The interactions of evolutionary forces are difficult to analyse in free-living populations. However, when properly understood, they provide valuable insights into evolutionary biology and conservation genetics. This is particularly important for the interplay of genetic drift and natural selection in immune genes that confer resistance to disease. The Galápagos Islands are inhabited by four closely related species of mockingbirds (Mimus spp.). We used 12 different-sized populations of Galápagos mockingbirds and one population of their continental relative northern mockingbird (Mimus polyglottos) to study the effects of genetic drift on the molecular evolution of immune genes, the Toll-like receptors (TLRs: TLR1B, TLR4 and TLR15). We found that neutral genetic diversity was positively correlated with island size, indicating an important effect of genetic drift. However, for TLR1B and TLR4, there was little correlation between functional (e.g., protein) diversity and island size, and protein structural properties were largely conserved, indicating only a limited effect of genetic drift on molecular phenotype. By contrast, TLR15 was less conserved and even its putative functional polymorphism correlated with island size. The patterns observed for the three genes suggest that genetic drift does not necessarily dominate selection even in relatively small populations, but that the final outcome depends on the degree of selection constraint that is specific for each TLR locus.
- MeSH
- genetický drift MeSH
- hustota populace MeSH
- Passeriformes * genetika MeSH
- populační genetika MeSH
- selekce (genetika) MeSH
- toll-like receptor 4 * genetika MeSH
- toll-like receptory genetika MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND: The numbers of coronavirus disease 2019 (COVID-19) deaths per million people differ widely across countries. Often, the causal effects of interventions taken by authorities are unjustifiably concluded based on the comparison of pure mortalities in countries where interventions consisting different strategies have been taken. Moreover, the possible effects of other factors are only rarely considered. METHODS: We used data from open databases (European Centre for Disease Prevention and Control, World Bank Open Data, The BCG World Atlas) and publications to develop a model that could largely explain the differences in cumulative mortality between countries using non-interventional (mostly socio-demographic) factors. RESULTS: Statistically significant associations with the logarithmic COVID-19 mortality were found with the following: proportion of people aged 80 years and above, population density, proportion of urban population, gross domestic product, number of hospital beds per population, average temperature in March and incidence of tuberculosis. The final model could explain 67% of the variability. This finding could also be interpreted as follows: less than a third of the variability in logarithmic mortality differences could be modified by diverse non-pharmaceutical interventions ranging from case isolation to comprehensive measures, constituting case isolation, social distancing of the entire population and closure of schools and borders. CONCLUSIONS: In particular countries, the number of people who will die from COVID-19 is largely given by factors that cannot be drastically changed as an immediate reaction to the pandemic and authorities should focus on modifiable variables, e.g. the number of hospital beds.
- MeSH
- COVID-19 mortalita MeSH
- dospělí MeSH
- HIV infekce epidemiologie MeSH
- hrubý domácí produkt MeSH
- hustota populace MeSH
- incidence MeSH
- komorbidita MeSH
- kouření epidemiologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- městské obyvatelstvo statistika a číselné údaje MeSH
- mladiství MeSH
- nadváha epidemiologie MeSH
- obložnost MeSH
- pandemie prevence a kontrola MeSH
- poskytování zdravotní péče organizace a řízení MeSH
- prevalence MeSH
- SARS-CoV-2 * MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- socioekonomické faktory MeSH
- teplota MeSH
- tuberkulóza epidemiologie MeSH
- věkové rozložení MeSH
- veřejné zdravotnictví MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mužské pohlaví MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Evropa MeSH
We evaluated the relationship of stocking density to survival, growth performance and fin condition of European perch Perca fluviatilis with hand feeding and self-feeders. Hand-fed perch (body weight 19.1 ± 5.1 g and total length 107 ± 9 mm) were reared at 0.5, 1.0, 1.5 and 2.0 fish/L. Self-feeding perch (body weight 25.4 ± 3.9 g and total length 128 ± 7 mm) were reared at stocking densities of 0.6, 1.0 and 1.4 fish/L. Pond-reared perch served as a comparison group for fin damage assessment. We found no differences in survival rate among stocking densities with either feeding method. Hand-fed fish displayed the highest weight gain and SGR at stocking density of 0.5 fish/L. The self-feeding fish showed a non-linear association of weight gain with stocking density with the highest growth at 1.0 fish/L. Fin length was noticeably greater in pond-reared fish compared with RAS-reared fish regardless of feeding method. In both experiments, fin length relative to standard length showed a negative relationship with stocking density, with pectoral fins showing the greatest effect. Fin condition deteriorated with increasing stocking density, and growth was highest at 0.5 and 1.0 fish/L in hand-fed and self-feeding fish, respectively.
- MeSH
- hustota populace MeSH
- metody výživy veterinární MeSH
- okounovití růst a vývoj zranění fyziologie MeSH
- ploutve zvířat zranění patologie MeSH
- rybářství * MeSH
- vodní hospodářství * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
Overpopulation exacerbates environmental and health problems, from climate change to biodiversity loss and pandemics. It is the 'upstream' driver of numerous existential threats. Addressing this compassionately - always - should be axiomatic for doctors. Our profession, by dramatically reducing death-rates since the 1800s while birth-rates remained high, sadly bears - unintendedly - some responsibility for the increase: one billion then, eight billion looming. Therefore, as doctors, we must surely be uniquely motivated to: be involved in rights-based policies and services with unbroken supply chains ensuring optimal contraceptive care being available to all couples worldwide, remove well-known tangible (contraceptives unavailable) and intangible (cultural, religious and mis-informational) barriers to women's choice to access family planning everywhere, while achieving full gender equity, especially in education, warn how overpopulation risks all planetary life, through optimal environmental education both for colleagues and the public, and campaign for a maximum of two children (replacement fertility - or less) on principle. Doctors and Overpopulation was established in 1972. Before and since, this issue has become taboo, still affecting many doctors and even people claiming to care passionately about a sustainable future: the environmental NGOs. Their silence implies conservation goals are achievable regardless of human numbers, while many studies show they are not. It is time for an open discussion about this taboo. Therefore we, concerned doctors of 2020, reiterate here the doctors' 48-year long cri de Coeur.
- MeSH
- antikoncepce MeSH
- dítě MeSH
- hustota populace * MeSH
- klimatické změny MeSH
- lékaři * MeSH
- lidé MeSH
- porodnost MeSH
- zdravotní politika * MeSH
- Check Tag
- dítě MeSH
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
A key aim in wildlife disease ecology is to understand how host and parasite characteristics influence parasite transmission and persistence. Variation in host population density can have strong impacts on transmission and outbreaks, and theory predicts particular transmission-density patterns depending on how parasites are transmitted between individuals. Here, we present the results of a study on the dynamics of Morogoro arenavirus in a population of multimammate mice (Mastomys natalensis). This widespread African rodent, which is also the reservoir host of Lassa arenavirus in West Africa, is known for its strong seasonal density fluctuations driven by food availability. We investigated to what degree virus transmission changes with host population density and how the virus might be able to persist during periods of low host density. A seven-year capture-mark-recapture study was conducted in Tanzania where rodents were trapped monthly and screened for the presence of antibodies against Morogoro virus. Observed seasonal seroprevalence patterns were compared with those generated by mathematical transmission models to test different hypotheses regarding the degree of density dependence and the role of chronically infected individuals. We observed that Morogoro virus seroprevalence correlates positively with host density with a lag of 1-4 months. Model results suggest that the observed seasonal seroprevalence dynamics can be best explained by a combination of vertical and horizontal transmission and that a small number of animals need to be infected chronically to ensure viral persistence. Transmission dynamics and viral persistence were best explained by the existence of both acutely and chronically infected individuals and by seasonally changing transmission rates. Due to the presence of chronically infected rodents, rodent control is unlikely to be a feasible approach for eliminating arenaviruses such as Lassa virus from Mastomys populations.
- MeSH
- Arenavirus imunologie MeSH
- hustota populace MeSH
- infekce viry z čeledi Arenaviridae epidemiologie MeSH
- myši MeSH
- nemoci hlodavců epidemiologie MeSH
- protilátky virové MeSH
- séroepidemiologické studie MeSH
- zdroje nemoci veterinární MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Tanzanie MeSH
The evolutionary forces shaping life history divergence within species are largely unknown. Turquoise killifish display differences in lifespan among wild populations, representing an ideal natural experiment in evolution and diversification of life history. By combining genome sequencing and population genetics, we investigate the evolutionary forces shaping lifespan among wild turquoise killifish populations. We generate an improved reference genome assembly and identify genes under positive and purifying selection, as well as those evolving neutrally. Short-lived populations from the outer margin of the species range have small population size and accumulate deleterious mutations in genes significantly enriched in the WNT signaling pathway, neurodegeneration, cancer and the mTOR pathway. We propose that limited population size due to habitat fragmentation and repeated population bottlenecks, by increasing the genome-wide mutation load, exacerbates the effects of mutation accumulation and cumulatively contribute to the short adult lifespan.
- MeSH
- akumulace mutací * MeSH
- biologická evoluce MeSH
- dlouhověkost genetika MeSH
- ekosystém MeSH
- Fundulidae MeSH
- genom genetika MeSH
- hustota populace * MeSH
- modely u zvířat MeSH
- molekulární evoluce * MeSH
- stárnutí genetika MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Ground-nesting birds face many challenges to reproduce successfully, with nest predation being the main cause of reproductive failure. Visual predators such as corvids and egg-eating raptors, are among the most common causes of nest failure; thus, parental strategies that reduce the risk of visual nest predation should be favored by selection. To date, most research has focused on egg crypsis without considering adult crypsis, although in natural circumstances the eggs are covered by an incubating parent most of the time. Here we use a ground-nesting shorebird, the Kentish plover (Charadrius alexandrinus) as model species to experimentally test whether decoy parents influence nest predation. Using artificial nests with a male decoy, a female decoy or no decoy, we found that the presence of a decoy increased nest predation (N = 107 nests, p < 0.001). However, no difference was found in predation rates between nests with a male versus female decoy (p > 0.05). Additionally, we found that nests in densely vegetated habitats experienced higher survival compared to nests placed in sparsely vegetated habitats. Nest camera images, predator tracks and marks left on eggs identified the brown-necked raven (Corvus ruficollis) as the main visual nest predator. Our study suggests that the presence of incubating parents may enhance nest detectability to visual predators. However, parents may reduce the predation risk by placing a nest in sites where they are covered by vegetation. Our findings highlight the importance of nest site selection not only regarding egg crypsis but also considering incubating adult camouflage.
- MeSH
- ekosystém MeSH
- hnízdění fyziologie MeSH
- hustota populace MeSH
- ovum fyziologie MeSH
- predátorské chování fyziologie MeSH
- pryskyřičné cementy chemie MeSH
- ptáci fyziologie MeSH
- rozmnožování fyziologie MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
We used a field experiment to test the effects of population density on the growth rate and survival of Austrolebias bellottii, a Neotropical annual killifish. Effects differed between the sexes: males at high densities achieved a smaller final size and experienced higher mortality while no such effects were observed in females. This sex-specific effect could be an indirect consequence of mate competition.
- MeSH
- Fundulidae růst a vývoj fyziologie MeSH
- hustota populace MeSH
- rozmnožování MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Cíl práce: Věda nemusí začínat vědou. Může začínat filosofií. Toto dílo navazuje na velká díla minulosti, konkrétně na Anti-Cato Julia Caesara a zejména na Anti-Dühring Bedřicha Engelse. Práce, která je vystavěna na Hegelově dialektice a jejích kategoriích teze – antiteze – syntéza, považuje Nairobi Statement za tezi a přichází s kritikou jejích chyb a nedostatků, čímž se stává její antitezí. Design: Position statement. Název a sídlo pracoviště: Centrum ambulantní gynekologie, Brno. Centrum prenatální diagnostiky, Brno. Katedra filozofie, Filozofická fakulta Masarykovy univerzity, Brno. Metodika: Tento Statement je založen na kritické analýze dokumentu Nairobi Statement. Výsledky: Nairobi Statement (2019) potvrdil Programme of Action (1994), který zdůraznil význam individuálních lidských bytostí pro udržitelný rozvoj, zatímco vyloučil slovo „populace“ z veřejného diskurzu. Nadto doporučil zaměřit se na celou šíři sexuální a reprodukční medicíny na úkor „pouhého“ plánovaného rodičovství. Selhání Programme of Action však nemůže být zjevnější při pohledu na nárůst lidské populace – 5,6 miliardy v roce 1994, 7,8 miliard v roce 2019. Chybou Nairobi Statement je, že nadále ignoruje problém rapidního populačního růstu a přelidnění a jeho zásadních environmentálních a dalších implikací. Nicméně nejzásadnějšími chybami jsou A) nepřijetí skutečnosti, že bez udržitelné populace nemůže být dosaženo udržitelného rozvoje; B) chybějící celosvětová výzva k malým rodinám, která pomůže řešit populační moment, a tak ukončit a konečně i zvrátit populační růst. Závěr: Anti-Nairobi jde proti současnému, obecně přijímanému paradigmatu o „udržitelném“ rozvoji, jak je vyjádřen v Nairobi Statement. Uznává a podporuje cíle a úkoly, které si Nairobi Statement vytyčilo, považuje je však za nedostatečné. Proto přichází s dalšími cíli a úkoly, které jsou k opravdu udržitelnému rozvoji nezbytné. Konečně, v duchu Hegelovské dialektiky, Anti-Nairobi implicitně očekává vznik syntézy coby přemostění a usmíření teze a její antiteze.
Objective: Science does not need to start with science. It can start with philosophy. This work follows the great works of the past, namely Julius Caesar's Anti-Cato and especially Friedrich Engels' Anti-Dühring. It is built upon the threefold thesis – antithesis – synthesis approach of Hegelian dialectics. This Statement considers the Nairobi Statement a thesis and brings forth a critique of its flaws and incompleteness, thus becoming its antithesis. Design: Position statement. Setting: Center for Outpatient Gynecology, Brno, Czech Republic; Center for Prenatal Diagnosis, Brno, Czech Republic; Department of Philosophy, Faculty of Arts, Masaryk University, Brno, Czech Republic. Methods: This Statement is based on a critical analysis of the Nairobi Statement. Results: The Nairobi Statement (2019) reaffirms the Cairo Summit's Programme of Action (1994), which emphasized individual human beings while excluding population from the discourse, and by extension recommended a wide range of sexual and reproductive health and rights instead of specific family planning endeavors. Cairo's failure is largely visible through the increase in world population from 5.6 billion in 1994 to 7.8 billion in 2019 (also projected to grow through the end of the century). The Nairobi Statement's flaw is that it ignores the problem of overpopulation and its vast environmental and other implications. However, the most significant missed opportunities are A) lack of acknowledgment that there cannot be sustainable development without sustainable population and B) non-existent calls for small families worldwide, which helps combat population momentum and thus end and reverse population growth. Conclusion: Anti-Nairobi goes against the current leading paradigm on “sustainable” development as expressed in the Nairobi Statement. While acknowledging the Statement's triple zero goals, it suggests an additional set of goals. Finally, in the spirit of Hegelian dialectics, it implicitly awaits a synthesis to bridge both the thesis and its antithesis.
- Klíčová slova
- malé rodiny,
- MeSH
- antikoncepce MeSH
- hustota populace MeSH
- lidé MeSH
- populace MeSH
- reprodukční chování * MeSH
- trvale udržitelný růst * MeSH
- Check Tag
- lidé MeSH
Nest architecture is a fundamental character shaping immune strategies of social insects. The arboreal ant Temnothorax unifasciatus nests in cavities such as oak galls where the entire colony lives in a unique small chamber. In these conditions, physiological and behavioural strategies likely prevail over compartmentalisation and are presumably tuned with colony size. We designed two experiments to study chemical and behavioural immune strategies against the entomopathogenic fungus Metarhizium anisopliae in colonies of different sizes. First, we compared spore germination and length of germinal tubes inside artificial nests, designed to impede the contact between the ants and the fungus, in colonies of different size. In the absence of direct contact, Temnothorax unifasciatus colonies inhibit fungal growth inside their nests, presumably through volatile compounds. The analysis revealed a positive correlation between fungistatic activity and colony size, indicating that workers of smaller colonies do not invest a higher per capita effort in producing such substances compared to larger colonies. Second, we performed a removal experiment of contaminated and non-contaminated items introduced inside the nests of colonies of different size. Small colonies challenged with contaminated fibres showed an increased removal of all the items (both contaminated and non-contaminated) compared to small colonies challenged with non-contaminated fibres only. Conversely, larger colonies moved items regardless of the presence of the spores inside the nest. Colony size qualitatively affected removal of waste items showing a pathogen elicited reaction in small colonies to optimise the reduced workforce, while the removal behaviour in larger colonies revealed to be expressed constitutively.
