Size matters: systematic and ecological implications of allometry in the responses of chironomid midge morphological ratios to experimental temperature manipulations

2005 ◽  
Vol 83 (4) ◽  
pp. 553-568 ◽  
Author(s):  
Brendan G McKie ◽  
Peter S Cranston
Keyword(s):  
Body Size ◽  
Phylogenetic Reconstruction ◽  
Size Variation ◽  
Adaptive Significance ◽  
Adult Size ◽  
Allometric Relationships ◽  
Terrestrial Environment ◽  
Environmental Regimes ◽  
Wide Range ◽  
Ecological Implications

Separated populations of wide-ranging ectothermic species may be subjected to differing ambient environmental regimes, with consequences for adult size and related allometric characteristics. We investigated effects of environmentally induced size variation in freshwater Australian Chironomidae (Diptera) on several morphometric ratios used to account for such variation in taxonomic classification. Echinocladius martini Cranston, 2000 (Orthocladiinae) and Australopelopia prionoptera Cranston, 2000 (Tanypodinae) larvae were sampled from tropical and temperate populations separated by approximately 1800 km, and reared to adult at temperatures representing the continent-wide range encountered by these species. Additionally, adults were sampled regularly from a field population to assess seasonal variation. Body size was related inversely to rearing temperature for both species. Nonlinear (allometric) relationships were observed consistently between body size and ratios pertaining to the antennae (AR, the ratio of the terminal to subapical flagellomeres) and legs (BV, the ratio of proximal segments to distal tarsomeres), demonstrating that these ratios inadequately factor out within-species, size-related divergence. Responses of other ratios varied erratically with sex, species, and population. We advocate cautious use of these ratios in taxonomy and phylogenetic reconstruction. We discuss possible adaptive significance of allometry in the male antennae related to the "tuning" of sound-sensitive structures to the expected terrestrial environment encountered at emergence.

METABOLIC RATE AND ITS TEMPERATURE-ADAPTIVE SIGNIFICANCE IN SIX GEOGRAPHIC RACES OF PEROMYSCUS

1965 ◽  
Vol 43 (2) ◽  
pp. 309-323 ◽  
Author(s):  
J. S. Hayward
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Metabolic Rate ◽  
Single Equation ◽  
Adaptive Significance ◽  
The Body ◽  
Single Group ◽  
Critical Temperatures ◽  
Wide Range ◽  
Per Se

The metabolic rate characteristics of six races of Peromyscus, selected from a wide range of habitats, have been determined over the temperature range 0° to 35 °C. After acclimation to standardized laboratory conditions, critical temperatures and metabolic responses to temperatures below thermoneutrality were largely a function of body size: the larger the mouse, the greater its thermoregulatory efficiency. Body size per se is not correlated with the gross climate of the respective habitats. A single equation which predicts the metabolic rate of these races at any temperature between 0° and 27 °C, from a knowledge of body weight and body temperature, is derived.When considered as a single group, the basal oxygen consumption of all races varied with body weight0,60 over the body weight range of 14.7 to 36.0 g and was insignificantly different from the accepted interspecies approximation. The basal metabolic rates of each race showed no temperature-adaptive differences, especially when considered in relation to body composition. It is concluded that basal metabolic rate is nonadaptive to climate in these races of Peromyscus and consequently has played no important part in their distribution and speciation.

The Atacama toad (Rhinella atacamensis) exhibits an unusual clinal pattern of decreasing body size towards more arid environments

BMC Zoology ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Felipe Durán ◽  
Marco A. Méndez ◽  
Claudio Correa
Keyword(s):  
Body Size ◽  
Geographic Variation ◽  
Water Availability ◽  
Size Variation ◽  
Mean Annual Precipitation ◽  
Arid Environments ◽  
Theoretic Approach ◽  
Adult Size ◽  
The North ◽  
Data Support

Abstract Background The causes of geographic variation of body size in ectotherms have generally been attributed to environmental variables. Research in amphibians has favored mechanisms that involve water availability as an explanation for the geographic variation of body size. However, there are few studies at intraspecific level on amphibians that inhabit desert or semi-desert environments, where hydric restrictions are stronger. Here, we describe and inquire as to the causes of the geographic variation of body size in the semi-desert toad Rhinella atacamensis, a terrestrial anuran that is distributed over 750 km along a latitudinal aridity gradient from the southern extreme of the Atacama Desert to the Mediterranean region of central Chile. We measured the snout-vent length of 315 adults from 11 representative localities of the entire distribution of the species. Then, using an information-theoretic approach, we evaluate whether the data support eight ecogeographic hypotheses proposed in literature. Results Rhinella atacamensis exhibits a gradual pattern of decrease in adult body size towards the north of its distribution, where the climate is more arid, which conforms to a Bergmann’s cline. The best model showed that the data support the mean annual precipitation as predictor of body size, favoring the converse water availability hypothesis. Conclusions Most studies in amphibians show that adult size increases in arid environments, but we found a converse pattern to expected according to the hydric constraints imposed by this type of environment. The evidence in R. atacamensis favors the converse water availability hypothesis, whose mechanism proposes that the foraging activity determined by the precipitation gradient has produced the clinal pattern of body size variation. The variation of this trait could also be affected by the decreasing productivity that exists towards the north of the species distribution. In addition, we found evidence that both pattern and mechanism are independent of sex. Lastly, we suggest that behavioral traits, such as nocturnal habits, might also play an important role determining this differential response to aridity. Therefore, the support for the converse water availability hypothesis found in this study shows that amphibians can respond in different ways to water restrictions imposed by arid environments.

scholarly journals Seasonal body size reductions with warming covary with major body size gradients in arthropod species

2017 ◽  
Vol 284 (1851) ◽  
pp. 20170238 ◽  
Author(s):  
Curtis R. Horne ◽  
Andrew G. Hirst ◽  
David Atkinson
Keyword(s):  
Body Size ◽  
Size Variation ◽  
Seasonal Temperature ◽  
Adult Size ◽  
Aquatic Species ◽  
Terrestrial Species ◽  
Total Percentage ◽  
Arthropod Species ◽  
Seasonal Temperature Variation ◽  
Developmental Conditions

Major biological and biogeographical rules link body size variation with latitude or environmental temperature, and these rules are often studied in isolation. Within multivoltine species, seasonal temperature variation can cause substantial changes in adult body size, as subsequent generations experience different developmental conditions. Yet, unlike other size patterns, these common seasonal temperature–size gradients have never been collectively analysed. We undertake the largest analysis to date of seasonal temperature-size gradients in multivoltine arthropods, including 102 aquatic and terrestrial species from 71 global locations. Adult size declines in warmer seasons in 86% of the species examined. Aquatic species show approximately 2.5-fold greater reduction in size per °C of warming than terrestrial species, supporting the hypothesis that greater oxygen limitation in water than in air forces aquatic species to exhibit greater plasticity in body size with temperature. Total percentage change in size over the annual cycle appears relatively constant with annual temperature range but varies between environments, such that the overall size reduction in aquatic-developing species (approx. 31%) is almost threefold greater than in terrestrial species (approx. 11%). For the first time, we show that strong correlations exist between seasonal temperature–size gradients, laboratory responses and latitudinal–size clines, suggesting that these patterns share common drivers.

scholarly journals Independent evolution towards larger body size in the distinctive Faroe Island mice

2021 ◽  
Author(s):  
Ricardo Wilches ◽  
William H Beluch ◽  
Ellen McConnell ◽  
Diethard Tautz ◽  
Yingguang Frank Chan
Keyword(s):  
Body Size ◽  
Meta Analysis ◽  
Small Body ◽  
Laboratory Mouse ◽  
Large Body ◽  
Natural Populations ◽  
Size Variation ◽  
Phenotypic Traits ◽  
Island Population ◽  
Multiple Loci

Abstract Most phenotypic traits in nature involve the collective action of many genes. Traits that evolve repeatedly are particularly useful for understanding how selection may act on changing trait values. In mice, large body size has evolved repeatedly on islands and under artificial selection in the laboratory. Identifying the loci and genes involved in this process may shed light on the evolution of complex, polygenic traits. Here, we have mapped the genetic basis of body size variation by making a genetic cross between mice from the Faroe Islands, which are among the largest and most distinctive natural populations of mice in the world, and a laboratory mouse strain selected for small body size, SM/J. Using this F2 intercross of 841 animals, we have identified 111 loci controlling various aspects of body size, weight and growth hormone levels. By comparing against other studies, including the use of a joint meta-analysis, we found that the loci involved in the evolution of large size in the Faroese mice were largely independent from those of a different island population or other laboratory strains. We hypothesize that colonization bottleneck, historical hybridization, or the redundancy between multiple loci have resulted in the Faroese mice achieving an outwardly similar phenotype through a distinct evolutionary path.

scholarly journals Overview of the Genetic Diversity of African Macrotermes (Termitidae: Macrotermitinae) and Implications for Taxonomy, Ecology and Food Science

Insects ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 518
Author(s):  
Bronwyn Egan ◽  
Zwannda Nethavhani ◽  
Barbara van Asch
Keyword(s):  
Negative Impact ◽  
Phylogenetic Reconstruction ◽  
Morphological Characters ◽  
Food Science ◽  
Cryptic Diversity ◽  
African Species ◽  
Genetic Groups ◽  
Wide Range ◽  
Coi Sequences ◽  
High Level

Macrotermes termites play important ecological roles and are consumed by many communities as a delicacy and dietary complement throughout Africa. However, lack of reliable morphological characters has hampered studies of Macrotermes diversity in a wide range of scientific fields including ecology, phylogenetics and food science. In order to place our preliminary assessment of the diversity of Macrotermes in South Africa in context, we analysed a comprehensive dataset of COI sequences for African species including new and publicly available data. Phylogenetic reconstruction and estimates of genetic divergence showed a high level of incongruity between species names and genetic groups, as well as several instances of cryptic diversity. We identified three main clades and 17 genetic groups in the dataset. We propose that this structure be used as a background for future surveys of Macrotermes diversity in Africa, thus mitigating the negative impact of the present taxonomic uncertainties in the genus. The new specimens collected in Limpopo fell into four distinct genetic groups, suggesting that the region harbours remarkable Macrotermes diversity relative to other African regions surveyed in previous studies. This work shows that African Macrotermes have been understudied across the continent, and that the genus contains cryptic diversity undetectable by classic taxonomy. Furthermore, these results may inform future taxonomic revisions in Macrotermes, thus contributing to advances in termitology.

scholarly journals Mammalian body size is determined by interactions between climate, urbanization, and ecological traits

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Maggie M. Hantak ◽  
Bryan S. McLean ◽  
Daijiang Li ◽  
Robert P. Guralnick
Keyword(s):  
Body Size ◽  
Resource Availability ◽  
Critical Role ◽  
Size Variation ◽  
Ecological Factors ◽  
Species Traits ◽  
Body Size Variation ◽  
Resource Availability Hypothesis ◽  
Urban Heat ◽  
Thermal Buffering

AbstractAnthropogenically-driven climate warming is a hypothesized driver of animal body size reductions. Less understood are effects of other human-caused disturbances on body size, such as urbanization. We compiled 140,499 body size records of over 100 North American mammals to test how climate and human population density, a proxy for urbanization, and their interactions with species traits, impact body size. We tested three hypotheses of body size variation across urbanization gradients: urban heat island effects, habitat fragmentation, and resource availability. Our results demonstrate that both urbanization and temperature influence mammalian body size variation, most often leading to larger individuals, thus supporting the resource availability hypothesis. In addition, life history and other ecological factors play a critical role in mediating the effects of climate and urbanization on body size. Larger mammals and species that utilize thermal buffering are more sensitive to warmer temperatures, while flexibility in activity time appears to be advantageous in urbanized areas. This work highlights the value of using digitized, natural history data to track how human disturbance drives morphological variation.

scholarly journals Diversity of Pod Shape in Pisum

Diversity ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 203
Author(s):  
Thomas Henry Noel Ellis ◽  
Julie M. I. Hofer ◽  
Eleni Vikeli ◽  
Michael J. Ambrose ◽  
Paola Higuera-Poveda ◽  
...  
Keyword(s):  
Allelic Variation ◽  
Size Variation ◽  
Width Ratio ◽  
Negative Regulators ◽  
Wide Range ◽  
Yield Determination ◽  
Organ Specific ◽  
Length Width ◽  
End Use ◽  
Pod Length

The seed-containing pod is the defining structure of plants in the legume family, yet pods exhibit a wide range of morphological variation. Within a species pod characters are likely to be correlated with reproductive strategy, and within cultivated forms will correspond to aspects of yield determination and/or end use. Here variation in pod size, described as pod length: pod width ratio, has been analyzed in pea germplasm represented by 597 accessions. This pod size variation is discussed with respect to population structure and to known classical pod morphology mutants. Variability of the pod length: width ratio can be explained by allelic variation at two genetic loci that may correspond to organ-specific negative regulators of growth.

scholarly journals Age of maturation and behavioral tactics in male yellow ground squirrel Spermophilus fulvus during mating season

2014 ◽  
Vol 60 (6) ◽  
pp. 700-711 ◽  
Author(s):  
Nina A. Vasilieva ◽  
Ekaterina V. Pavlova ◽  
Sergey V. Naidenko ◽  
Andrey V. Tchabovsky
Keyword(s):  
Body Size ◽  
Ground Squirrel ◽  
Life History Theory ◽  
Social Activity ◽  
Indirect Evidence ◽  
Adult Size ◽  
Adult Males ◽  
Mating Season ◽  
Active Season ◽  
Good Physical Condition

Abstract Life-history theory predicts that in hibernators age of maturation is related positively to body size and negatively to the duration of active season aboveground. Yellow souslik is a large-sized ground squirrel with long hibernation, which suggests late maturation. We used four-year field observations of marked individuals to determine the age of maturation in males through analysis of age-dependent variation in body size, mass, androgen status, timing of spring emergence, ranging patterns and social behavior during the mating season. Yearling males were smaller, lighter, had lower level of fecal testosterone, emerged later and had smaller home ranges than older males. Social activity and the number of females encountered did not differ between age classes. After the second hibernation none of the studied parameters varied with age. Cluster analysis revealed two behavioral tactics: “active” males (adults only) emerged earlier, ranged more widely, initiated more contacts, encountered more females and were heavier than “passive” males (both yearling and adult). Thus, males of S. fulvus reached adult size and matured after two hibernations, which is relatively fast for such a big species with short active period. Indirect evidence for copulations and high variation among yearlings in all parameters suggest that some of them might successfully compete with adults. Active tactic of wandering and searching for females is energetically costly, and probably only adult males in good physical condition can afford it, whereas passive tactic of residing is energy saving and good for adults in poor condition and for yearlings that are continuing to grow.

scholarly journals Intraspecific Variation in Maximum Ingested Food Size and Body Mass in Varecia rubra and Propithecus coquereli

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Adam Hartstone-Rose ◽  
Jonathan M. G. Perry
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Individual Variation ◽  
Size Variation ◽  
Maximum Size ◽  
Least Squares Regression ◽  
Scaling Relationship ◽  
Varecia Rubra ◽  
Food Size ◽  
The Relationship

In a recent study, we quantified the scaling of ingested food size (Vb )—the maximum size at which an animal consistently ingests food whole—and found that Vb scaled isometrically between species of captive strepsirrhines. The current study examines the relationship between Vb and body size within species with a focus on the frugivorous Varecia rubra and the folivorous Propithecus coquereli. We found no overlap in Vb between the species (all V. rubra ingested larger pieces of food relative to those eaten by P. coquereli), and least-squares regression of Vb and three different measures of body mass showed no scaling relationship within each species. We believe that this lack of relationship results from the relatively narrow intraspecific body size variation and seemingly patternless individual variation in Vb within species and take this study as further evidence that general scaling questions are best examined interspecifically rather than intraspecifically.

scholarly journals The role of local versus biogeographical processes in influencing diversity and body‐size variation in mammal assemblages

2016 ◽  
Vol 6 (5) ◽  
pp. 1447-1456 ◽  
Author(s):  
Luiz Carlos S. Lopez ◽  
Marcos S. L. Figueiredo ◽  
Maria Paula de Aguiar Fracasso ◽  
Daniel Oliveira Mesquita ◽  
Ulisses Umbelino Anjos ◽  
...  
Keyword(s):  
Body Size ◽  
Size Variation ◽  
Body Size Variation ◽  
Mammal Assemblages
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