Population Life Tables Research Articles

The Adaptability of Beet Webworm (Loxostege sticticalis) to Soybeans and Other Different Host Plants

The beet webworm Loxostege sticticalis has caused significant economic losses to the production of agriculture and animal husbandry in China. Preference testing of larva feeding and adult oviposition and flight capability tests were carried out on five host plants: soybean, pigweed, pea, broad bean, and alfalfa. An experimental population life table and population growth trends over the subsequent 200 days were constructed. The test results show that the larvae showed no significant preference among different plants. However, adults lay more eggs on soybeans. The pests failed to complete a generation when fed on broad beans and alfalfas. When fed on pigweed, they showed the shortest larvae development period, the heaviest pupal weight, the longest adult longevity, and the largest egg-laying amount. The net reproductive rate (R0), intrinsic rate of increase (r), finite rate of increase (λ), and simulated population growth trend of the pests fed on pigweed show the highest values, and those fed on peas showed the lowest values. The total flight distance and flight time of adults fed on pigweed and soybeans were significantly greater compared to those fed on peas. In summary, beet webworms fed on pigweed showed the fastest development and reproduction, the largest population, and the strongest flight capability.

Infection with pathogenic fungi is a major threat to the mass production of the parasitoid wasp Habrobracon hebetor: 20 generations under surveillance

Pathogen infection is one of the most important challenges threatening the success of mass rearing of natural enemies either in insectaries or in augmentative biological control programs. In this investigation, we studied the biological and population growth parameters of a naturally infected colony of the parasitoid wasp Habrobracon hebetor (Say) (Hymenoptera: Braconidae) over 20 generations (G1inf − G20inf) of rearing on Ephestia kuehniella (Zeller) (Pyralidae: Lepidoptera) under laboratory conditions. Based on morphological characteristics and ITS sequences, two types of fungal colonies were isolated from the diseased females and identified as Thermothielavioides terrestris and Aspergillus flavus. The results showed that although no significant differences were found in the female longevity and fecundity of H. hebetor on E. kuehniella up to G15inf, the duration of the immature period was extended as the number of generations increased. In addition, the intrinsic rate of increase (r) and finite rate of increase (λ) had no significant differences up to G8inf. The net reproductive rate (R0) of G15inf had no significant differences with G2inf, G8inf, and G10inf. On the other hand, in G15inf, R0 was significantly higher than G4inf, G6inf, and G20inf. The findings underscore the negative impact of fungal infection on population growth parameters compared with uninfected population. This study showed that naturally fungal infection of the parasitoid affected the population growth and life table parameters through mass rearing, compared and discussed with the healthy parasitoid.

Tree-based analysis of longevity predictors and their ten-year changes: a 35-Year mortality follow-up

BackgroundPrior studies on longevity often examine predictors in isolation and rely solely on baseline information, limiting our understanding of the most important predictors and their dynamic nature. In this study, we used an innovative regression tree model to explore the common characteristics of those who lived longer than their age and sex peers in 35-years follow-up. We identified different pathways leading to a long life, and examined to how changes in characteristics over 10 years (from 1979 to 1989) affect the findings on longevity predictors.MethodsData was obtained from the “Tampere Longitudinal Study on Ageing” (TamELSA) in Finland. Survey data was collected in 1979 from 1056 participants aged 60–89 years (49.8% men). In 1989, a second survey was conducted among 432 survivors from the 1979 cohort (40.2% men). Dates of death were provided by the Finnish Population Register until 2015. We employed an individual measure of longevity known as the realized probability of dying (RPD), which was calculated based on each participant’s age and sex, utilizing population life tables. RPD is based on a comparison of the survival time of each individual of a specific age and sex with the survival time of his/her peers in the total population. A regression tree analysis was used to examine individual-based longevity with RPD as an outcome.ResultsThis relative measure of longevity (RPD) provided a complex regression tree where the most important characteristics were self-rated health, years of education, history of smoking, and functional ability. We identified several pathways leading to a long life such as individuals with (1) good self-rated health (SRH), short smoking history, and higher education, (2) good SRH, short smoking history, lower education, and excellent mobility, and (3) poor SRH but able to perform less demanding functions, aged 75 or older, willing to do things, and sleeping difficulties. Changes in the characteristics over time did not change the main results.ConclusionThe simultaneous examination of a broad range of potential predictors revealed that longevity can be achieved under very different conditions and is achieved by heterogeneous groups of people.

Effect of alfalfa downy mildew (Peronospora aestivalis) infection on the growth and development of Therioaphis trifolii (Homoptera: Aphidiidae)

Downy mildew disease, which is caused by Peronospora aestivalis (Mastigomycotina: Peronosporaceae) and the spotted alfalfa aphid Therioaphis trifolii (Hemiptera: Aphididae), affects Medicago sativa (alfalfa) production. P. aestivalis and T. trifolii frequently occur together under natural conditions. In this study, alfalfa-P. aestivalis-T. trifolii were used as the research objects to explore the effects of different degrees of P. aestivalis infection on the growth and reproduction of T. trifolii, and the life table of T. trifolii population was constructed based on the fecundity parameters. The results revealed that alfalfa downy mildew infection had a significant effect on T. trifolii population. T. trifolii fed on mildly infected alfalfa plants exhibited the longest life span (18.9 d) and the highest number of nymphs (30.6) compared to those fed on alfalfa in other treatments. In terms of population life table parameters, the intrinsic rate of increase (0.626) and finite rate of increase (1.869) of T. trifolii fed on moderately infected alfalfa were the highest, and the generation time (8.310) and population doubling time (1.108) were the shortest, indicating that moderately infected alfalfa are conducive to T. trifolii population development. This study provides insights into the effects of alfalfa downy mildew on the main reproductive parameters and population of T. trifolii on M. sativa.

Life expectancy for dogs from the City of Buenos Aires

The aim of the present study was to develop the first life tables for the dog population of the Autonomous City of Buenos Aires by constructing life expectancy tables. Data on canines received for final disposal at the Luis Pasteur Zoonosis Institute of the Autonomous City of Buenos Aires from January 2018 to December 2021 were used to prepare the life tables. Of the 11,429 dogs that died in that period, the overall life expectancy at birth was 11.88 years (95% CI = 11.37–12.39). There was no difference in life expectancy at birth by sex or by pure versus cross breeds. According to neuter status, life expectancy at birth in neutered (13.98 years) was significantly higher than in entire (11.46 years) (p-value = 0.00001). Life tables varied according to the breed studied, with the Pekingese having the highest life expectancy at birth 16.42 years (95% CI: 15.87–16.98), and the Pit bull having the lowest life expectancy at birth 10.13 years (95% CI: 9.58–10.68). The current study provides useful information for veterinary professionals and pet owners and is a valuable tool for planning and developing effective health policies.

The Burden of Type 2 Diabetes on the Productivity and Economy in Sub-Saharan Africa: A Life Table Modelling Analysis from a South African Perspective.

The prevalence of type 2 diabetes (T2D) is rapidly increasing in Sub-Saharan Africa (SSA). T2D increases the risk of premature death and reduces quality of life and work productivity. This population life table modelling analysis evaluated the impact of T2D in terms of productivity-adjusted life years (PALYs) on the South African working-age population. Life table modelling was employed to simulate the follow-up of individuals aged 20-65 with T2D in South Africa (SA). Two life table models were developed to simulate health outcomes for a SA cohort with and without diabetes. The difference in the number of deaths, years of life lost (YLL), and PALYs lost between the two cohorts represented the burden of diabetes. Scenarios were simulated in which the proportions of gross domestic productivity (GDP), productivity indices, labour force dropout, and mortality risk trends were adjusted to lower and upper uncertainty bounds. Data were sourced from the International Diabetes Federation, Statistics SA, and both publicly available and published sources. We utilised the World Health Organization (WHO) standard annual discount rate of 3% for YLL and PALYs. In 2019, an estimated 9.5% (7.68% men and 11.37% women) or 3.2 million total working-age people had T2D in SA. Simulated follow-up until retirement predicted 669,427 excess mortality, a loss of 6.2 million years of life (9.3%) and 13 million PALYs (30.6%) in SA. On average, this resulted in 3.1 PALYs lost per person. Based on the GDP per full-time employee in 2019, the PALYs loss equated to US$223 billion, or US$69,875 per person. This study emphasises the significant impact of T2D on society and the economy. Relatively modest T2D prevention and treatment management enhancement could lead to substantial economic benefits in SA.

Variations in life history parameters, population dynamics, and transcriptome regulation of Brachionus plicatilis exposed to triclosan

Triclosan (TCS) poses an ecological health risk due to its lipophilic nature, long half-life, and bioconcentration. To evaluate the toxicity of TCS on aquatic organisms, the life history parameters, population dynamics, and transcriptome regulation of Brachionus plicatilis exposed to TCS were investigated. In this study, the fecundity of rotifers was promoted by 25 μg/L of TCS and inhibited by higher concentrations (100 μg/L, 200 μg/L). The reproductive period of rotifers was shortened by 46.24 % but the post-reproductive period was prolonged by 176.47 % in 200 μg/L TCS. Both population growth and life table parameters indicated that a high concentration of TCS (200 μg/L) had negative impacts on population growth. Transcriptomic analysis showed that the effects of TCS on the life history parameters and population dynamics of rotifers were determined by regulating the expression of functional genes in cilium organization and cilium assembly and involved in pathways of focal adhesion.

FIVE BIODEMOGRAPHIC PRINCIPLES OF AGING THAT EMERGED FROM RESEARCH ON THE MEDITERRANEAN FRUIT FLY

Abstract Because of its large size, visually-distinct sex differences, abundance in the wild and ease of rearing at both industrial and individual levels, the Mediterranean fruit fly (medfly) is an ideal model organism for conducting research on the demography of aging. I will present details on and implications for what I consider to be the five most interesting and important aging-related discoveries from the NIA-funded research my colleagues and I conducted over the past three decades using the medfly model. These discoveries include (1)Deceleration of mortality at advanced ages; (2)Equivocality of the gender gap due to context-specific sex mortality relationships; (3)Supine behavior as a biomarker of both morbidity onset and time-to-death; (4)A dietary disconnect between maximizing longevity vs maximizing lifetime reproduction; and (5)the life table population identity in which the fraction age x in a stationary population equals the fraction with x years to live. I will end with brief comments about the use of non-conventional model organisms for research on aging in both the laboratory and the field.

Estimation of the Population Dynamics of Taxus cuspidata by Using a Static Life Table for Its Conservation

Taxus cuspidata is a rare and endangered plant species with an extremely small population which is endemic to China. This study focused on the natural T. cuspidata population in Jilin Province in China. Conventional population ecology survey methods were used to describe its population structure characteristics. Then, we chose diameter structure instead of temporal structure to establish a static population life table, draw a population survival curve, and quantify the future development trend by using population dynamic analysis and time sequence prediction. The results showed that: (1) the static life table suggested that the population of T. cuspidata was stable overall. The population survival curve tended to be Deevey Ⅱ, with a high early seedling mortality, and the later population growth tended to be stable; (2) the survival curve suggested that the population initially experienced higher mortality rates in the early stage. However, as time progressed and the population aged, the mortality rates decreased, resulting in a more stable population in the middle and late stages; (3) The diameter class structure of T. cuspidata was stable overall, and the dynamic indices showed that the population was fluctuating. The population was influenced by external disturbances and showed some resistance to human disturbance; (4) time sequence prediction analysis showed that the mortality rate of young individuals was high, natural renewal could be maintained, and the population size would remain at a certain amount in the future. The result shows that the Jilin region is a highly suitable area for the growth of Taxus cuspidata’s population in Northeast China. We recommend in situ conservation of remaining wild populations, relocation of germplasm resources, and reduction of human activities; these actions will be beneficial to Taxus cuspidata’s long-term survival.

Life expectancy tables for cats from the city of Buenos Aires

The aim of the present study was to develop the first life tables for the domestic feline population of the Autonomous City of Buenos Aires by constructing general cohort tables. To develop the life tables, data from felines received for final disposition at the Luis Pasteur Zoonosis Institute of the city from January 2018 to December 2021 were used. Of the 7945 cats that died in that period, the overall life expectancy at birth was 11.01 years (95% CI=10.55- 11.46 years). When life expectancy was analyzed according to sex, significant differences were found, being higher in females, 12.26 years (95% CI: 11.78- 12.73) than in males, 10.92 years (95% CI: 10.50- 11.35). According to neutered status, life expectancy at birth in the neutered, 13.19 years, was significantly higher than in the entire, 5.55 years (p-value=0.00001). Likewise, life expectancy among purebred cats was significantly higher, 14.81 years (95% CI: 14.51- 15.10), than for cross breed cats, 10.97 years (CI: 10.81- 11.13). Regarding the variations in mortality according to the warm or cold season of the year, no differences were observed between the two seasons. The most prevalent causes of death were related to urinary system failures and neoplasms, over 444 records analyzed. This study provides useful information for veterinary professionals and pet owners and is a valuable tool for the planning and development of effective health policies.

Timely assessment of 5-year relative survival of esophageal cancer patients in Taizhou, Zhejiang province.

Timely assessment of 5-year relative survival of esophageal cancer patients in Taizhou, Zhejiang province.

Estimation of Excess Mortality in Germany During 2020-2022.

Background This study estimates the burden of COVID-19 on mortality in Germany. It is expected that many people have died because of the new COVID-19 virus who otherwise would not have died. Estimating the burden of the COVID-19 pandemic on mortality by the number of officially reported COVID-19-related deaths has been proven to be difficult due to several reasons. Because of this, a better approach, which has been used in many studies, is to estimate the burden of the COVID-19 pandemic by calculating the excess mortality for the pandemic years. An advantage of such an approach is that additional negative impacts of a pandemic on mortality are covered as well, such as a possible pandemic-induced strain on the healthcare system. Methods To calculate the excess mortality in Germany for the pandemic years 2020 to 2022, we compare the reported number of all-cause deaths (i.e., the number of deaths independently of underlying causes) with the number of statistically expected all-cause deaths. For this, the state-of-the-art method of actuarial science, based on population tables, life tables, and longevity trends, is used to estimate the expected number of all-cause deaths from 2020 to 2022 if there had been no pandemic. Results The results show that the observed number of deaths in 2020 was close to the expected number with respect to the empirical standard deviation; approximately 4,000 excess deaths occurred. By contrast, in 2021, the observed number of deaths was two empirical standard deviations above the expected numberand even more than four times the empirical standard deviation in 2022. In total, the number of excess deaths in the year 2021 is about 34,000and in 2022 about 66,000 deaths, yielding a cumulated 100,000 excess deaths in both years. The high excess mortality in 2021 and 2022 was mainly due to an increase in deaths in the age groups between 15 and 79 years and started to accumulate only from April 2021 onward. A similar mortality pattern was observed for stillbirths with an increase of about 9.4% in the second quarter and 19.4% in the fourth quarter of the year 2021 compared to previous years. Conclusions These findings indicate that something must have happened in spring 2021 that led to a sudden and sustained increase in mortality, although no such effects on mortality had been observed during the early COVID-19 pandemic so far. Possible influencing factors are explored in the discussion.

Inequality in quality-adjusted life expectancy by educational attainment in Norway: an observational study

BackgroundHealth inequalities are often assessed in terms of life expectancy or health-related quality of life (HRQoL). Few studies combine both aspects into quality-adjusted life expectancy (QALE) to derive comprehensive estimates of lifetime health inequality. Furthermore, little is known about the sensitivity of estimated inequalities in QALE to different sources of HRQoL information. This study assesses inequalities in QALE by educational attainment in Norway using two different measures of HRQoL.MethodsWe combine full population life tables from Statistics Norway with survey data from the Tromsø study, a representative sample of the Norwegian population aged ≥ 40. HRQoL is measured using the EQ-5D-5L and EQ-VAS instruments. Life expectancy and QALE at 40 years of age are calculated using the Sullivan-Chiang method and are stratified by educational attainment. Inequality is measured as the absolute and relative gap between individuals with lowest (i.e. primary school) and highest (university degree 4 + years) educational attainment.ResultsPeople with the highest educational attainment can expect to live longer lives (men: + 17.9% (95%CI: 16.4 to 19.5%), women: + 13.0% (95%CI: 10.6 to 15.5%)) and have higher QALE (men: + 22.4% (95%CI: 20.4 to 24.4%), women: + 18.3% (95%CI: 15.2 to 21.6%); measured using EQ-5D-5L) than individuals with primary school education. Relative inequality is larger when HRQoL is measured using EQ-VAS.ConclusionHealth inequalities by educational attainment become wider when measured in QALE rather than LE, and the degree of this widening is larger when measuring HRQoL by EQ-VAS than by EQ-5D-5L. We find a sizable educational gradient in lifetime health in Norway, one of the most developed and egalitarian societies in the world. Our estimates provide a benchmark against which other countries can be compared.

Comparative genome and phylogenetic analysis revealed the complex mitochondrial genome and phylogenetic position of Conopomorpha sinensis Bradley

Conopomorpha sinensis Bradley is a destructive pest that causes severe economic damage to litchi and longan. Previous C. sinensis research has focused on population life tables, oviposition selectivity, pest population prediction, and control technology. However, there are few studies on its mitogenome and phylogenetic evolution. In this study, we sequenced the whole mitogenome of C. sinensis by the third-generation sequencing, and analyzed the characteristics of its mitogenome by comparative genome. The complete mitogenome of C. sinensis is a typical circular and double-stranded structure. The ENC-plot analyses revealed that natural selection could affect the information of codon bias of the protein-coding genes in the mitogenome of C. sinensis in the evolutionary process. Compared with 12 other Tineoidea species, the trnA-trnF gene cluster of tRNA in the C. sinensis mitogenome appears to have a new arrangement pattern. This new arrangement has not been found in other Tineoidea or other Lepidoptera, which needs further exploration. Meanwhile, a long AT repeated sequence was inserted between trnR and trnA, trnE and trnF, ND1 and trnS in the mitogenome of C. sinensis, and the reason for this sequence remains to be further studied. Furthermore, the results of phylogenetic analysis showed that the litchi fruit borer belonged to Gracillariidae, and Gracillariidae was monophyletic. The results will contribute to an improved understanding of the complex mitogenome and phylogeny of C. sinensis. It also will provide a molecular basis for further research on the genetic diversity and population differentiation of C. sinensis.

A censored quantile regression approach for relative survival analysis: Relative survival quantile regression.

We propose a censored quantile regression model for the analysis of relative survival data. We create a hybrid data set consisting of the study observations and counterpart randomly sampled pseudopopulation observations imputed from population life tables that adjust for expected mortality. We then fit a censored quantile regression model to the hybrid data incorporating demographic variables (e.g., age, biologic sex, calendar time) corresponding to the population life tables of demographically-similar individuals, a population versus study covariate, and its interactions with the variables of interest. These latter variables can be interpreted as relative survival parameters that depict the differences in failure quantiles between the study participants and their populationcounterparts.

Who live longer than their age peers: individual predictors of longevity among older individuals

BackgroundThere are a very few studies focusing on the individual-based survival with a long follow-up time.AimTo identify predictors and determine their joint predictive value for longevity using individual-based outcome measures.MethodsData were drawn from Tampere Longitudinal Study on Aging (TamELSA), a study of individuals’ age 60–89 years (N = 1450) with a mortality follow-up of up to 35 years. Two measures of longevity were used: the longevity difference (LD) and realized probability of dying (RPD), both of which compare each individual’s longevity with their life expectancy as derived from population life tables. Independent variables were categorized into five domains: sociodemographic, health and functioning, subjective experiences, social activities, and living conditions. Linear regression models were used in three steps: bivariate analysis for each variable, multivariate analysis based on backward elimination for each domain, and one final model.ResultsThe most important predictors of both outcomes were marital status, years smoked regularly, mobility, self-rated health, endocrine and metabolic diseases, respiratory diseases, and unwillingness to do things or lack of energy. The explained variance in longevity was 13.8% for LD and 14.1% for RPD. This demonstrated a large proportion of unexplained error margins for the prediction of individual longevity, even though many known predictors were used.Discussion and conclusionsSeveral predictors associated with longer life were found. Yet, on an individual level, it remains difficult to predict who will live longer than their age peers. The stochastic element in the process of aging and in death may affect this prediction.

Population Fitness of Eupeodes corollae Fabricius (Diptera: Syrphidae) Feeding on Different Species of Aphids.

Simple SummaryAs a candidate for controlling aphid populations, Eupeodes corollae Fabricius also performs a pollination function which is critical to agricultural systems. We evaluated the population life tables and flight performance of E. corollae fed on three prey species (Aphis craccivora Koch, Myzus persicae Sulzer and Megoura japonica Matsumura) to select suitable aphid species for keeping E. corollae indoors. The results showed that E. corollae completed development and reproduction on these three aphid species while achieving the shortest generation time, the maximum fecundity, and the highest intrinsic natural growth rate and flight ability on M. japonica. Our study indicated that M. japonica is the most suitable prey for E. corollae, providing a basis for utilizing the ecological service function of the hoverfly.Eupeodes corollae Fabricius, as one of the most common beneficial predatory insects in agricultural ecosystems, provides pollination and biological control services that help improve crop yield and maintain biodiversity. However, systematic research is needed on the species of aphids used for propagation. To develop highly fit populations of the important insect predator and crop pollinator, E. corollae, for research and commercial use, further research is needed to develop the most nutritious diet and efficient propagation methods. Here, the fitness of E. corollae was assessed in the laboratory after larvae were fed an aphid diet of Aphis craccivora Koch, Myzus persicae Sulzer or Megoura japonica Matsumura. The larval survival rate on M. japonica was significantly lower than on A. craccivora and M. persicae. The developmental duration for larvae (7.6 d) and pupae (6.9 d) was longest on A. craccivora. The pupal emergence rate on A. craccivora (98.0%) was significantly higher than on the other two, and lowest (64.7%) on M. japonica. On A. craccivora, M. persicae, and M. japonica, respectively, the generation time was 24.85 d, 23.12 d and 21.05 d; the value for the intrinsic rate of natural increase was 0.19, 0.20, and 0.21; and the value for the finite rate of increase was 1.21, 1.22, and 1.23. For flight variables, E. corollae attained the fastest velocity and longest distance and duration on M. japonica. The M. japonica diet, thus, provided the shortest generation time, the highest intrinsic rate of natural increase and finite rate of increase, the maximum fecundity and the greatest flight ability. Thus, to improve the survival rate of E. corollae larvae, A. craccivora or M. persicae can be used to feed newly hatched larvae, and M. japonica can be used for second- and third-instar larvae. These results provide a theoretical basis for feeding E. corollae and optimizing its ecosystem services.

Monitoring the lifetime risk of revision knee arthroplasty over a decade : a population-level analysis of Australian national registry data.

This study aimed to describe the use of revision knee arthroplasty in Australia and examine changes in lifetime risk over a decade. De-identified individual-level data on all revision knee arthroplasties performed in Australia from 2007 to 2017 were obtained from the Australian Orthopaedic Association National Joint Replacement Registry. Population data and life tables were obtained from the Australian Bureau of Statistics. The lifetime risk of revision surgery was calculated for each year using a standardized formula. Separate calculations were undertaken for males and females. In total, 43,188 revision knee arthroplasty procedures were performed in Australia during the study period, with a median age at surgery of 69 years (interquartile range (IQR) 62 to 76). In 2017, revision knee arthroplasty rates were highest for males aged 70 to 79 years (102.9 procedures per 100,000 population). Lifetime risk of revision knee arthroplasty for females increased slightly from 1.61% (95% confidence interval (CI) 1.53% to 1.69%) in 2007 to 2.22% (95% CI 2.13% to 2.31%) in 2017. A similar pattern was evident for males, with a lifetime risk of 1.43% (95% CI 1.36% to 1.51%) in 2007 and 2.02% (95% CI 1.93% to 2.11%) in 2017. A decline in procedures performed for loosening/lysis (from 41% in 2007 to 24% in 2017) and pain (from 14% to 9%) was evident, while infection became an increasingly common indication (from 19% in 2007 to 29% in 2017). Well-validated national registry data can help us understand the epidemiology of revision knee arthroplasty, including changing clinical indications. Despite a small increase over a decade, the lifetime risk of revision knee arthroplasty in Australia is low at one in 45 females and one in 50 males. These methods offer a population-level approach to quantifying revision burden that can be used for ongoing national surveillance and between-country comparisons. Cite this article: Bone Joint J2022;104-B(5):613-619.

Life tables of annual life expectancy and mortality for companion dogs in the United Kingdom

A life table is a tabulated expression of life expectancy and mortality-related information at specified ages in a given population. This study utilised VetCompass data to develop life tables for the UK companion dog population and broken down by sex, Kennel Club breed group, and common breeds. Among 30,563 dogs that died between 1st January 2016 and 31st July 2020, life expectancy at age 0 was 11.23 [95% confidence interval (CI): 11.19–11.27] years. Female dogs (11.41 years; 95% CI: 11.35–11.47) had a greater life expectancy than males (11.07 years; 95% CI: 11.01–11.13) at age 0. Life tables varied widely between breeds. Jack Russell Terrier (12.72 years; 95% CI: 12.53–12.90) and French Bulldog (4.53 years; 95% CI: 4.14–5.01) had the longest and shortest life expectancy at age 0, respectively. Life tables generated by the current study allow a deeper understanding of the varied life trajectory across many types of dogs and offer novel insights and applications to improve canine health and welfare. The current study helps promote further understanding of life expectancy, which will benefit pet owners and the veterinary profession, along with many other sectors.

Rapid adaptation of Brachionus dorcas (Rotifera) to tetracycline antibiotic stress.

Although natural populations can rapidly adapt to selection pressures, the fitness consequences of selection are controversial. In this study, a selection experiment was conducted with replicate populations of Brachionus dorcas that were exposed to two sublethal concentrations (26.8 and 78.3mg/L) of oxytetracycline (OTC), followed by two common garden experiments (population growth and life table experiments). During the 102-day (approximately 36 asexual generations) selection experiment, a markedly increased growth rate but a significantly decreased mictic ratio over time in the populations exposed to OTC when compared to the control populations suggested that the former adapted to the selection pressures and that a trade-off exists between asexual and sexual reproduction. The high and stable population growth rates after 90 days of OTC selection illustrate an example of evolutionary rescue. After 102 days of selection, OTC-selected populations showed higher population growth rates than the control populations when exposed to OTC, indicating significantly increased tolerance. OTC-selected populations showed a lower average growth rate, longer average generation time and life expectancy at hatching, and higher average net reproduction rate and proportion of mictic offspring than the control populations in the absence of OTC, which indicate that OTC selection results in two fitness costs and three fitness gains and that the effect of OTC selection on fitness differs with the measured fitness variables. Both the evolutionary potential of populations under the stress of higher concentrations of OTC and the fitness costs and gains of selection in the absence of OTC indicate that past exposures to pollutants cannot be neglected when evaluating the effects of current stressors on natural populations.