-
Frontiers in Plant Science 2023Estimating population density is a fundamental study in ecology and crop pest management. The density estimation of small-scale animals, such as insects, is a...
Estimating population density is a fundamental study in ecology and crop pest management. The density estimation of small-scale animals, such as insects, is a challenging task due to the large quantity and low visibility. An herbivorous insect is the big enemy of crops, which often causes serious losses. Feeding of insects results in changes in physiology-related chemical compositions of crops, but it is unknown whether these changes can be used to estimate the population density of pests. The brown planthopper (BPH), , is a serious insect pest hiding under rice canopy to suck the sap of rice stems. BPH density is a crucial indicator for determining whether the control using pesticides will be carried out or not. Estimating BPH density is still dependent on manmade survey and light-trap methods, which are time-consuming and low-efficient. Here, we developed a new method based on the physiological traits of rice leaves. The feeding of BPHs significantly decreased the contents of chlorophyll (the SPAD readings), water, silicon, and soluble sugar in rice leaves. Four ratio physiological indices based on these four physiological traits of the BPH-damaged rice leaves to those of healthy leaves were established, and they were significantly correlated with BPH density in rice plants. A rice growth stage-independent linear model based on the four ratio physiological indices and adding the other two variables, BPH damage duration and population increase rate, was developed. This model exhibited a reasonable accuracy for estimating BPH density. This new method will promote the development of density estimation of pest populations toward nonprofessionalization and automation.
PubMed: 37636116
DOI: 10.3389/fpls.2023.1152698 -
Geospatial Health Oct 2023England and Wales experienced three waves of influenza during the 1918/19 Spanish Flu pandemic. A previous analysis showed that these three waves had fundamentally...
England and Wales experienced three waves of influenza during the 1918/19 Spanish Flu pandemic. A previous analysis showed that these three waves had fundamentally different spatial and temporal characteristics. This present study compares London's experience of the three waves to discern possible geographic differences on a metropolitan level. Borough mortality data for each wave were normalized and then scaled, with spatial autocorrelation techniques displayed by GIS software and analysed for each wave. Registrar General in England and Wales reporting provided data concerning measures of 'health' and 'wealth' for each metropolitan borough. Spearman's rank correlation determined the correlation of each wave's mortality to each of the other waves including the 'health,' 'wealth' and population density factors. The comparisons showed that there is a spatial difference among the waves. The first two are spatially similar, with both exhibiting 'random' autocorrelation patterns, while the third wave exhibits a 'clustered' pattern. The borough mortality of the first two waves strongly correlated with each other, with both having similar 'health,' 'wealth' and population density factors. However, the third wave's mortality did not correlate with any of the first two and actually behaved in an opposite manner with regard to the 'health,' 'wealth,' and population density factors. These results do not appear in the literature and create new opportunities for research to explain London's mortality during the Spanish Flu pandemic of 1918/19.
Topics: Humans; History, 20th Century; London; Influenza, Human; Influenza Pandemic, 1918-1919; Wales; Pandemics
PubMed: 37860851
DOI: 10.4081/gh.2023.1235 -
Genes Oct 2023In theoretical biology, a prevailing hypothesis posits a profound interconnection between effective population size (), genetic diversity, inbreeding, and genetic load....
In theoretical biology, a prevailing hypothesis posits a profound interconnection between effective population size (), genetic diversity, inbreeding, and genetic load. The domestication and improvement processes are believed to be pivotal in diminishing genetic diversity while elevating levels of inbreeding and increasing genetic load. In this study, we performed a whole genome analysis to quantity genetic diversity, inbreeding, and genetic load across seven wild species and five domesticated sheep breeds. Our research demonstrates that the genetic load and diversity of species in the genus have no discernible impact on recent , and three species within the subgenus tend to carry a higher genetic load and lower genetic diversity patterns. The results coincide with these species' dramatic decline in population sizes within the subgenus ~80-250 thousand years ago. European mouflon presented with the lowest , lower genetic diversity, and higher individual inbreeding coefficient but a lower genetic load (missense and LoF). This suggests that the small of European mouflon could reduce harmful mutations compared to other species within the genus . We showed lower genetic diversity in domesticated sheep than in Asiatic mouflon, but counterintuitive patterns of genetic load, i.e., lower weak genetic load (missense mutation) and no significant difference in strong genetic load (LoF mutation) between domestic sheep and Asiatic mouflon. These findings reveal that the "cost of domestication" during domestication and improvement processes reduced genetic diversity and purified weak genetic load more efficiently than wild species.
Topics: Animals; Sheep; Sheep, Domestic; Domestication; Population Density; Genetic Load; Mutation
PubMed: 37895326
DOI: 10.3390/genes14101977 -
The Journal of Animal Ecology Dec 2023The structure of animal societies is a key determinant of many ecological and evolutionary processes. Yet, we know relatively little about the factors and mechanisms...
The structure of animal societies is a key determinant of many ecological and evolutionary processes. Yet, we know relatively little about the factors and mechanisms that underpin detailed social structure. Among other factors, social structure can be influenced by habitat configuration. By shaping animal movement decisions, heterogeneity in habitat features, such as vegetation and the availability of resources, can influence the spatiotemporal distribution of individuals and subsequently key socioecological properties such as the local population size and density. Differences in local population size and density can impact opportunities for social associations and may thus drive substantial variation in local social structure. Here, we investigated spatiotemporal variation in population size at 65 distinct locations in a small songbird, the great tit (Parus major) and its effect on social network structure. We first explored the within-location consistency of population size from weekly samples and whether the observed variation in local population size was predicted by the underlying habitat configuration. Next, we created social networks from the birds' foraging associations at each location for each week and examined if local population size affected social structure. We show that population size is highly repeatable within locations across weeks and years and that some of the observed variation in local population size was predicted by the underlying habitat, with locations closer to the forest edge having on average larger population sizes. Furthermore, we show that local population size affected social structure inferred by four global network metrics. Using simple simulations, we then reveal that much of the observed social structure is shaped by social processes. Across different population sizes, the birds' social structure was largely explained by their preference to forage in flocks. In addition, over and above effects of social foraging, social preferences between birds (i.e. social relationships) shaped certain network features such as the extent of realized social connections. Our findings thus suggest that individual social decisions substantially contribute to shaping certain social network features over and above effects of population size alone.
Topics: Humans; Animals; Songbirds; Population Density; Social Behavior; Passeriformes; Ecosystem; Social Structure
PubMed: 37837224
DOI: 10.1111/1365-2656.14015 -
World Neurosurgery Nov 2023According to the World Federation of Neurosurgical Societies (WFNS), a minimum neurosurgery workforce density should be 1 per 200,000 population for optimum access to...
BACKGROUND AND OBJECTIVE
According to the World Federation of Neurosurgical Societies (WFNS), a minimum neurosurgery workforce density should be 1 per 200,000 population for optimum access to neurosurgical care. Pakistan lags behind in the number of neurosurgeons, and disproportionate geographical distribution further increases disparity. Our objective was to geographically map the density of neurosurgeons and emergency neurosurgical services (ENS) in Pakistan.
METHODS
This survey was circulated among 307 neurosurgeons. Data were analyzed using SPSS v21. The number of neurosurgeons and ENS were plotted on the population density map using ArcGIS Pro 3.0.0 software.
RESULTS
Three hundred and seven neurosurgeons working at 74 centers responded to our survey (93.3% coverage). The current density of neurosurgeons in Pakistan is 0.14/100,000. The 2 more populous provinces, Punjab and Sindh, have 42.3% (130) and 35.8% (110) neurosurgeons, respectively. They also housed nearly 3 quarters of all the neurosurgery centers in urban districts. Karachi and Lahore accommodate 135 (44%) of all the country's neurosurgeons, having 0.29 and 0.51 neurosurgeons/100,000 respectively. Management of traumatic brain injury is offered at 65 centers (87.8%). Nearly all centers are equipped with computed tomography (CT) scan machine (74; 97%), but magnetic resonance imaging (MRI) facility is available at 55 (72%) centers and 37 (49%) centers have angiography suites. Sixty nine centers (93.2%) have C-arm fluoroscopes available.
CONCLUSIONS
The geographical mapping of neurosurgeons and neurosurgical facilities is highly skewed towards urban centers, increasing disparity in access to timely neurosurgical emergency services. Four times more neurosurgeons are required in Pakistan to bridge the gap in neurosurgical workforce.
Topics: Humans; Neurosurgeons; Pakistan; Neurosurgery; Neurosurgical Procedures; Emergency Medical Services
PubMed: 37683928
DOI: 10.1016/j.wneu.2023.08.133 -
The Surgeon : Journal of the Royal... Dec 2023Time-sensitive emergencies in areas of low population density have statistically poorer outcomes. This includes incidents of major trauma. This study assesses the effect... (Observational Study)
Observational Study
BACKGROUND
Time-sensitive emergencies in areas of low population density have statistically poorer outcomes. This includes incidents of major trauma. This study assesses the effect that population density at a receiving hospital of a major trauma patient has on survival.
METHODS
Patients meeting Trauma Audit Research Network criteria for major trauma from 2016 to 2020 in Ireland were included in this retrospective observational study. Incident data were retrieved from the Major Trauma Audit, while data on population density were calculated from Irish state sources. The primary outcome measure of survival to discharge was compared to population density using logistic regression, adjusted for demographic and incident variables. Records were divided into population density tertiles to assess for between-group differences in potential predictor variables.
RESULTS
Population density at a receiving hospital had no impact on mortality in Irish major trauma patients from our logistic regression model (OR = 1.01, 95% CI 0.98-1.05, p = 0.53). Factors that did have an impact were age, Charlson Comorbidity Index, Injury Severity Score, and the presence of an Orthopaedic Surgery service at the receiving hospital (all p < 0.001). Age and Charlson Comorbidity Index differed slightly by population density tertile; both were higher in areas of high population density (all p < 0.001).
CONCLUSIONS
Survival to discharge in Irish major trauma patients does not differ substantially based on population density. This is an important finding as Ireland moves to a new trauma system, with features based on population distribution. An Orthopaedic Surgery service is an important feature of a major trauma receiving hospital and its presence improves outcomes.
Topics: Humans; Ireland; Population Density; Patient Discharge; Logistic Models; Injury Severity Score; Retrospective Studies; Wounds and Injuries
PubMed: 37652802
DOI: 10.1016/j.surge.2023.08.003 -
Marine Pollution Bulletin Nov 2023In this study, we conducted the first assessment of the litter abundance, diversity and predictors in Mozambique, by collecting approximately 2 tons of litter along six...
In this study, we conducted the first assessment of the litter abundance, diversity and predictors in Mozambique, by collecting approximately 2 tons of litter along six beaches across the country. We tested whether population, touristic industry, fishing, and recreation activities predict the quantity of macro litter for each of the 11 types and 141 subtypes of litter. Overall, we found that plastics made up 60.1 % of the items across all sampled beaches. Following plastics, clothing objects accounted for the second most weight (20.4 %) while foam objects were the second most abundant (15.7 %). More importantly, our results show that the tourism industry is a strong predictor for lower levels of litter across most types of litter while population density and fishing activity were strong predictors for higher levels. Our findings suggest that the tourism industry plays a crucial role in the country by maintaining the beaches clean.
Topics: Environmental Monitoring; Mozambique; Tourism; Waste Products; Bathing Beaches; Plastics
PubMed: 37804669
DOI: 10.1016/j.marpolbul.2023.115615 -
Ecology and Evolution May 2024Canid species are highly adaptable, including to urban and peri-urban areas, where they can come into close contact with people. Understanding the mechanisms of wild...
Canid species are highly adaptable, including to urban and peri-urban areas, where they can come into close contact with people. Understanding the mechanisms of wild canid population persistence in these areas is key to managing any negative impacts. The resource dispersion hypothesis predicts that animal density increases and home range size decreases as resource concentration increases, and may help to explain how canids are distributed in environments with an urban-natural gradient. In Australia, dingoes have adapted to human presence, sometimes living in close proximity to towns. Using a targeted camera trap survey and spatial capture-recapture models, we estimated spatial variation in the population density and detection rates of dingoes on Worimi Country in the Great Lakes region of the NSW coast. We tested whether dingo home range and population densities varied across a gradient of human population density, in a mixed-use landscape including, urban, peri-urban, and National Park environs. We found human population density to be a strong driver of dingo density (ranging from 0.025 to 0.433 dingoes/km across the natural-urban gradient), and to have a negative effect on dingo home range size. The spatial scale parameter changed depending on survey period, being smaller in the peak tourism period, when human population increases in the area, than in adjacent survey periods, potentially indicating reduced home range size when additional resources are available. Our study highlights the potential value of managing anthropogenic resource availability to manage carnivore densities and potential risk of human-carnivore interactions.
PubMed: 38779530
DOI: 10.1002/ece3.11404 -
MicroPublication Biology 2023Many genetic pathways and environmental factors have been shown to affect adult body size. Larval density often varies considerably between vials, even when the same...
Many genetic pathways and environmental factors have been shown to affect adult body size. Larval density often varies considerably between vials, even when the same number of females of the same genotype are allowed to lay eggs in the vials for the same amount of time. To more accurately quantify the effects that larval population density has on pupal size, we established cultures of 1, 2, 10, 25, 50, 75 or 100 first instar larvae into vials and measured pupal length. We collected Oregon-R eggs on apple juice plates in six different cages and generated replicate cultures. We found that pupal size decreases as larval density in the culture increases by 25 individuals. The difference between male and female length remained relatively constant at each density (0.2 mm), but overall size decreased. The mean size differences between vials with 1 larvae and 100 larvae is 0.1(+/-0.02) mm in females and 0.11(+/-0.02) mm in males. These results suggest that fecundity and sex ratio could complicate results in Drosophila size studies.
PubMed: 38111843
DOI: 10.17912/micropub.biology.000959 -
Biological Reviews of the Cambridge... Dec 2023Coral recruitment describes the addition of new individuals to populations, and it is one of the most fundamental demographic processes contributing to population size.... (Review)
Review
Coral recruitment describes the addition of new individuals to populations, and it is one of the most fundamental demographic processes contributing to population size. As many coral reefs around the world have experienced large declines in coral cover and abundance, there has been great interest in understanding the factors causing coral recruitment to vary and the conditions under which it can support community resilience. While progress in these areas is being facilitated by technological and scientific advances, one of the best tools to quantify recruitment remains the humble settlement tile, variants of which have been in use for over a century. Here I review the biology and ecology of coral recruits and the recruitment process, largely as resolved through the use of settlement tiles, by: (i) defining how the terms 'recruit' and 'recruitment' have been used, and explaining why loose terminology has impeded scientific advancement; (ii) describing how coral recruitment is measured and why settlement tiles have value for this purpose; (iii) summarizing previous efforts to review quantitative analyses of coral recruitment; (iv) describing advances from hypothesis-driven studies in determining how refuges, seawater flow, and grazers can modulate coral recruitment; (v) reviewing the biology of small corals (i.e. recruits) to understand better how they respond to environmental conditions; and (vi) updating a quantitative compilation of coral recruitment studies extending from 1974 to present, thus revealing long-term global declines in density of recruits, juxtaposed with apparent resilience to coral bleaching. Finally, I review future directions in the study of coral recruitment, and highlight the need to expand studies to deliver taxonomic resolution, and explain why time series of settlement tile deployments are likely to remain pivotal in quantifying coral recruitment.
Topics: Animals; Humans; Anthozoa; Coral Reefs; Population Density; Seawater; Time Factors
PubMed: 37340617
DOI: 10.1111/brv.12987