Somatic Maintenance Research Articles

A dynamic energy budget model of Fenneropenaeus chinensis with applications for aquaculture and stock enhancement

Dynamic energy budget (DEB) theory provides a framework for quantifying metabolic processes and biological rates. DEB models have been widely applied to aquaculture species, but this type of model has great potential for application to fisheries for stock assessment and enhancement. The shrimp Fenneropenaeus chinensis, widely distributed along the coast of China and Korea, is the most important fisheries and aquaculture species in China. With the AmP method, DEB parameters were estimated for the population along the coast of China. The parameter estimation achieved an overall goodness of fit with MRE of 0.131 and SMSE of 0.178. In comparison with similar species, the values of a few main parameters are relatively high including reserve capacity (Em), somatic maintenance (ṗM) and allocation fraction to growth and somatic maintenance (κ). This may reflect an adaptation to variation of environmental conditions. The model can predict the physiological behaviours including respiration, ammonia excretion and feeding rates reasonably well. It shows overall capability to predict the growth and reproduction with acceptable confidence in three main geographic regions. There are clear differences between the female and male with much faster growth rate of the former. Validations of the model have shown that it can adequately predict growth of the shrimp in both its natural distribution waters and land-based culture systems. This study provides important information for further development of modeling tools which can contribute to estimating the carrying capacity for stock enhancement and optimizing production from integrated multi-trophic aquaculture.

The energetic basis of population growth in animal kingdom

Population growth, and other population characteristics, have been computed and made available online for over 2000 animal species in the Add-my-Pet (AmP) collection, assuming constant food and temperature environments. The AmP collection – online database of Dynamic Energy Budget model parameters, implied properties and referenced underlying data – provides an unique opportunity to study how energetics of individuals relates to population growth. For the comparisons of traits, we assume that the background hazard rate is zero, but aging applies to all species and ‘thinning’ to species with high reproduction rates. The new concept ‘thinning’ is a state-dependent hazard rate such that the feeding rate of a cohort does not change in time: the increase of individual feeding rates due to growth is exactly compensated by a reduction in numbers. Thinning affects population growth rate, but the impact differs substantially between species. Some 11% of species do not survive thinning, even at abundant food. The population growth rate relates to the underlying energetics; we discuss and suggest explanations for how population growth rates fit into all known patterns in the co-variation of parameter values: body size-scaling, metabolic acceleration, waste-to-hurry, supply-demand spectrum and altricial-precocial spectrum. We show that, after reproduction, age at puberty dominates population growth. The specific population growth rate scales with maximum body weight in the same way as the weight-specific respiration scales with body weight. DEB theory, which explains both, shows, however, that no direct relationship exists between the population growth rate and respiration. We suggest that the similarity in scaling results from the equality between specific population growth and specific growth rate at maximum growth of structure, and might be an evolutionary relict from times that life consisted of dividing unicellulars; population and body growth are directly connected for unicellulars. We show that the specific growth rate at maximum growth equals 1.5 times the von Bertalanffy growth rate, in a DEB context, which is a new interpretation of the latter growth rate. We expected the population growth rate to co-vary with specific somatic maintenance rate, based on a previously discovered pattern, called the waste-to-hurry strategy, where growth and reproduction are increased by simultaneously increasing assimilation and somatic maintenance in species that live off temporarily abundant food supplies. We did find this effect in ecdysozoa and spiralia, which comprise roughly 95% of animal species, but hardly so in tetrapods. The reason might be that specific somatic maintenance also co-varies with specific maturity levels at puberty for tetrapods. The scaled functional response at which the population growth rate is zero is very close to that at which puberty can just be reached in absence of thinning, and somewhat higher in presence of thinning. The specific population growth rate at abundant food correlates negatively with the functional response for which population growth rate is zero. It also correlates negatively with the precociality index, i.e. the ratio of maturity levels at puberty and birth: the more precocial, the larger neonate size, the smaller reproduction rate, especially in restricted taxa such as mammals and cartilaginous fish. Like other traits, the population growth rate shows considerable segregation among taxa, where mammals have a relatively low rate, glires a relatively high rate among mammals, followed by marsupials; afrotherians have the lowest population growth rates.

Effects of polystyrene diet on Tenebrio molitor larval growth, development and survival: Dynamic Energy Budget (DEB) model analysis

The presence of polystyrene (PS) waste increases constantly. Styrofoam, the most popular form of PS, is one of the major plastic pollutants in the environment. An efficient and environmentally friendly method of PS recycling is still needed. The biodegradation of PS by insects has been presented by researchers as a promising alternative to chemical, mechanical and thermal methods. The main aim of this study was to assess the survival, growth, and development of yellow mealworms (the larvae of Tenebrio molitor) fed with PS to determine if the insects are able to use PS as a source of mass and energy. The Dynamic Energy Budget (DEB) model was used to analyze the effects of food type on the growth trajectory and metabolism of tested organisms. We investigated five possible modes of influence of PS diet on DEB model parameters including a decrease of food availability, an increase in somatic maintenance power, an increase in costs for structure, allocation of energy, and a decrease in somatic maintenance power. Our results show that changes in the development of larvae fed with PS are mainly caused by a decrease in reserves density and reaction of the organism to the insufficient food supply. The inability or difficulty in completing the life cycle of T. molitor larvae fed with PS raises doubts about the use of mealworms as an effective technology for utilizing polystyrene.

Cyberbullying victimization and somatic complaints: A prospective examination of cognitive emotion regulation strategies as mediators

Background/Objective: The main purpose of this study was to examine the relationships among cybervictimization, maladaptive cognitive emotion regulation strategies and somatic complaints in a 4-month follow-up study. Method: A total of 1,024 high school students (456 male and 568 female, M (SD)=13.69 years (1.3 years), range 12–18 years, voluntarily participated in this study. Measures of cybervictimization and cognitive strategies were obtained at Time 1. Four months later (Time 2), measures of somatic complaints were obtained. Results: Multiple mediation analyses were conducted to determine the mediating roles of maladaptive strategies in the link between cybervictimization and somatic complaints. As expected, path-analytic results showed that cybervictimization predicted somatic symptoms. Furthermore, some maladaptive regulation strategies, namely self-blame and rumination, partially mediated the link between cybervictimization and somatic symptoms evaluated 4-months later. Conclusions: The findings are discussed in terms of the role that maladaptive cognitive emotion regulation strategies might play with regards to physical health in cyberbullying episodes. In general, these findings have important implications for developing an understanding about the affective determinants of somatic health problem initiation and maintenance after a victimization and for developing intervention programs specifically for cybervictimized adolescents.

Age and location influence the costs of compensatory and accelerated growth in a hibernating mammal

Abstract The increase of structural growth rates to compensate for a poor initial body condition, defined as compensatory growth, may have physiological costs, but little is known about its effects on individual fitness in the wild. Yellow-bellied marmots (Marmota flaviventer) are obligate hibernators and depend on fat accumulation acquired during an approximately 4-month summer to survive overwinter. We investigated the costs of survival and longevity of rapid growth in a wild population of yellow-bellied marmots. We used trapping data collected from 2002 to 2014 to calculate individual relative seasonal growth and assess its effects on longevity and annual survival of juveniles, yearlings, and adults. Sites were distributed in two main areas, down-valley and up-valley; the latter has a higher elevation and is an overall harsher environment. We found that relative seasonal growth had no effect on individual longevity or on juvenile and adult annual survival. For yearlings, the effect of relative seasonal growth on survival depended on the location: yearlings with high relative seasonal growth had lower survival if located up-valley, and higher survival if located down-valley. In conclusion, juveniles and adults do not appear to have detectable costs of rapid growth, although there are costs to yearling survival depending on environmental conditions. Substantial structural growth occurs when marmots are yearlings and our results are likely driven by the high conflicting demands of somatic growth versus maintenance at this stage. Thus, the costs of rapid growth are age and site dependent and may be seen in the short term for species facing temporal constraints on growth.

Trade-off between somatic and germline repair in a vertebrate supports the expensive germ line hypothesis

The disposable soma theory is a central tenet of the biology of aging where germline immortality comes at the cost of an aging soma [T. B. L. Kirkwood, Nature 270, 301-304 (1977); T. B. L. Kirkwood, Proc. R. Soc. Lond. B Biol. Sci. 205, 531-546 (1979); T. B. L. Kirkwood, S. N. Austad, Nature 408, 233-238 (2000)]. Limited resources and a possible trade-off between the repair and maintenance of the germ cells and growth and maintenance of the soma may explain the deterioration of the soma over time. Here we show that germline removal allows accelerated somatic healing under stress. We tested "the expensive germ line" hypothesis by generating germline-free zebrafish Danio rerio and testing the effect of the presence and absence of the germ line on somatic repair under benign and stressful conditions. We exposed male fish to sublethal low-dose ionizing radiation, a genotoxic stress affecting the soma and the germ line, and tested how fast the soma recovered following partial fin ablation. We found that somatic recovery from ablation occurred substantially faster in irradiated germline-free fish than in the control germline-carrying fish where somatic recovery was stunned. The germ line did show signs of postirradiation recovery in germline-carrying fish in several traits related to offspring number and fitness. These results support the theoretical conjecture that germline maintenance is costly and directly trades off with somatic maintenance.

HermaDEB: An evolutionary IBM for energy allocation in hermaphrodites

Size-advantage hypothesis models (SAH) allow an understanding of which sex occurs first and when the sex is changed in hermaphrodite species, through the optimal allocation of energy in terms of male versus female roles. Whereas sex allocation depends directly on how an organism allocates energy throughout its lifetime, the dynamic energy budget theory (DEB), describes the uptake and use of energy and nutrients, as well as the physiological organization throughout an organism’s life cycle, including growth, maintenance, reproduction, and aging.We propose an evolutionary individual-based model to bridge the gap between metabolic models and the sexual allocation model. In this paper, we describe an individual-based model used to study the size at the time of a sex change/maximum size, i.e., Lratio and the most important physiological factors influencing size at the time of a sex change, Lchangei. We show that the fraction that determines how much to invest in somatic maintenance and growth, κ, the cost of the structure relative to the energy allocated to the soma, and the somatic maintenance rate coefficient are the most influential factors. We also show that the ratio between male and female gamete costs has very little influence on Lchangei and Lratio.

Preferential retention of algal carbon in benthic invertebrates: Stable isotope and fatty acid evidence from an outdoor flume experiment.

According to the River Continuum Concept, headwater streams are richer in allochthonous (e.g. terrestrial leaves) than autochthonous (e.g. algae) sources of organic matter for consumers. However, compared to algae, leaf litter is of lower food quality, particularly ω‐3 polyunsaturated fatty acids (n‐3 PUFA), and would constrain the somatic growth, maintenance, and reproduction of stream invertebrates. It may be thus assumed that shredders, such as Gammarus, receive lower quality diets than grazers, e.g. Ecdyonurus, that typically feed on algae.The objective of this study was to assess the provision of dietary PUFA from leaf litter and algae to the shredder Gammarus and the grazer Ecdyonurus. Three different diets (algae, terrestrial leaves, and an algae–leaf litter mix) were supplied to these macroinvertebrates in a flume experiment for 2 weeks. To differentiate how diet sources were retained in these consumers, algae were isotopically labelled with 13C.Both consumers became enriched with 13C in all treatments, demonstrating that both assimilated algae. For Gammarus, n‐3 PUFA increased, whereas n‐6 PUFA stayed constant. By contrast, the n‐3 PUFA content of Ecdyonurus decreased as a consequence of declining algal supply.Results from compound‐specific stable isotope analysis provided evidence that the long‐chain n‐3 PUFA eicosapentaenoic acid (EPA) in both consumers was more enriched in 13C than the short‐chain n‐3 PUFA α‐linolenic acid, suggesting that EPA was taken up directly from algae and not from heterotrophic biofilms on leaf litter. Both consumers depended on algae as their carbon and EPA source and retained their EPA from high‐quality algae.

Resource-dependent evolution of female resistance responses to sexual conflict.

Sexual conflict can promote the evolution of dramatic reproductive adaptations as well as resistance to its potentially costly effects. Theory predicts that responses to sexual conflict will vary significantly with resource levels—when scant, responses should be constrained by trade‐offs, when abundant, they should not. However, this can be difficult to test because the evolutionary interests of the sexes align upon short‐term exposure to novel environments, swamping any selection due to sexual conflict. What is needed are investigations of populations that are well adapted to both differing levels of sexual conflict and resources. Here, we used this approach in a long‐term experimental evolution study to track the evolution of female resistance to sexual conflict in the fruit fly Drosophila melanogaster. In resource‐rich regimes, high‐conflict females evolved resistance to continual exposure to males. There was no difference in baseline survival, consistent with the idea that responses evolving under nutritional abundance experienced no trade‐offs with resistance. In the poor resource regimes, the ability of high‐conflict females to evolve resistance to males was severely compromised and they also showed lower baseline survival than low‐conflict females. This suggested high‐conflict females traded off somatic maintenance against any limited resistance they had evolved in response to sexual conflict. Overall, these findings provide experimental support for the hypothesis that evolutionary responses to sexual conflict are critically dependent upon resource levels.

The microbiota influences the Drosophila melanogaster life history strategy.

Organisms are locally adapted when members of a population have a fitness advantage in one location relative to conspecifics in other geographies. For example, across latitudinal gradients, some organisms may trade off between traits that maximize fitness components in one, but not both, of somatic maintenance or reproductive output. Latitudinal gradients in life history strategies are traditionally attributed to environmental selection on an animal's genotype, without any consideration of the possible impact of associated microorganisms ("microbiota") on life history traits. Here, we show in Drosophila melanogaster, a key model for studying local adaptation and life history strategy, that excluding the microbiota from definitions of local adaptation is a major shortfall. First, we reveal that an isogenic fly line reared with different bacteria varies the investment in early reproduction versus somatic maintenance. Next, we show that in wild fruit flies, the abundance of these same bacteria was correlated with the latitude and life history strategy of the flies, suggesting geographic specificity of the microbiota composition. Variation in microbiota composition of locally adapted D.melanogaster could be attributed to both the wild environment and host genetic selection. Finally, by eliminating or manipulating the microbiota of fly lines collected across a latitudinal gradient, we reveal that host genotype contributes to latitude-specific life history traits independent of the microbiota and that variation in the microbiota can suppress or reverse the differences between locally adapted fly lines. Together, these findings establish the microbiota composition of a model animal as an essential consideration in local adaptation.

Does Vitamin E Supplementation Enhance Growth Benefits of Breeding Helpers at No Oxidative Costs?

During early postnatal development, biomolecules are particularly exposed to the detrimental actions of unneutralized reactive oxygen species. These prooxidant molecules have been claimed to mediate the trade-off between growth and somatic maintenance. Vitamin E is a key exogenous antioxidant that plays an important role in protecting biological membranes against oxidative damage. However, evidence of the effect of vitamin E supplementation during early life on growth and oxidative status in wild populations is equivocal. We tested the effect of supplementing western bluebird nestlings (Sialia mexicana) with vitamin E on growth rate, antioxidant capacity, and oxidative damage to lipids. During the period of accelerated growth (5-8 d), bill growth rate was 21% higher in supplemented nestlings from nests with breeding helpers than in supplemented nestlings from unassisted nests. Vitamin E also boosted tarsus growth rate during the period of slow growth (11-18 d), and this effect was independent of the presence of breeding helpers. Differences in body size and mass, oxidative damage to lipids, and antioxidant capacity were not evident between supplemented and control nestlings at 18 d. Therefore, we conclude that vitamin E promoted faster bill and tarsus growth, but this transient effect disappeared as soon as the supplementation ceased. Our experimental study also supports the idea that tocopherols are rapidly metabolized, since we failed to detect any evident increase of vitamin E in supplemented nestlings at age 18 d. These results provide partial support for the hypothesis that growth rate is constrained by its costs in terms of increased susceptibility to oxidative stress.

Why Naked Mole-Rats Have High Oxidative Damage but Live a Long Life: A Simple Explanation Based on the Oxidative Stress Theory of Aging

Compared to mice with the same body mass, naked mole-rats have a lower metabolic rate, higher homeostasis-maintaining activities, higher oxidative damage levels, but a longer lifespan. These observations have raised serious challenges to the widely accepted oxidative stress theory of aging, which suggests a negative correlation between damage levels and lifespan. Here, we introduce a simple theoretical model based on energy conservation and the oxidative stress theory. Employing the model and the physiological parameters of mice and naked mole-rats, we explain why naked mole-rats have higher damage levels despite their higher somatic maintenance efforts; why damage levels in naked mole-rats seem not to change over age; and how these factors concertedly result in a longer lifespan in naked mole-rats. Our results highlight the energy tradeoff between biosynthesis and somatic maintenance, and suggest that the rate of damage accumulation over age and the existence of a threshold of damage for death are the keys to solve the paradox raised by naked mole-rats.

Dietary Restriction Improves Fitness of Aging Parents But Reduces Fitness of Their Offspring in Nematodes.

Dietary restriction (DR) is a well-established intervention to extend lifespan across taxa. Recent studies suggest that DR-driven lifespan extension can be cost-free, calling into question a central tenant of the evolutionary theory of aging. Nevertheless, boosting parental longevity can reduce offspring fitness. Such intergenerational trade-offs are often ignored but can account for the “missing costs” of longevity. Here, we use the nematode Caenorhabditis remanei to test for effects of DR by fasting on fitness of females and their offspring. Females deprived of food for 6 days indeed had increased fecundity, survival, and stress resistance after re-exposure to food compared with their counterparts with constant food access. However, offspring of DR mothers had reduced early and lifetime fecundity, slower growth rate, and smaller body size at sexual maturity. These findings support the direct trade-off between investment in soma and gametes challenging the hypothesis that increased somatic maintenance and impaired reproduction can be decoupled.

Somatic Mutations and Genome Stability Maintenance in Clonal Coral Colonies.

One challenge for multicellular organisms is maintaining genome stability in the face of mutagens across long life spans. Imperfect genome maintenance leads to mutation accumulation in somatic cells, which is associated with tumors and senescence in vertebrates. Colonial reef-building corals are often large, can live for hundreds of years, rarely develop recognizable tumors, and are thought to convert somatic cells into gamete producers, so they are a pivotal group in which to understand long-term genome maintenance. To measure rates and patterns of somatic mutations, we analyzed transcriptomes from 17 to 22 branches from each of four Acropora hyacinthus colonies, determined putative single nucleotide variants, and verified them with Sanger resequencing. Unlike for human skin carcinomas, there is no signature of mutations caused by UV damage, indicating either higher efficiency of repair than in vertebrates, or strong sunscreen protection in these shallow water tropical animals. The somatic mutation frequency per nucleotide in A.hyacinthus is on the same order of magnitude (10-7) as noncancerous human somatic cells, and accumulation of mutations with age is similar. Loss of heterozygosity variants outnumber gain of heterozygosity mutations ∼2:1. Although the mutation frequency is similar in mammals and corals, the preponderance of loss of heterozygosity changes and potential selection may reduce the frequency of deleterious mutations in colonial animals like corals. This may limit the deleterious effects of somatic mutations on the coral organism as well as potential offspring.

Coordinated Behavioral and Physiological Responses to a Social Signal Are Regulated by a Shared Neuronal Circuit.

Successful reproduction in animals requires orchestration of behavior and physiological processes. Pheromones can induce both "releaser" (behavioral) and "priming" (physiological) effects [1] in vertebrates [2, 3] and invertebrates [4, 5]. Therefore, understanding the mechanisms underlying pheromone responses could reveal how reproduction-related behaviors and physiology are coordinated. Here, we describe a neuronal circuit that couples the reproductive system and behavior in adult Caenorhabditis elegans hermaphrodites. We found that the response of the oogenic germline to the male pheromone requires serotonin signal from NSM and HSN neurons that acts via the mod-1 receptor in AIY and RIF interneurons and is antagonized by pigment-dispersing factor (PDF). Surprisingly, the same neurons and pathways have been previously implicated in regulation of exploratory behavior in the absence of male-produced signals [6]. We demonstrate that male pheromone acts via this circuit in hermaphrodites to reduce exploration and decrease mating latency, thereby tuning multiple fitness-proximal processes. Our results demonstrate how a single circuit could coordinate behavioral and physiological responses to the environment, even those that unfold on different timescales. Our findings suggest the existence of a centralized regulatory mechanism that balances organismal resources between reproductive investment and somatic maintenance.

Antibacterial immune functions of subadults and adults in a semelparous spider.

Although capacity to mount an efficient immune response plays a critical role in individuals’ survival, its dynamics across ontogenetic stages is still largely unexplored. Life stage-dependent variation in the encountered diversity and prevalence of parasites were proposed to contribute to stage-dependent changes in immunity, but differences in life history objectives between developmental stages may also lead to stage-specific changes in efficiency of given immune mechanisms. The reason for this is that juveniles and subadults are unable to reproduce, therefore they invest resources mainly into survival, while adults have to partition their resources between survival and reproduction. The general trade-off between somatic maintenance and reproductive effort is expected to impair immune function. Especially so in semelparous organisms that only reproduce once throughout their lifetime, hence they do not face the trade-off between current and future reproduction. We hypothesised that in a semelparous species individuals would be characterised by decreased investment into somatic maintenance after maturation, in order to maximise their reproductive output. Accordingly, we predicted that (1) elements of somatic maintenance, such as immunity, should be relatively weaker in adults in comparison to subadults, and (2) increased reproductive investment in adults should be associated with lower immune efficiency. We quantified two markers of immunity in subadult and adult individuals of the semelparous wolf spider Pardosa agrestis (Westring, 1861), namely bacterial growth inhibition power and bacterial cell wall lytic activity. We found that subadults showed significantly higher cell wall lytic activity than adults, but the two life stages did not differ in their capacity to inhibit bacterial growth. Also, we found weaker immune measures in mated females compared to virgins. Furthermore, in mated females bacterial growth inhibition power was negatively associated with fecundity.

БЕЗПЕЧНІСТЬ ТА ЯКІСТЬ МОЛОКА СИРОГО ВИРОБЛЕНОГО В КОЛЕКТИВНИХ ГОСПОДАРСТВАХ

Overabundant of a general bacterial pollution, the maintenance of somatic cells, an inhibitory substances presence and added water are the basic hygienic indicators which reduced quality fresh (crude) cow milk . For research, modern reconstructed dairy farms were used, where milking is carried out in milking halls and adheres to all sanitary norms and hygiene requirements and old farms where milking is carried out in milk pipelines and portable milking machines and satisfactory sanitary requirements are met. The obsolete equipment farms have not special clean and disinfectant detergents to sanitary equipment processing. Part of premium quality milk, fully responds of European requirement’s, which these collective farms give for processing was 8.3% only. The basic milk part (61.8 %) from these farms corresponded to the higher and first quality class, the milk share of the second class of quality made 14.5 %. Also it is identified that the considerable part of made milk (15.4 %) was not classified quality. According to results of somatic cells maintenance check, farms with a modern equipment’s got premium class quality milk and this index was in 2.6 times smaller in comparison with the farms, using obsolete milking technology. This is due to the fact that modern technology involves the milking of cows suffering from subclinical mastitis in individual milking halls. This condition does not always carried out by farms with obsolete equipment. Principal cause of decrease quality class and milk safety by these farms to become a consequence of high maintenance somatic cells level and microbiological pollution, it is result of sanitary pre-milking, processing of dairy vessels requirements default and untimely & inefficient milk cooling. Keywords: fresh (crude) cow milk, quality and safety, bacterial pollution, preprocessing, a sanitary condition of the dairy equipment.

Evolution of ageing as a tangle of trade-offs: energy versus function.

Despite tremendous progress in recent years, our understanding of the evolution of ageing is still incomplete. A dominant paradigm maintains that ageing evolves due to the competing energy demands of reproduction and somatic maintenance leading to slow accumulation of unrepaired cellular damage with age. However, the centrality of energy trade-offs in ageing has been increasingly challenged as studies in different organisms have uncoupled the trade-off between reproduction and longevity. An emerging theory is that ageing instead is caused by biological processes that are optimized for early-life function but become harmful when they continue to run-on unabated in late life. This idea builds on the realization that early-life regulation of gene expression can break down in late life because natural selection is too weak to optimize it. Empirical evidence increasingly supports the hypothesis that suboptimal gene expression in adulthood can result in physiological malfunction leading to organismal senescence. We argue that the current state of the art in the study of ageing contradicts the widely held view that energy trade-offs between growth, reproduction, and longevity are the universal underpinning of senescence. Future research should focus on understanding the relative contribution of energy and function trade-offs to the evolution and expression of ageing.

Somatic maintenance impacts the evolution of mutation rate

BackgroundThe evolution of multi-cellular animals has produced a conspicuous trend toward increased body size. This trend has introduced at least two novel problems: an expected elevated risk of somatic disorders, such as cancer, and declining evolvability due to generally reduced population size, lower reproduction rate and extended generation time. Low population size is widely recognized to explain the high mutation rates in animals by limiting the presumed universally negative selection acting on mutation rates.ResultsHere, we present evidence from stochastic modeling that the direction and strength of selection acting on mutation rates is highly dependent on the evolution of somatic maintenance, and thus longevity, which modulates the cost of somatic mutations.ConclusionsWe argue that the impact of the evolution of longevity on mutation rates may have been critical in facilitating animal evolution.

A dynamic energy budget–integral projection model (DEB-IPM) to predict population-level dynamics based on individual data: a case study using the small and rapidly reproducing species Engraulis japonicus — RETRACTED

The coupling of a dynamic energy budget (DEB) model with an integral projection model (IPM; i.e. generating a DEB-IPM) is a promising new method to predict the population-level dynamics of species based on individuals. In a single framework, the DEB component provides links to the individual-level physiological processes, and the IPM component provides an alternative way to investigate ecological changes in quantitative life history characteristics and population dynamics. In this paper we present a DEB-IPM to analyse a Japanese anchovy (Engraulis japonicus) population in Chinese seas. The coupled model describes the dynamics of a population of individuals, where each individual follows an energy budget. Primary model parameters (e.g. energy conductance, ὺ; allocation coefficient, κ; and volume-specific somatic maintenance, [ṗM]) were estimated. The mean population growth rate (rp) was calculated to be 3.4year–1. The predicted demographic rates (e.g. growth, survival and reproduction) were well within observed ranges, and fit within average recorded values, and captured known seasonal trends. DEB-IPMs could be a useful tool to capture the dynamics of biodiversity amidst global environmental changes.