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The social amoeba Dictyostelium discoideum switches between solitary growth and social fruitification depending on nutrient availability. Under starvation, cells aggregate and form fruiting bodies consisting of spores and altruistic stalk cells. Once cells socially committed, they complete fruitification, even if a new source of nutrients becomes available. This social commitment is puzzling because it hinders individual cells from resuming solitary growth quickly. One idea posits that traits that facilitate premature de-commitment are hindered from being selected. We studied outcomes of the premature de-commitment through forced refeeding. Our results show that when refed cells interacted with non-refed cells, some of them became solitary, whereas a fraction was redirected to the altruistic stalk, regardless of their original fate. The refed cells exhibited reduced cohesiveness and were sorted out during morphogenesis. Our findings provide an insight into a division of labor of the social amoeba, in which less cohesive individuals become altruists. [ABSTRACT FROM AUTHOR]

The temporal variation of the degree of fluctuating asymmetry of the characters of skull morphology, as a measure of the developmental stability, is evaluated in the common shrew (Sorexaraneus L., 1758) in Central Siberia. Four-year cycles in this population under conditions of climatic stability in the past century were accompanied by significant changes in the level of developmental stability, suggesting a negative impact under a high density. Population fluctuations under the conditions of climatic instability in this century commonly occur without essential changes in the developmental stability, which can be related to both the impact of oscillations in the environmental conditions and an increase in the carrying capacity of the habitat due to the increase in temperature. Deterioration of developmental stability takes place occasionally in the case of an adverse overpopulation impact in the year of peak population abundance that is beyond the certain threshold level, which has increased due to climate change. The results indicate the importance of simultaneous monitoring of population abundance and developmental stability to provide information on possible mechanisms of changes in the population dynamics that occur due to climate change. [ABSTRACT FROM AUTHOR]

The degree of developmental stability of individuals and populations is most often estimated by their level of fluctuating asymmetry (FA) — the random deviations from perfect symmetry. In our previous work, we recorded high levels of FA (FAMI index: frequency of asymmetric manifestation of an individual) in Pelophylax ridibundus populations that inhabit biotopes at Sazliyka River, south Bulgaria with high levels of anthropogenic pollution (domestic sewage pollution). At the same time, in the biotopes located in the upper reaches of the river (less disrupted habitats), the populations showed low levels of FA. Currently, we present the results of the study of the values of several morphological parameters: snout-vent length (SVL), body weight (BW), and body condition factor (CF) in the same populations of P. ridibundus. In addition, we evaluate the correlation between the values of these morphological parameters and the values of fluctuating asymmetry (the FAMI index), using the Kendall rank correlation analysis. The analysis of the relationships between the parameters characterizing the physical fitness of frogs and the indicator of developmental stability — the FAMI index — did not establish statistically significant correlations in the analyses in the whole groups of P. ridibundus from each site and in the correlations between sexes. We believe that the approaches to the study of developmental stability (analysis of fluctuating asymmetry levels) and those related to the assessment of physical fitness (health status) of frogs should be applied independently of each other. [ABSTRACT FROM AUTHOR]

A matrix manipulation new to the quantitative study of develomental stability reveals unexpected morphometric patterns in a classic data set of landmark-based calvarial growth. There are implications for evolutionary studies. Among organismal biology's fundamental postulates is the assumption that most aspects of any higher animal's growth trajectories are dynamically stable, resilient against the types of small but functionally pertinent transient perturbations that may have originated in genotype, morphogenesis, or ecophenotypy. We need an operationalization of this axiom for landmark data sets arising from longitudinal data designs. The present paper introduces a multivariate approach toward that goal: a method for identification and interpretation of patterns of dynamical stability in longitudinally collected landmark data. The new method is based in an application of eigenanalysis unfamiliar to most organismal biologists: analysis of a covariance matrix of Boas coordinates (Procrustes coordinates without the size standardization) against their changes over time. These eigenanalyses may yield complex eigenvalues and eigenvectors (terms involving i = - 1 ); the paper carefully explains how these are to be scattered, gridded, and interpreted by their real and imaginary canonical vectors. For the Vilmann neurocranial octagons, the classic morphometric data set used as the running example here, there result new empirical findings that offer a pattern analysis of the ways perturbations of growth are attenuated or otherwise modified over the course of developmental time. The main finding, dominance of a generalized version of dynamical stability (negative autoregressions, as announced by the negative real parts of their eigenvalues, often combined with shearing and rotation in a helpful canonical plane), is surprising in its strength and consistency. A closing discussion explores some implications of this novel pattern analysis of growth regulation. It differs in many respects from the usual way covariance matrices are wielded in geometric morphometrics, differences relevant to a variety of study designs for comparisons of development across species. [ABSTRACT FROM AUTHOR]

How plants respond to density via modular plasticity is obscure, probably because relevant studies using covariance analysis (ANCOVA) and allometric analysis rarely focus on multiple stages of plant growth, and also the two approaches are seldom used simultaneously. In this study, a field experiment evaluated the effects of three density levels on resource allocation traits in Abutilon theophrasti and tested the degree to which these were explained by indirect effects of density on biomass over time. Results showed inconsistent responses in allocation traits and allometric relationships at each growth stage. At 30 days of plant growth, high density increased root/stem, root/leaf, and stem/leaf, but did not affect any allometric relationships. At 50 days, density altered most mass and ratio traits, but not for allometric exponents. At 70 days, density altered allometric relationships, but did not affect plant allocation patterns. The stage-dependent allometric relationships and the fact that allocation plasticity and allometric plasticity did not coincide both suggested that one-stage allometric plasticity might be apparent plasticity. In response to the increase of density, plants first altered the strategy of biomass partitioning and then growth rate or developmental stage, indicating that density effects intensified over time. For plasticity in a modular trait, size effects can be regarded as a component of (indirect) environmental effects, with the residual variation after removal of size effects being the other component of plant (direct) active response. The insights into apparent plasticity of allometry and two components of plasticity should be of essential importance to investigating phenotypic plasticity and its ecological and evolutionary implications. [ABSTRACT FROM AUTHOR]

Patterns of appearance of wing venation abnormalities in the black-veined white Aporia crataegi L. were studied. These abnormalities form four types of bilateral compositions and vary quantitatively in the degree of phenotypic expression. This implies that wing venation abnormalities in A. crataegi may be regarded as stable states of threshold nonmetric traits with hidden quantitative variability, i.e., "phenes." Different venation abnormalities vary in the pattern of appearance, either showing a trend toward joint occurrence in one individual or occurring independently of each other. Some abnormalities appear mainly asymmetrically, randomly, and independently in different body sides, while others tend to occur symmetrically. Only those abnormalities which appear independently of each other, randomly, and independently in different body sides can be considered random developmental errors and indicators of developmental instability. Such abnormalities were rare, making up less than 20% of the total number. [ABSTRACT FROM AUTHOR]

Within-plant variation in seed size may merely reflect developmental instability, or it may be adaptive in facilitating diversifying bet-hedging, that is, production of phenotypically diverse offspring when future environments are unpredictable. To test the latter hypothesis, we analyzed patterns of variation in seed size in 11 populations of the perennial vine Dalechampia scandens grown in a common greenhouse environment. We tested whether population differences in the mean and variation of seed size covaried with environmental predictability at two different timescales. We also tested whether within-plant variation in seed size was correlated with independent measures of floral developmental instability and increased under stressful conditions. Populations differed genetically in the amount of seed-size variation occurring among plants, among infructescences within plants, and among seeds within infructescences. Within-individual variation was not detectably correlated with measures of developmental instability and did not increase under stress, but it increased weakly with short-term environmental unpredictability of precipitation at the source-population site. These results support the hypothesis that greater variation in seed size is adaptive when environmental predictability is low. [ABSTRACT FROM AUTHOR]

Parental mind-mindedness, the parent's propensity to treat the child as an intentional agent, has repeatedly shown to promote children's development of social understanding and secure attachment. Less is known about whether the impact of maternal and paternal mind-mindedness extends to children's social and behavior problems. We investigated the combined effect of mothers' and fathers' (N = 104) mind-mindedness at 4, 12, and 30 months on children's social competence and externalizing and internalizing behavior problems at 4.5 years. Besides, we examined the stability, continuity, parental concordance, and inter-parental differences in the use of mind-related comments. Appropriate mind-mindedness (i.e., correct interpretations of the child's mental states) and nonattuned mind-mindedness (i.e., misinterpretations of the child's mental states) were observed during parent-child free-play interactions. Social competence, internalizing and externalizing behavior problems were assessed using both parents' reports. Hierarchical multiple regression analyses showed that, at 12 months, infrequent use of appropriate mind-related comments of both parents predicted children's externalizing problems, while their frequent use of nonattuned comments predicted children's low social competence. Furthermore, mothers' frequent use of nonattuned comments at 12 and 30 months and fathers' nonattuned comments at 30 months predicted children's externalizing behavior. The findings suggest that both parents' low use of mind-related comments, and frequent misinterpretations of their child's mind, may act as risk factors for later social and behavior problems of their child. [ABSTRACT FROM AUTHOR]

The functions of HSP90 chaperones in the protein-folding system and regulation of specific substrates affecting multiple signal pathways and cellular processes were considered. The triple role of HSP90 in stress was described: binding damaged proteins and directing them for refolding or degradation, regulation of the heat-shock gene induction, and alteration in the gene expression program. Based on the results of studies of the model species Arabidopsis thaliana, the role of HSP90 in growth maintenance and morphogenesis stability, developmental plasticity, and mechanisms of stress tolerance in plants was shown. A model for the interaction of the HSP90 functions under normal and stressful conditions is presented. [ABSTRACT FROM AUTHOR]

The value of fluctuating asymmetry (FA) of trees and small mammals is considered as an indicator of developmental instability. The urban territories with recreation zones, sites with increased radiation background, and the areas affected by mining facilities have been analyzed as anthropogenically transformed areas. The following tree and small mammalian species are the objects of the study: Siberian silver birch ( Betula platyphylla), spreading birch ( B. divaricata), dwarf birch ( B. exilis), shrub alder ( Duschekia fruticosa), basket willow ( Salix viminalis), northern red-backed vole ( Clethrionomys rutilus), tundra vole ( Microtus oeconomus), Laxmann's shrew ( Sorex caecutiens), and tundra shrew ( S. tundrensis). In total, 60000 leaves have been measured and 3500 rodent sculls have been examined. The issues of selection of bioindicator species and the factors distorting the results of environmental quality assessment according to developmental instability are discussed. A statistically significant increase in FA of plants is recorded in urban territories as compared with the wildlife biotopes. A positive correlation of FA value with transport load, concentration of heavy metals in soil, and atmospheric air pollution is observed. The proximity to a roadway and the state of road pavement influence the FA value. The main source of pollution in the administrative center (Yakutsk) is motor vehicles; correspondingly, large streets and crossroads with a high transport load are the most polluted sites. As for the industrial center (city of Mirnyi), pollution spreads from the areas affected by mining to the residential area. The main pollution source in a small administrative center (city of Aldan) is the federal highway. It is recommended to concurrently use the FA characteristics of plant and animals in the area affected by the mining industry. Characteristic of this industry is withdrawal of large areas of natural landscapes; typically, transformed plots alternate weakly affected plots. The specific features of the effects of diamond, gold, and coalmining industries, as well as oil and gas field development, are discussed, which should be taken into account in sampling for bioindication. The problem of bioindication in the areas completely devoid of soil and plant cover can be solved by biotesting via assessment of bunching onion seed germination rate and the rate of mitotic aberrations. An increase in the FA level in trees and small mammals is observed in the areas transformed by the mining industry displaying a chronically increased radiation background and oil-polluted as a result of technogenic accidents. The use of FA index makes it possible to estimate the environmental quality and to compare the state of territories located under different natural and climatic conditions and influenced by multicomponent anthropogenic impacts differing in their strength and genesis, which interferes with their comparison. [ABSTRACT FROM AUTHOR]

The features of the asymmetry of the shape of laminas of English oak (Quercus robur) are studied. In six randomly selected populations, a Generalized Procrustes analysis showed the mixture of fluctuating asymmetry (FA) and directional asymmetry (DA). One population showed pure FA. Covariance symmetric matrix revealed more variance of the landmarks along the symmetry axis in comparison to the asymmetric matrix explaining the variation of bilaterally symmetrical landmarks. A weak correlation association between the Procrustean coordinate values of the covariance symmetric matrices and asymmetric matrixes is obtained (r = 0.25, p < 0.01). The variation coefficients of the factor "side" and "side x population" among the studied six populations were 48.24 and 44.93%, respectively. The study demonstrates that the cluster analysis of the principal components matrix of asymmetry could be used for the analysis of genotypic variability. [ABSTRACT FROM AUTHOR]

Developmental and functional abnormalities of the reproductive system of fishes are examined in connection with the changes in conditions of their existence, in particular, the anthropogenic influence. The author's own data and literature sources on abnormalities of gametogenesis and gonadogenesis in a number of sturgeon species in relation to anthropogenic pressure on the water bodies are analyzed, and their systematization is performed. It is shown that these abnormalities, which are disorders of the stability of development, can serve as indicators of the environmental health. [ABSTRACT FROM AUTHOR]

The study of the developmental stability in natural populations is a promising direction of population developmental biology, which opens new possibilities for estimation of the nature of the observed phenotypic diversity and understanding the mechanisms of population dynamics and microevolutionary transformations. This direction of the studies allows one to approach the estimation of the condition of natural populations. A special analysis of possible changes in the developmental stability indicators under different anthropogenic effects allows one to characterize this approach as one of the main within the methodology of the health of environment estimation based on the organism condition characteristics by the developmental homeostasis. The approach seems promising for the estimation and monitoring of the condition of natural populations of different species as well as for the environmental quality estimation. [ABSTRACT FROM AUTHOR]

The Drosophila bipectinata species complex comprises of four very closely related species namely D. bipectinata, D. parabipectinata, D. malerkotliana and D. pseudoananassae. It was found that irrespective of the evolutionary divergence among the species, FA which is reflective of the developmental precision remains nearly same in four species. During the present study, the level of FA in different morphological traits was studied in interspecific hybrids and compared with that of parental species with the view that it would throw light on the degree of divergence between the parental species. If they have not diverged much, the interspecific hybrids may have a similar FA level, incompatibilities between their genomes being negligible. On the other hand, if there is substantial divergence, the level of FA may be higher due to incompatibility between the genomes of the parental species. The morphological traits taken were sternopleural bristle number and wing length in both males and females and ovariole number and sex-comb tooth number in females and males respectively. However, except in a few cases, we could not detect any significant differences in the level of FA in hybrids as compared to pure species. On the other hand, a number of abnormalities like poor viability, dystrophied ovaries, asymmetrical eyes etc., could be detected in hybrids from crosses involving D. pseudoananassae as one of the parents. Therefore, we conclude that specific developmental pathways are more susceptible to developmental disturbances due to genomic incompatibilities than the large complex system bringing about developmental stability. [ABSTRACT FROM AUTHOR]

The value of fluctuating asymmetry is considered to be an indicator of the developmental instability of the organism. The consequences of activities of the mining industry facilities, which are characterized by alienation and transformation of large areas of natural landscapes, are analyzed as an anthropogenic factor. The objects of study were small mammals (northern red-backed ( Clethrionomys rutilus) and gray red-backed ( Clethrionomys rufocanus) voles, tundra vole ( Microtus oeconomus), Laxmann's ( Sorex caecutiens) and tundra ( S. tundrensis) shrews) and trees (Japanese white birch ( Betula platyphylla), Betula divaricate, Betula exilis, Duschekia fruticosa, and busket willow ( Salix viminalis)). In total, 3500 skulls and approximately 30000 leaves collected in the taiga zone of Yakutia were studied. The index of fluctuating asymmetry, as well as population parameters and composition of small mammal communities, were analyzed. The data on the value of the fluctuating asymmetry in the studied species in natural habitats are given. It is shown that, in natural conditions, this parameter can rise with deterioration in living conditions, particularly at the ecological periphery of the range. Anthropogenic transformation of natural landscapes creates an 'anthropogenic periphery' and causes changes similar to the adaptive responses at the northern limit of the distribution of species. It was found that, through pollution and disruption of ecosystems, the mining industry affects all levels of organization of the living matter, but the population and cenotic parameters give an unambiguous response only at macroanthropogenic transformations. Increase in the level of fluctuating asymmetry is the most sensitive indicator of anthropogenic impact and it should also be taken into account that disruptions in the developmental stability of an organism reflect the destructive processes occurring in the population and community. [ABSTRACT FROM AUTHOR]

Individuals under stress and those of intrinsically low quality may have insufficient resources to invest in developing equally on both sides. Such individuals may thus display higher levels of fluctuating asymmetry (FA)-small, random departures from perfect bilateral symmetry. These small deviations from symmetry are often less than 1 % of trait size, similar to variation in symmetry generated by measurement error. Studies regarding FA must thoroughly assess measurement error if reliable conclusions regarding FA and fitness parameters are to be drawn. Although many studies regarding facial symmetry in humans have been conducted, few have been carried out on non-human primates. The primary aim of this study was to assess whether facial FA in a non-human primate, the olive baboon ( Papio anubis) can be reliably measured from digital photographs. Facial FA was measured in three sets of bilaterally symmetrical landmarks from digital images of 35 olive baboons at Gashaka-Gumti National Park, Nigeria. Measurement error was found to be low indicating a high level of reliability based on comparisons of values from two photos of the same individual ( r = 0.85). Measurement error was found to be related to the size of the face. This suggests that orientation error increases in large faces and could potentially influence FA scores. These findings highlight the need for FA studies to measure and control error caused by orientation and position of subjects if FA is to be of utility to behavioural ecology and conservation (e.g. if FA reflects whether individuals in a population are suffering from environmental or genetic stress). [ABSTRACT FROM AUTHOR]

The expression of structural plumage colours (i.e. those generated by feather microstructures) often acts as a signal of quality, but the signal content of these traits remains relatively unknown. However, a hypothesis posits that the production of structural colouration depends on developmental stability because variation in developmental programs can affect the precise feather structures that generate structural colour. Here, I test this hypothesis by exploring the relationship between crown colouration, calculated by using a model of avian visual perception, and fluctuating asymmetry (FA) of tail feathers in Blue Tits ( Cyanistes caeruleus). As predicted, there was a negative correlation between the ultraviolet (UV)-blue reflectance of the crown patch and FA of feathers. There was indirect evidence for a relationship between fledging success and UV-blue colour, but not for a condition dependence of this trait. These results suggest that the signal content of the structural colouration of Blue Tits may be information regarding individuals' developmental stability. As the colour components of the crown colouration were calculated with an avian visual perception model, this indicates that Blue Tits can perceive differences in FA through variation in the expression of structural colour. [ABSTRACT FROM AUTHOR]

Some cases of Robertsonian (Rb) polymorphism in the common shrew (Sorex araneus L.) are believed not to be associated with hybrid zones. One of the hypotheses explaining the persistence of such Rb polymorphism is that they are maintained by some form of selection for Rb heterozygotes. To test this hypothesis, we compared several parameters between homozygotes and Rb heterozygotes for the mp chromosome pair. We used shrews from Jurowce population in Poland, situated within the range of the Białowieża race, where Rb polymorphism persists far from any known hybrid zone. We found no differences between the two karyotypic classes in maximum metabolic rate during running (forced activity). However, the Rb heterozygotes showed significantly higher maximum metabolic rate during swimming (forced activity combined with thermal stress). The levels of fluctuating asymmetry (FA) of homozygous and Rb heterozygous shrews were indistinguishable, indicating no effect of chromosomal heterozygosity on developmental stability of shrews. We suggest that selective advantages, such as the higher metabolic performance in activity combined with cold stress, may outweigh the expected negative effects of Rb heterozygosity upon fertility, and help to maintain huge areas of the Rb polymorphism in this species.Heredity (2009) 102, 155–162; doi:10.1038/hdy.2008.102; published online 1 October 2008 [ABSTRACT FROM AUTHOR]

Environmental stress has been suggested to be a major evolutionary force, both through inducing strong selection and because of its direct impact on developmental buffering processes that alter the evolvability of organisms. In particular, temperature has attracted much attention because of its importance as an ecological feature and the relative ease with which it can be experimentally manipulated in the lab. Evolution Canyon, Lower Nahal Oren, Israel, is a well studied natural site where ecological parameters are suspected to drive evolutionary differentiation. In this study, using Drosophila melanogaster isofemale lines derived from wild flies collected on both slopes of the canyon, we investigated the effect of developmental temperature upon the different components of phenotypic variation of a complex trait: the wing. Combining geometric and traditional morphometrics, we find only limited evidence for a differentiation among slopes. Investigating simultaneously phenotypic plasticity, genetic variation among isofemale lines, variation among individuals and fluctuating asymmetry, we could not identify a consistent effect of the stressful conditions encountered on the south facing slope. The prevailing structuring effect is that of the experimentally manipulated temperature which clearly influences wing mean size and shape. Variability, in contrast, is not consistently affected by temperature. Finally, we investigated the specific relationship between individual variation and fluctuating asymmetry. Using metric multi-dimensional scaling we show that the related patterns of wing shape variation are not identical, supporting the view that the underlying developmental processes are to a certain extent different. [ABSTRACT FROM AUTHOR]

Mating between relatives generally results in reduced offspring viability or quality, suggesting that selection should favor behaviors that minimize inbreeding. However, in natural populations where searching is costly or variation among potential mates is limited, inbreeding is often common and may have important consequences for both offspring fitness and phenotypic variation. In particular, offspring morphological variation often increases with greater parental relatedness, yet the source of this variation, and thus its evolutionary significance, are poorly understood. One proposed explanation is that inbreeding influences a developing organism’s sensitivity to its environment and therefore the increased phenotypic variation observed in inbred progeny is due to greater inputs from environmental and maternal sources. Alternatively, changes in phenotypic variation with inbreeding may be due to additive genetic effects alone when heterozygotes are phenotypically intermediate to homozygotes, or effects of inbreeding depression on condition, which can itself affect sensitivity to environmental variation. Here we examine the effect of parental relatedness (as inferred from neutral genetic markers) on heritable and nonheritable components of developmental variation in a wild bird population in which mate choice is often constrained, thereby leading to inbreeding. We found greater morphological variation and distinct contributions of variance components in offspring from highly related parents: inbred offspring tended to have greater environmental and lesser additive genetic variance compared to outbred progeny. The magnitude of this difference was greatest in late-maturing traits, implicating the accumulation of environmental variation as the underlying mechanism. Further, parental relatedness influenced the effect of an important maternal trait (egg size) on offspring development. These results support the hypothesis that inbreeding leads to greater sensitivity of development to environmental variation and maternal effects, suggesting that the evolutionary response to selection will depend strongly on mate choice patterns and population structure. [ABSTRACT FROM AUTHOR]

Variability contrasts with variation in that variability describes the potential for variation, not simply the expressed variation. The power of studying variability lies in creating a conceptual framework around which the relationship between the genotype and phenotype can be understood. Here, we attempt to demonstrate the importance of phenotypic variability, how it structures variation, and how fundamental developmental processes structure variability. Given the broad scope of this topic, we focus on three widely studied properties of variability: canalization, developmental stability and morphological integration. We have organized the paper to emphasize the importance of differentiating between the theory surrounding these components of phenotypic variability, their measurement and the biological factors surrounding their expression. First, we define these properties of variability, how they relate to each other and to variability as a whole. Second, we summarize the common methods of measurement for canalization, developmental stability and morphological integration and the reasoning behind these methods. Finally, we focus on jaw development as an example of how the basic processes of development affect variability and the resultant variation, with emphasis on how processes at all levels of the organismal hierarchy interact with one another and contribute to phenotypic variability. [ABSTRACT FROM AUTHOR]

Developmental stability reflects the degree to which phenotypic expression is unaffected by random accidents or developmental noise. Developmental stability may be measured by phenodeviance or fluctuating asymmetry (FA), and estimation of developmental stability has attracted substantial interest because it appears to represent a relatively simple method to identify sub lethal stress exposure and to assess animal welfare. As a part of a long-term study, the work presented here primarily aimed to investigate impacts on developmental instability in farmed salmon offspring ten months post hatch attributable to maternal cortisol administration prior to spawning and mild hyperthermia exerted during incubation. Main results show that maternal cortisol enhancement increased the level of FA in pectoral and pelvic fins, but did not affect the frequency of malformations in offspring. Mild hyperthermia during incubation increased weight and fork length and also increased pelvic fin FA. Malformed fish were heavier and longer than the normal ones, and pelvic fin asymmetry was positively related to condition factor. These results illustrate plausible lasting impacts on offspring development due to the maternal endocrinological state at spawning and indicate that developmental instability in farmed salmon juveniles may mirror aspects of the broodstock’s housing conditions. [ABSTRACT FROM AUTHOR]

Fluctuating asymmetry (FA), used as an indicator of developmental stability, has long been hypothesized to be negatively correlated with genetic variability as a consequence of more variable organisms being better suited to buffer developmental pathways against environmental stress. However, it is still a matter of debate if this is due to metabolic properties of enzymes encoded by certain key loci or rather to overall genomic heterozygosity. Previous analyses suggest that there might be a general difference between homeo- and poikilotherms in that only the latter tend to exhibit the negative correlation predicted by theory. In the present study, we addressed these questions by analysing roe deer (Capreolus capreolus) from five German populations with regard to FA in metric and non-metric skull and mandible traits as well as variability at eight microsatellite loci. Genetic variability was quantified by heterozygosity and mean d2 parameters, and although the latter did not show any relationship with FA, we found for the first time a statistically significant negative correlation of microsatellite heterozygosity and non-metric FA among populations. Because microsatellites are non-coding markers, this may be interpreted as evidence for the role of overall genomic heterozygosity in determining developmental stability. To test if the threshold character of non-metric traits is responsible for the metric vs non-metric difference we also carried out calculations where we treated our metric traits as threshold values. This, however, did not yield significant correlations between FA and genetic variability either.Heredity (2007) 98, 392–400. doi:10.1038/sj.hdy.6800954; published online 21 March 2007 [ABSTRACT FROM AUTHOR]

The Berg hypothesis posits that, in plants with specialized pollination systems, floral characters should evolve to become integrated with each other and decoupled from vegetative characters. We test this hypothesis by comparing serially homologous and morphologically similar characters in leaves and involucral bracts in the Neotropical vine Dalechampia scandens, which has a specialized pollination system based on resin-collecting bees. The involucral bracts serve a number of specialized floral functions, including signaling and protection, that may put them under stronger selection for precision than the less specialized leaves. The homology and morphological similarity of the leaves and bracts allow us to make a sharper test of Berg’s hypothesis than is possible in most other systems. We found support for the hypothesis in that the bracts had lower coefficients of variation than the leaves for comparable traits. Also in support of the hypothesis, we found essentially zero phenotypic correlations between bracts and leaves at the same time that we found moderate correlations between different leaves and between different bracts. In contradiction to the hypothesis, however, we did not find higher correlations among traits within bracts than within leaves, and we found no evidence of bracts being more developmentally stable than the leaves. [ABSTRACT FROM AUTHOR]

Whether fluctuating asymmetry (FA) provides a useful metric indicator of the degree of environmental stress experienced by populations is still a contentious issue. We investigated whether the degree of FA in skeletal elements is useful in elucidating the degree of environmental stress experienced by frog populations, and further, tested the proposition that a trait’s sensitivity to stress—as reflected in the degree of FA—is related to the degree of directional selection experienced by the given trait. We compared the degree of FA in four bilateral skeletal elements of male and female moor frogs ( Rana arvalis) originating from low (acidified) and neutral pH populations. While the degree of uncorrected FA was unrelated to the degree of acidity, the growth rate and age of the individuals, the size-corrected FA was significantly higher in low than in neutral pH populations and decreased with individual ages and growth rates. In addition, both measures of FA were significantly higher in males and in particular in traits presumably under high sexual selection as indicated by the degree of sexual size dimorphism. All in all, the results indicate that individuals from acidified localities are smaller, younger and exhibit a significantly higher degree of FA than individuals from neutral pH populations. These results constitute the first assessment of FA in amphibians and suggest that the degree of FA in skeletal traits can be a useful indicator of the degree of environmental stress experienced by amphibian populations. [ABSTRACT FROM AUTHOR]

In the Danish region of Kværkeby, a mutation in an, as yet, unknown single autosomal gene has resulted in a dominant resistance (R-) allele in the flea beetle Phyllotreta nemorum L. (Coleoptera: Chrysomelidae: Alticinae). It enables the beetle to overcome the defences of Barbarea vulgaris ssp. arcuata (Opiz.) Simkovics G-type (Brassicaceae) and use it as a host plant. In this study, we investigated the pleiotropic effects associated with the presence of this particular R-allele in female P. nemorum. These females had the R-allele backcrossed into the genetic background of non-resistant beetles. The effects were investigated under both favourable and stressful conditions (cold shock). The presence of the R-allele in a non-resistant genetic background caused a very high mortality in resistant individuals during the early stages of development under both conditions, but it did not affect the adult life-history traits longevity, body size and fecundity, under both conditions. Regardless of temperature treatment, resistant females in general were found to lay significantly more eggs. Developmental stability, as measured by tibia length fluctuating asymmetry, was not correlated with overall developmental stress in this study. [ABSTRACT FROM AUTHOR]

The developmental stability indices, leaf width based fluctuating asymmetry (FA1), and lateral vein length based directional asymmetry (RDA1) of Platanus acerifolia were studied. All the leaves were sampled from 14 sites that were categorized based on different urban environmental stress levels (UESL) in Shanghai metropolitan, China. Besides, foliar stomatal density and stomatal length were also studied as the subsidiary indices to test the availability of developmental stability indices as the indicator under a stressful environment. Results showed seasonal variation of FA1 and RDA1 existed among the 14 sites, but the data showed significant negative correlation between FA1 and UESL (FA1 = 0.029 − 0.000 9UESL + 0.000 3UESL2, r = 0.766 5, P = 0.001 4). However, a similar trend was not found between RDA1 and UESL. Furthermore, the significant correlation among FA1 and leaf stomatal length and stomatal density implied they could be used as indicators of urban stress levels on a small scale. It seemed that RDA1 was possibly a normal parameter during leaf development but it was unavailable for use as an indicator of urban stresses. [ABSTRACT FROM AUTHOR]

The study of fluctuating asymmetry has been controversial because of conflicting results found in much of the primary literature. It has been suggested that the source of this conflict is the fact that the basis of fluctuating asymmetry is poorly understood and that, as a consequence, methodology of fluctuating asymmetry studies may be flawed. A new model for the phenomenological basis of fluctuating asymmetry, that variation in fluctuating asymmetry is in large part due to the random exponential growth of cell populations (geometric Brownian motion) that are terminated randomly around a genetically programmed development time, is presented here. If termination of development has a genetic component, then scaling effects and kurtosis in the distribution of fluctuating asymmetry should increase with genetic redundancy of the population. This model prediction was tested by comparing the distribution of multivariate size and shape fluctuating asymmetry in large samples collected from both wild populations and four moderately inbred lines of Drosophila simulans. It was found that while wild populations were best described by a lognormal distribution with power-law scaled tails, the inbred lines derived from the wild stock were dramatically normalized (half-normal) in three of four cases. As predicted, the scaling exponent of the upper tail of the distribution of fluctuating asymmetry increased with inbreeding while the kurtosis and mean fluctuating asymmetry decreased with inbreeding. The model suggests an additional explanation of leptokurtosis in fluctuating asymmetry. Kurtosis and scaling of the statistical distribution of fluctuating asymmetry in a population is related directly to genetic differences between individuals and these differences affect their ability to buffer the process of development against random perturbations.Heredity (2006) 97, 258–268. doi:10.1038/sj.hdy.6800848; published online 31 May 2006 [ABSTRACT FROM AUTHOR]

Multiple mating by social insect queens is a common phenomenon despite likely imposing substantial costs on queens. Mating with several males could be adaptive if a more genetically diverse worker force is better able to always handle any task sufficiently well, leading to a higher colony homeostasis. If multiple-paternity colonies are more homeostatic, then I propose that they may constitute less stressful rearing environments for developing sexuals. The effective stress levels experienced by developing males and queens may, however, also depend on colony productivity and sex-ratio preferences. I tested these hypotheses in the ant Lasius niger by examining whether the fluctuating asymmetry, means and coefficients of variation of a set of phenotypic traits in males and new queens co-varied with the effective number of patrilines per colony, colony productivity or sex ratio. Little support was found that the level of intra-colonial genetic diversity affects the variation of phenotype in sexuals. In 1 out of 2 years, however, females from colonies with high effective patriline numbers were heavier relative to their head width than were females from colonies with few patrilines. Support was found for the hypothesis that colonies with more resources may invest more in individual sexuals, and tendencies suggested that sexuals may receive better treatment when they belong to the majority sex of their colony. [ABSTRACT FROM AUTHOR]

The status of amphibians in populations subjected to anthropogenic influence of various natures has been evaluated. We studied the effect of complex anthropogenic influences as well as chemical and radiation pollution. The status of the specimens in populations was evaluated by morphological (developmental stability as the level of fluctuating asymmetry) and cytogenetic (micronucleus test) methods. Disturbed developmental stability and cytogenetic homeostasis have been observed in populations affected by anthropogenic factors, which indicates the changed status of the organism. [ABSTRACT FROM AUTHOR]

We have generalized the materials of population-phenogenetic studies of the weeping birch in different environmental conditions using developmental stability analysis and photosynthetic activity measurements. [ABSTRACT FROM AUTHOR]

Ontogenetic and population studies traditionally develop independently. At the same time, the relevance of specific analysis of a specimen as ontogenesis for both correct assessment of populations and their dynamics in time and space and understanding the mechanisms underlying population processes is becoming more and more clear. Developmental stability serves as the most general description of the developing organism status. The level of developmental noise commonly evaluated by fluctuating asymmetry is the main index of developmental stability. High developmental stability is maintained on the basis of genetic coadaptation under optimal developmental conditions. Coordinated changes in developmental stability and other homeostatic indices, including genetic, physiological, biochemical, and immune indices suggest that we consider the general status of the organism by evaluating its developmental stability. Evaluation of developmental stability as a measure of environmental stress, apparently, is the most promising. In practical terms, this allows us to evaluate and monitor environmental health under both natural and various anthropogenic conditions. Outlooks of this approach as relates to studies of developmental stability are discussed. [ABSTRACT FROM AUTHOR]

By definition, the ontogenetic and population organization levels are fundamentally different. Studies at these levels are traditionally independent. However, it becomes increasingly evident that special analysis of individuals in terms of ontogeny is necessary for correct estimation of populations and their spatiotemporal dynamics, as well as for understanding the mechanisms of population processes. [ABSTRACT FROM AUTHOR]

Fluctuating asymmetry (FA, small and random deviations from perfect symmetry in otherwise bilaterally symmetrical traits) is assumed to depend directly on developmental stability (DS). However, since the processes related to DS operate at a microscopic level, the translation of microscopic errors to the macroscopic character asymmetries (i.e. the DS-FA relation) could be mediated by the cost of growth. To investigate the consequences of this hypothesis, I constructed a model with the following assumptions: the degree of development of a trait depends on the amount of resources allocated to growth, which may differ between individuals and between traits; the cost of growth increases with development, and developmental noise causes random asymmetries in biosynthesis in the two sides of the body. The model predicts that FA follows a parabolic trajectory as growth investment levels increase, regardless of DS. However, depending on the range of variation of investment levels, different relationships (positive, negative or flat) between trait size and asymmetry could be expected. This model may also explain why FA is correlated with the degree of stress in some traits but not in others, and why some traits present a higher level of FA than others. The model also suggests that FA measured on growing traits, at a certain size, could be a more reliable indicator of DS than FA measured on fully grown traits. A study analysing FA patterns of developing and fully grown feathers in the house sparrow ( Passer domesticus) corroborates that the levels of FA, and the relationship between asymmetry and feather length, depend on the degree of feather development. [ABSTRACT FROM AUTHOR]

I address the question of how fluctuating asymmetry (FA)—the distribution of random deviations from bilateral symmetry—varies ontogenetically in the mammalian skeleton. This question is significant because of the light that such patterns can shed on the causes of variation in developmental stability in bone as well as other structures. Based on large ontogenetic skeletal series of Macaca mulatta and Homo sapiens, I report that the FA variances of skeletal metric traits increase ontogenetically. Coupled with the finding that FA variances also accumulate to greater magnitudes in slower growing mammals, this result is consistent with the hypotheses that FA in bone is primarily caused by (a) cumulative effects of asymmetrical mechanical factors, (b) accumulation of variation in the (local) regulation of growth, or (c) a tendency for bone morphology to drift through undirected remodeling. I discuss the implications of these optional explanations for primate evolution and bone development. [ABSTRACT FROM AUTHOR]

Fluctuating asymmetry, the random departure from perfect bilateral symmetry, is a common measure of developmental instability that has been hypothesized to be inversely correlated with heterozygosity. Although this claim has been widely repeated, several studies have reported no such association. Therefore, we test the generality of this association, using meta-analysis, by converting test statistics for the relationship between heterozygosity (H) and fluctuating asymmetry (FA) into a common effect size, the Pearson’s product-moment correlation coefficient. We have analysed a database containing 41 studies with a total of 118 individual samples. Overall we found an unweighted mean negative effect size; r=-0.09 (i.e. a negative correlation between H and FA). Significant heterogeneity in effect size was mainly caused by a difference between ectothermic and endothermic animals, and to a lesser extent by the use of different study designs (i.e. within-population vs. among-populations). Mean effect size for endothermic animals was positive and significantly different from the mean effect size for ectothermic animals. Only for within-population studies of ectothermic animals did we find a significantly negative effect size (r=-0.23 ± 0.09). The distribution of effect sizes in relation to sample size provided little evidence for patterns typical of those produced by publication bias. Our analysis suggests, at best, only a weak association between H and FA, and heterozygosity seems to explain only a very small amount of the variation in developmental instability among individuals and populations (r2=0.01 for the total material). [ABSTRACT FROM AUTHOR]

Broad-sense heritability of fluctuating asymmetry and developmental instability in the winter moth were analysed in a full-sib breeding experiment. Effects of both genetic background and common environment on both tibia FA (measured for the three pairs of legs) and body size were studied. As body size has previously been shown to be a reliable indicator of larval feeding success and expected fitness, the relationship between FA and body size was investigated as well. This relationship is of interest because it has been argued that the low heritability of FA results from a strong relationship between FA and fitness. Broad-sense h2 of body size equalled zero whereas the effect of common environment was strong. The heritability of FA was low and not statistically significant for separate tibias. For FA based on the average of the three tibias h2 equalled 0.07 and differed significantly from zero. The heritability of developmental instability equalled 0.09. Thus the use of the hypothetical repeatability to translate the h2 of FA to h2 of developmental instability did not result in a strong increase in this species. Individual asymmetry was not correlated with fitness (as estimated by body size), indicating that the low heritabilities of FA are not a consequence of a strong correlation with fitness. Between-trait correlations in the unsigned FA were significant. However, these correlations are not necessarily indicative of an individual asymmetry parameter as the signed FA values were positively correlated as well, suggesting interdependent development of the three pairs of legs. Further research is necessary to investigate what the effects of interdependent development are on patterns in FA. [ABSTRACT FROM AUTHOR]

Two kinds of asymmetries are common in bilateral characters: fluctuating asymmetry (FA), a type of nondirectional variation between left and right sides, and directional asymmetry (DA), in which one side is consistently larger than the other. FA has been extensively used as a measure of developmental instability and is presumed to increase as stress from toxins or other sources increases. In this paper we tested the hypothesis that exposure of pregnant female mice to two different dosage levels of methoxychlor (MXC), an insecticide derived from DDT, would increase FA in one or more of 10 mandible characters measured in the offspring of these females. The data showed that exposure of pregnant females to MXC produced no detectable effect on FA in their offspring, but at the higher dosage level (10 μg/g body weight), did change FA to DA in one of the characters. MXC also had a significant effect on the mean size of five of the mandible dimensions, all of which were located primarily in the anterior portion of the mandible. [ABSTRACT FROM AUTHOR]

Understanding the mechanisms that determine the development of a bilaterally symmetrical trait is crucial to the interpretation of patterns of fluctuating asymmetry (FA). Experimental and theoretical studies have indicated that feedback mechanisms both within and between developing traits, may participate in the developmental control of asymmetry. This study provides evidence that naturally occurring patterns of FA are affected by interactions between different traits. We found positive between trait correlations in signed FA values for tibia lengths on different legs, but not between wing and tibia FA in two moth species. Further research should investigate if trait functionality is related to this presumed correlated development. An extension of the Rashevsky–Turing model of morphogenesis further showed that correlations between the signed FA values can be generated by feedback mechanisms that regulate growth patterns between traits. We argue that such feedback mechanisms can be expected to be widespread and show that between trait correlations in the unsigned FA then become confounded with correlations in the signed FA. In addition, correlated development appeared to invalidate the use of the hypothetical repeatability to translate correlations between the unsigned FA values into correlations in the presumed underlying developmental instability. In conclusion, the presence of an organism wide asymmetry, which are most frequently found in morphologically integrated traits, may be even less common than previously thought. [ABSTRACT FROM AUTHOR]

Eumantispa spp. usually show markedly asymmetrical wing venation, and this character is used in defining the genus. This is illustrated and discussed in relation to fluctuating asymmetry, which is used as a measure of environmental stress. © Rapid Science Ltd. 1998 [ABSTRACT FROM AUTHOR]

The treatment of buckwheat with biostimulants Floravit E and Atonic Plus in dilutions 10-10 and 3 × 10, accordingly, had no effect on the stability and development of plants, as one can judge by the fluctuating asymmetry of metrical and meristic traits. Treatment with Atonic Plus led to a reduction of fluctuating asymmetry when control plants had a high value of asymmetry. Floravit E in the dilution 10 caused an increase of fluctuating asymmetry of half leaf width. The same effect was observed when growing buck-wheat in a lead-contaminated soil. [ABSTRACT FROM AUTHOR]

The dynamics of developmental stability of two burying beetle species displays the trend of an increase in fluctuating asymmetry indices at almost all of the studied sites. It is assumed that the most likely cause of the observed alterations is the deviations from optimal conditions, which result mainly from global climate change. [ABSTRACT FROM AUTHOR]

The developmental stability of small-leaved lime ( Tina cordata Mill.) was estimated in populations on territories of the Kerzhenskii State Nature Reserve, Nizhni Novgorod District, and in an industrial region of Nizhni Novgorod. The developmental stability was estimated according to the fluctuating asymmetry of the leaf measurements. The results obtained suggest that, in the urbanized territory, the homeostatic developmental mechanisms are weakened, as expressed in the increased degree of leaf asymmetry. [ABSTRACT FROM AUTHOR]