Low Longevity Research Articles

The Outcomes of Liver Transplantation in Highly Dependent Incapacitated Patients with Intellectual and Developmental Disabilities.

Background/Objectives: Data regarding the outcomes of liver transplantation in disabled, highly dependent, and legally incapacitated adults are scarce, likely due to the infrequency of these procedures in such populations. Multicenter studies in adult transplant centers have shown that patients with coexisting intellectual and developmental disabilities (IDDs) may be denied transplantation because of their expected low longevity and the complexities associated with managing post-transplant care. We examined the long-term patient and graft outcomes in highly dependent, incapacitated patients with IDDs who underwent elective transplantation for chronic liver disease. Methods: Six adult patients who underwent liver transplantation for primary biliary cholangitis (n = 2), hepatitis C cirrhosis (n = 2), Wilson's disease (n = 1), and autoimmune hepatitis (n = 1) were included. The main causes of their disability were infantile cerebral palsy, myotonia, and Niemann-Pick disease. Results: Four of the six patients were women, with a median age of 26 (range: 23-36) years. Only one patient died during follow-up. Their 1- and 5-year survival rates were 100 and 75%, respectively, which were not statistically different from those of the general cohort of electively transplanted patients (95.8 and 90.1%, respectively) (p = 0.35). Conclusions: Adult patients who are highly dependent, disabled, or legally incapable should not be denied liver transplantation because of poor long-term survival rates. Physiological disorders and psychiatric comorbidities should not prevent patients from receiving life-saving surgeries due to poor postoperative compliance or low quality of life.

Analysis of reproduction success, growth and milk trajectories and response to nutritional challenge in two Alpine goat lines selected on divergent longevity

This study aims to investigate whether the variation in reproduction success, growth, and milk trajectories is associated with different adaptive strategies in the short term (response to an acute nutritional challenge), using two Alpine goat lines. A total of 382 Alpine goats (179 low longevity (low_LGV) and 203 high longevity (high_LGV)), selected for divergent functional longevity from a commercial population, were monitored for 4 years and recorded for BW, reproduction and milking performance. Every year, an average of fifty primiparous goats were exposed to a 2-d nutritional challenge in early lactation. A polynomial model was used to analyse the lifetime trajectory of lactation and BW. A piecewise model was used to analyse the individual milk yield and responses of milk components to the nutritional challenges. The statistical analysis revealed that the two lines had a similar performance for total milk yield in the first lactation, BW at birth and at first kidding, litter size and weight, kidding interval and interval from the first insemination to conception. BW trajectories revealed that low_LGV goats had a greater BW in pregnancy but then lost more weight in early lactation compared to high_LGV goats, which showed a greater BW after kidding. Milk trajectories showed that the high_LGV goats had a higher initial milk yield, an earlier but less marked lactation peak and more persistency in milk production in late lactation than low_LGV goats. Except for milk protein content, quite similar response and recovery profiles of milk yield and milk fat content were observed during the challenge for both lines. The response to the challenge was positively correlated to the initial level of milk production in early lactation but negatively correlated with milk production decline after the peak. This finding suggests that the low_LGV goats were more adapted to allocate resources to meet an expected physiological change such as gestation and lactation. However, high_LGV goats allocate more than low_LGV goats for structural mass and may better cope with an unexpected environmental change such as nutritional deficit.

Multivariate analysis of milk metabolite measures shows potential for deriving new resilience phenotypes

In a context of growing interest in breeding more resilient animals, a noninvasive indicator of resilience would be very valuable. We hypothesized that the time-course of concentrations of several milk metabolites through a short-term underfeeding challenge could reflect the variation of resilience mechanisms to such a challenge. We submitted 138 one-year-old primiparous goats, selected for extreme functional longevity (i.e., productive longevity corrected for milk yield [60 low longevity line goats and 78 high longevity line goats]), to a 2-d underfeeding challenge during early lactation. We measured the concentration of 13 milk metabolites and the activity of 1 enzyme during prechallenge, challenge, and recovery periods. Functional principal component analysis summarized the trends of milk metabolite concentration over time efficiently without preliminary assumptions concerning the shapes of the curves. We first ran a supervised prediction of the longevity line of the goats based on the milk metabolite curves. The partial least square analysis could not predict the longevity line accurately. We thus decided to explore the large overall variability of milk metabolite curves with an unsupervised clustering. The large year × facility effect on the metabolite concentrations was precorrected for. This resulted in 3 clusters of goats defined by different metabolic responses to underfeeding. The cluster that showed higher β-hydroxybutyrate, cholesterol, and triacylglycerols increase during the underfeeding challenge was associated with poorer survival compared with the other 2 clusters. These results suggest that multivariate analysis of noninvasive milk measures show potential for deriving new resilience phenotypes.

Longevity and the association with cattle health in Dutch dairy farms

Longevity of a herd is defined as the average age of all cattle over two years old at the moment of death (either natural, by euthanasia or by slaughter), and is increasing since 2018. The aim of this study was to evaluate the association between longevity and cattle health indicators in Dutch dairy herds. Anonymized census data were available for 16,200 Dutch dairy herds (∼98 % of the dairy herds) between 2016 and 2020. All herds were categorized into one of six longevity groups: herds with a high longevity (>seven years old), increasing longevity (mean increase of one year and two months between 2017 and 2020), median longevity (∼five years and eight months, without major fluctuations in longevity), decreasing longevity (mean decrease eight months), low longevity (<four years and ten months) and a varying longevity of ∼five years and eight months, with fluctuation in longevity throughout the study period. Data were aggregated to herd and quarter of the year level. Cattle health parameters were analysed with multivariable population-averaged models with health indicators as dependent variables, and longevity and other management and herd level factors as explanatory variables. Belonging to the group of herds with a high longevity was associated with lower calf- and cow mortality, a higher percentage of cows with a high somatic cell count (HSCC), fewer inseminations per pregnancy for heifers and more inseminations for cows, a higher antibiotic use in adult dairy cows and a lower antibiotic use in calves compared to the average Dutch dairy herd. Further analysis showed that the higher percentage of cows with a HSCC could be explained by the higher share of older cows. Herds with a low longevity had a higher calf- and cow mortality, a lower percentage of cows with a HSCC, more inseminations for heifers and fewer for cows, lower antibiotic use in cows and higher antibiotic use in calves compared to the average Dutch dairy herd. To conclude, there were differences in cattle health between groups of herds with a different longevity.

GERMINACIÓN Y ASPECTOS MORFOLÓGICOS DE PLÁNTULAS DE Echinocactus platyacanthus Link &amp; Otto TRATADAS CON RAYOS GAMMA

&lt;p&gt;&lt;strong&gt;Background.&lt;/strong&gt; The sweet biznaga (&lt;em&gt;Echinocactus platyacanthus&lt;/em&gt;) is endemic to Mexico, whose seeds show low germination, viability, longevity, genetics, and latency; therefore, gamma irradiation is an alternative to stimulate the emergence and growth of seedlings, by causing variations in the chemical composition of DNA, which causes cytological, biochemical, physiological and morphological changes in plants. &lt;strong&gt;Objective.&lt;/strong&gt; The objective of the present investigation was to evaluate the effect of different doses of gamma &lt;sup&gt;60&lt;/sup&gt;Co radiation on seed germination and seedling vigor of &lt;em&gt;E. platyacanthus&lt;/em&gt;. &lt;strong&gt;Methodology.&lt;/strong&gt; &lt;em&gt;E. platyacanthus&lt;/em&gt; seeds were irradiated at 0, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500 and 550 Gy of &lt;sup&gt;60&lt;/sup&gt;Co gamma rays, then they were sown in transparent plastic containers covered with filter paper and were distributed in a completely randomized design with four repetitions in a germination chamber, the percentage of germination and survival of seedlings in the container was recorded 30 days after sowing (das). The seedlings were transplanted at 30 das into black polyethylene bags with tezontle and established in a completely randomized design with 12 treatments and four replications, in a tunnel-type greenhouse. At 20 and 30 days after transplantation (dat) seedling vigor was measured based on height (cm), stem diameter (mm) and root length (mm) and at 20 dat survival was recorded (%) of seedling in the substrate. An analysis of variance and Tukey's test for comparison of means (p ≤ 0.05) were performed. &lt;strong&gt;Results.&lt;/strong&gt; Gamma irradiation stimulated seed germination from 10 to 29%. In seedlings, root height and length were modified with intermediate doses of gamma rays (100 to 200 Gy); but higher doses negatively affected these indicators. Survival of containerized M&lt;sub&gt;1&lt;/sub&gt; seedlings was up to 63% higher than the control, depending on the irradiation dose. &lt;strong&gt;Implications.&lt;/strong&gt; Irradiation with &lt;sup&gt;60&lt;/sup&gt;Co gamma rays improves seed germination, survival and vigor of &lt;em&gt;E. platyacanthus&lt;/em&gt; seedlings. &lt;strong&gt;Conclusions.&lt;/strong&gt; Irradiation with &lt;sup&gt;60&lt;/sup&gt;Co gamma rays stimulated seed germination and improved some characteristics of vigor in &lt;em&gt;E. platyacanthus&lt;/em&gt; seedlings, by modifying root height and length according to age. In addition, it increased the survival of containerized seedlings.&lt;/p&gt;

Selection on functional longevity in a commercial population of dairy goats translates into significant differences in longevity in a common farm environment

Resilience is the ability of an animal to cope with environmental disturbances, such as pathogens or negative energy balance. To improve resilience through breeding, we need resilience indicators. Functional longevity might be a good indicator of a dairy goat's lifetime resilience as it results from the ability to cope with and recover from all the challenges faced throughout its lifetime. The aim of this study was to validate the use of functional longevity as an indicator of resilience for selection. To address this question, we created 2 genetic lines of Alpine goats using hyperselected artificial insemination bucks with the most extreme estimated breeding values for functional longevity and the same milk yield performance. A total of 440 goats, 228 in the high longevity (high_LGV) and 221 in the low longevity (low_LGV) lines, were bred and monitored for 4 yr. Health treatments, serum IgG concentration as a proxy of passive immune transfer in early life, kidding, age, and reason of culling were systematically noted. Weight and body morphology were monitored. Weight and growth during the first year of life were similar in both goat lines. In contrast, the low_LGV goats had a lower weight during the beginning of first lactation than high_LGV goats. The milk fat-to-protein ratio was also significantly higher in low_LGV goats during first lactation. A multivariable Cox regression was fitted to the data to decipher survival at different stages of life in the 2 lines. The overall survival of high_LGV goats was significantly better than low_LGV goats (hazard ratio = 0.63, confidence interval = 0.47; 0.86) even after we included treatment, growth, serum IgG concentration at birth, and year effects in the model. The line effect was not constant over time; no significant effect was found during the first year, and the difference was observed after first kidding. This result suggested that survival at an early stage of life and during later productive life are under different genetic regulation. Altogether, this monitoring of the goat lines indicated that functional longevity-based selection helps to improve resilience by improving survival and mitigating some indicators of fat mobilization during early lactation.

Capacidade antioxidante equivalente ao trolox em sementes de Coffea arabica L.

ABSTRACT The causes of the low desiccation tolerance and low longevity of coffee seeds have not yet been fully elucidated, and a full understanding of their complex physiology is of great interest. Among several alternatives, the loss of antioxidant capacity in seeds may be related to their rapid loss in quality during storage. The objective of this study was to determine the total antioxidant capacity of coffee harvested at different ripeness stages before and after the storage of seeds with different water contents and to relate antioxidant capacity to physiological quality. Seeds in the greenish-yellow or cherry stages, recently harvested or stored for nine months at 10 °C with 40, 30, 20 and 12% water content (wet basis - wb), were submitted to physiological and biochemical quality evaluations, and the Trolox equivalent antioxidant capacity (TEAC) was determined. The germination and root protrusion of coffee seeds from greenish-yellow and cherry fruits were not affected by drying, but seeds harvested at physiological maturity had greater vigor when the moisture content was lower. The quality of coffee seeds decreased during storage, and this decrease was greater in seeds stored with higher water contents. Coffee seeds in the greenish-yellow stage had a higher antioxidant capacity than those in the cherry stage when recently harvested, but there was a substantial reduction in this capacity during storage at both maturation stages. Coffee seed deterioration is related to a reduction in antioxidant capacity, and the isoenzymatic profiles of the antioxidant process are little affected by the seed maturation stage. The deterioration of coffee seeds during storage is related to a reduction in their total antioxidant capacity, regardless of their maturation stage, being more pronounced in the greenish-yellow stage.

Strong influence of degree of substitution on carboxymethyl cellulose stabilized sulfidated nanoscale zero-valent iron

Carboxymethyl cellulose (CMC) has been widely adopted as stabilizer to enhance the subsurface mobility of nanoscale zerovalent iron (nZVI). However, CMC surface modification also cause severe decrease of the longevity and electron utilization efficiency (εe) of nZVI, which is still not well understood. In this study, we demonstrate the negative influence of CMC on the properties of sulfidated nZVI (S-nZVI) could be reversed by increasing the degree of substitution (D.S.) of CMC. Consistent with previous study, the sample CMC-S-nZVI prepared with commercial CMC with degree of substitution (D.S.) of 0.75 exhibited a considerable low longevity of 33 days with εe of 4.5%, much lower than that of sulfidated nZVI (S-nZVI, 113 days and 13%). In sharp contrast, the sample HCMC-S-nZVI synthesized with CMC with super high D.S. of 1.76 demonstrated significantly enhanced longevity of 139 days and εe of 20%. The enhancement was attributed to compatible molecular structure of CMC with super high D.S. Moreover, the HCMC-S-nZVI also exhibited higher mobility in porous media than CMC-S-nZVI. Our work provides a feasible way to prepare S-nZVI with desired properties including high subsurface transportability, high longevity and high εe.

WORK–LIFE BALANCE IN THE CURRENT JAPANESE CONTEXT

Background: Work style reform in Japan is under way in response to a predicted shortfall in the workforce owing to the country’s low birth rate and high longevity, health problems due to excessive working hours, and the need for diversification of employment. A legal limit for physicians’ overtime work will be introduced in 2024.&#x0D; Objectives: This study examines the work–life balance among Japan’s doctors in the context of ongoing work style reform.&#x0D; Methodology: The study applied included selective reviews of demographic shifts, legislation against long working hours, and trends in doctors’ participation in the labor force.&#x0D; Results: Japan’s doctors work long hours, which creates a conflict between their working and private lives. The proportion of female doctors in Japan is the lowest among the Organisation for Economic Co-operation and Development (OECD) countries. Employment trends among women doctors by age group show an M-curve: many quit their jobs upon marriage or childbirth. Gender role stereotyping has led male Japanese doctors to devote themselves entirely to their professions and working excessively long hours: they leave all family work to their female partners. This stereotyping obliges female doctors to undertake household chores in addition to their career tasks, which makes it difficult for them to re-enter their careers. Because of the harsh working conditions (including long working hours), there has been a decline in newly graduated doctors in some medical specialties.&#x0D; Conclusions: For sustainable, effective health care in Japan, it is necessary to improve the work conditions for Japan’s doctors towards achieving work–life harmony.

An Efficient Distributed Elliptic Positioning for Underground Remote Sensing

Remote surveying of unknown bound geometries, such as the mapping of underground water supplies and tunnels, remains a challenging task. The obstacles and absorption in media make the long-distance telecommunication and localization process inefficient due to mobile sensors’ power limitations. This work develops a new short-range sequential localization approach to reduce the required amount of signal transmission power. The developed algorithm is based on a sequential localization process that can utilize a multitude of randomly distributed wireless sensors while only employing several anchors in the process. Time delay elliptic and frequency range techniques are employed in developing the proposed algebraic closed-form solution. The proposed method is highly effective as it reaches the Cramer–Rao Lower Bound performance level. The estimated positions can act as initializations for the iterative Maximum Likelihood Estimator (MLE) via the Taylor series linearization to acquire even higher positioning accuracy as needed. By reducing the need for high power at the transmit modules in the sensors, the developed localization approach can be used to design a compact sensor with low power consumption and greater longevity that can be utilized to explore unknown bounded geometries for life-long efficient observation mapping.

Cold coffee seeds storage with different water content

Coffee seeds are classified as intermediate because they have low tolerance to desiccation and low longevity. Consequently, moisture control and storage conditions are important factors in maintaining the physiological quality of these seeds. Thus, the objective in this work was to evaluate the water content effect on coffee seed longevity. Seeds of five Coffea arabica cultivars from the 2016/2017 crop were used. Part of the harvested seeds was dried in the shade until reach 12% moisture and the other part did not go through drying process, remaining with 40% water content. The seeds were stored in a cold chamber at 10 oC for a period of nine months, and the physiological quality was evaluated every three months by germination, root protrusion, seedlings with expanded cotyledonary leaves, seedling dry mass and enzymatic analysis of catalase enzymes and superoxide dismutase. Regardless of the cultivar, wet seeds coffee storage provides better maintenance of physiological quality for up to nine months. Seedling vigor is reduced throughout the storageperiod, regardless of seed water content. Key words: Coffea arabica; Moisture; Seed quality; Storage.

Long-term population trends of Rhinolophus hipposideros and Myotis myotis in Poland

Bats are particularly susceptible to environmental changes because of their low reproductive rate, longevity, and high metabolic rates, which lead to relatively high food requirements. Thus, bat populations take a relatively long time to recover from increased mortality rates, and monitoring schemes should cover long time periods. In this work, we analyzed the population trajectories of two bat species, Rhinolophus hipposideros and Myotis myotis, the most numerous in five caves in southern Poland, which are known as important bat hibernacula on a continental scale. Data were collected by regular counts in 1985–2020, depending on the particular cave; in addition, previous data on the number of hibernating bats in these caves, available since 1951, were taken from existing publications. We analyzed time-series data using average locality indices and TRIM (TRends and Indices for Monitoring data) methods, and both produced similar results. Generally, the populations of the two studied bat species showed recent increasing trends, especially visible as an effect of recovery after years of decline. The situation recorded in southern Poland is very similar to that described in other places in Europe, where recoveries of bat populations have also been observed in the last decades. Although it is difficult to present results from formal analyses, because of the lack of good data, at least some factors—less exposure to contaminants (pesticides, heavy metals), improving food availability due to climate change, and a lower predation rate (including human pressure), both in the breeding season and during wintering—positively affected both species.

Effect of physiological priming on stored coffee seeds

Abstract: The physiological priming has been used to standardize and increase the speed of development of seed lots. The use of this technique is essential in coffee cultivation, as the crop has low longevity associated with slow and uneven germination. The objective was to evaluate the effect of physiological priming on the physiological quality of coffee seeds stored with different water contents. Seeds of two cultivars of Coffea arabica were used: cv. Catuaí Vermelho IAC144 and Topázio MG1190. A portion of the seeds were dried in the shade until reaching 12% moisture, and the other did not undergo drying. The seeds were stored in a cold chamber at 10 °C for nine months. Every three months, the physiological priming technique was performed with subsequent evaluation of the physiological quality by germination tests, root protrusion, normal seedlings at fifteen days, strong normal seedlings, seedlings with expanded cotyledonary leaves and seedling dry weight. Seeds that did not undergo drying subjected to the physiological priming technique maintained physiological quality after nine months of storage. Physiological priming was detrimental to dry seeds stored for nine months.

Longevity Adjustment of Retirement Age and Intragenerational Inequality

We find that segments of society that have shorter life expectancy can expect a lower income from their pensions and lifetime utility due to the longevity of other groups participating in the same pension scheme. Linking the pension age to average life expectancy magnifies the negative effect on the lifetime utility of those who suffer low longevity. Furthermore, when the income of those with greater longevity increases, those with shorter life expectancy become even worse off. Conversely, when the income of those with shorter life expectancy increases, they end up paying more into the pension scheme, which benefits those who live longer. The relative sizes of the low‐ and high‐longevity groups in the population determine the magnitude of these effects. We calibrate the model based on data on differences in life expectancy of different socioeconomic groups and find that low‐income workers suffer from a 10–13% drop in pension benefits from being forced to pay into the same scheme as high‐income workers.

Dating saltmarshes using tree rings on a halophilous plant

Dating saltmarshes is a fundamental step to conserve them suitably, because the oldest saltmarshes are becoming increasingly rare and host a particular biodiversity. In a French Atlantic saltmarsh, we counted tree rings on Suaeda vera, a ligneous plant of the European saltmarshes. We considered that the age of the stem may give the minimal age of the saltmarsh on which it grows as this is a specialist species of this habitat. By combining the dating of the saltmarsh using this proxy with a classical dating based on a photo-interpretation method, we found that the count of tree rings on S. vera gives an accurate dating of the minimal age of a saltmarsh patch. However, because of the rather low longevity of this species (maximum of 27 years in the investigated area), old maps and aerial photographs still remain essential to date the oldest saltmarsh patches. We further discuss: (1) the potential use of cross-dating on dead stems of the plant to reconstruct the long-history of saltmarshes; (2) the potential link between the growth velocity of S. vera and the spatial dynamics of saltmarshes.

Review: Application and Prospective Discussion of Machine Learning for the Management of Dairy Farms.

Simple SummaryMachine learning (ML) offers new approaches for analyzing data and is particularly interesting for large datasets. Dairy farmers implement a wide range of sensors, which create large amounts of data, in farming. Therefore, they offer an interesting area for data-driven research. In this review, we show how ML methods have already been used in the scientific literature and describe the potential that these may offer for the future. We found that ML methods were applied to predict data in a variety of areas in dairy farming such as milk yield or energy consumption; however, larger integrated datasets are required to improve the reliability of the algorithms developed.Dairy farmers use herd management systems, behavioral sensors, feeding lists, breeding schedules, and health records to document herd characteristics. Consequently, large amounts of dairy data are becoming available. However, a lack of data integration makes it difficult for farmers to analyze the data on their dairy farm, which indicates that these data are currently not being used to their full potential. Hence, multiple issues in dairy farming such as low longevity, poor performance, and health issues remain. We aimed to evaluate whether machine learning (ML) methods can solve some of these existing issues in dairy farming. This review summarizes peer-reviewed ML papers published in the dairy sector between 2015 and 2020. Ultimately, 97 papers from the subdomains of management, physiology, reproduction, behavior analysis, and feeding were considered in this review. The results confirm that ML algorithms have become common tools in most areas of dairy research, particularly to predict data. Despite the quantity of research available, most tested algorithms have not performed sufficiently for a reliable implementation in practice. This may be due to poor training data. The availability of data resources from multiple farms covering longer periods would be useful to improve prediction accuracies. In conclusion, ML is a promising tool in dairy research, which could be used to develop and improve decision support for farmers. As the cow is a multifactorial system, ML algorithms could analyze integrated data sources that describe and ultimately allow managing cows according to all relevant influencing factors. However, both the integration of multiple data sources and the obtainability of public data currently remain challenging.

How does fire affect germination of grasses in the Cerrado?

AbstractFire is a frequent disturbance in the Cerrado and is one of the major factors affecting vegetation structure and diversity. Fire events open gaps within the herbaceous layer and increase temperature fluctuation in the soil surface. In addition to being an important environmental filter for germination, fire is a germination cue for species with physiological dormancy. This study aimed to evaluate the germination of native grasses, using daily temperature fluctuations and heat shock to overcome physiological dormancy in native grasses. We also evaluated seed longevity after dispersal for some species. We conducted the daily temperature fluctuation experiments on seeds of ten native grass species, which were collected and then placed in germination chambers simulating thermal fluctuation throughout the day (19–55°C). We also subjected seeds to different heat-shock treatments: 100°C for 1 min, 100°C for 3 min and 200°C for 1 min. To determine seed longevity, we stored seeds for 6 and 12 months after collection and then set them to germinate (27°C, 12/12 h light). Non-germinated seeds from all experiments were tested for viability. Most species had low longevity and germination percentages. Those that had physiological dormancy were stimulated to germinate when exposed to temperature fluctuations. One species resisted temperatures up to 200°C. For all other species, neither treatment affected germination percentages. Our results indicate the importance of these environmental filters for seedling recruitment of these species, considering the low longevity and the presence of physiological dormancy.

Estimating some demographic parameters of Aphidius matricariae Haliday (Hymenoptera: Braconidae), the parasitoid of the greenbug aphid, Schizaphis graminum (Rondani) (Hemiptera: Aphididae), at different temperatures

Some demographic parameters of the indigenous parasitoid, Aphidius matricariae Haliday (Hymenoptera: Braconidae) parasitizing the greenbug, Schizaphis graminum (Rondani) (Hemiptera: Aphididae), were estimated at 3 different temperatures (20, 25, and 30 ± 1 °C; 70 ± 5% RH; 16 L:8D). According to age-specific theory, the demographic parameters of the parasitoid were computed by related formulas. The results showed that duration of mummy’s formation to adult emergence and oviposition to adult emergence were significantly prolonged at 30 °C. The high temperature (30 °C) markedly shortened the longevity and lifespan of the wasp. The lowest value of fecundity (6.35 ± 0.85) significantly occurred when the female wasps were exposed to 30 °C. The estimated values of rm were remarkably high when the female wasps were exposed to 20 (0.320 ± 0.011) and 25 °C (0.310 ± 0.009). The lowest and highest values of the R0 significantly occurred at 30 (6.167 ± 0.754) and 20 °C (55.306 ± 6.316). The λ, T, DT, and rw values were noticeably decreased at high temperature, and there was non-significant difference between the two other temperatures. High temperature decreased the number of females produced per female per day (mx) and survival rate (lx) of the parasitoid wasp. The highest mx and lx happened at 20 and 25 °C, respectively. Therefore, the results showed that the parasitoid wasp was sensitive to the high temperature, as its low reproduction, survival, and short adult longevity were recorded. Considering the characteristics, the wasp appeared to be well-adapt with the temperatures below 30 °C. Understanding the optimal temperatures for the life history traits of A. matricariae could promote the performance of the parasitoid wasp in different climatic regions, and this might advance the mass production of the parasitoid applied in IPM program for successful biological control of S. graminum.

Age and growth of the endangered fan mussel Pinna nobilis in the western Mediterranean Sea

The present work, which is the first comparative study of the growth of the fan mussel Pinna nobilis in the western Mediterranean, encompasses 12 populations of this species living in different environments in France and Spain. Two hundred nine shells were processed and used to obtain growth records from the posterior adductor muscle scar. Size-at-age data were fitted to the Von Bertalanffy growth model. Considerable variability in growth parameters and age was detected among the populations. The results show that the only two fan mussel populations remaining in Spain, which live in an estuary and a coastal lagoon, occupy habitats that are optimal for fast growth, but individuals show low longevity, complicating the long-term conservation of the species. Multivariate analyses groups the populations into three groups (SO, EO and LG), and a general model is proposed for each group; the model can be used as an approximation to calculate the ages of individuals living in similar environments.

Seed dormancy and longevity variability of Hirschfeldia incana L. during storage

AbstractWe studied the variability of germination, dormancy and viability loss of Hirschfeldia incana seeds in relation to seed size. Seeds were stored at 35°C under humid [75% relative humidity (RH)] or dry (33% RH) conditions. Seed germination and electrolyte leakage were evaluated periodically. Small seeds had lower longevity at humid or dry storage conditions (5 or 407 days, respectively) than large or intermediate seeds (7–9 or 536–727 days, respectively). Moreover, H. incana shows variability in seed dormancy related to seed size within a population, with small seeds having lower dormancy (13%) than intermediate (50%) or large seeds (72%). Dormancy was partially released after a short storage at 35°C and humid conditions. Under dry storage conditions, endogenous dormancy cycles were observed for over a year, and longer times of storage had a dormancy-breaking effect through dry after-ripening. Results suggest a dual strategy producing non-dormant seeds with low longevity that will germinate immediately after dispersal, and seeds with greater longevity that will delay germination. Membrane permeability increased linearly with ageing at both humid and dry storage (R2 = 0.60). Small seeds showed greater conductivity than intermediate or large seeds (0.7, 0.4 or 0.3 mS g–1 dry weight, respectively, at the 80% germination). The conductivity test could be used to evaluate the quality of H. incana seeds and would allow us to identify dormant (non-germinating) seed lots as viable. However, the influence of storage conditions and variability within a seed population on seed longevity should be taken into account when evaluating seed quality.