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1.
Theor Popul Biol ; 154: 1-26, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37453615

RESUMO

We consider a population distributed between two habitats, in each of which it experiences a growth rate that switches periodically between two values, 1-ɛ>0 or -(1+ɛ)<0. We study the specific case where the growth rate is positive in one habitat and negative in the other one for the first half of the period, and conversely for the second half of the period, that we refer as the (±1) model. In the absence of migration, the population goes to 0 exponentially fast in each environment. In this paper, we show that, when the period is sufficiently large, a small dispersal between the two patches is able to produce a very high positive exponential growth rate for the whole population, a phenomena called inflation. We prove in particular that the threshold of the dispersal rate at which the inflation appears is exponentially small with the period. We show that inflation is robust to random perturbation, by considering a model where the values of the growth rate in each patch are switched at random times: we prove that inflation occurs for low switching rate and small dispersal. We also consider another stochastic model, where after each period of time T, the values of the growth rates in each patch is chosen randomly, independently from the other patch and from the past. Finally, we provide some extensions to more complicated models, especially epidemiological and density dependent models.


Assuntos
Ecossistema , Modelos Biológicos , Dinâmica Populacional , Crescimento Demográfico
2.
Oecologia ; 202(2): 239-250, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37253787

RESUMO

The general assumption that the survival patterns of tropical and southern temperate birds are similar lacks empirical data from higher latitudes. Regional comparisons of New World species are rare, and this assumption has been based on data from African studies. Here, we estimate the survival rates of 88 tropical and southern temperate bird populations (69 species) from eight localities in South America to evaluate the hypothesis that the survival of these populations is homogeneous at the regional scale. We estimated survival based on the Cormack-Jolly-Seber model and compared values from different environments. The survival estimates ranged from 0.30 to 0.80 (0.56 ± 0.12). Apparent survival did not differ significantly between low-latitude tropical environments (03°S) and the other sites from high-latitudes (between 22° and 34°S). Despite a predicted positive trend, body size was not significantly related to survival among passerines. On the other hand, phylogenetic relationships explained more than a third of the variation in bird survival. Based on the largest available database on South American bird species, our findings support the hypothesis that bird survival is homogeneous, at the regional scale, along the southern hemisphere. In particular, we reinforce the hypothesis that climatic variation has a limited influence on bird survival in the southern hemisphere.


Assuntos
Clima Tropical , Filogenia , América do Sul , Tamanho Corporal
3.
Theor Popul Biol ; 145: 109-125, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35247370

RESUMO

Synthetic gene drive constructs are being developed to control disease vectors, invasive species, and other pest species. In a well-mixed random mating population a sufficiently strong gene drive is expected to eliminate a target population, but it is not clear whether the same is true when spatial processes play a role. In species with an appropriate biology it is possible that drive-induced reductions in density might lead to increased inbreeding, reducing the efficacy of drive, eventually leading to suppression rather than elimination, regardless of how strong the drive is. To investigate this question we analyse a series of explicitly solvable stochastic models considering a range of scenarios for the relative timing of mating, reproduction, and dispersal and analyse the impact of two different types of gene drive, a Driving Y chromosome and a homing construct targeting an essential gene. We find in all cases a sufficiently strong Driving Y will go to fixation and the population will be eliminated, except in the one life history scenario (reproduction and mating in patches followed by dispersal) where low density leads to increased inbreeding, in which case the population persists indefinitely, tending to either a stable equilibrium or a limit cycle. These dynamics arise because Driving Y males have reduced mating success, particularly at low densities, due to having fewer sisters to mate with. Increased inbreeding at low densities can also prevent a homing construct from eliminating a population. For both types of drive, if there is strong inbreeding depression, then the population cannot be rescued by inbreeding and it is eliminated. These results highlight the potentially critical role that low-density-induced inbreeding and inbreeding depression (and, by extension, other sources of Allee effects) can have on the eventual impact of a gene drive on a target population.


Assuntos
Tecnologia de Impulso Genético , Depressão por Endogamia , Humanos , Endogamia , Masculino , Reprodução
4.
Malar J ; 21(1): 161, 2022 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-35658961

RESUMO

BACKGROUND: It is often assumed that the population dynamics of the malaria vector Anopheles funestus, its role in malaria transmission and the way it responds to interventions are similar to the more elaborately characterized Anopheles gambiae. However, An. funestus has several unique ecological features that could generate distinct transmission dynamics and responsiveness to interventions. The objectives of this work were to develop a model which will: (1) reconstruct the population dynamics, survival, and fecundity of wild An. funestus populations in southern Tanzania, (2) quantify impacts of density dependence on the dynamics, and (3) assess seasonal fluctuations in An. funestus demography. Through quantifying the population dynamics of An. funestus, this model will enable analysis of how their stability and response to interventions may differ from that of An. gambiae sensu lato. METHODS: A Bayesian State Space Model (SSM) based on mosquito life history was fit to time series data on the abundance of female An. funestus sensu stricto collected over 2 years in southern Tanzania. Prior values of fitness and demography were incorporated from empirical data on larval development, adult survival and fecundity from laboratory-reared first generation progeny of wild caught An. funestus. The model was structured to allow larval and adult fitness traits to vary seasonally in response to environmental covariates (i.e. temperature and rainfall), and for density dependency in larvae. The effects of density dependence and seasonality were measured through counterfactual examination of model fit with or without these covariates. RESULTS: The model accurately reconstructed the seasonal population dynamics of An. funestus and generated biologically-plausible values of their survival larval, development and fecundity in the wild. This model suggests that An. funestus survival and fecundity annual pattern was highly variable across the year, but did not show consistent seasonal trends either rainfall or temperature. While the model fit was somewhat improved by inclusion of density dependence, this was a relatively minor effect and suggests that this process is not as important for An. funestus as it is for An. gambiae populations. CONCLUSION: The model's ability to accurately reconstruct the dynamics and demography of An. funestus could potentially be useful in simulating the response of these populations to vector control techniques deployed separately or in combination. The observed and simulated dynamics also suggests that An. funestus could be playing a role in year-round malaria transmission, with any apparent seasonality attributed to other vector species.


Assuntos
Anopheles , Malária , Animais , Anopheles/fisiologia , Teorema de Bayes , Feminino , Malária/prevenção & controle , Mosquitos Vetores/fisiologia , Dinâmica Populacional , Tanzânia
5.
J Phycol ; 57(5): 1619-1635, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34153125

RESUMO

Macrocystis pyrifera is a major habitat forming kelp in coastal ecosystems of temperate regions of the northern and southern hemispheres. We investigated the seasonal occurrence of adult sporophytes, morphological characteristics, and reproductive phenology at two sites within a wave-protected harbour and two wave-exposed sites in southern New Zealand every 3-4 months between 2012 and 2013. Seasonality in reproduction was assessed via the number of sporophylls, the occurrence of sori on sporophylls, and non-sporophyllous laminae (fertile pneumatocyst-bearing blades and fertile apical scimitars), meiospore release, and germination. We found that M. pyrifera was present and reproductive year-round in three of the four sites, and patterns were similar for the wave-exposure conditions. Sori were found on pneumatocyst-bearing blades and apical scimitars in addition to the sporophylls, and viable meiospores were released from all three types of laminae. Morphological variations between sites with different wave exposure indicate that sporophytes from wave-protected sites have bigger blades and holdfasts and are longer than those from wave-exposed sites. We discuss the implications of these biological variables for the ecology of M. pyrifera inhabiting different wave exposure environments in southern New Zealand.


Assuntos
Kelp , Macrocystis , Movimentos da Água , Ecossistema , Nova Zelândia , Reprodução
6.
Microb Ecol ; 77(4): 1025-1035, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30088023

RESUMO

This work reports the comparison of the genome sequence and the ability to inhibit fungal growth of two Pseudomonas protegens related strains that were isolated from the same hydroponic culture of lamb's lettuce. The two strains were very similar in their core genome but one strain, Pf4, contained three gene clusters for the production of secondary metabolites, i.e., pyoluteorin (plt), pyrrolnitrin (prn), and rhizoxin (rzx), that were missing in the other strain, Pf11. The difference between the two strains was not due to simple insertion events, but to a relatively complex differentiation focused on the accessory genomes. In dual culture assays, both strains inhibited nearly all tested fungal strains, yet Pf4 exerted a significantly stronger fungal growth inhibition than Pf11. In addition to the differences in the secondary metabolite production associated genes abundance, the genome of Pf4 was more stable, smaller in size and with a lower number of transposons. The preservation of a dynamic equilibrium within natural populations of different strains comprised in the same species but differing in their secondary metabolite repertoire and in their genome stability may be functional to the adaptation to environmental changes.


Assuntos
Antifúngicos/farmacologia , Genoma Bacteriano , Pseudomonas/química , Pseudomonas/genética , Pythium/efeitos dos fármacos , Rhizoctonia/efeitos dos fármacos , Antifúngicos/química , Hidroponia , Pythium/crescimento & desenvolvimento , Rhizoctonia/crescimento & desenvolvimento
7.
Am J Phys Anthropol ; 163(1): 44-52, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28109124

RESUMO

OBJECTIVES: The early groups of hunter-gatherers who peopled South America faced significant ecological changes in their trophic niche for a relatively short period after the initial peopling. In particular, the incorporation of cultigens during the Holocene led to a wider trophic niche and probably to an increased carrying capacity of the environment. Here, we study the relationship between the incorporation of domestic resources during the Holocene and the demographic dynamics of human populations at a regional scale in South America. MATERIAL AND METHODS: We employ mitochondrial DNA (mtDNA), radiocarbon data and Bayesian methods to estimate differences in population size, human occupation and explore the demographic changes of human populations in three regions (i.e., South-Central Andes, Northwest, and South Patagonia). We also use archaeological evidence to infer the main diet changes in these regions. RESULTS: The absolute population size during the later Late Holocene was fifteen times larger in the South-Central Andes than in Northwest Patagonia, and two times larger in the latter region than in South Patagonia. The South-Central Andes display the earlier and more abrupt population growth, beginning about 9000 years BP, whereas Northwest Patagonia exhibits a more slow growth, beginning about 7000-7500 years BP. South Patagonia represents a later and slower population increase. DISCUSSION: In this work we uncovered a well-supported pattern of the demographic change in the populations from South-Central Andes and Patagonia, obtained on the basis of different data and quantitative approaches, which suggests that the incorporation of domestic resources was paramount for the demographic expansion of these populations during the Holocene.


Assuntos
Migração Humana , Indígenas Sul-Americanos , Crescimento Demográfico , Antropologia Física , Teorema de Bayes , DNA Mitocondrial/genética , Dieta , Ecologia , Feminino , História Antiga , Migração Humana/história , Migração Humana/estatística & dados numéricos , Humanos , Indígenas Sul-Americanos/genética , Indígenas Sul-Americanos/estatística & dados numéricos , América do Sul
8.
J Math Biol ; 75(3): 733-758, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28124077

RESUMO

We propose and analyze a simplified version of a partial differential equation (PDE) model for chronic myeloid leukemia (CML) derived from an agent-based model proposed by Roeder et al. This model describes the proliferation and differentiation of leukemic stem cells in the bone marrow and the effect of the drug Imatinib on these cells. We first simplify the PDE model by noting that most of the dynamics occurs in a subspace of the original 2D state space. Then we determine the dominant eigenvalue of the corresponding linearized system that controls the long-term behavior of solutions. We mathematically show a non-monotonous dependence of the dominant eigenvalue with respect to treatment dose, with the existence of a unique minimal negative eigenvalue. In terms of CML treatment, this shows that there is a unique dose that maximizes the decay rate of the CML tumor load over long time scales. Moreover this unique dose is lower than the dose that maximizes the initial tumor load decay. Numerical simulations of the full model confirm that this phenomenon is not an artifact of the simplification. Therefore, while optimal asymptotic dosage might not be the best one at short time scales, our results raise interesting perspectives in terms of strategies for achieving and improving long-term deep response.


Assuntos
Leucemia Mielogênica Crônica BCR-ABL Positiva/terapia , Modelos Biológicos , Antineoplásicos/uso terapêutico , Humanos , Mesilato de Imatinib/uso terapêutico , Tempo
9.
Ecol Lett ; 19(10): 1209-18, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27515951

RESUMO

In variable environments, organisms must have strategies to ensure fitness as conditions change. For plants, germination can time emergence with favourable conditions for later growth and reproduction (predictive germination), spread the risk of unfavourable conditions (bet hedging) or both (integrated strategies). Here we explored the adaptive value of within- and among-year germination timing for 12 species of Sonoran Desert winter annual plants. We parameterised models with long-term demographic data to predict optimal germination fractions and compared them to observed germination. At both temporal scales we found that bet hedging is beneficial and that predicted optimal strategies corresponded well with observed germination. We also found substantial fitness benefits to varying germination timing, suggesting some degree of predictive germination in nature. However, predictive germination was imperfect, calling for some degree of bet hedging. Together, our results suggest that desert winter annuals have integrated strategies combining both predictive plasticity and bet hedging.


Assuntos
Clima Desértico , Ecossistema , Germinação/fisiologia , Plantas/classificação , Estações do Ano , Sementes/fisiologia , Evolução Biológica , Modelos Biológicos
10.
Bull Entomol Res ; 106(6): 749-758, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27312045

RESUMO

Ten economically important species belonging to the Tephritidae have been recorded in Union of the Comoros (an island nation off the coast of East Africa). Little is known about the distribution of these species and how they are affected by climatic factors in the Comoros archipelago. The main objectives of this study were to characterize: (i) the population dynamics of tephritid fruit flies in relation to season and host fruit availability and (ii) the geographic distribution of tephritids in relation to temperature and rainfall. The study was conducted during 2 years at 11 sites on three islands (Grande Comore, Anjouan, and Mohéli) in the archipelago. The site elevations ranged from 55 to 885 m a.s.l. At each site, flies were collected weekly in eight traps (four different lures, each replicated twice). Fruit phenology was also recorded weekly. The dominant tephritid species detected was the invasive Bactrocera dorsalis Hendel followed by Ceratitis capitata Wiedemann. Tephritid species were generally more abundant during the hot and rainy seasons than during the cold and dry seasons. Bactrocera dorsalis numbers were higher on Grande Comore than on the two other islands. On Anjouan and Mohéli, B. dorsalis numbers were very low in 2014 but sharply increased in 2015, suggesting a recent invasion of these islands. Abundances were significantly related to the fruiting of mango, strawberry guava, and guava for B. dorsalis and to the fruiting of mango, guava, and mandarin for C. capitata. Bactrocera dorsalis was more abundant in hot and humid low-altitude areas, while C. capitata was more abundant in dry medium-altitude areas, suggesting the occurrence of climatic niche partitioning between the two species.


Assuntos
Clima , Tephritidae/fisiologia , Altitude , Distribuição Animal , Animais , Comores , Comportamento Alimentar , Frutas/fisiologia , Umidade , Espécies Introduzidas , Dinâmica Populacional , Temperatura
11.
Ecol Lett ; 17(3): 380-7, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24393387

RESUMO

In bet hedging, organisms sacrifice short-term success to reduce the long-term variance in success. Delayed germination is the classic example of bet hedging, in which a fraction of seeds remain dormant as a hedge against the risk of complete reproductive failure. Here, we investigate the adaptive nature of delayed germination as a bet hedging strategy using long-term demographic data on Sonoran Desert winter annual plants. Using stochastic population models, we estimate fitness as a function of delayed germination and identify evolutionarily stable strategies for 12 abundant species in the community. Results indicate that delayed germination meets the criteria as a bet hedging strategy for all species. Density-dependent models, but not density-independent ones, predicted optimal germination strategies that correspond remarkably well with observed patterns. By incorporating naturally occurring variation in seed and seedling dynamics, our results present a rigorous test of bet hedging theory within the relevant environmental context.


Assuntos
Adaptação Biológica/fisiologia , Evolução Biológica , Germinação/fisiologia , Modelos Biológicos , Fenômenos Fisiológicos Vegetais , Arizona , Clima Desértico , Densidade Demográfica , Dinâmica Populacional , Sementes/fisiologia , Especificidade da Espécie , Fatores de Tempo
12.
Environ Sci Pollut Res Int ; 31(8): 11727-11734, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38224435

RESUMO

Bromate is receiving increased attention as a typical disinfection by-product in aquatic environments, but bromate toxicity tests on invertebrate such as Brachionus calyciflorus rotifer are inadequate. In the present study, the long-term toxicity tests on B. calyciflorus were performed during 21 days under the exposure of different bromate concentrations and two algal density conditions. Furthermore, we evaluated the feeding behaviors of the rotifers under the impact of bromate. The maximum population density of rotifers was significantly reduced at 100 and 200 mg/L bromate exposure at the two algal density conditions. However, we observed that the maximum population density and population growth rate of rotifers were higher at 3.0 × 106 cells/mL algal density than those at 1.0 × 106 cells/mL under the same conditions of bromate exposure. These results suggest that higher food density may have alleviated the negative effects of bromate on rotifers. Meanwhile, the ingestion rate at an algal density of 3.0 × 106 cells/mL was higher than that at 1.0 × 106 cells/mL. The present study provides a basic reference to comprehensively evaluate the toxic effects of bromate on aquatic organisms.


Assuntos
Rotíferos , Poluentes Químicos da Água , Animais , Bromatos/toxicidade , Alimentos , Ingestão de Alimentos , Crescimento Demográfico , Poluentes Químicos da Água/toxicidade
13.
Artigo em Inglês | MEDLINE | ID: mdl-38618854

RESUMO

BACKGROUND: Many countries faced health workforce challenges even before the pandemic, such as impending retirements, negative population growth, or sub-optimal allocation of resources across health sectors. Current quantitative models are often of limited use, either because they require extensive individual-level data to be properly calibrated, or (in the absence of such data) because they are too simplistic to capture important demographic changes or disruptive epidemiological shocks such as the SARS-CoV-2 pandemic. Method: We propose a population-dynamic and stock-flow-consistent approach to physician supply forecasting that is complex enough to account for dynamically changing behaviour, while requiring only publicly available time-series data for full calibration. We demonstrate the utility of this model by applying it to 21 European countries to forecast the supply of generalist and specialist physicians to 2040, and the impact of increased health care utilisation due to Covid on this supply. RESULTS: Compared with the workforce needed to maintain physician density at 2019 levels, we find that in many countries there is indeed a significant trend towards decreasing generalist density at the expense of increasing specialist density. The trends for specialists are exacerbated by expectations of negative population growth in many Southern and Eastern European countries. Compared to the expected demographic changes in the population and the health workforce, we expect a limited impact of Covid on these trends, even under conservative modelling assumptions. Finally, we generalise the approach to a multi-professional, multi-regional and multi-sectoral model for Austria, where we find an additional suboptimal distribution in the supply of contracted versus non-contracted (private) physicians. CONCLUSION: It is therefore vital to develop tools for decision-makers to influence the allocation and supply of doctors across specialties and sectors to address these imbalances.

14.
Plants (Basel) ; 13(2)2024 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-38256765

RESUMO

Phalaris brachystachys (short-spiked canary grass) is considered to be among the most troublesome cereal weeds in Mediterranean areas. A bioeconomic model, based on population dynamics, competition and economic sub-models, was developed to simulate the long-term economic consequence of using herbicide-based strategies: no herbicide application, full herbicide dose (standard rate) and two reduced dose rates (75 and 50% of the standard rate) to control P. brachystachys in a biennial wheat-sunflower rotation. Simulation results indicated that only herbicide application at a full dose (90% control) and 3/4 dose (80% control) produced positive economic results, with the full dose being the best strategy (EUR 98.65 ha-1 year-1). A sensitivity analysis showed that the economic outcome, in terms of annualized net return, was strongly influenced by changes in yield, price, and fixed costs. In addition, the annualized net return was more sensitive to parameter changes at reduced herbicide doses than at full rate. In the wheat-sunflower rotation system, the application of the full dose of herbicide was the most economical and stable strategy in the long-term. Reduced doses are not a recommended option from an economic point of view. Bioeconomic models provide practical insight into different management approaches for effective weed control.

15.
Pest Manag Sci ; 80(7): 3149-3159, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38345491

RESUMO

BACKGROUND: Agricultural land-use change is an important driver of pest population dynamics, and can alter source-sink dynamics and the concentration-dilution effects of the landscape. Understanding the effects of land use on pests at both landscape and regional levels is essential for the development of sustainable pest management strategies given the large changes occurring in cropping systems in China. At the landscape level, we investigated the impacts of landscape composition and edge density on pheromone trap catch of codling moth (Cydia pomonella) in apple orchards, in Aksu, Xinjiang, China. At the regional scale, we conducted a meta-analysis using data from studies performed across the Aksu area in recent decades, to assess the relationship between trends in codling moth abundance and the area of apple cultivation. RESULTS: Both extensive planting of apple and large areas of annual crops in the landscape increased the abundance of codling moth, whereas the presence of secondary host plants (peach, pear, walnut, plum, and apricot) had a negative effect. Seminatural habitats and landscape edge density did not significantly affect codling moth abundance. The responses of different generations of codling moth to landscape factors were varied. At the regional level, codling moth occurrence was positively correlated with the expansion of apple production areas. CONCLUSION: Expansion of apple cultivation increases the abundance of codling moth in agricultural landscapes. We recommend decreasing the area devoted to monocultures of apple when designing agricultural landscapes and increasing plantings of secondary host crops to dilute and reduce the abundance of codling moth. © 2024 Society of Chemical Industry.


Assuntos
Malus , Mariposas , Animais , Mariposas/crescimento & desenvolvimento , Mariposas/fisiologia , Malus/crescimento & desenvolvimento , China , Dinâmica Populacional , Agricultura/métodos , Produção Agrícola/métodos , Produtos Agrícolas/crescimento & desenvolvimento
16.
Food Microbiol ; 36(2): 207-15, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24010599

RESUMO

The aim of this study was to explore diversity and dynamic of indigenous LAB strains associated with a long ripened hard cheese produced from raw milk and undefined natural starter such as PDO Grana Padano cheese. Samples of milk, curd, natural whey culture and cheeses (2nd, 6th, 9th and 13th months of ripening) were collected from 6 cheese factories in northern Italy. DNA was extracted from each sample and from 194 LAB isolates. tRNA(Ala)-23S rDNA-RFLP was applied to identify isolates. Strain diversity was assessed by (GTG)5 rep-PCR and RAPD(P1)-PCR. Finally, culture-independent LH-PCR (V1-V2 16S-rDNA), was considered to explore structure and dynamic of the microbiota. Grana Padano LAB were represented mainly by Lactobacillus rhamnosus, Lactobacillus casei, Lactobacillus paracasei, Lactobacillus delbrueckii, Lactobacillus helveticus and Pediococcus acidilactici, while the structure and dynamic of microbiota at different localities was specific. The strength of this work is to have focused the study on isolates coming from more than one cheese factories rather than a high number of isolates from one unique production. We provided a valuable insight into inter and intraspecies diversity of typical LAB strains during ripening of traditional PDO Grana Padano, contributing to the understanding of specific microbial ecosystem of this cheese.


Assuntos
Biodiversidade , Queijo/microbiologia , Lactobacillaceae/isolamento & purificação , Leite/microbiologia , Animais , Bovinos , DNA Bacteriano/genética , DNA Ribossômico/genética , Manipulação de Alimentos , Ácido Láctico/metabolismo , Lactobacillaceae/classificação , Lactobacillaceae/genética , Lactobacillaceae/metabolismo , Técnica de Amplificação ao Acaso de DNA Polimórfico
17.
J Insect Physiol ; 146: 104499, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36914090

RESUMO

To face recurrent temperature changes, tettigoniids inhabiting temperate climates overwinter as eggs in a diapause stage, being able to postpone embryogenesis for one or more years. To date, it is unclear if species living in warm regions, especially under the Mediterranean climate, could exhibit a diapause for a single year or enter a prolonged diapause due to higher summer temperatures experienced by eggs immediately after oviposition. In this two-year study, we tested the effect of summer temperatures on diapause of six Mediterranean tettigoniid species under natural field conditions. We found that five species can exhibit a facultative diapause depending on mean summer temperatures. For two species, a substantial shift in egg development from 50 to 90% occurred over an interval of c. 1 °C after the first summer period. All the species increased considerably their development (nearly 90%) after the second summer period irrespective of temperatures. Overall, this study suggests that diapause strategy and the different thermal sensibility of embryonic development varies considerably across species potentially affecting their population dynamics.


Assuntos
Diapausa de Inseto , Diapausa , Ortópteros , Feminino , Animais , Temperatura , Óvulo
18.
Viruses ; 15(6)2023 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-37376612

RESUMO

Japanese encephalitis virus (JEV) causes acute viral encephalitis in humans and reproductive disorders in pigs. JEV emerged during the 1870s in Japan, and since that time, JEV has been transmitted exclusively throughout Asia, according to known reporting and sequencing records. A recent JEV outbreak occurred in Australia, affecting commercial piggeries across different temperate southern Australian states, and causing confirmed infections in humans. A total of 47 human cases and 7 deaths were reported. The recent evolving situation of JEV needs to be reported due to its continuous circulation in endemic regions and spread to non-endemics areas. Here, we reconstructed the phylogeny and population dynamics of JEV using recent JEV isolates for the future perception of disease spread. Phylogenetic analysis shows the most recent common ancestor occurred about 2993 years ago (YA) (95% Highest posterior density (HPD), 2433 to 3569). Our results of the Bayesian skyline plot (BSP) demonstrates that JEV demography lacks fluctuations for the last two decades, but it shows that JEV genetic diversity has increased during the last ten years. This indicates the potential JEV replication in the reservoir host, which is helping it to maintain its genetic diversity and to continue its dispersal into non-endemic areas. The continuous spread in Asia and recent detection from Australia further support these findings. Therefore, an enhanced surveillance system is needed along with precautionary measures such as regular vaccination and mosquito control to avoid future JEV outbreaks.


Assuntos
Vírus da Encefalite Japonesa (Espécie) , Encefalite Japonesa , Humanos , Animais , Suínos , Vírus da Encefalite Japonesa (Espécie)/genética , Encefalite Japonesa/epidemiologia , Filogenia , Teorema de Bayes , Austrália/epidemiologia , Genótipo
19.
Data Brief ; 47: 108929, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36819895

RESUMO

Deeper understanding on natural forest dynamics requires long-term data series from forests that have not been affected by human interventions, which are often scarce especially in the Pannonian Bioregion. Unmanaged, but regularly inventoried forest reserves provide an opportunity to fill this gap. The dataset provides repeated inventory data for 233 permanent plots situated in the core areas of six forest reserves selected from primary forests (Kékes), long abandoned forests (Kecskés-galya, Szalafo, Várhegy) and abandoned ones (Hidegvíz-völgy, Nagy Istrázsa-hegy). The sampled old stands represent the four most widespread hilly forest types in Hungary: Carpathian submountainous beech forest; sessile oak-hornbeam forest; Turkey oak and sessile oak forest; downy oak forest. In each plot, stand level attributes included main mensuration variables (canopy closure, stand height, tree density, basal area, living and dead volume, lying deadwood and admixture of the main tree species). Tree level attributes (diameter at breast height, height measured and estimated, crown position in the canopy, health status, tree history of all trees or shrubs having diameter larger or equal to 5 cm) were also measured in two inventories (after 6-16 years) for a total of 6,986 individual trees sampled in all plots. Fagus sylvatica L., Quercus petraea agg., Q. cerris L., Q. pubescens Willd., Carpinus betulus L., Acer campestre L. and Cornus mas L. were the most abundant. The individual tree history classification refers to regeneration ingrowth, growing phase, mortality, decaying phase and disappearance events, that can be used for calculation of various stand dynamics attributes. The dataset offers valuable opportunities for quantifying changes in stand structures and tree population dynamic attributes after the abandonment of management. Inventory data can be integrated with environmental and climatic information to understand the drivers of forest stand dynamics under a changing climate.

20.
Mar Pollut Bull ; 193: 115232, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37406400

RESUMO

The harmful irregular jellyfish blooms in recent years are difficult to be deciphered by macro hydrographic condition changes. To fundamentally explain the dynamic of jellyfish populations, we shifted the focus to the polyp stage of jellyfish life cycle and local benthic ecosystems. We monitored the population dynamics of Aurelia coerulea polyps in Jiaozhou Bay and other benthic biofouling species in situ to explore the adaptive mechanism of polyps and interspecific interactions in the benthic microhabitat. Our results showed that as temperature increased, the polyps multiplied on the bare substrate, however, other benthic fouling organisms simultaneously invaded the polyp colony according to their different colonisation methods and physiological characteristics. In addition, the polyps were extremely tolerant to food scarcity in the natural environment at low temperatures. Our study indicated that it is necessary to consider the local benthic ecosystem and implement ecosystem-based management strategies to predict and manage problematic jellyfish blooms.


Assuntos
Ecossistema , Cifozoários , Animais , Estágios do Ciclo de Vida , Dinâmica Populacional , Temperatura Baixa
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