The impact of rapid evolution on population dynamics in the wild: experimental test of eco-evolutionary dynamics

Ustilago maydis virus H1 (Umv-H1) is a mycovirus that infects Ustilago maydis, a fungal pathogen of maize. As Zea mays was domesticated, it carried with it many associated symbionts, such that the subsequent range expansion and cultivation of maize should have affected maize symbionts' evolutionary history dramatically. Because transmission of Umv-H1 takes place only through cytoplasmic fusion during mating of U. maydis individuals, the population dynamics of U. maydis and maize are expected to affect the population structure of the viral symbiont strongly. Here, the impact of changes in the evolutionary history of U. maydis on that of Umv-H1 was investigated. The high mutation rate of this virus allows inferences to be made about the evolution and divergence of Umv-H1 lineages as a result of the recent changes in U. maydis geographical and genetic structure. The phylogeographical history and genetic structure of Umv-H1 populations in the USA and Mexico were determined by using analyses of viral nucleotide sequence variation. Infection and recombination frequencies, genetic diversity and rates of neutral evolution were also assessed, to make inferences regarding evolutionary processes underlying the population genetic structure of ancestral and descendent populations. The results suggest that Mexico represents the ancestral population of Umv-H1, from which the virus has been carried with U. maydis populations into the USA. Thus, the population dynamics of one symbiont represent a major evolutionary force on the co-evolutionary dynamics of symbiotic partners.

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Rapid Evolution of a Sexual Reproduction Gene in Centric Diatoms of the Genus Thalassiosira

Applied and Environmental Microbiology ◽

10.1128/aem.67.8.3501-3513.2001 ◽

2001 ◽

Vol 67 (8) ◽

pp. 3501-3513 ◽

Cited By ~ 42

Author(s):

E. Virginia Armbrust ◽

H. M. Galindo

Keyword(s):

Population Dynamics ◽

Sexual Reproduction ◽

Related Species ◽

Rapid Evolution ◽

Sequence Divergence ◽

Thalassiosira Pseudonana ◽

Centric Diatom ◽

Additional Species ◽

Gamete Recognition ◽

The Impact

ABSTRACT Sexual reproduction is commonly assumed to occur in the vast majority of diatoms due to the intimate association of this process with cell size control. Surprisingly, however, little is known about the impact of sexual events on diatom population dynamics. TheSig1 gene is strongly upregulated during sexual reproduction in the centric diatom Thalassiosira weissflogii and has been hypothesized to encode a protein involved in gamete recognition. In the present study, degenerate PCR primers were designed and used to amplify a portion ofSig1 from three closely related species in the cosmopolitan genus Thalassiosira, Thalassiosira oceanica, Thalassiosira guillardii, andThalassiosira pseudonana. Identification ofSig1 in these three additional species facilitated development of this gene as a molecular marker for diatom sexual events. Examination of the new sequences indicated that multiple copies of Sig1 are probably present in the genome. Moreover, compared to the housekeeping geneβ -tubulin, the Sig1genes of isolates of T. weissflogii collected from different regions of the Atlantic and Pacific oceans displayed high levels of divergence. The Sig1 genes of the four closely related Thalassiosira species also displayed high levels of sequence divergence compared to the levels observed with a second gene, Fcp, probably explaining why Sig1could not be amplified from more distantly related species. The high levels of sequence divergence both within and between species suggest that Sig1 is rapidly evolving in a manner reminiscent of the manner observed in other genes that encode gamete recognition proteins. A simple model is presented for Sig1 evolution and the implications of such a rapidly evolving sexual reproduction gene for diatom speciation and population dynamics.

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Gradual plasticity alters population dynamics in variable environments: thermal acclimation in the green alga Chlamydomonas reinhartdii

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2017.1942 ◽

2018 ◽

Vol 285 (1870) ◽

pp. 20171942 ◽

Cited By ~ 18

Author(s):

Colin T. Kremer ◽

Samuel B. Fey ◽

Aldo A. Arellano ◽

David A. Vasseur

Keyword(s):

Population Dynamics ◽

Environmental Variability ◽

Rapid Evolution ◽

Ecological Dynamics ◽

Lake Ecosystems ◽

High Resolution Data ◽

Temperature Changes ◽

Variable Environments ◽

The Impact ◽

Plastic Responses

Environmental variability is ubiquitous, but its effects on populations are not fully understood or predictable. Recent attention has focused on how rapid evolution can impact ecological dynamics via adaptive trait change. However, the impact of trait change arising from plastic responses has received less attention, and is often assumed to optimize performance and unfold on a separate, faster timescale than ecological dynamics. Challenging these assumptions, we propose that gradual plasticity is important for ecological dynamics, and present a study of the plastic responses of the freshwater green algae Chlamydomonas reinhardtii as it acclimates to temperature changes. First, we show that C. reinhardtii 's gradual acclimation responses can both enhance and suppress its performance after a perturbation, depending on its prior thermal history. Second, we demonstrate that where conventional approaches fail to predict the population dynamics of C. reinhardtii exposed to temperature fluctuations, a new model of gradual acclimation succeeds. Finally, using high-resolution data, we show that phytoplankton in lake ecosystems can experience thermal variation sufficient to make acclimation relevant. These results challenge prevailing assumptions about plasticity's interactions with ecological dynamics. Amidst the current emphasis on rapid evolution, it is critical that we also develop predictive methods accounting for plasticity.

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The impact of expectations and satisfaction on the initiation and maintenance of smoking cessation: An experimental test.

Health Psychology ◽

10.1037/0278-6133.27.3(suppl.).s197 ◽

2008 ◽

Vol 27 (3, Suppl) ◽

pp. S197-S206 ◽

Cited By ~ 18

Author(s):

Andrew W. Hertel ◽

Emily A. Finch ◽

Kristina M. Kelly ◽

Christie King ◽

Harry Lando ◽

...

Keyword(s):

Smoking Cessation ◽

Experimental Test ◽

The Impact

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Long-term population dynamics of the red deer and European roe deer at the protected and not-protected areas in Mountain Crimea

Ukrainian Journal of Ecology ◽

10.15421/2017_88 ◽

2017 ◽

Vol 7 (4) ◽

pp. 65-72

Author(s):

V. N. Shmagol' ◽

V. L. Yarysh ◽

S. P. Ivanov ◽

V. I. Maltsev

Keyword(s):

Population Dynamics ◽

Protected Areas ◽

Red Deer ◽

Nature Reserve ◽

Roe Deer ◽

Precipitation Amount ◽

Annual Precipitation ◽

Population Number ◽

The Impact

The long-term population dynamics of the red deer (Cervus elaphus L.) and European roe deer (Capreolus capreolus L.) at the mountain and forest zone of Crimea during 1980-2017 is presented. Fluctuations in numbers of both species are cyclical and partly synchronous. Period of oscillations in the population of red deer is about 25 years, the average duration of the oscillation period of number of roe deer is 12.3 years. During the fluctuations in the number the increasing and fall in population number of the red deer had been as 26-47 %, and roe deer – as 22-34 %. Basing on the dada obtained we have assumed that together with large-scale cycles of fluctuations in population number of both red deer and roe deer the short cycles of fluctuations in the number of these species with period from 3.5 to 7.5 years take place. Significant differences of the parameters of cyclical fluctuations in the number of roe deer at some sites of the Mountainous Crimea: breaches of synchronicity, as well as significant differences in the duration of cycles are revealed. The greatest deviations from the average values of parameters of long-term dynamics of the number of roe deer in Crimea are noted for groups of this species at two protected areas. At the Crimean Nature Reserve the cycle time of fluctuations of the numbers of roe deer was 18 years. At the Karadag Nature Reserve since 1976 we can see an exponential growth in number of roe deer that is continued up to the present time. By 2016 the number of roe deer reached 750 individuals at a density of 437 animals per 1 thousand ha. Peculiarity of dynamics of number of roe deer at some sites proves the existence in the mountain forest of Crimea several relatively isolated groups of deer. We assumed that "island" location of the Crimean populations of red deer and European roe deer, their relatively little number and influence of permanent extreme factors of both natural and anthropogenic origination have contributed to a mechanism of survival of these populations. The elements of such a mechanism include the following features of long-term dynamics of the population: the reduction in the period of cyclic population fluctuations, while maintaining their amplitude and the appearance of additional small cycles, providing more flexible response of the population to the impact of both negative and positive environmental factors. From the totality of the weather conditions for the Crimean population of roe deer the recurring periods of increases and downs in the annual precipitation amount may have relevance. There was a trend of increase in the roe deer population during periods of increasing annual precipitation.

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The environmental and ecological determinants of elevated Ross River Virus exposure in koalas residing in urban coastal landscapes

Scientific Reports ◽

10.1038/s41598-021-83919-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Brian J. Johnson ◽

Amy Robbins ◽

Narayan Gyawali ◽

Oselyne Ong ◽

Joanne Loader ◽

...

Keyword(s):

Animal Movement ◽

Ross River Virus ◽

Mosquito Vector ◽

Large Numbers ◽

Culex Annulirostris ◽

Coastal Landscapes ◽

In The Wild ◽

Virus Exposure ◽

Elevated Exposure ◽

The Impact

AbstractKoala populations in many areas of Australia have declined sharply in response to habitat loss, disease and the effects of climate change. Koalas may face further morbidity from endemic mosquito-borne viruses, but the impact of such viruses is currently unknown. Few seroprevalence studies in the wild exist and little is known of the determinants of exposure. Here, we exploited a large, spatially and temporally explicit koala survey to define the intensity of Ross River Virus (RRV) exposure in koalas residing in urban coastal environments in southeast Queensland, Australia. We demonstrate that RRV exposure in koalas is much higher (> 80%) than reported in other sero-surveys and that exposure is uniform across the urban coastal landscape. Uniformity in exposure is related to the presence of the major RRV mosquito vector, Culex annulirostris, and similarities in animal movement, tree use, and age-dependent increases in exposure risk. Elevated exposure ultimately appears to result from the confinement of remaining coastal koala habitat to the edges of permanent wetlands unsuitable for urban development and which produce large numbers of competent mosquito vectors. The results further illustrate that koalas and other RRV-susceptible vertebrates may serve as useful sentinels of human urban exposure in endemic areas.

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Population dynamics driven by truncated stable processes with Markovian switching

Journal of Applied Probability ◽

10.1017/jpr.2020.102 ◽

2021 ◽

Vol 58 (2) ◽

pp. 505-522

Author(s):

Zhenzhong Zhang ◽

Jinying Tong ◽

Qingting Meng ◽

You Liang

Keyword(s):

Population Dynamics ◽

Sufficient Conditions ◽

Necessary And Sufficient Conditions ◽

Markovian Switching ◽

Stable Processes ◽

Necessary And Sufficient ◽

The Impact

AbstractWe focus on the population dynamics driven by two classes of truncated $\alpha$-stable processes with Markovian switching. Almost necessary and sufficient conditions for the ergodicity of the proposed models are provided. Also, these results illustrate the impact on ergodicity and extinct conditions as the parameter $\alpha$ tends to 2.

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Parasitism of Aedes albopictus by Ascogregarina taiwanensis lowers its competitive ability against Aedes triseriatus

Parasites & Vectors ◽

10.1186/s13071-021-04581-0 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Emma Stump ◽

Lauren M. Childs ◽

Melody Walker

Keyword(s):

Population Dynamics ◽

Competitive Advantage ◽

Aedes Albopictus ◽

Abiotic Factors ◽

Mosquito Species ◽

Disease Spread ◽

Aedes Triseriatus ◽

La Crosse Virus ◽

The Impact ◽

Ascogregarina Taiwanensis

Abstract Background Mosquitoes are vectors for diseases such as dengue, malaria and La Crosse virus that significantly impact the human population. When multiple mosquito species are present, the competition between species may alter population dynamics as well as disease spread. Two mosquito species, Aedes albopictus and Aedes triseriatus, both inhabit areas where La Crosse virus is found. Infection of Aedes albopictus by the parasite Ascogregarina taiwanensis and Aedes triseriatus by the parasite Ascogregarina barretti can decrease a mosquito’s fitness, respectively. In particular, the decrease in fitness of Aedes albopictus occurs through the impact of Ascogregarina taiwanensis on female fecundity, larval development rate, and larval mortality and may impact its initial competitive advantage over Aedes triseriatus during invasion. Methods We examine the effects of parasitism of gregarine parasites on Aedes albopictus and triseriatus population dynamics and competition with a focus on when Aedes albopictus is new to an area. We build a compartmental model including competition between Aedes albopictus and triseriatus while under parasitism of the gregarine parasites. Using parameters based on the literature, we simulate the dynamics and analyze the equilibrium population proportion of the two species. We consider the presence of both parasites and potential dilution effects. Results We show that increased levels of parasitism in Aedes albopictus will decrease the initial competitive advantage of the species over Aedes triseriatus and increase the survivorship of Aedes triseriatus. We find Aedes albopictus is better able to invade when there is more extreme parasitism of Aedes triseriatus. Furthermore, although the transient dynamics differ, dilution of the parasite density through uptake by both species does not alter the equilibrium population sizes of either species. Conclusions Mosquito population dynamics are affected by many factors, such as abiotic factors (e.g. temperature and humidity) and competition between mosquito species. This is especially true when multiple mosquito species are vying to live in the same area. Knowledge of how population dynamics are affected by gregarine parasites among competing species can inform future mosquito control efforts and help prevent the spread of vector-borne disease.

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