Individual Fitness Components Research Articles

MHC Class II Supertypes Affect Survival and Lifetime Reproductive Success in a Migratory Songbird.

The major histocompatibility complex (MHC) plays a critical role in the immune response against pathogens. Its high polymorphism is thought to be mainly the consequence of host-pathogen co-evolution, but elucidating the mechanism(s) driving MHC evolution remains challenging for natural populations. We investigated the diversity of MHC class II genes in a wild population of pied flycatchers Ficedula hypoleuca and tested its associations with two key components of individual fitness: lifetime reproductive success and survival. Among 180 breeding adults in our study population, we found 182 unique MHC class II exon 2 alleles. The alleles showed a strong signal of positive selection and grouped into nine functional supertypes based on physicochemical properties at the inferred antigen-binding sites. Three supertypes were found in > 98% of the sampled individuals, indicating that they are nearly fixed in the population. We found no rare supertypes in the population, as all supertypes were present in > 70% of individuals. Three supertypes were related to different components of individual fitness: two were associated with lower offspring production over time, while the third was positively associated with survival. Overall, the substantial allelic and functional diversity and the relationship between specific supertypes and fitness are in accordance with the notion that balancing selection maintains MHC class II diversity in the study population, possibly with fluctuating selection as the underlying mechanism. The absence of rare supertypes in the population suggests that the balancing selection is not driven by rare-allele advantage.

Coherent long-term body-size responses across all Northwest Atlantic herring populations to warming and environmental change despite contrasting harvest and ecological factors.

Body size is a key component of individual fitness and an important factor in the structure and functioning of populations and ecosystems. Disentangling the effects of environmental change, harvest and intra- and inter-specific trophic effects on body size remains challenging for populations in the wild. Herring in the Northwest Atlantic provide a strong basis for evaluating hypotheses related to these drivers given that they have experienced significant warming and harvest over the past century, while also having been exposed to a wide range of other selective constraints across their range. Using data on mean length-at-age 4 for the sixteen principal populations over a period of 53 cohorts (1962-2014), we fitted a series of empirical models for temporal and between-population variation in the response to changes in sea surface temperature. We find evidence for a unified cross-population response in the form of a parabolic function according to which populations in naturally warmer environments have responded more negatively to increasing temperature compared with those in colder locations. Temporal variation in residuals from this function was highly coherent among populations, further suggesting a common response to a large-scale environmental driver. The synchrony observed in this study system, despite strong differences in harvest and ecological histories among populations and over time, clearly indicates a dominant role of environmental change on size-at-age in wild populations, in contrast to commonly reported effects of fishing. This finding has important implications for the management of fisheries as it indicates that a key trait associated with population productivity may be under considerably less short-term management control than currently assumed. Our study, overall, illustrates the need for a comparative approach within species for inferences concerning the many possible effects on body size of natural and anthropogenic drivers in the wild.

Impact of Whole-Body Electromyostimulation and Resistance Training on the Level of Functional Fitness in Elderly Women

ABSTRACT 
 Objective: This study aimed to investigate the effect of whole-body electromyostimulation (WB-EMS) and resistance training (RT) on the level of functional fitness in a group of elderly women.
 Participants: 63 women (60-65 years) were randomly divided into 2 experimental groups (19 in WB-EMS, 22 in RT) and one control group (22 women). Both experimental groups underwent a ten-week lasting interventional program, the control group was asked to maintain their usual daily regimen and lifestyle.
 Methods: Senior fitness test battery (SFT) determined the level of functional fitness in participants, and the dual-energy X-ray absorptiometry (DXA) assessed the body composition. 
 Results: The RT group reported a statistically significant difference between pre-and post-test in values of the Chair Stand test (p = 0.04), 8 Foot up and Go (p = 0.03), in the Back Scratch test left side (p = 0.02) and the Chair Sit and Reach test right side (p = 0.05). The WB-EMS interventional program had a positive statistically significant effect only the on level of flexibility of the lower limbs measured by the Chair Sit and Reach test left side (p = 0.05).
 Conclusions: The results of all individual components of functional fitness measured by SFT in both experimental groups (WB-EMS, RT) show an improving tendency. Comparing WB-EMS and RT groups, better results were confirmed in the RT group.
 Study limitations: Extending the length of intervention programs could have a more significant effect on the level of functional fitness in elderly women.
 Keywords: ageing, functional fitness, Senior fitness test, DXA, resistance training, WB-EMS

Multilevel selection on social network traits differs between sexes in experimental populations of forked fungus beetles

Both individual and group behavior can influence individual fitness, but multilevel selection is rarely quantified on social behaviors. Social networks provide a unique opportunity to study multilevel selection on social behaviors, as they describe complex social traits and patterns of interaction at both the individual and group levels. In this study, we used contextual analysis to measure the consequences of both individual network position and group network structure on individual fitness in experimental populations of forked fungus beetles (Bolitotherus cornutus) with two different resource distributions. We found that males with high individual connectivity (strength) and centrality (betweenness) had higher mating success. However, group network structure did not influence their mating success. Conversely, we found that individual network position had no effect on female reproductive success but that females in populations with many social interactions experienced lower reproductive success. The strength of individual-level selection in males and group-level selection in females intensified when resources were clumped together, showing that habitat structure influences multilevel selection. Individual and emergent group social behavior both influence variation in components of individual fitness, but impact the male mating success and female reproductive success differently, setting up intersexual conflicts over patterns of social interactions at multiple levels.

Efficacy of created and restored nesting sites for the conservation of colonial Laridae in the South of France.

By rapidly modifying key habitat components, habitat restoration is at risk of producing attractive cues for animals without providing habitats of sufficient quality. As such, individual fitness components, such as reproduction, could be reduced and restored habitats could become ecological traps. This risk notably appears by using artificial constructions in restoration projects, yet few studies have evaluated their efficacy in a robust way. We investigated this by analyzing 154 islets that were created or restored to improve the conservation status of 7 colonial Laridae species in the South of France. From 2007 to 2016, we compared occupancy dynamics and breeding parameters of these species between the restored sites and 846 unmanaged nesting sites. We also explored species' preference for different nesting site characteristics and their respective effect on breeding parameters. Restored nesting sites were 2-9 times as attractive as unmanaged sites for all species except the Black-headed Gull (Chroicocephalus ridibundus). Colonization probability was up to 100 times higher in sites already used by other species the previous year and increased with distance to the shore until >0.2 when distance was over 250m. Abandonment probability was 29-70% lower when breeding was successful the previous year in all species except the Sandwich Tern (Thalasseus sandvicensis). Productivity and breeding success probability were 2 times higher on managed sites. Distance from the shore was an important attractive characteristic of artificial nesting sites in all species. Other nesting site characteristics had species-specific effects on colonization, abandonment, and breeding success. Our results indicate that managed nesting sites are successful conservation tools for colonial Laridae in the Mediterranean and do not act as ecological traps. Our study showed that testing the ecological trap hypothesis is a robust way to evaluate the success of restoration projects of breeding habitats.

Suppression of yolk formation, oviposition and egg quality of locust (Locusta migratoria manilensis) infected by Paranosema locustae.

Locusta migratoria manilensis is one of the most important agricultural pests in China. The locust has high fecundity and consumes large quantities of food, causing severe damage to diverse crops such as corn, sorghum, and rice. Immunity against pathogens and reproductive success are two important components of individual fitness, and many insects have a trade-off between reproduction and immunity when resources are limited, which may be an important target for pest control. In this study, adult females L. migratoria manilensis were treated with different concentrations (5 × 106 spores/mL or 2 × 107 spores/mL) of the entomopathogenic fungus Paranosema locustae. Effects of input to immunity on reproduction were studied by measuring feeding amount, enzyme activity, vitellogenin (Vg) and vitellogenin receptor (VgR) production, ovary development, and oviposition amount. When infected by P. locustae, feeding rate and phenol oxidase and lysozyme activities increased, mRNA expression of Vg and VgR genes decreased, and yolk deposition was blocked. Weight of ovaries decreased, with significant decreases in egg, length and weight.Thus, locusts used nutritive input required for reproduction to resist invasion by microsporidia. This leads to a decrease in expression of Vg and VgR genes inhibited ovarian development, and greatly decreased total fecundity. P. locustae at 2 × 107 spores/mL had a more obvious inhibitory effect on the ovarian development in migratory locusts. This study provides a detailed trade-off between reproduction and immune input of the female, which provides a reliable basis to find pest targets for biological control from those trade-off processes.

The Short-Term Reliability of the Conceptualised 'Combat Readiness Assessment'.

: BackgroundMilitary fitness testing has historically assessed individual fitness components. Fitness assessments of this nature do not adequately monitor the physical requirements of military operations. The development of a more combat-specific fitness test would enhance accuracy in assessing the soldiers’ readiness for the demands of war. This study aimed to assess the short-term reliability of the conceptualised ‘Combat Readiness Assessment’ (CRA) following a single familiarisation trial with 21 male phase-two British Army Royal Electrical and Mechanical Engineer (REME) recruits (age (years) 19.7 ± 2.5) split into two groups (N = 11 and 10) to conform with recruit availability. The CRA was designed to be a multifaceted fitness assessment aimed at replicating the physical demands of a combat situation for military personnel. Methods: Three repeated assessments of the CRA were completed over a 10-day period (trial one as a familiarisation) to assess the short-term reliability of the CRA post familiarisation. The CRA was completed carrying a 4 kg rifle (SA80 A2) and involved a 400 m (M) run wearing an 11 kg backpack (removed after the 400 M) followed by weighted carries, sprints, casualty drags and agility tasks. Completion time (seconds) was recorded to assess performance. Intraclass correlations (ICCs) (2,1) with 95% confidence intervals (CI), the standard error of the measurement (SEM) and the coefficient of variation (CV) were calculated for completion time for trials 1-3 (T1-3) and 2-3 (T2-3) to assess reliability post-familiarisation. Mean Absolute Percentage Error (MAPE) was calculated for T1-2 and T2-3. Descriptive statistics were calculated for completion time for T1-3 and T2-3. Results: The reliability following a familiarisation trial from T1-3 (ICC: 0.75; SEM: 7.1 s; CV: 9.97%) to T2-3 (ICC: 0.88; SEM: 6.4 s; CV: 10.05%) increased. Mean trial time decreased post familiarisation from T1-3 (210.9 ± 21.03 s) to T2-3 (206.3 ± 20.73 s). Conclusions: These findings are inconclusive regarding the short-term reliability of the CRA. The small sample size resulted in wide 95% confidence intervals associated with the ICCs, making the true ICC value hard to determine. The ICCs and MAPE suggest that the reliability of the CRA increased following a familiarisation trial, but this requires further research with a larger cohort to determine with confidence.

Habitat and climate shape growth patterns in a mountain ungulate.

Uptake and use of energy are of key importance for animals living in temperate environments that undergo strong seasonal changes in forage quality and quantity. In ungulates, energy intake strongly affects body mass gain, an important component of individual fitness. Energy allocation among life‐history traits can be affected by internal and external factors. Here, we investigate large‐scale variation in body growth patterns of Alpine chamois Rupicapra rupicapra rupicapra, in relation to sex, age, temperature, and habitat variations across 31 (sub)populations in the Central European Alps. Taking advantage of an exceptionally large dataset (n = 178,175) of chamois hunted over 27 consecutive years between 1993 and 2019 in mountain ranges with different proportions of forest cover, we found that (i) patterns of body mass growth differ between mountain ranges, with lower body mass but faster mass growth with increasing proportion of forest cover and that (ii) the effect of spring and summer temperatures on changes in body growth patterns are larger in mountain ranges with lower forest cover compared to mountain ranges with higher forest cover. Our results show that patterns of body mass growth within a species are more plastic than expected and depend on environmental and climatic conditions. The recent decline in body mass observed in Alpine chamois populations may have greater impacts on populations living above the treeline than in forests, which may buffer against the effects of increasing temperatures on life‐history traits.

Comprehensive and special physical fitness of judo athletes of provincial national teams in the age groups: youngster (U16) and junior (U21)

The research aimed to determine the relationship between the universal and special physical fitness of judoists. The study involved players from the youngster (U16) and junior (U21) age group from provincial teams. The International Physical Fitness Test was used to measure comprehensive fitness, and the Special Judo Fitness Test was applied to assess special fitness. The research has shown that juniors exhibit a higher level of all-round (excluding flexibility) and special fitness than youngsters. More relationships between comprehensive physical fitness and special fitness were demonstrated in the youngster group. Leg muscle strength, endurance, agility, and abdominal strength were found to have the most significant impact on the overall level of all-round fitness in the youngster age group, while in the age group under 21, endurance, hand strength, and arm strength had the most significant impact. It has been shown that the combination of individual components of versatile fitness in a given training cycle may bring positive effects in shaping those features in both age groups. Besides, it has been shown that when taking account of the athlete’s ontogenetic development and his/her sensitive period, the relationships between the components of comprehensive fitness and comprehensive and special fitness can significantly affect the effectiveness of the training process in both age groups.

Differences in resource acquisition, not allocation, mediate the relationship between behaviour and fitness: a systematic review and meta-analysis.

Within populations, individuals often show repeatable variation in behaviour, called 'animal personality'. In the last few decades, numerous empirical studies have attempted to elucidate the mechanisms maintaining this variation, such as life-history trade-offs. Theory predicts that among-individual variation in behavioural traits could be maintained if traits that are positively associated with reproduction are simultaneously associated with decreased survival, such that different levels of behavioural expression lead to the same net fitness outcome. However, variation in resource acquisition may also be important in mediating the relationship between individual behaviour and fitness components (survival and reproduction). For example, if certain phenotypes (e.g. dominance or aggressiveness) are associated with higher resource acquisition, those individuals may have both higher reproduction and higher survival, relative to others in the population. When individuals differ in their ability to acquire resources, trade-offs are only expected to be observed at the within-individual level (i.e. for a given amount of resource, if an individual increases its allocation to reproduction, it comes at the cost of allocation to survival, and vice versa), while among individuals traits that are associated with increased survival may also be associated with increased reproduction. We performed a systematic review and meta-analysis, asking: (i) do among-individual differences in behaviour reflect among-individual differences in resource acquisition and/or allocation, and (ii) is the relationship between behaviour and fitness affected by the type of behaviour and the testing environment? Our meta-analysis consisted of 759 estimates from 193 studies. Our meta-analysis revealed a positive correlation between pairs of estimates using both survival and reproduction as fitness proxies. That is, for a given study, behaviours that were associated with increased reproduction were also associated with increased survival, suggesting that variation in behaviour at the among-individual level largely reflects differences among individuals in resource acquisition. Furthermore, we found the same positive correlation between pairs of estimates using both survival and reproduction as fitness proxies at the phenotypic level. This is significant because we also demonstrated that these phenotypic correlations primarily reflect within-individual correlations. Thus, even when accounting for among-individual differences in resource acquisition, we did not find evidence of trade-offs at the within-individual level. Overall, the relationship between behaviour and fitness proxies was not statistically different from zero at the among-individual, phenotypic, and within-individual levels; this relationship was not affected by behavioural category nor by the testing condition. Our meta-analysis highlights that variation in resource acquisition may be more important in driving the relationship between behaviour and fitness than previously thought, including at the within-individual level. We suggest that this may come about via heterogeneity in resource availability or age-related effects, with higher resource availability and/or age leading to state-dependent shifts in behaviour that simultaneously increase both survival and reproduction. We emphasize that future studies examining the mechanisms maintaining behavioural variation in populations should test the link between behavioural expression and resource acquisition - both within and among individuals. Such work will allow the field of animal personality to develop specific predictions regarding the mediating effect of resource acquisition on the fitness consequences of individual behaviour.

Seasonal fitness parameters and selection indices in the natural population of Drosophila melanogaster Meig.

Aim. The purpose of investigation was to study the seasonal selection indices and its components in the natural population of Drosophila melanogaster Meig. Methods. The material for the study was the Gaidary-spring and Gaidary-autumn lines, obtained from the natural population of Gaidary in different seasons of the year. Fecundity and mortality/survival rates in the pre-reproductive period of development were studied. Based on these indicators, the selection indices were calculated according to the Crow`s formula. Results. In terms of individual components of fitness, such as egg production of females, the number of adult offspring, embryonic and pupal mortality, the spring and autumn populations of Gaidary did not show significant differences. Selection indices (Itot) in the autumn population of Gaidary were higher than in the spring population: in the embryonic period of development – by 50.4%, in the postembryonic period – by 67.5%. Differences in the intensity of selection are due to the variance of fertility, which was higher in the autumn population. Conclusions. Seasonal changes in the intensity of selection in different periods of ontogenesis are cumulative, which leads to increased selection pressure in the population of Gaidary in the autumn compared to spring.
 Keywords: Drosophila melanogaster Meig., natural population, fecundity, embryonic mortality, pupal mortality, Crow’s indices.

Relationship between Biological, Training, and Physical Fitness Variables in the Expression of Performance in Non-Professional Runners.

Sports performance is a multifactorial trait that can be associated with individual and environmental characteristics. In this study, the sample comprised 35 male runners, enrolled in the “InTrack” project. Information regarding variables related to runners’ training was obtained via an online questionnaire, while anthropometric and body composition variables, as well as physical fitness components (muscular power, isometric strength, local muscular endurance, agility, and aerobic capacity) were measured, and a global physical fitness score (based on physical fitness components measured) was computed. The Weltman test (3200 m) was used to estimate runners’ pace and their stride frequency. Linear regression was used, taking the running pace as dependent variable. The final model, comprising biological, physical fitness, spatiotemporal, and training variables, explained 86% of the running performance variance. Muscular power (β = −1.02; 95% CI = (−1.69)–(−0.35)), abdominal muscle endurance (β = −4.81; 95% CI = (−7.52)–(−2.10)), isometric strength (β = −422.95; 95% CI = (−689.65)–(−156.25)), global physical fitness (β = 27.14; 95% CI = 9.52–45.03), and stride frequency (β = −2.99; 95% CI = (−4.29)–(−1.69)) were significantly associated with performance, meaning that better results in tests and increasing the stride frequency leads to better performance. Individual characteristics and physical fitness components were demonstrated to be significant predictors for running performance.

Mechanisms driving component Allee effects during invasions: using a biological control agent as model invader

1. A demographic Allee effect refers to increasing per capita population growth with increasing abundance. It arises from component Allee effects, which exist when some component of individual fitness has a positive relationship with density. Newly arrived populations tend to be small, and their establishment success is influenced by various factors, including demographic Allee effects. Identifying mechanisms driving the Allee effect is of relevance for understanding establishment failure, developing strategies for improving biological control and conservation, and for managing biological invasions.2. We utilised an invasive plant biocontrol agent, Neolema ogloblini, as model to study Allee effects experienced by invading populations. We investigated mating failure and predator satiation as two component Allee effects that could potentially drive a demographic Allee effect in N. ogloblini populations.3. We released unmated adults onto isolated host patches using five release sizes and evaluated the mating status of females after 3 weeks in the field. The probability of being mated increased as number of males recovered increased, suggesting the presence of a mating‐failure component Allee effect in very small populations of N. ogloblini. Exclosures were used to evaluate survival of immatures of N. ogloblini developing in small group sizes, either in the presence or absence of generalist predators. Results revealed high levels of predation, but a positive relationship between larval survival and group size in the presence of generalist predators could not be verified.4. Our study identified relevant life‐history traits contributing to establishment failure in N. ogloblini and demonstrates the value of biocontrol agents as models to study mechanisms of species invasion.

Cis-regulatory evolution spotlights species differences in the adaptive potential of gene expression plasticity

Phenotypic plasticity is the variation in phenotype that a single genotype can produce in different environments and, as such, is an important component of individual fitness. However, whether the effect of new mutations, and hence evolution, depends on the direction of plasticity remains controversial. Here, we identify the cis-acting modifications that have reshaped gene expression in response to dehydration stress in three Arabidopsis species. Our study shows that the direction of effects of most cis-regulatory variants differentiating the response between A. thaliana and the sister species A. lyrata and A. halleri depends on the direction of pre-existing plasticity in gene expression. A comparison of the rate of cis-acting variant accumulation in each lineage indicates that the selective forces driving adaptive evolution in gene expression favors regulatory changes that magnify the stress response in A. lyrata. The evolutionary constraints measured on the amino-acid sequence of these genes support this interpretation. In contrast, regulatory changes that mitigate the plastic response to stress evolved more frequently in A. halleri. Our results demonstrate that pre-existing plasticity may be a stepping stone for adaptation, but its selective remodeling differs between lineages.

1008-P: Utility of a Comprehensive Physical Fitness Score by the Tests of Physical Fitness in Screening of Metabolic Diseases

A significant number of patients with metabolic diseases, including diabetes, remain undiagnosed worldwide. Although individual components of physical fitness have been shown to be predictive of metabolic diseases, it remains unclear whether a comprehensive assessment by physical fitness tests can be used to screen for metabolic diseases without clinical testing. Thus, we developed a new Physical Score consisting of comprehensive physical fitness indicators and elucidated the association between the resultant Physical Score and metabolic diseases, i.e., diabetes, hypertension, dyslipidemia, fatty liver, and metabolic syndrome, among Japanese. Analyzed were 49,850 persons (30,039 men) aged 30 to 69 y who underwent physical fitness tests. Principal component analysis was performed on the correlation matrix of the physical fitness test results (grip strength, single-leg balance, and trunk flexibility) according to sex and age. We defined the Physical Score as the first principal component score. The mean of the Physical Score was 0±1.1 (min -4.8, max 7.1). Multivariate logistic regression analysis showed that the risk of metabolic diseases increased approximately 1.2-1.4 times per 1 point reduction in the Physical Score (Table). The Physical Score is a useful and simple non-invasive tool for screening Japanese people for metabolic diseases.View largeDownload slideView largeDownload slide DisclosureT. Sato: None. K. Fujihara: None. M. H. Yamada: None. Y. Yaguchi: None. M. Kitazawa: None. M. Yamamoto: None. S. Kodama: None. K. Kato: None. H. Sone: Research Support; Self; Astellas Pharma Inc., Eisai Co., Ltd., Kyowa Kirin Co., Ltd., Novo Nordisk, Ono Pharmaceutical Co., Ltd., Taisho Pharmaceutical Co., Ltd., Takeda Pharmaceutical Co.

Flexible habitat use in a migratory songbird expanding across a human-modified landscape: is it adaptive?

Behavioural plasticity during habitat selection plays a key role in determining whether organisms may thrive under human-induced rapid environmental changes. As organisms rely on environmental cues to make decisions, these behavioural responses may be maladaptive. We studied the European stonechat Saxicola torquatus as a model open-habitat bird species breeding in three structurally different land-use types generated by agriculture and forestry activities. In this mosaic landscape, we compared the relative attractiveness and the breeding habitat quality of intensive grassland, Christmas tree plantations and clear-cut patches in plantation forests to test whether habitat selection was adaptive. We examined the settlement pattern of territorial males to evaluate habitat preference. We recorded key parameters reflecting reproductive performances, adult and first-year survival to estimate the individual fitness of the birds and assess the quality of the different land-use types for breeding. Stonechats preferentially settled in clear-cut patches, but their fitness was not found to be markedly different in comparison with the other occupied habitats. Although they produced slightly lower-quality offspring in clear-cut patches, we did not find a negative consequence on first-year survival probabilities or any among-habitat differences in adult survival. With our analysis integrating multiple components of individual fitness, we show that all occupied land-use types are similarly rewarding for the breeding stonechats. Our study shows that some species can benefit from novel land-use types emerging in the landscape as a result of human activities. Flexible habitat selection in the stonechat has most probably contributed to its recent population increase in Western Europe.

Analysis of movement recursions to detect reproductive events and estimate their fate in central place foragers

BackgroundRecursive movement patterns have been used to detect behavioral structure within individual movement trajectories in the context of foraging ecology, home-ranging behavior, and predator avoidance. Some animals exhibit movement recursions to locations that are tied to reproductive functions, including nests and dens; while existing literature recognizes that, no method is currently available to explicitly target different types of revisited locations. Moreover, the temporal persistence of recursive movements to a breeding location can carry information regarding the fate of breeding attempts, but it has never been used as a metric to quantify recursive movement patterns. Here, we introduce a method to locate breeding attempts and estimate their fate from GPS-tracking data of central place foragers. We tested the performance of our method in three bird species differing in breeding ecology (wood stork (Mycteria americana), lesser kestrel (Falco naumanni), Mediterranean gull (Ichthyaetus melanocephalus)) and implemented it in the R package ‘nestR’.MethodsWe identified breeding sites based on the analysis of recursive movements within individual tracks. Using trajectories with known breeding attempts, we estimated a set of species-specific criteria for the identification of nest sites, which we further validated using non-reproductive individuals as controls. We then estimated individual nest survival as a binary measure of reproductive fate (success, corresponding to fledging of at least one chick, or failure) from nest-site revisitation histories during breeding attempts, using a Bayesian hierarchical modeling approach that accounted for temporally variable revisitation patterns, probability of visit detection, and missing data.ResultsAcross the three species, positive predictive value of the nest-site detection algorithm varied between 87 and 100% and sensitivity between 88 and 92%, and we correctly estimated the fate of 86–100% breeding attempts.ConclusionsBy providing a method to formally distinguish among revisited locations that serve different ecological functions and introducing a probabilistic framework to quantify temporal persistence of movement recursions, we demonstrated how the analysis of recursive movement patterns can be applied to estimate reproduction in central place foragers. Beyond avian species, the principles of our method can be applied to other central place foraging breeders such as denning mammals. Our method estimates a component of individual fitness from movement data and will help bridge the gap between movement behavior, environmental factors, and their fitness consequences.

Inter- and intraspecific variability of plant individual growth and its role on species ranking in grasslands

Abstract Aims Individual growth constitutes a major component of individual fitness. However, measuring growth rates of herbaceous plants non-destructively at the individual level is notoriously difficult. This study, based on an accurate non-destructive method of aboveground biomass estimation, aims to assess individual relative growth rates (RGRs) of some species, identify its environmental drivers and test its consequences on community patterning. We specifically address three questions: (i) to what extent environmental conditions explain differences in individual plant growth between sites, (ii) what is the magnitude of intraspecific variability of plant individual growth within and between sites and (iii) do species-averaged (dis-)advantage of individual growth compared with the whole vegetation within a site correlate with species ranking at the community level? Methods We monitored the growth of individuals of four common perennial species in 18 permanent grasslands chosen along a large pedoclimatic gradient located in the Massif Central, France. We measured soil properties, levels of resources and meteorological parameters to characterize environmental conditions at the site level. This design enables us to assess the influence of environmental conditions on individual growth and the relative extent of inter-individual variability of growth explained within and between sites. We determined the ranking of each of the four species in each site with botanical surveys to assess the relationship between species-averaged growth (dis-)advantage relative to the whole community and species rank in the community. Important Findings We found that environmental conditions explain a significant proportion of individual growth variability, and that this proportion is strongly variable between species. Light availability was the main driver of plant growth, followed by rainfall amount and potential evapotranspiration, while soil properties had only a slight effect. We further highlighted a moderate to high within-site inter-individual variability of growth. We finally showed that there was no correlation between species ranking and species-averaged individual growth.

Association Between Physical Fitness and Bone Strength and Structure in 3- to 5-Year-Old Children.

The positive association between physical fitness and bone structure has been widely investigated in children and adolescents, yet no studies have evaluated this influence in young children (ie, preschoolers). Fit children will present improved bone variables when compared with unfit children, and no sex-based differences will emerge in the sample. Cross-sectional study. Level 3. Handgrip strength, standing long jump (SLJ), speed/agility, balance, and cardiorespiratory fitness (CRF) were assessed using the Assessing FITness levels in PREschoolers (PREFIT) test battery in 92 children (50 boys; age range, 3-5 years). A peripheral quantitative computed tomography scan was performed at 38% of the length of the nondominant tibia. Cluster analysis from handgrip strength, SLJ, speed/agility, and CRF was developed to identify fitness groups. Bone variables were compared between sexes and between cluster groups. The association between individual physical fitness components and different bone variables was also tested. Three cluster groups emerged: fit (high values on all included physical fitness variables), strong (high strength values and low speed/agility and CRF), and unfit (low strength, speed/agility, and CRF). The fit group presented higher values than the strong and unfit groups for total and cortical bone mineral content, cortical area, and polar strength strain index (all P < 0.05). The fit group also presented a higher cortical thickness when compared with the unfit group (P < 0.05). Handgrip, SLJ, and speed/agility predicted all bone variables except for total and cortical volumetric bone mineral density. No differences were found for bone variables between sexes. The results suggest that global fitness in preschoolers is a key determinant for bone structure and strength but not volumetric bone mineral density. Physical fitness is a determinant for tibial bone mineral content, structure, and strength in very young children. Performing physical fitness tests could provide useful information related to bone health in preschoolers.

Physical and physiological impacts of ocean warming alter phenotypic selection on sperm morphology

Abstract Global warming may threaten fertility, which is a key component of individual fitness and vital for population persistence. For males, fertility relies on the ability of sperm to collide and fuse with eggs; consequently, sperm morphology is predicted to be a prime target of selection owing to its effects on male function. In aquatic environments, warming will expose gametes of external fertilizers to the physiological effects of higher temperature and the physical effects of lower viscosity. However, the consequences of either effect for fertility, and for selection acting on sperm traits to maintain fertility, are poorly understood. Here, we test how independent changes in water temperature and viscosity alter male fertility and selection on sperm morphology in an externally fertilizing marine tubeworm. To create five fertilization environments, we manipulate temperature to reflect current‐day conditions (16.5°C), projected near‐term warming (21°C) and projected long‐term warming (25°C), then adjust two more environments at 21°C and 25°C to the viscosity of environments at 16.5°C and 21°C, respectively. We then use a split‐ejaculate design to measure the fertility of focal males, and selection on their sperm, in each environment. Projected changes in temperature and viscosity act independently to reduce male fertility, but act jointly to alter selection on sperm morphology. Specifically, environments resulting from projected warming alter selection on the sperm midpiece in ways that suggest shifts in the energetic challenges of functioning under stressful conditions. Selection also targets sperm head dimensions and tail length, irrespective of environment. We provide the first evidence that projected changes in ocean temperature and viscosity will not only impact the fertility of marine external fertilizers, but expose their gametes to novel selection pressures that may drive them to adapt in response if gamete phenotypes are sufficiently heritable. A free Plain Language Summary can be found within the Supporting Information of this article.