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We complete the study of the model introduced in [11]. It is a two-color urn model with multiple drawing and random (non-balanced) time-dependent reinforcement matrix. The number of sampled balls at each time-step is random. We identify the exact rates at which the number of balls of each color grows to infinity and define two strongly consistent estimators for the limiting reinforcement averages. Then we prove a Central Limit Theorem, which allows to design a statistical test for such averages., arXiv admin note: text overlap with arXiv:2102.06287

Emergence of the colistin resistance gene, mcr-1, has attracted worldwide attention. Despite the prevalence of mcr-1-positive Escherichia coli (MCRPEC) strains in human carriage showing a significant decrease between 2016 and 2019, genetic differences in MCRPEC strains remain largely unknown. We therefore conducted a comparative genomic study on MCRPEC strains from fecal samples of healthy human subjects in 2016 and 2019. We identified three major differences in MCRPEC strains between these two time points. First, the insertion sequence ISApl1 was often deleted and the percentage of mcr-1-carrying IncI2 plasmids was increased in MCRPEC strains in 2019. Second, the antibiotic resistance genes (ARGs), aac(3)-IVa and blaCTX-M-1, emerged and coexisted with mcr-1 in 2019. Third, MCRPEC strains in 2019 contained more virulence genes, resulting in an increased proportion of extraintestinal pathogenic E. coli (ExPEC) strains (36.1%) in MCRPEC strains in 2019 compared to that in 2016 (10.5%), implying that these strains could occupy intestinal ecological niches by competing with other commensal bacteria. Our results suggest that despite the significant reduction in the prevalence of MCRPEC strains in humans from 2016 to 2019, MCRPEC exhibits increased resistance to other clinically important ARGs and contains more virulence genes, which may pose a potential public health threat.

This study deals with the problem of the population shrinking in habitats affected by aging and excessive migration outflows. First, a control-oriented population dynamics model was proposed that catches the effect of depopulation. The model also includes the effect of spatial interaction-driven migration flows on population size. The resulting model is a non-homogeneous ordinary differential equation. It includes such phenomena that are important from the control point of view, such as the influence of migration costs on population dynamics, the impact of aging on population size, or the effect of the habitats' carrying capacity on migration flows. Based on the model, controllability conditions are formulated and a control strategy was developed that is meant to avoid the depopulation of the habitat. The control method acts on the migration costs to achieve the control goal and requires only population size measurements. Simulation measurements are presented in the paper to show the effectiveness of the proposed modeling and control methods.

The healthy migrant and salmon bias hypotheses stipulate that those who are healthier are more likely to migrate (a selection effect) and unhealthy migrants have a greater tendency to return to their origin communities than healthier migrants. It remains unclear whether the hypotheses are relevant for mental health, although they have robust evidence for physical health. The current study expands the theoretical foundation underlying these hypotheses by exploring the impact of migration status on depression among the middle-aged and older population in China.Longitudinal data from the China Health and Retirement Longitudinal Study (CHARLS) in 2011, 2013, 2015 and 2018 were used. Participants were divided into three groups, non-migrants, permanent migrants, and return-migrants according to their migration status. The Chinese version of 10-item Center for Epidemiologic Studies Depression Scale was used to assess clinically relevant depressive symptoms. Incidence were estimated by each migration status and compared across strata using log-rank tests. Cox regression models were fit to assess the relationship between migration status and depression incidence.A total of 9264 middle-aged and elderly participants were included, of whom 7047 (76.1 %) were non-migrants, 1065 (11.5 %) were permanent migrants, and 1152 (12.4 %) were return-migrants, respectively. Incidence rates of depression by different migration statuses were 76.6/10Migration statuses of participants may have changed over time, but due to the lack of raw data on migration status in 2013 and 2015, we used migration status at baseline. We were also not able to contextualize the migration experiences among those who migrated, and these trajectories may be heterogeneous.Using depression as an indicator of mental health, the healthy migrant hypothesis was supported among middle-aged and elderly permanent migrants living in urban areas while the salmon bias hypothesis was not. Significant urban-rural inequities in mental health existed among different types of migrants. Especially among permanent migrants who have migrated and converted Hukou from their original registration place to their current residence.

For the two-patch logistic model, we study the effect of dispersal intensity and dispersal asymmetry on the total population abundance and its distribution. Two complete classifications of the model parameter space are given: one concerning when dispersal causes smaller or larger total biomass than no dispersal, and the other addressing how the total biomass changes with dispersal intensity and dispersal asymmetry. The dependencies of the population abundance of each individual patch on dispersal intensity and dispersal asymmetry are also fully characterized. In addition, the maximal and minimal total population sizes induced by dispersal are determined for the logistic model with an arbitrary number of patches, and a weak order-preserving result correlated the local population abundances with and without dispersal is established.

Epithelial-mesenchymal transition (EMT) is a biological process that plays a central role in embryonic development, tissue regeneration, and cancer metastasis. Transforming growth factor-β (TGFβ) is a potent inducer of this cellular transition, comprising transitions from an epithelial state to partial or hybrid EMT state(s), to a mesenchymal state. Recent experimental studies have shown that, within a population of epithelial cells, heterogeneous phenotypical profiles arise in response to different time- and TGFβ dose-dependent stimuli. This offers a challenge for computational models, as most model parameters are generally obtained to represent typical cell responses, not necessarily specific responses nor to capture population variability. In this study, we applied a data-assimilation approach that combines limited noisy observations with predictions from a computational model, paired with parameter estimation. Synthetic experiments mimic the biological heterogeneity in cell states that is observed in epithelial cell populations by generating a large population of model parameter sets. Analysis of the parameters for virtual epithelial cells with biologically significant characteristics (e.g., EMT prone or resistant) illustrates that these sub-populations have identifiable critical model parameters. We perform a series of in silico experiments in which a forecasting system reconstructs the EMT dynamics of each virtual cell within a heterogeneous population exposed to time-dependent exogenous TGFβ dose and either an EMT-suppressing or EMT-promoting perturbation. We find that estimating population-specific critical parameters significantly improved the prediction accuracy of cell responses. Thus, with appropriate protocol design, we demonstrate that a data-assimilation approach successfully reconstructs and predicts the dynamics of a heterogeneous virtual epithelial cell population in the presence of physiological model error and parameter uncertainty.

Rabies causes approximately 20,000 human deaths in India each year. Nearly all of these occur following dog bites. Large-scale, high-coverage dog rabies vaccination campaigns are the cornerstone of rabies elimination strategies in both human and dog populations, although this is particularly challenging to achieve in India as a large proportion of the dog population are free-roaming and unowned. Further, little is known about free-roaming dog ecology in India which makes defining optimum vaccination strategies difficult. In this study, data collected using a mobile phone application during three annual mass vaccination and neutering (surgical sterilisation of both males and females) campaigns of free-roaming dogs in Ranchi, India (during which a total of 43,847 vaccinations, 26,213 neuter surgeries and 28,172 re-sight observations were made) were interrogated, using two novel approaches to estimate the proportion of neutered dogs that were lost from the city (assumed due to mortality or migration) between campaign years. Analysis revealed high losses of neutered dogs each year, ranging from 25.3% (28.2-22.8) to 55.8% (57.0-54.6). We also estimated that the total population declined by 12.58% (9.89-15.03) over the three-year period. This demonstrates that there is a high turnover of free-roaming dogs and that despite neutering a large number of dogs in an annual sterilisation campaign, the decline in population size was modest over a three-year time period. These findings have significant implications for the planning of rabies vaccination campaigns and population management programmes as well as highlighting the need for further research into the demographics of free-roaming, unowned dogs in India.

Population projections rely on one-sex renewal models. Consequently, changing the projection of male mortality does not affect the projection of birth, contradicting commonsense. A two-sex renewal model is presented in this paper to provide a better description of reproduction and more reasonable population projections. This model is nonlinear and includes the one-sex renewal models as special cases. In this model, age-specific birth rates are defined for two sexes jointly; total fertility, net reproduction rate, and intrinsic growth rate are also derived for two sexes jointly; and age-specific populations approach or converge to stable status. Applying the two-sex renewal model to Australia, it indicates that one-sex models underestimated the intrinsic growth rate by 14 percent. Compared to the results of one-sex models, the two-sex model would provide higher growth rate for low-fertility countries, and lower growth rate for high-fertility countries. In other words, the one-sex models are commonly biased. If the two-sex model is applied to all the countries, it would project smaller populations for the world in the future.

Cultural macroevolution concerns a long-term evolutionary process involving transmission of non-genetic or cultural traits between populations as well as birth and death of populations. To understand the spatial dynamics of cultural macroevolution, we present a one-locus model of cultural diffusion in which a cultural trait is transmitted on a network of populations. Borrowing the method of ancestral backward process from population genetics, our model explores the lineage of a trait variant sampled in the present generation to quantify when and where the variant was invented. Mathematical analysis of the model enables us to predict the distribution of cultural age in each population of the network, estimate the frequencies of trait variants originating from given populations, and discuss the time it takes for a trait variant to diffuse between a given pair of populations. We also perform numerical analysis on random scale-free network of populations to investigate the effect of network topology and innovation rate on the age and origin of variants in each population. The result suggests that trait variants are more likely to derive from a population with higher innovation rate. Our numerical analysis also shows that trait variants invented in populations with higher network-centrality values are likely to be maintained at a higher frequency and transmitted to other populations in a shorter time period.

OBJECTIVE: To estimate associations of residential mobility with body mass index (BMI), physical activity and diet and whether associations differ across demographics. DESIGN: Longitudinal cohort with four waves of survey follow-up over 15 years. PARTICIPANTS AND SETTING: 2110 adolescents and young adults originally from the Twin Cities of Minnesota that responded to at least 2 waves of follow-up, beginning at ages 15 to 23. MAIN OUTCOME MEASURE(S): Self-reported BMI, physical activity, fast food consumption, breakfast frequency, sugary drink consumption, fruit and vegetable consumption, and screen-time. ANALYSIS: Each outcome was modeled as a continuous variable using hierarchical linear regression. Residential mobility – change in residential address – was the main effect of interest. Models adjusted for demographics, marriage during follow-up and previous level of the outcome. Inverse propensity weights accounted for loss to follow-up. RESULTS: No weight-related outcomes differed between movers and non-movers in the whole sample. When examining effect modification by age, as participants aged moving was increasingly associated with improvements in weight-related outcomes, particularly BMI. CONCLUSIONS AND IMPLICATIONS: Results suggest that moving may be associated with poorer weight-related outcomes during a brief window from late teens and early-20s, and less associated with weight related outcomes in the mid-20s and 30s.

International audience; A longstanding research divide exists in plant ecology: either focusing on plant clonality, with no ambition to address nonclonal plants, or focusing on all plants, ignoring that many ecological processes can be affected by the fact that some plants are clonal while others are not. This gap cascades into a lack of distinction and knowledge about the similarities and differences between clonal and nonclonal plants. Here we aim to bridge this gap by identifying areas that would benefit from the incorporation of clonal growth into one integrated research platform: namely, response to productivity and disturbance, biotic interactions, and population dynamics. We are convinced that this will provide a roadmap to gain valuable insights into the ecoevolutionary dynamics relevant to all plants.

We adopt an operatorial method, based on truncated bosons, to describe the dynamics of populations in a closed region with a non trivial topology. The main operator that includes the various mechanisms and interactions between the populations is the Hamiltonian, constructed with the density and transport operators. The whole evolution is derived from the Schrodinger equation, and the densities of the populations are retrieved from the normalized expected values of the density operators. We show that this approach is suitable for applications in very large domain, solving the computational issues that typically occur when using an Hamiltonian based on fermionic ladder operators.

We consider Bazykin's model to address harvesting induced stability exchanges through bifurcation analysis. We examine the existence of hydra effects and analyze the stock pattern under predator harvesting. Prey harvesting cannot produce hydra effects in our model, whereas predator harvesting may cause multiple hydra effects. Our study reveals that type II response function and mutual interference among predators jointly induce multiple hydra effects and bistability. Bifurcations such as single Hopf-bifurcation, multiple Hopf-bifurcations and multiple saddle-node bifurcations appear for increasing harvesting rate on the predators. However, over-exploitation of the predators cannot generate any such bifurcation in our study. In simulations, the maximum sustainable yield (MSY) exists at a globally stable state. When predator is culled under increasing effort, basin of attraction of the equilibrium corresponding to the higher predator stock gets expanded, which alternatively is in favor of stock benefit for predators. The ecological theory developed in this study might be useful to understand conservation policy and fishery management.

To clarify the effects of sublethal concentration of insecticide on the growth, development and reproduction of Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), the sublethal and transgenerational effects of the LC30 of six insecticides on adults and progeny (F1 and F2 generations) were studied using age-stage, two-sex life tables. Exposure to six insecticides had significant negative impacts on the life-history traits of B. dorsalis and led to reduced adult longevity and fecundity in F0, a longer larval stage duration in F1, and reduced fertility and survival. The intrinsic rate of increase (r), finite rate of increase (λ), and net reproductive rate (R0) were reduced in F1, with the greatest reduction observed in the chlorpyrifos treatment. In the F2 generation, the adverse effects were weakened, only the cyantraniliprole treatment had lower values than the control, and the fecundity of other treatments returned to normal. Obvious “hormesis” phenomena were not observed in any of the generations. Based on the population hazard index, chlorpyrifos had the best control effect in the early stage, and cyantraniliprole had the best control effect in the long term. These results indicate that the LC30 of the six insecticides exert different transgenerational effects on the B. dorsalis population.

The cotton mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) has become a serious threat to agricultural and ornamental plants in Southwest Iran. Pest-control studies have found Nephus hiekei Fursch (Coleoptera: Coccinellidae), in large numbers on Phenacoccus solenopsis Tinsley, as a potential predator. However, there has been no investigation on this predator. In this research, the biology and age-stage, two-sex life table parameters of N. hiekei feeding on Ph. solenopsis were investigated at three constant temperatures (27, 32 and 37 ± 1 °C, 65 ± 5% RH and a photoperiod of 16: 8 (L: D) h. The duration of total pre-adult stage was found to decrease raising temperature from 26.98 ± 0.36 days at 27 °C to 14.24 ± 0.27 days at 37 °C. The oviposition period lasted 63.95 ± 3.14, 66.42 ± 3.34 and 25.20 ± 1.59 days at 27, 32, and 37 °C, respectively. Females laid an average of 365.68 ± 22.36, 543.79 ± 27.27 and 106.25 ± 6.38 eggs, at these three temperatures, respectively. The intrinsic rate of increase (rm = 0.1333 ± 0.0050 d–1), finite rate of increase (λ = 1.1423 ± 0.0057 d–1) and net reproductive rate (R0 = 188.89 ± 28.34 offspring) as well as gross reproductive rate (GRR = 308.31 ± 39.54 offspring) were greatest at 32 °C. The shortest mean generation time (T = 26.74 ± 0.65 days) was recorded at 37 °C and the longest at 27 °C (T = 56.48 ± 1.0 days). These results indicate that N. hiekei can successfully survive and reproduce at temperatures of around 32 °C, and has good potential to be an effective biological control agent of Ph. solenopsis.

Modelling in demographic ecology offers insights into population stability and instability in village societies. In this study we explore the hypothesis that among storage dependent fisher-hunter-gatherers, access to high resource diversity favors reduced demographic volatility over time. To better understand this relationship, we generate summed probability distributions (SPDs) from legacy radiocarbon records to model the population histories of Middle to late Holocene groups residing in the Mid-Fraser Canyon and the Lower Fraser Valley, British Columbia. Our analysis indicates that Lower Fraser populations (with high subsistence resource diversity) were highly stable after 4000 years ago. In contrast, Mid-Fraser populations (with lower subsistence resource diversity) were very low 2000–4000 cal. BP, peaked at high densities by ca. 1200–1300 cal. BP, and were again low until the final centuries before first contacts with Europeans. We argue that climate related impacts on anadromous fish resources likely affected Mid-Fraser populations to a more substantial degree than those of the Lower Fraser. These results offer wider implications concerning demographic volatility and its effects on cultural stability and social change. Our study offers a means by which legacy radiocarbon data may be studied using a permutation-based statistical inference of SPDs.

Predator-prey interactions present heightened opportunities for pathogen spillover, as predators are at risk of exposure to infectious agents harbored by prey. Epizootics with high morbidity and mortality have been recorded following prey-to-predator spillover events, which have had significant conservation implications for sensitive species. Using felids as a detailed case study, we have documented both virulent and clinically silent infections in apex predators following transfer of microbes from prey. We draw on these examples and others to examine the mechanisms that determine frequency and outcome of predator exposure to prey-based pathogens. We propose that predator-prey dynamics should be more thoroughly considered in empirical research and disease dynamic modeling approaches in order to reveal answers to outstanding questions relating to pathogen bioaccumulation.

The small brown planthopper (SBPH), Laodelphax striatellus (Fallen), is an economically important pest that affects rice. In this study, we analyzed the sublethal effects of triflumezopyrim on the biological and demographic parameters of SBPHs in the laboratory. Treatment of third-instar SBPHs with the LC30 of triflumezopyrim prolonged the lives of male adults. The F0 individuals exhibited a significant decrease in fecundity (25.8%) after exposure to triflumezopyrim. The fecundity and egg hatchability of the progeny (F1 individuals) were not significantly affected by treatment with the LC30 of triflumezopyrim, but the mean generation time increased significantly. In addition, the intrinsic rate of increase, finite rate of increase, net reproductive rate, and doubling time did not exhibit any significant changes. However, long-term exposure to the LC75 of triflumezopyrim resulted in a significant decrease in the number of males in the SBPH population. The results of this study indicate that triflumezopyrim can be utilized in pest control programs for SBPHs.

Metabolism controls the pace of life, driving major ecological patterns. We propose that the scaling of metabolism with temperature influences neutral processes of community assembly by controlling population dynamics independently of species identities. This perspective provides new insights into the prevalence of niche and neutral processes through universal energetic constraints.

The invasive herb Lupinus polyphyllus has been focus of a number of fact sheets worldwide but a comprehensive summary of the species’ taxonomy and morphology, distribution, habitat requirements, and biology has been lacking. This paper gives a thorough account of the species’ systematic position and taxonomy, highlighting the difficulties to delimit taxa, which is related to interbreeding among members of this genus. However, L. polyphyllus var. polyphyllus is apparently the taxon that has naturalized and is regionally invasive in temperate-humid climates worldwide. We also present an updated distribution map of L. polyphyllus in the native and invaded ranges, which highlights seven regions in the world where the species has been established. We show that the climatic niche of L. polyphyllus in the invaded range shifts towards higher summer precipitation and lower isothermality, probably because the invaded range includes subcontinental regions of eastern Europe and western Siberia. The habitats of L. polyphyllus range from rather dry to wet, have moderately acidic to strongly acidic soils, and the species’ indicator values across Europe suggest that it occurs along a gradient from very nutrient poor sites to intermediate to rich sites from northern to southern Europe. The species shows high resistance to both drought and frost. In Central Europe, the species has a stronghold in alpic mountain hay meadows, abandoned meadows and pastures, low and medium altitude hay meadows, anthropogenic herb stands and temperate thickets and scrubs. In northern Europe, the species occurs in anthropogenic herb stands along roads and railroads as well as in abandoned pastures and fields. We also found some doubtful information about L. polyphyllus in the literature. This refers to its description as “rhizomatous perennial” although it lacks rhizomes; an apparently very high longevity of its seeds, which may only be true under artificial conditions in an ex situ seed repository; and a very deep rooting depth, which may not represent the average rooting depth but rather an extreme value. Knowledge about the interrelationships between the species’ future population dynamics and spread and ongoing climate warming is lacking. Finally, our review points out that there is currently no evidence-based strategy for a cost-efficient management of L. polyphyllus although it is among the most problematic non-native plant species in Europe due to its environmental and socio-economic impacts.

Carrying capacity is a key concept in ecology. A body of theory, based on the logistic equation, has extended predictions of carrying capacity to spatially distributed, dispersing populations. However, this theory has only recently been tested empirically. The experimental results disagree with some theoretical predictions of when they are extended to a population dispersing randomly in a two-patch system. However, they are consistent with a mechanistic model of consumption on an exploitable resource (consumer-resource model). We argue that carrying capacity, defined as the total equilibrium population, is not a fundamental property of ecological systems, at least in the context of spatial heterogeneity. Instead, it is an emergent property that depends on the population's intrinsic growth and dispersal rates.

Bacteria invest in a slow-growing subpopulation, called persisters, to ensure survival in the face of uncertainty. This hedging strategy is remarkably similar to financial hedging, where diversifying an investment portfolio protects against economic uncertainty. We provide a new, to our knowledge, theoretical foundation for understanding cellular hedging by unifying the study of biological population dynamics and the mathematics of financial risk management through optimal control theory. Motivated by the widely accepted role of volatility in the emergence of persistence, we consider several models of environmental volatility described by continuous-time stochastic processes. This allows us to study an emergent cellular hedging strategy that maximizes the expected per capita growth rate of the population. Analytical and simulation results probe the optimal persister strategy, revealing results that are consistent with experimental observations and suggest new opportunities for experimental investigation and design. Overall, we provide a new, to our knowledge, way of conceptualizing and modeling cellular decision making in volatile environments by explicitly unifying theory from mathematical biology and finance.

Cooperation significantly impacts a species’ population dynamics as individuals choose others to associate with based upon fitness opportunities. Models of these dynamics typically assume that individuals can freely move between groups. Such an assumption works well for facultative co-operators (e.g. flocking birds, schooling fish, and swarming locusts) but less so for obligate co-operators (e.g. canids, cetaceans, and primates). With obligate co-operators, the fitness consequences from associations are stronger compared to facultative co-operators. Consequently, individuals within a group should be more discerning and selective over their associations, rejecting new members and even removing current members. Incorporating such aspects into population models may better reflect obligately cooperative species. In this paper, we create and analyze a model of the population dynamics of obligate co-operators. In our model, a behavioral game determines within-group population dynamics that then spill over into between-group dynamics. Our analysis shows that group number increases when population dynamics are stable, but additional groups lead to unstable population dynamics and an eventual collapse of group numbers. Using a more general analysis, we identify a fundamental mismatch between the stability of the behavioral dynamics and the stability of the population dynamics. When one is stable, the other is not. Our results suggest that group turnover may be inherent to the population dynamics of obligate co-operators. The instability arises from a non-chaotic deterministic process, and such dynamics should be predictable and testable.

Carposina sasakii Matsumura (Lepidoptera: Carposinidae), is one of the most serious fruit-boring pests in over ten species of fruit trees, and is especially damaging apples in the northern of China. The application of new planting systems, i.e., high-density and dwarfing rootstock orchard systems with mixed apple varieties, makes it important to study the fitness of C. sasakii on these apple varieties to gain fundamental knowledge for use in pest management involving this insect. In this study, life table data of C. sasakii were collected using Golden Delicious and Red Fuji apples as hosts. The egg-larva duration of male C. sasakii reared on Golden Delicious apples (22.81 d) was significantly shorter than that reared on Red Fuji apples (24.27 d). The egg-larva mortality in Golden Delicious apples (59.00%) was lower than that in Red Fuji apples (72.49%). The mortality of the pupal stage, however, was higher in Golden Delicious (10.51%) than in Red Fuji (0%). The total oviposition period (TPOP) on Golden Delicious apples (32.94 d) was significantly shorter than in individuals reared on Red Fuji apples (34.19 d). The intrinsic rate of increase (r = 0.0581 d−1), net reproductive rate (R0 = 7.57 offspring), and finite rate of increase (λ = 1.0598 d−1) were all higher on Golden Delicious than those on Red Fuji. When the net reproductive rate (R0) was used, the harvest rate of pupae was higher (0.8678) when reared on Golden Delicious apples than when reared on Red Fuji apples (0.8398). When a large cohort size (n = 200) was used for effective bootstrap sample, the PE values for C. sasakii reared on Golden Delicious apples and Red Fuji apples were both almost equal to 1. For C. sasakii culturing purposes, Golden Delicious apples would be more productive than Red Fuji.

Amblyseius eharai, a native predatory mite in Korea, has a potential as a biological control agent for small-sized pests. However, its ecological characteristics remain unclear. Thus, the objective of this study was to construct temperature-dependent development and oviposition models of A. eharai and evaluate its life table parameters. Its development was examined at 11 temperatures (18.0, 20.1, 21.6, 24.0, 24.1, 27.4, 28.6, 30.2, 32.0, 33.2, and 35.9 °C). The life table analysis was conducted using experimental data from 6 temperatures (18.0, 21.6, 24.1, 27.4, 30.2, and 33.2 °C). Development and fecundity of A. ehari were well described by the Briere 1 model and an extreme value function, respectively. The intrinsic rate of increase (r) was the highest (0.2619) at 27.4 °C and the lowest (0.0792) at 18.0 °C. Based on r values of A. eharai obtained in this study and published information of Calepitrimerus vitis, A. ehari has higher r values than C. vitis. A. eharai appears to have good potential as a biological control agent against C. vitis in vineyards.

Introduction In order to care for an increasingly diverse population, the surgical workforce must improve in gender, racial, and ethnic diversity. We aim to identify deficiencies in the surgical pipeline. Methods Data from the United States Census, Bureau of Labor Statistics, and Association of American Medical Colleges were collected from 2004 to 2018, and evaluated for changing population over time. Results Women comprise 51% of the population, 32% of surgeons, and representation is increasing at a rate of 0.4% per year. 13% of the population and 6% of surgeons are black, and representation is decreasing at a rate of −0.1% per year. Hispanics represent 18% of the population, 6% of surgeons, and representation is increasing at a rate of 0.04% per year. Conclusions While the proportion of women and Hispanic surgeons is slowly increasing, the proportion of black surgeons is decreasing. Recruitment methods need to be focused to improve surgical workforce diversity.

Background Context fear memory dysregulation is a hallmark symptom of several neuropsychiatric disorders, including generalized anxiety disorder and posttraumatic stress disorder. The hippocampus (HC) and prelimbic (PrL) subregion of the medial prefrontal cortex have been linked with context fear memory retrieval in rodents, but the mechanisms by which HC-PrL circuitry regulates this process remain poorly understood. Methods Spatial and genetic targeting of HC-PrL circuitry was used for RNA sequencing (n = 31), chemogenetic stimulation (n = 44), in vivo calcium imaging (n = 20), ex vivo electrophysiology (n = 8), and molecular regulation of plasticity cascades during fear behavior (context fear retrieval) (n = 16). Results We showed that ventral HC (vHC) neurons with projections to the PrL cortex (vHC-PrL projectors) are a transcriptomically distinct subpopulation compared with adjacent nonprojecting neurons, and we showed complementary enrichment for diverse neuronal processes and central nervous system–related clinical gene sets. We further showed that stimulation of this population of vHC-PrL projectors suppresses context fear memory retrieval and impairs the ability of PrL neurons to dynamically distinguish between distinct phases of fear learning. Using transgenic and circuit-specific molecular targeting approaches, we demonstrated that unique patterns of activity-dependent gene transcription associated with brain-derived neurotrophic factor signaling within vHC-PrL projectors causally regulated activity in excitatory and inhibitory PrL neurons during context fear memory retrieval. Conclusions Together, our data show that activity-dependent brain-derived neurotrophic factor release from molecularly distinct vHC-PrL projection neurons modulates postsynaptic signaling in both inhibitory and excitatory PrL neurons, modifying activity in discrete populations of PrL neurons to suppress freezing during context fear memory retrieval.

This paper considers predator-prey systems in which the predator moves between two patches. One patch is a source, where the predator and prey can persist, while the other is a sink where the predator cannot survive. Our aim is to show whether or not the dispersal is beneficial to the predator's total abundance at equilibrium. Using dynamical systems theory, we demonstrate conditions under which a dispersing predator can persist. Our analysis shows that the predator equilibrium abundance at intermediate dispersal rates can be higher than that without dispersal, while extremely large or small dispersal rates could result in predator's extinction. Moreover, we find an explicit expression for the total abundance, which clearly shows the role of dispersal rates and asymmetry on the predator's abundance. Numerical simulations confirm and extend our results.

Objectives: To assess levels of numerical, structural, timing and spatial aspects of ageing of the Aboriginal and Torres Strait Islander population. Methods: Population projections for 15 Australian regions were created by a multi‐state cohort‐component model. Results: The older (45‐plus) population grew from 29,815 in 1986 to 167,259 in 2016. In the subsequent 30 years, we project growth to 448,785 people. Growth rates of the older population vary: from 200% in the 60–64‐year‐old group to 800% growth in the 85‐plus age group by mid‐century. This strong numerical ageing is reflected in a shift in structural ageing by about six percentage points. Selected areas outside of capital cities are structurally older than many cities. Numerical ageing is strongest in capital cities and New South Wales. Cohort flow is the primary driver of ageing. Conclusions: Numerical and structural ageing is projected to increase significantly to mid‐century with important spatial variations. Population ageing is largely irreversible. Implications for public health: High numerical growth in the older Aboriginal and Torres Strait Islander population poses implications for increased demand for a range of health and care services. Variations in spatial and timing aspects of ageing indicate demand will peak earlier in some geographical locations relative to others.

In (st)age-structured populations, the long-run population growth rate is negatively affected by temporal variation in vital rates. In most cases, natural selection should minimize temporal variation in the vital rates to which the long-run population growth is most sensitive, resulting in demographic buffering. By reviewing empirical studies on demographic buffering in wild populations, we found overall support for this hypothesis. However, we also identified issues when testing for demographic buffering. In particular, solving scaling problems for decomposing, measuring, and comparing stochastic variation in vital rates and accounting for density dependence are required in future tests of demographic buffering. In the current context of climate change, demographic buffering may mitigate the negative impact of environmental variation and help populations to persist in an increasingly variable environment. This article is available under the Creative Commons CC-BY-NC-ND license and permits non-commercial use of the work as published, without adaptation or alteration provided the work is fully attributed.

Classical stochastic demography predicts that environmental stochasticity reduces population growth rates and, thereby, can increase extinction risk. In contrast, in a 1978 Theoretical Population Biology paper, Gillespie demonstrated with his stochastic additive scale and concave fitness function (SAS-CFF) model that environmental stochasticity can promote genetic diversity. Extending the SAS-CFF to account for demography, I examine the simultaneous effects of environmental stochasticity on genetic diversity and population persistence. Explicit expressions for the per-capita growth rates of rare alleles and the population at low-density are derived. Consistent with Gillespie’s analysis, if the log-fitness function is concave and allelic responses to the environment are not perfectly correlated, then per-capita growth rates of rare alleles are positive and genetic diversity is maintained in the sense of stochastic persistence i.e. allelic frequencies tend to stay away from zero almost-surely and in probability. Alternatively, if the log-fitness function is convex, then per-capita growth rates of rare alleles are negative and an allele asymptotically fixates with probability one. If the population’s low-density, per-capita growth rate is positive, then the population persists in the sense of stochastic persistence, else it goes asymptotically extinct with probability one. In contrast to per-capita growth rates of rare alleles, the population’s per-capita growth rate is a decreasing function of the concavity of the log-fitness function. Moreover, when the log-fitness function is concave, allelic diversity increases the population’s per-capita growth rate while decreasing the per-capita growth rate of rare alleles; when the log-fitness function is convex, environmental stochasticity decreases the per-capita growth rate of rare alleles, but increases the population’s per-capita growth rate. Collectively, these results (i) highlight how mechanisms promoting population persistence may be at odds with mechanisms promoting genetic diversity, and (ii) provide conditions under which population persistence relies on existing standing genetic variation.

Turtles and tortoises (chelonians) have been integral components of global ecosystems for about 220 million years and have played important roles in human culture for at least 400,000 years. The chelonian shell is a remarkable evolutionary adaptation, facilitating success in terrestrial, freshwater and marine ecosystems. Today, more than half of the 360 living species and 482 total taxa (species and subspecies combined) are threatened with extinction. This places chelonians among the groups with the highest extinction risk of any sizeable vertebrate group. Turtle populations are declining rapidly due to habitat loss, consumption by humans for food and traditional medicines and collection for the international pet trade. Many taxa could become extinct in this century. Here, we examine survival threats to turtles and tortoises and discuss the interventions that will be needed to prevent widespread extinction in this group in coming decades.

Frankliniella occidentalis (Pergande) is a major insect pest of greenhouse crops such as leaf vegetables, flowers and vegetable fruits worldwide. The life history characteristics of F. occidentalis were investigated at control temperature and humidity (27.3 ± 0.54 °C, 79.9 ± 2.79% RH) (mean ± SD), a 10 °C-range fluctuation in temperature (27.1 ± 5.28 °C, 81.5 ± 4.03% RH), a 20 °C-range fluctuation in temperature (26.5 ± 10.09 °C, 80.4 ± 5.76% RH), a 20%-range fluctuation in humidity (26.8 ± 0.37 °C, 80.7 ± 9.55% RH) and a 30%-range fluctuation in humidity (27.3 ± 0.41 °C, 76.3 ± 15.28% RH). Overall, the life history traits of F. occidentalis were more negatively affected by fluctuating environmental conditions. The impact of temperature fluctuation was more severe than that of humidity fluctuation. Additionally, the degree of impact increased as the fluctuation range of the temperature increased, while the reverse trend was observed with humidity fluctuations. With the 20 °C-range fluctuation in temperature, F. occidentalis died at the 1st instar larval stage. The offspring’s sex ratio was significantly higher at the 20%- and 30%-range fluctuations in humidity (0.47 and 0.49, respectively) compared to the control (0.35) and at the 10 °C-range fluctuation in temperature (0.33). From the fertility life table analysis, the intrinsic rate of increase (r) was higher at the 30%-range fluctuation in humidity and control conditions as 0.218 and 0.205, respectively. At the 10 °C-range fluctuation in temperature conditions, r was significantly lower as 0.169. High fluctuations in temperature and low fluctuations in humidity appear to be the best conditions for controlling F. occidentalis populations in greenhouses.

Seven species of flying foxes of the genus Pteropus have been described from the Caroline Islands and Mariana Islands of Micronesia. Among the five extant species, P. ualanus of Kosrae is the least studied. We review the history of research on P. ualanus and summarize data from recent surveys. Early historical accounts suggest that P. ualanus was abundant until a severe population bottleneck, attributed to an infectious disease, allegedly reduced the population to two individuals during 1926–1927. During 1982 and 1983, we found three colonies and a minimum of 600–700 bats in the mountains. Subsequently two new colonies became established in coastal localities by 1994 and 2002 and currently represent the largest colonies. During 2013 and 2014, Hayes visited four confirmed and two possible colonies (three in the mountains, three along the coast) ranging in size from two to 1038 individuals and counted a minimum of 1765 individuals. Long-term changes occurred in the size of colonies. Because not all individuals were counted and at least one other colony likely exists, the population probably exceeds 2000 and may exceed 3000 individuals. The population may not have reached its carrying capacity and may still be increasing. Potential existential threats include infectious disease, typhoons, overhunting, and habitat loss.

High-quality palaeoenvironmental proxies and well-preserved archaeological record make Fennoscandia as an excellent area for the studies of long-term human-environment interaction in high-latitude settings. Here, we use palaeoenvironmental data and temporal frequency distributions of 754 shoreline dated hunter-gatherer sites to analyse the relationship between environmental changes and hunter-gatherer population dynamics, mobility, social organisation, and conflicts in the Baltic Sea coast of western Finland. Our results suggest, firstly, that hunter-gatherer population dynamics were strongly influenced by changes in the productivity of terrestrial and marine environments. Secondly, the degree of residential mobility, as indicated by the frequency of house pit sites, was correlated with population size. Thirdly, large villages and large co-residential units were tightly associated with the highest population size and their frequency dropped sharply when population size started to decrease. Fourthly, intensity of conflicts, as indicated by frequency of defensive structures, was the highest slightly after the highest population sizes, when environmental productivity had started to decline. Increased conflicts were probably caused by the imbalance between human population and its resources. Lastly, dramatic population crash (76% within 200 years) occurred just after the intensity peak in conflicts. The crash was partly density dependent (conflicts) and partly density independent phenomenon as it coincided with the onset of the Late Holocene acceleration in the cooling trend in climate. Continuing decline in the environmental productivity during the Late Holocene did not allow hunter-gatherer population to recover from the collapse. All this highlights the importance of environmental forcing on hunter-gatherer populations in northern Europe.

Purpose This study was designed to examine the extent to which parents' allostatic load (AL) and adolescents' perceived discrimination are interrelated in the prediction of adolescents' AL among rural-to-urban migrants in China, as well as the possible buffering role of social support. Methods Multi-informant data were collected in this study. A total of 158 rural-to-urban migrant adolescents (Meanage = 11.62 years) and one of each of their parents (Meanage = 39.84 years) were recruited from the suburbs of Beijing, China. Both adolescents' and parents' AL scores were based on 10 physiological indices. Migrant adolescents were asked to report their perceived discrimination and social support. Results Parents' AL was significantly positively related to adolescents' AL. The relationship between parents' and adolescents' AL was stronger among adolescents reporting higher perceived discrimination than among those reporting lower. Social support moderated the adverse effects of parents' AL and perceived discrimination on adolescents' AL. Specifically, among adolescents reporting higher social support, the relationships between parents' and adolescents' AL were not significant for those with either high or low perceived discrimination. However, among adolescents reporting lower social support, the positive association was significant for those with high perceived discrimination but not for those with low perceived discrimination. Conclusions Parents' AL was a strong predictor of migrant adolescents' AL, and perceived discrimination acted as a catalyst to increase the association. The relationships of parental AL and perceived discrimination with AL were not significant for adolescents who received high social support.

Residential mobility has become a common experience for people in most parts of the world. As the number of people moving to different cities, states, and countries increases, it is critical to understand how this residential mobility affects one's thoughts, emotions, and actions. Psychological research on residential mobility over a decade is such an endeavor. We briefly summarize the earlier research in psychology that demonstrated the importance of residential mobility in understanding important psychological constructs such as self-concepts, social relationships, and well-being. We then review recent evidence in psychology and relevant fields that replicated and extended the earlier research. We discuss what is missing in the current literature and what additional research is needed in the future.

Microbial cells in nature live within dense multispecies conglomerates, forming a self-organizing ecosystem. In such assemblies, genotypes interact with each other in a myriad of ways, driving community dynamics and functionalities. The role of interactions between genotypes and their consequences for spatial structure and functional outcomes are being increasingly studied to understand the ecology and evolution of microbial communities. An increasing body of work with simple microbial populations has elucidated that phenotypic variation, that is, differences within isogenic cells can have important consequences for population dynamics and evolution. However, the role of individual level behavioral differences for community level dynamics is relatively unknown. I argue that it is necessary to study phenotypic variation and microscale processes in order to understand the emergence and consequences of interactions within microbial communities. I highlight possible explanations that can explain the emergence of variation in multi-genotypic assemblages and propose possible consequences on community dynamics.

This paper discusses the recent progress in understanding the properties of transient dynamics in complex ecological systems. Predicting long-term trends as well as sudden changes and regime shifts in ecosystems dynamics is a major issue for ecology as such changes often result in population collapse and extinctions. Analysis of population dynamics has traditionally been focused on their long-term, asymptotic behavior whilst largely disregarding the effect of transients. However, there is a growing understanding that in ecosystems the asymptotic behavior is rarely seen. A big new challenge for theoretical and empirical ecology is to understand the implications of long transients. It is believed that the identification of the corresponding mechanisms along with the knowledge of scaling laws of the transient's lifetime should substantially improve the quality of long-term forecasting and crisis anticipation. Although transient dynamics have received considerable attention in physical literature, research into ecological transients is in its infancy and systematic studies are lacking. This text aims to partially bridge this gap and facilitate further progress in quantitative analysis of long transients in ecology. By revisiting and critically examining a broad variety of mathematical models used in ecological applications as well as empirical facts, we reveal several main mechanisms leading to the emergence of long transients and hence lays the basis for a unifying theory.

This paper analyzes source–sink systems with asymmetric dispersal between two patches. Complete analysis on the models demonstrates a mechanism by which the dispersal asymmetry can lead to either an increased total size of the species population in two patches, a decreased total size with persistence in the patches, or even extinction in both patches. For a large growth rate of the species in the source and a fixed dispersal intensity, (i) if the asymmetry is small, the population would persist in both patches and reach a density higher than that without dispersal, in which the population approaches its maximal density at an appropriate asymmetry; (ii) if the asymmetry is intermediate, the population persists in both patches but reaches a density less than that without dispersal; (iii) if the asymmetry is large, the population goes to extinction in both patches; (iv) asymmetric dispersal is more favorable than symmetric dispersal under certain conditions. For a fixed asymmetry, similar phenomena occur when the dispersal intensity varies, while a thorough analysis is given for the low growth rate of the species in the source. Implications for populations in heterogeneous landscapes are discussed, and numerical simulations confirm and extend our results.

Marshallagia marshalli is a multi-host gastrointestinal nematode that infects a variety of artiodactyl species from temperate to Arctic latitudes. Eggs of Marshallagia are passed in host faeces and develop through three larval stages (L1, L2, and L3) in the environment. Although eggs normally hatch as L1s, they can also hatch as L3s. We hypothesised that this phenotypic plasticity in hatching behaviour may improve fitness in subzero and highly variable environments, and this may constitute an evolutionary advantage under current climate change scenarios. To test this, we first determined if the freeze tolerance of different free-living stages varied at different temperatures (−9 °C, −20 °C and −35 °C). We then investigated if there were differences in freeze tolerance of M. marshalli eggs sourced from three discrete, semi-isolated, populations of wild bighorn and thinhorn sheep living in western North America (latitudes: 40°N, 50°N, 64°N). The survival rates of eggs and L3s were significantly higher than L1s at −9 °C and −20 °C, and survival of all three stages decreased significantly with increasing freeze duration and decreasing temperature. The survival of unhatched L1s was significantly higher than the survival of hatched L1s. There was no evidence of local thermal adaptation in freeze tolerance among eggs from different locations. We conclude that developing to the L3 in the egg may result in a fitness advantage for M. marshalli, with the egg protecting the more vulnerable L1 under freezing conditions. This phenotypic plasticity in life-history traits of M. marshalli might be an important capacity, a potential exaptation capable of enhancing parasite fitness under temperature extremes.

Pediculus humanus capitis are human ectoparasites which cause infestations, mostly in children, worldwide. Understanding the life cycle of head lice is an important step in knowing how to treat lice infestations, as the parasite behavior depends considerably on its age and gender. In this work we propose a mathematical model for head lice population dynamics in hosts who could be or not quarantined and treated. Considering a lice population structured by age and gender we formulate the model as a system of hyperbolic PDEs, which can be reduced to compartmental systems of delay or ordinary differential equations. Besides studying fundamental properties of the model, such as existence, uniqueness and nonnegativity of solutions, we show the existence of (in certain cases multiple) equilibria at which the infestation persists on the host’s head. Aiming to assess the performance of treatments against head lice infestations, by mean of computer experiments and numerical simulations we investigate four possible treatment strategies. Our main results can be summarized as follows: (i) early detection is crucial for quick and efficient eradication of lice infestations; (ii) dimeticone-based products applied every 4 days effectively remove lice in at most three applications even in case of severe infestations and (iii) minimization of the reinfection risk, e.g. by mean of synchronized treatments in families/classrooms is recommended.

Objective To compare publicly available information on aged care systems in 7 countries to determine the degree of transferability for research on aged care between these countries. Design A cross-country comparative analysis. Setting Aged care systems in 7 countries classified as liberal welfare states (Australia, Canada, Japan, New Zealand, Switzerland, United Kingdom, and United States). Measures This study involved the search and review of international data sets, government reports and national statistics, and relevant peer-reviewed literature. Information was extracted for 24 variables at the macro (societal), meso (organizational), and micro (individual) levels to enable a multilevel comparison of aged care systems in each country. Results The structured search identified 63 relevant documents. All 7 countries included in the review were overall generally comparable across the 3 domains with some expected variations. Comparison of information was not possible for all variables owing to a paucity of publicly available information reported in a consistent manner. Using Australia as a reference point, Canada and New Zealand were the most comparable with Australia, followed by the United Kingdom, United States, and Switzerland. Japan was the least comparable country with Australia based on the variables considered. Conclusions and implications This is the most recent collation and detailed comparison of national-level information on aged care systems in countries classified as liberal welfare states. This information provides policy makers in these countries the data necessary to determine the degree contemporary research findings from another country are transferable to their local aged care system. Efforts to improve the health, well-being, and quality of care for older people continue to be hampered by the overall paucity of consistently reported standardized data to enable valid international comparisons. Optimal use of standardized data also requires developing explicit criteria to describe the key factors to be considered in determining transferability of an intervention from 1 country to another.

International audience; There is growing theoretical evidence that spatial structure can affect the ecological and evolutionary outcomes of host-parasite interactions. Locally restricted interactions have been shown in particular to affect host resistance and tolerance. In this study we investigate the evolution of several types of host disease resistance strategies, alone or in combination, in spatially structured populations. We construct a spatially explicit, individual-based stochastic model where hosts and parasites interact with each other in a spatial lattice, and interactions are restricted to a given neighbourhood of varying size. We investigate several host resistance strategies, including constitutive (expressed in all resistant hosts), induced (expressed only upon infection), and combinations thereof. We show that a costly constitutive resistance cannot reach fixation, whereas an inducible resistance strategy may become fixed in the population if the cost remains low, particularly if it impacts host recovery. We also demonstrate that mixed strategies can be maintained in the host population, and that a higher investment in a recovery-boosting inducible resistance allows for a higher investment in a constitutive response. Our simulations reveal that the spatial structure of the population impacts the selection for resistance in a complex fashion. While single strategies of resistance are generally favoured in less structured populations, mixed strategies can sometimes prevail only in highly structured environments, e.g. when combining constitutive and transmission-blocking induced responses Overall these results shed new light on the dynamics of disease resistance in a spatially-structured host-pathogen system, and advance our theoretical understanding of the evolutionary dynamics of disease resistance, a necessary step to elaborate more efficient and sustainable strategies for disease management.

Quantitative fishery harvest strategies in many countries throughout the world are based on maximum sustainable yield (MSY) reference points (RPs); in particular, the fishing mortality rate that produces MSY (i.e. F m s y ) and the population biomass ( B m s y ) that results from fishing at F m s y . There is often great interest in the sensitivity of MSY RPs to their inputs and underlying assumptions. We perturb (i.e. ω ) inputs to generate influence curves which we denote as F m s y ( ω ) and B m s y ( ω ) as functions of ω . We derive diagnostic equations for the slopes of F m s y ( ω ) and B m s y ( ω ) at the origin (i.e. no perturbation). These equations provide a conceptual understanding of how F m s y and B m s y will change in response to changes in inputs, which one does not get from a simple computational sensitivity analysis. We show that a leading factor determining the sensitivity of F m s y is the amount of curvature in the equilibrium yield curve near F m s y . Another leading factor affecting the sensitivity of B m s y is if the stock–recruitment function indicates low density-dependence in recruitment productivity. With some exceptions, we find that F m s y will increase if the body growth rate or asymptotic size increases, 2) proportions mature increase at younger ages, and 3) natural mortality rates decrease and the Ricker stock–recruitment function is used. If the fishery selectivity function of age is monotone increasing then F m s y will also usually increase if peak selectivity is shifted to an older age. Usually the signs of the slopes for B m s y and F m s y are the same.

The objective of this study was to identify migration patterns from an open illicit drug scene (the Downtown Eastside [DTES] neighborhood) and describe factors associated with these migration patterns. Data were derived from three cohorts of people who use illicit drugs in Vancouver, Canada. Defined using latent class growth analysis, we identified four distinct migration trajectory groups: 1) consistently living in the DTES (47.8%); 2) early migration out, with a median time of migrating out of DTES of 5.3 months (21.5%); 3) late migration out, with a median time of migrating out of DTES of 38.0 months (20.1%); and 4) frequent revisit back-and-forth to DTES (10.6%). In a multivariable model, compared to the “consistently living in the DTES” group, factors associated with the “frequent revisit” group included being enrolled in non-pharmacological addiction treatment and having an HCV-positive serostatus. Factors associated with the “early migration out” group included being enrolled in detoxification or in other non-pharmacological addiction treatment, later calendar year, being on income assistance, living in a single room occupancy hotel, and having an HCV-positive serostatus. These findings point to the need for appropriate distribution of services in order to meet the needs of this population.

Rumex dentatus L. and Polygonum glabrum Willd. (Polygonaceae) are important weeds of wheat and rice fields, respectively, in India and Pakistan. Adults and larvae of Galerucella placida Baly (Coleoptera: Chrysomelidae) feed both weeds. Therefore, we studied the biology of G. placida on two weed leaves using age-stage, two-sex life table at 21 °C, 65 ± 5% r.h. and 12L: 12D. We also studied food utilization indices of G. placida on these leaves. Further, we investigated the quantities of nutrients (total carbohydrates, proteins, lipids, amino acids and nitrogen) and antinutrients (total phenols, flavonols and tannins) of the leaves. Correlation analysis suggested that fecundity and the intrinsic rate of increase (rm) of G. placida were positively correlated with nutrients of leaves, while negatively correlated with antinutrients. Faster larval development, higher longevity of adults and greater fecundity of G. placida were recorded on R. dentatus than P. glabrum. The rm was higher on R. dentatus than P. glabrum. The nutrients were greater in R. dentatus than P. glabrum, while antinutrients were lower in R. dentatus than P. glabrum. The growth rate and consumption index were greater on R. dentatus than P. glabrum. The above results suggested that better nutritional quality of R. dentatus than P. glabrum influenced faster larval development, higher longevity of adults and greater fecundity of G. placida on R. dentatus. This study concluded that R. dentatus could be used for mass rearing of G. placida in biocontol program prior to release in fields for control of both these weeds.

The somatic growth of individuals governs many aspects of a species’ life history and is an important parameter in the assessment of populations. Population growth parameters are typically derived by relating the length of individuals to their age, with ages commonly estimated from growth bands formed in calcified structures such as the vertebrae or dorsal fin spines. However, routinely utilized vertebrae aging methods may not be reliable for many elasmobranchs (sharks, rays and skates), motivating alternative approaches. This study evaluates the performance of seven techniques that estimate von Bertalanffy growth parameters from mark-recapture tagging data. Evaluation of the performance was done by applying each estimation technique to: 1) simulated error-free mark-recapture tagging data and comparing the estimated versus known simulated growth parameters; 2) simulated mark-recapture data considering individual growth variability, measurement error, different length-at-capture distributions, as well as different sample sizes and comparing the estimated versus known simulated growth parameters; and 3) mark-recapture data of 14 North Atlantic elasmobranch stocks and discussing the estimated growth parameters with respect to biological plausibility and conventional length-at-age data. All investigated estimation techniques returned the known simulated growth parameters when the data is without error. When errors are introduced in the simulation, Bayesian implementations of Fabens' (BFa) and Francis’ (BFr) methods were found to be most reliable. For the observed mark-recapture data only BFa gave biologically plausible results for all 14 elasmobranch stocks. Overall, the results suggest that BFa is a reliable alternative to conventional length-at-age methods for estimating growth parameters, especially in data-limited situations which commonly occur with elasmobranchs. The only prior information needed is limited expert knowledge on maximum length in the population or stock in question. A user guide is provided to facilitate application of the method., Fisheries Research, 256, ISSN:0165-7836