scholarly journals Heritability and selection on body size in a natural population of Drosophila buzzatii.

Genetics ◽  
1995 ◽  
Vol 141 (1) ◽  
pp. 181-189
Author(s):  
A Leibowitz ◽  
M Santos ◽  
A Fontdevila
Keyword(s):  
Genetic Variation ◽  
Body Size ◽  
Random Sample ◽  
Phenotypic Variation ◽  
Development Time ◽  
Wing Length ◽  
Genetic Differences ◽  
Phenotypic Differences ◽  
Drosophila Buzzatii ◽  
Average Development

Abstract An attempt was made to assess whether the phenotypic differences in body size (as measured by wing length) between wild-caught mating and single Drosophila buzzatii males could be attributed to genetic differences between the samples. Mating males were found to be larger and less variable than a random sample of the population. The progeny of the mating males (produced by crossing to a random female from a stock derived from the same population) were on average larger than those of the single males, but not significantly so (P = 0.063), and less phenotypically variable. This difference in variance between the samples suggests that there are indeed genetic differences between the paternal samples but tests for significant differences in the additive genetic component of variance proved inconclusive. For both samples it was found that while the ratio of additive genetic variation in the laboratory to phenotypic variation in the field yielded estimates of ĥs2(N) congruent to 10% the regression of offspring reared in the laboratory on parents from the wild was not significantly different from zero. In addition, it was found that the average development time of the progeny of the mating males is shorter than that of the random sample.

scholarly journals Seasonality and genetic architecture of development time and body size of the birch feeding sawfly Priophorus pallipes

2001 ◽  
Vol 78 (1) ◽  
pp. 31-40 ◽  
Author(s):  
ANTTI KAUSE ◽  
JEAN-PHILIPPE MORIN
Keyword(s):  
Genetic Variation ◽  
Body Size ◽  
Diet Quality ◽  
Development Time ◽  
Genetic Correlations ◽  
Reaction Norms ◽  
High Quality ◽  
Genetic Characteristics ◽  
Mature Leaves ◽  
Final Mass

We tested, using the sawfly Priophorus pallipes feeding on leaves of mountain birch, whether the expression of genetic (co)variation of larval development time and body size can be altered by exposing larvae to diets with differential seasonal changes in quality. In nature, larvae feed mainly on mature leaves, but occasionally they are forced to consume senescing leaves. Sixty families were assayed on three experimentally simulated diets: mature leaves of high quality, senescing leaves of rapidly declining quality, and senesced leaves of low quality. The intuitively obvious positive phenotypic and genetic correlations between development time and final mass were observed when the larvae consumed leaves of stable high quality, but low and declining food quality prevented long-growing individuals and families from achieving high final mass, switching the correlations to close to zero or negative in these treatments. The amount of genetic variation for body size showed a non-linear change across the diet quality gradient, whereas genetic variation for development time increased with decreasing diet quality. The among-trait difference in the degree reaction norms crossed along the diet gradient caused the changes in the expression of genetic (co)variation within the environments. Our results show that seasonally varying diet quality induces dramatic changes in the genetic (co)variation of development time and body size, and that simultaneous analysis of reaction norms and environment-specific expression of genetic (co)variation is necessary for the understanding of the genetic characteristics underlying the construction of phenotypes in heterogeneous environments.

scholarly journals Artificial selection on male size depletes genetic variance but not covariance of life history traits in the yellow dung fly

2019 ◽  
Author(s):  
WU Blanckenhorn ◽  
V Llaurens ◽  
C Reim ◽  
Y Teuschl ◽  
E Postma
Keyword(s):  
Genetic Variation ◽  
Life History ◽  
Body Size ◽  
Artificial Selection ◽  
Development Time ◽  
Life History Traits ◽  
Genetic Variance ◽  
Genetic Correlations ◽  
Male Size ◽  
First Clutch

SUMMARYThe evolutionary potential of organisms depends on the presence of sufficient genetic variation for traits subject to selection, as well as on the genetic covariances among them. While genetic variation ultimately derives from mutation, theory predicts the depletion of genetic (co)variation under consistent directional or stabilizing selection in natural populations. We estimated and compared additive genetic (co)variances for several standard life history traits, including some for which this has never been assessed, before and after 24 generations of artificial selection on male size in the yellow dung fly Scathophaga stercoraria (Diptera: Scathophagidae) using a series of standard half-sib breeding experiments. As predicted, genetic variances (VA), heritabilities (h2) and evolvabilities (IA) of body size, development time, first clutch size, and female age at first clutch were lower after selection. As independent selection lines were crossed prior to testing, we can rule out that this reduction is due to genetic drift. In contrast to the variances, and against expectation, the additive genetic correlations between the sexes for development time and body size remained strong and positive (rA = 0.8–0.9), while the genetic correlation between these traits within the sexes tended to strengthen (but not significantly so). Our study documents that the effect of selection on genetic variance is predictable, whereas that on genetic correlations is not.

scholarly journals Analysing phenotypic variation in barn swallows (Hirundo rustica) across China to assess subspecies status

2020 ◽  
Vol 131 (2) ◽  
pp. 319-331 ◽  
Author(s):  
Yu Liu ◽  
Elizabeth S C Scordato ◽  
Zhengwang Zhang ◽  
Matthew Evans ◽  
Rebecca J Safran
Keyword(s):  
Body Size ◽  
Statistical Analysis ◽  
Phenotypic Variation ◽  
Hirundo Rustica ◽  
Barn Swallow ◽  
Phenotypic Differentiation ◽  
Phenotypic Differences ◽  
North Eastern ◽  
Different Populations ◽  
Barn Swallows

Abstract Phenotypic variation is often used to delineate species and subspecies boundaries. Statistical analysis of phenotypic variation within a species is helpful both for understanding biodiversity and for its conservation. At least three named subspecies of barn swallows (Hirundo rustica) have distributions that span China, yet, to date, no systematic study of phenotypic differentiation has been applied to understand the delineation of these subspecies. In this study, we collected 510 samples of barn swallow from 23 populations in China, including two recognized subspecies, H. r. rustica and H. r. gutturalis, and one potential subspecies, H. r. mandschurica. With these samples, we examined and found morphometric and colour differences among different populations. Western Chinese barn swallows (H. r. rustica) have larger body size and could be clearly differentiated from eastern H. r. gutturalis and H. r. mandschurica, while north-eastern populations (named H. r. mandschurica) have darker, redder ventral plumage than H. r. rustica and H. r. gutturalis. However, we inferred that although there were phenotypic differences between H. r. mandschurica and H. r. gutturalis, they were not sufficiently distinct to assign them to separate subspecies based on the 75% rule for defining subspecies.

scholarly journals Large body size variation is associated with low communication success in tandem running ants

2020 ◽  
Vol 75 (1) ◽  
Author(s):  
Thomas Wagner ◽  
Lena Bachenberg ◽  
Simone M. Glaser ◽  
Avgousta Oikonomou ◽  
Melissa Linn ◽  
...  
Keyword(s):  
Body Size ◽  
Phenotypic Variation ◽  
Walking Speed ◽  
Size Variation ◽  
Recruitment Strategy ◽  
Negative Effects ◽  
Tandem Running ◽  
Phenotypic Differences ◽  
Communication Processes ◽  
Temnothorax Nylanderi

Abstract Diversity in animal groups is often assumed to increase group performance. In insect colonies, genetic, behavioural and morphological variation among workers can improve colony functioning and resilience. However, it has been hypothesized that during communication processes, differences between workers, e.g. in body size, could also have negative effects. Tandem running is a common recruitment strategy in ants and allows a leader to guide a nestmate follower to resources. A substantial proportion of tandem runs fail because leader and follower lose contact. Using the ant Temnothorax nylanderi as a model system, we tested the hypothesis that tandem running success is impaired if leader and follower differ in size. Indeed, we found that the success rate of tandem pairs drops considerably as size variation increases: tandem runs were unsuccessful when the leader–follower size difference exceeded 10%, whereas ~ 80% of tandem runs were successful when ants differed less than 5% in body length. Possible explanations are that size differences are linked to differences in walking speed or sensory perception. Ants did not choose partners of similar size, but extranidal workers were larger than intranidal workers, which could reduce recruitment mistakes because it reduced the chance that very large and very small ants perform tandem runs together. Our results suggest that phenotypic differences between interacting workers can have negative effects on the efficiency of communication processes. Whether phenotypic variation has positive or negative effects is likely to depend on the task and the phenotypic trait that shows variation. Significance statement Diversity is often assumed to increase colony performance in social insects. However, phenotypic differences among workers could also have negative effects, e.g. during communication. Tandem running is a common recruitment strategy in ants, but tandem runs often fail when ants lose contact. We used the ant Temnothorax nylanderi to test the hypothesis that body size differences between tandem leader and follower impair tandem communication. We show that the success rate of tandem pairs drops considerably as size variation increases, possibly because ants of varying size also differ in walking speed. Our study supports the hypothesis that phenotypic variation among workers might not always be beneficial and can negatively impact the efficiency of communication processes.

scholarly journals Expansive Phenotypic Landscape of Botrytis cinerea Shows Differential Contribution of Genetic Diversity and Plasticity

2016 ◽  
Vol 29 (4) ◽  
pp. 287-298 ◽  
Author(s):  
Jason A. Corwin ◽  
Anushriya Subedy ◽  
Robert Eshbaugh ◽  
Daniel J. Kliebenstein
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Botrytis Cinerea ◽  
Phenotypic Variation ◽  
Genotypic Variation ◽  
Environmental Variation ◽  
In Planta ◽  
Phenotypic Differences ◽  
Relative Contribution

The modern evolutionary synthesis suggests that both environmental variation and genetic diversity are critical determinants of pathogen success. However, the relative contribution of these two sources of variation is not routinely measured. To estimate the relative contribution of plasticity and genetic diversity for virulence-associated phenotypes in a generalist plant pathogen, we grew a population of 15 isolates of Botrytis cinerea from throughout the world, under a variety of in vitro and in planta conditions. Under in planta conditions, phenotypic differences between the isolates were determined by the combination of genotypic variation within the pathogen and environmental variation. In contrast, phenotypic differences between the isolates under in vitro conditions were predominantly determined by genetic variation in the pathogen. Using a correlation network approach, we link the phenotypic variation under in vitro experimental conditions to phenotypic variation during plant infection. This study indicates that there is a high level of phenotypic variation within B. cinerea that is controlled by a mixture of genetic variation, environment, and genotype × environment. This argues that future experiments into the pathogenicity of B. cinerea must account for the genetic and environmental variation within the pathogen to better sample the potential phenotypic space of the pathogen.

scholarly journals Environmental effects on body size variation in Drosophila melanogaster and its cellular basis

1997 ◽  
Vol 70 (1) ◽  
pp. 35-43 ◽  
Author(s):  
G. H. DE MOED ◽  
G. DE JONG ◽  
W. SCHARLOO
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Body Size ◽  
Cell Size ◽  
Wing Length ◽  
Size Variation ◽  
Cell Number ◽  
Food Level ◽  
Mean Size ◽  
Food Conditions

Eight isofemale lines of Drosophila melanogaster were raised at four temperatures and at four yeast concentrations in their food. Temperature and food show a significant interaction in determining wing length and thorax length, affecting mean size per line and genetic variation between lines. The combination of low temperature and poor food conditions leads to a sharp increase in the genetic variation over lines of both body size characters. The increase in genetic variation in wing length under less favourable conditions is due to an increase in genetic variation of both cell size and cell number. Changes in wing area in response to both temperature and food level follow a common cell size/cell number trajectory. Changes in wing size are obtained by line-specific changes in the cellular composition of the wing, rather than by changes specific for the environmental factor.

scholarly journals Feminisation of complex traits in Drosophila melanogaster via female-limited X chromosome evolution

2020 ◽  
Author(s):  
Katrine K. Lund-Hansen ◽  
Jessica K. Abbott ◽  
Edward H. Morrow
Keyword(s):  
Genetic Variation ◽  
Body Size ◽  
X Chromosome ◽  
Complex Traits ◽  
Development Time ◽  
Chromosome Evolution ◽  
Reproductive Fitness ◽  
Male Genome ◽  
X Chromosome Evolution ◽  
Locomotion Activity

AbstractA handful of studies have investigated sexually antagonistic constraints on obtaining sex-specific fitness optima, though exclusively through male-genome-limited evolution experiments. In this paper, we established a female-limited X chromosome evolution experiment, where we used an X chromosome balancer to enforce the inheritance of the X chromosome through the matriline, thus removing exposure to male selective constraints. This approach eliminates the effects of sexually antagonistic selection on the X chromosome, permitting evolution towards a single sex-specific optimum. After multiple generations of selection, we found strong evidence that body size and development time had moved towards a female-specific optimum, whereas reproductive fitness and locomotion activity remained unchanged. The changes in body size and development time are consistent with previous results, and suggest that the X chromosome is enriched for sexually antagonistic genetic variation controlling these traits. The lack of change in reproductive fitness and locomotion activity could be due to a number of mutually non-exclusive explanations, including a lack of sexually antagonistic variance on the X chromosome or confounding effects of the use of the balancer chromosome. This study is the first to employ female-genome-limited selection and adds to the understanding of the complexity of sexually antagonistic genetic variation.

scholarly journals The ecological genetics of growth in Drosophila 1. Body size and developmental time on different diets 1. Body size and developmental time on different diets

1960 ◽  
Vol 1 (2) ◽  
pp. 288-304 ◽  
Author(s):  
Forbes W. Robertson
Keyword(s):  
Body Size ◽  
Development Time ◽  
Small Body ◽  
Growth Period ◽  
Developmental Time ◽  
Ecological Genetics ◽  
Genetic Differences ◽  
Environment Interaction ◽  
Gene Environment Interaction ◽  
Gene Environment

1. The interrelations between environment and the phenotypic expression of genetic differences have not received the attention they merit. Laboratory studies in quantitative inheritance, either by choice of character or experimental conditions, have not shed much light on this problem. Selection for the same character in different environments is likely to involve qualitative differences in physiology and development. Comparative study of such changes will throw light on the genetics of development generally, which in turn is relevant to how far the selection response can be pushed in a given direction. Since statistical variation between individuals must ultimately be interpreted in biological terms, the unnatural barriers between quantitative and physiological genetics must be broken down to clear the way for a greater variety of experimental analysis and a more widely based approach to the interpretation of individual differences in populations. The ecology of the animal provides the point of departure and guide to the kind of environmental variation which should be studied first. Since the suggested approach cuts across the conventional limits of quantitative, physiological and population genetics and exploits the concepts and methods of these alternative approaches to a common end, it is convenient to have a descriptive label. The term ‘ecological genetics’ has been adopted.2. This introductory paper is the first of a series dealing with experiments orientated along these lines. Since environmental variation largely consists of variation in the quantity and composition of the diet, the growth of individuals from a cage population of Drosophila melanogaster and also other strains has been studied on a variety of aseptic, synthetic diets. Body size and duration of the larval period are taken as measures of growth. There is a well-marked ability to regulate body size, by extending the duration of development, provided the diet is not too deficient. When the diet is further reduced development time is further lengthened and body size is reduced as well.3. To test for genetic differences in reaction to the diet, strains have been created by selecting for large or small body size, and their performance, together with that of the cross between them, has been compared with the performance of unselected individuals on alternative diets for the first few generations of mass selection. There is evidence of gene-environment interaction quite early in selection, and after six generations striking differences were detected. It is concluded that genetic differences in reaction to different sub-optimal diets are widespread in the population.4. The within-culture variance is increased by growing larvae on progressively more deficient diets and is approximately twice as great on a low-protein diet as on the usual live yeast medium. This increase is attributed to the segregation of genetic differences which are unimportant and contribute little to the variance under more favourable conditions.5. Comparison of body size and development time in repeated tests with two diets lacking fructose or deficient in ribonucleic acid revealed evidence of a plasticity of response to minor nutritional variation which is characterized by a positive association between body size and the duration of the growth period. This relationship is the reverse of that associated with crude variation in the diet which leads to a negative association between development time and body size. This plasticity of response probably represents an aspect of physiological homeostasis. Genetic differences in the magnitude and direction of this response probably contribute to gene-environment interaction generally, and this probably accounts for apparent discrepancies in alternative estimates of the response to selection for large and small body size when these are based on deviations from the unselected. This suggests the need for determining how far body size may be increased either by altering the growth rate or by extending the growth period, and also how far strains differentiated in such respects differ in their reaction to controlled differences in nutrition.

scholarly journals Insect body size changes under future warming projections: a case study of Chironomidae (Insecta: Diptera)

Hydrobiologia ◽  
2021 ◽  
Author(s):  
Rungtip Wonglersak ◽  
Phillip B. Fenberg ◽  
Peter G. Langdon ◽  
Stephen J. Brooks ◽  
Benjamin W. Price
Keyword(s):  
Body Size ◽  
Ambient Temperature ◽  
Wing Length ◽  
The Body ◽  
Mesocosm Experiments ◽  
Future Warming ◽  
Increasing Temperature ◽  
Emergence Date ◽  
Average Body

AbstractChironomids are a useful group for investigating body size responses to warming due to their high local abundance and sensitivity to environmental change. We collected specimens of six species of chironomids every 2 weeks over a 2-year period (2017–2018) from mesocosm experiments using five ponds at ambient temperature and five ponds at 4°C higher than ambient temperature. We investigated (1) wing length responses to temperature within species and between sexes using a regression analysis, (2) interspecific body size responses to test whether the body size of species influences sensitivity to warming, and (3) the correlation between emergence date and wing length. We found a significantly shorter wing length with increasing temperature in both sexes of Procladius crassinervis and Tanytarsus nemorosus, in males of Polypedilum sordens, but no significant relationship in the other three species studied. The average body size of a species affects the magnitude of the temperature-size responses in both sexes, with larger species shrinking disproportionately more with increasing temperature. There was a significant decline in wing length with emergence date across most species studied (excluding Polypedilum nubeculosum and P. sordens), indicating that individuals emerging later in the season tend to be smaller.

Sign in / Sign up

Export Citation Format

Share Document