage of asexual reproduction by increasing the cost of sex. However, if the same females can perform either sexual or asexual life cycles, then females trying to reproduce asexually may not escape harassment. If resisting male harassment is costly, it might be beneficial for a female to accept a mating and undertake a sexual life cycle rather than ‘insist’ on an asexual one. We investigate the effects of sexual harassment on the maintenance of sex under different population densities. Our model shows that resisting matings pays off at low population densities, which leads to the complete extinction of males, and thus to the evolution of completely asexual populations. Facultative sex persists in a narrow range of slightly higher densities. At high densities, selection favours giving up resisting male mating attempts and thus sexual reproduction takes over. These interactions between the outcomes of sexual conflict and population density suggest an explanation for the rarity of facultative sex and also patterns of geographical parthenogenesis, where marginal environments with potentially low densities are associated with asexuality.

Defining and Disrupting Species Boundaries in Saccharomyces

2020 ◽  
Vol 74 (1) ◽  
pp. 477-495
Author(s):  
Jasmine Ono ◽  
Duncan Greig ◽  
Primrose J. Boynton
Keyword(s):  
Reproductive Isolation ◽  
Evolutionary History ◽  
Life Cycles ◽  
Sexual Life ◽  
Evolutionary Mechanisms ◽  
History Of ◽  
The One ◽  
Reproductive Isolation Mechanisms ◽  
Evolutionary Consequences ◽  
Isolation Mechanisms

The genus Saccharomyces is an evolutionary paradox. On the one hand, it is composed of at least eight clearly phylogenetically delineated species; these species are reproductively isolated from each other, and hybrids usually cannot complete their sexual life cycles. On the other hand, Saccharomyces species have a long evolutionary history of hybridization, which has phenotypic consequences for adaptation and domestication. A variety of cellular, ecological, and evolutionary mechanisms are responsible for this partial reproductive isolation among Saccharomyces species. These mechanisms have caused the evolution of diverse Saccharomyces species and hybrids, which occupy a variety of wild and domesticated habitats. In this article, we introduce readers to the mechanisms isolating Saccharomyces species, the circumstances in which reproductive isolation mechanisms are effective and ineffective, and the evolutionary consequences of partial reproductive isolation. We discuss both the evolutionary history of the genus Saccharomyces and the human history of taxonomists and biologists struggling with species concepts in this fascinating genus.

scholarly journals Transcriptome and Phenotypic Responses of Vibrio cholerae to Increased Cyclic di-GMP Level

2006 ◽  
Vol 188 (10) ◽  
pp. 3600-3613 ◽  
Author(s):  
Sinem Beyhan ◽  
Anna D. Tischler ◽  
Andrew Camilli ◽  
Fitnat H. Yildiz
Keyword(s):  
Vibrio Cholerae ◽  
Elevated Level ◽  
Life Cycles ◽  
Cell Physiology ◽  
Human Pathogen ◽  
Aquatic Life ◽  
Cellular Processes ◽  
Genes Encoding ◽  
El Tor ◽  
Phenotypic Responses

ABSTRACT Vibrio cholerae, the causative agent of cholera, is a facultative human pathogen with intestinal and aquatic life cycles. The capacity of V. cholerae to recognize and respond to fluctuating parameters in its environment is critical to its survival. In many microorganisms, the second messenger, 3′,5′-cyclic diguanylic acid (c-di-GMP), is believed to be important for integrating environmental stimuli that affect cell physiology. Sequence analysis of the V. cholerae genome has revealed an abundance of genes encoding proteins with either GGDEF domains, EAL domains, or both, which are predicted to modulate cellular c-di-GMP concentrations. To elucidate the cellular processes controlled by c-di-GMP, whole-genome transcriptome responses of the El Tor and classical V. cholerae biotypes to increased c-di-GMP concentrations were determined. The results suggest that V. cholerae responds to an elevated level of c-di-GMP by increasing the transcription of the vps, eps, and msh genes and decreasing that of flagellar genes. The functions of other c-di-GMP-regulated genes in V. cholerae are yet to be identified.

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