Exploring adaptive landscapes across deep time: A case study using echinoid body size

Evolution ◽  
2021 ◽  
Author(s):  
Nicolás Mongiardino Koch
Keyword(s):  
Body Size ◽  
Deep Time ◽  
Adaptive Landscapes

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.

Latitudinal body-mass trends in Oligo-Miocene mammals

Paleobiology ◽  
2016 ◽  
Vol 42 (4) ◽  
pp. 643-658
Author(s):  
John D. Orcutt ◽  
Samantha S. B. Hopkins
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Regional Scale ◽  
Latitudinal Gradients ◽  
Bergmann’S Rule ◽  
Strongly Correlated ◽  
Bergmann's Rule ◽  
Deep Time ◽  
Causal Factors ◽  
Primary Driver

AbstractPaleecological data allow not only the study of trends along deep-time chronological transects but can also be used to reconstruct ecological gradients through time, which can help identify causal factors that may be strongly correlated in modern ecosystems. We have applied such an analysis to Bergmann’s rule, which posits a causal relationship between temperature and body size in mammals. Bergmann’s rule predicts that latitudinal gradients should exist during any interval of time, with larger taxa toward the poles and smaller taxa toward the equator. It also predicts that the strength of these gradients should vary with time, becoming weaker during warmer periods and stronger during colder conditions. We tested these predictions by reconstructing body-mass trends within canid and equid genera at different intervals of the Oligo-Miocene along the West Coast of North America. To allow for comparisons with modern taxa, body mass was reconstructed along the same transect for modernCanisandOdocoileus. Of the 17 fossil genera analyzed, only two showed the expected positive relationship with latitude, nor was there consistent evidence for a relationship between paleotemperature and body mass. Likewise, the strength of body-size gradients does not change predictably with climate through time. The evidence for clear gradients is ambiguous even in the modern genera analyzed. These results suggest that, counter to Bergmann’s rule, temperature alone is not a primary driver of body size and underscore the importance of regional-scale paleoecological analyses in identifying such drivers.

Comparing three body condition indices in amphibians: a case study of yellow-bellied toad Bombina variegata

2010 ◽  
Vol 31 (4) ◽  
pp. 558-562 ◽  
Author(s):  
Rodica Plăiaşu ◽  
Tibor Hartel ◽  
Raluca Ioana Băncilă ◽  
Dan Cogălniceanu ◽  
Joost Smets
Keyword(s):  
Body Size ◽  
Body Condition ◽  
Condition Index ◽  
Quality Parameters ◽  
Direct Measurements ◽  
Wide Range ◽  
Bombina Variegata ◽  
Condition Indices ◽  
Three Body

AbstractBody condition is important because it is correlated with population and habitat quality parameters. Since the direct measurements are either lethal or unreliable, a wide range of non-lethal body condition indices has been proposed. The aim of our study was to apply and compare three body condition indices (Fulton's index, relative body condition mass index and residual index) using body size indicator – body mass data for 24 populations of the yellow bellied toad (Bombina variegata). The condition index should be independent of body size indicator, in this case snout vent length (SVL). Therefore we tested all three indices for the statistical independence of SVL and for the normality of distribution. Fulton's index violated the independence assumption, whereas the relative body condition mass index did not have a normal distribution. Residual index was found both independent of SVL and normally distributed. Moreover, the residual index highlighted biological significant differences on the basis of altitude and season. Our results recommend the residual index as a useful tool in amphibian monitoring and conservation.

Melanism and ontogeny: a case study in lizards of the Liolaemus fitzingerii group (Squamata: Liolaemini)

2016 ◽  
Vol 94 (3) ◽  
pp. 199-206 ◽  
Author(s):  
P.C. Escudero ◽  
I. Minoli ◽  
M.A. González Marín ◽  
M. Morando ◽  
L.J. Avila
Keyword(s):  
New Species ◽  
Body Size ◽  
Comparative Studies ◽  
Species Group ◽  
Evolutionary Adaptation ◽  
Body Measurements ◽  
Adaptation Studies ◽  
Present Evidence ◽  
Over Time

Color polymorphisms in general and melanism in particular have been the focus of many evolutionary adaptation studies. In lizards of the genus Liolaemus Wiegmann, 1834, patterns of melanism have been poorly studied, although they have been used as diagnostic characters for identifying and describing new species. We investigated the relationships between melanism, body size, sex, and time in a population of Rawson Lizard (Liolaemus xanthoviridis Cei and Scolaro, 1980) with extensive ventral melanism. The study took place in Bahía Isla Escondida, Chubut (Argentina), during three summer seasons (2012 to 2014). We tagged each individual, recorded body measurements and sex, and took ventral photographs to estimate the proportion of melanism. Our results showed that ventral melanism increased over time as each individual increased its snout–vent length (SVL). Body size explained 44% of the variation in melanism and males were more melanistic than females. Previous comparative studies of lizards in this species group showed no relationship between melanism and different taxonomic units or with thermal functionality. Here, we present evidence suggesting that melanism might be a character with an ontogenetic origin that is strongly associated with sex and body size. This pattern could be shared among species of this group of lizards, and even more importantly, it may be related to variable selection forces occurring throughout ontogeny.

scholarly journals The importance of sampling standardization for comparisons of insect herbivory in deep time: a case study from the late Palaeozoic

2018 ◽  
Vol 5 (3) ◽  
pp. 171991 ◽  
Author(s):  
Sandra R. Schachat ◽  
Conrad C. Labandeira ◽  
S. Augusta Maccracken
Keyword(s):  
Surface Area ◽  
Fossil Record ◽  
Insect Herbivory ◽  
Ecological Factors ◽  
Published Data ◽  
Deep Time ◽  
Leaf Surface Area ◽  
Number Of Leaves ◽  
The Impact

Sampling standardization has not been fully addressed for the study of insect herbivory in the fossil record. The effects of sampling within a single locality were explored almost a decade ago, but the importance of sampling standardization for comparisons of herbivory across space and time has not yet been evaluated. Here, we present a case study from the Permian in which we evaluate the impact of sampling standardization on comparisons of insect herbivory from two localities that are similar in age and floral composition. Comparisons of insect damage type (DT) diversity change dramatically when the number of leaves examined is standardized by surface area. This finding suggests that surface area should always be taken into account for comparisons of DT diversity. In addition, the three most common metrics of herbivory—DT diversity, proportion of leaves herbivorized and proportion of leaf surface area herbivorized—are inherently decoupled from each other. The decoupling of the diversity and intensity of insect herbivory necessitates a reinterpretation of published data because they had been conflated in previous studies. Future studies should examine the divergent ecological factors that underlie these metrics. We conclude with suggestions to guide the sampling and analysis of herbivorized leaves in the fossil record.

The manifestation and significance of sexual dimorphism in anguid lizards: a case study of Barisia monticola

1989 ◽  
Vol 67 (1) ◽  
pp. 68-72 ◽  
Author(s):  
James L. Vial ◽  
James R. Stewart
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Reproductive Behavior ◽  
Reproductive Potential ◽  
Head Size ◽  
Adult Males ◽  
Allometric Growth ◽  
Natural And Sexual Selection ◽  
Dimorphic Expression

The dimorphic expression of body size, body – head size relationships, and chromatic characters among anguid lizards is reviewed. These characteristics are quantitatively examined in a population of Barisia monticola. No sexual differences are found in body size. Head size is positively correlated with body size; however, allometric growth rates in head size are significantly greater in adult males than in females or juveniles. Adult males also differ significantly in eight of nine chromatic characters, the most pronounced being the presence of light dorsal scale markings. These differences are explored in the context of both natural and sexual selection. We hypothesize that the absence of dimorphism in overall body size is the result of natural selection operating to maximize female reproductive potential. In contrast, we predict that dimorphism expressed in body – head size relationships and dichromatism are consequences of sexual selection relating to agonistic and reproductive behavior of males.

scholarly journals Relative brain size and cognitive equivalence in fishes

2021 ◽  
Author(s):  
Zegni Triki ◽  
Mélisande Aellen ◽  
Carel P. van Schaik ◽  
Redouan Bshary
Keyword(s):  
Body Size ◽  
Cognitive Performance ◽  
Brain Size ◽  
Regression Line ◽  
Mean Value ◽  
Mammalian Brain ◽  
Regression Slope ◽  
Scan Data ◽  
The Brain

Scientists have long struggled to establish how larger brains translate into higher cognitive performance across species. While absolute brain size often yields high predictive power of performance, its positive correlation with body size warrants some level of correction. It is expected that larger brains are needed to control larger bodies without any changes in cognitive performance. Potentially, the mean value of intraspecific brain-body slopes provides the best available estimate for an interspecific correction factor. For example, in primates, including humans, an increase in body size translates into an increase in brain size without changes in cognitive performance. Here, we provide the first evaluation of this hypothesis for another clade, teleost fishes. First, we obtained a mean intraspecific brain-body regression slope of 0.46 (albeit a relatively large range of 0.26 to 0.79) from a dataset of 51 species, with at least ten wild adult specimens per species. This mean intraspecific slope value (0.46) is similar to that of the encephalisation quotient reported for teleost (0.5), which can be used to predict mean cognitive performance in fishes. Importantly, such mean value (0.46) is much higher than in endothermic vertebrate species (~ 0.3). Second, we used wild-caught adult cleaner fish Labroides dimidiatus as a case study to test whether variation in individual cognitive performance can be explained by body size. We first obtained the brain-body regression slope for this species from two different datasets, which gave slope values of 0.58 (MRI scan data) and 0.47 (dissection data). Then, we used another dataset involving 69 adult cleaners different from those tested for their brain-body slope. We found that cognitive performance from four different tasks that estimated their learning, numerical, and inhibitory control abilities, was not significantly associated with body size. These results suggest that the intraspecific brain-body slope can estimate cognitive equivalence for this species. That is, individuals that are on the brain-body regression line are cognitively equal. While rather preliminary, our results suggest that fish and mammalian brain organisations are fundamentally different, resulting in different intra- and interspecific slopes of cognitive equivalence.

scholarly journals Distinguishing Biology from Geology in Soft-Tissue Preservation

2014 ◽  
Vol 20 ◽  
pp. 275-288 ◽  
Author(s):  
John A. Cunningham ◽  
Philip C. J. Donoghue ◽  
Stefan Bengtson
Keyword(s):  
Soft Tissue ◽  
Laser Beam ◽  
Evolutionary History ◽  
Soft Tissues ◽  
Analytical Techniques ◽  
Tissue Preservation ◽  
Deep Time ◽  
X Ray ◽  
Soft Tissue Preservation

Knowledge of evolutionary history is based extensively on relatively rare fossils that preserve soft tissues. These fossils record a much greater proportion of anatomy than would be known solely from mineralized remains and provide key data for testing evolutionary hypotheses in deep time. Ironically, however, exceptionally preserved fossils are often among the most contentious because they are difficult to interpret. This is because their morphology has invariably been affected by the processes of decay and diagenesis, meaning that it is often difficult to distinguish preserved biology from artifacts introduced by these processes. Here we describe how a range of analytical techniques can be used to tease apart mineralization that preserves biological structures from unrelated geological mineralization phases. This approach involves using a series of X-ray, ion, electron and laser beam techniques to characterize the texture and chemistry of the different phases so that they can be differentiated in material that is difficult to interpret. This approach is demonstrated using a case study of its application to the study of fossils from the Ediacaran Doushantuo Biota.

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