scholarly journals Mechanistic macroecology: exploring the drivers of latitudinal variation in terrestrial body size in a General Ecosystem Model

2019 ◽  
Author(s):  
Michael Brian James Harfoot ◽  
Andrew Abraham ◽  
Derek P Tittensor ◽  
Gabriel C Costa ◽  
Søren Faurby ◽  
...  
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Resource Availability ◽  
Large Scale ◽  
Environmental Gradients ◽  
Ecosystem Model ◽  
Experimental Manipulation ◽  
Statistical Correlation ◽  
Biogeographic Patterns ◽  
Empirical Estimates

ABSTRACTMany mechanisms have been hypothesized to explain Bergmann’s rule - the correlation of body size with latitude. However, it is not feasible to assess the contribution of hypothesised mechanisms by experimental manipulation or statistical correlation. Here, we evaluate two of the principal hypothesised mechanisms, related to thermoregulation and resource availability, using structured experiments in a mechanistic global ecosystem model. We simulated the broad structure of assemblages and ecosystems using the Madingley model, a mechanistic General Ecosystem Model (GEM). We compared emergent modelled biogeographic patterns in body mass to empirical patterns for mammals and birds. We then explored the relative contribution of thermoregulation and resource availability to body mass clines by manipulating the model’s environmental gradients. Madingley produces body size gradients that are in broad agreement with empirical estimates. Thermoregulation and resource availability were both important controls on body mass for endotherms, but only temperature for ectotherms. Our results suggest that seasonality explains animal body mass patterns through a complex set of mechanisms. Process-based GEMs generate broadly realistic biogeographic body mass patterns. Ecologists can use them in novel ways: to explore causality, or for generating and testing hypotheses for large-scale, emergent ecological patterns. At the same time, macroecological patterns are useful for evaluating mechanistic models. Iteratively developing GEMs, and evaluating them against macroecological patterns, could generate new insights into the complex causes of such patterns.

scholarly journals Habitat productivity is a poor predictor of body size in rodents

2019 ◽  
Vol 66 (2) ◽  
pp. 135-143 ◽  
Author(s):  
Bader H Alhajeri ◽  
Lucas M V Porto ◽  
Renan Maestri
Keyword(s):  
Body Size ◽  
Least Squares ◽  
Body Mass ◽  
Resource Availability ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Positive Association ◽  
Generalized Least Squares ◽  
Habitat Productivity ◽  
Resource Availability Hypothesis

Abstract The “resource availability hypothesis” predicts occurrence of larger rodents in more productive habitats. This prediction was tested in a dataset of 1,301 rodent species. We used adult body mass as a measure of body size and normalized difference vegetation index (NDVI) as a measure of habitat productivity. We utilized a cross-species approach to investigate the association between these variables. This was done at both the order level (Rodentia) and at narrower taxonomic scales. We applied phylogenetic generalized least squares (PGLS) to correct for phylogenetic relationships. The relationship between body mas and NDVI was also investigated across rodent assemblages. We controlled for spatial autocorrelation using generalized least squares (GLS) analysis. The cross-species approach found extremely low support for the resource availability hypothesis. This was reflected by a weak positive association between body mass and NDVI at the order level. We find a positive association in only a minority of rodent subtaxa. The best fit GLS model detected no significant association between body mass and NDVI across assemblages. Thus, our results do not support the view that resource availability plays a major role in explaining geographic variation in rodent body size.

scholarly journals Environmental and ecological factors mediate taxonomic composition and body size of polyplacophoran assemblages along the Peruvian Province

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Christian M. Ibáñez ◽  
Melany Waldisperg ◽  
Felipe I. Torres ◽  
Sergio A. Carrasco ◽  
Javier Sellanes ◽  
...  
Keyword(s):  
Body Size ◽  
Species Composition ◽  
Size Structure ◽  
Environmental Gradients ◽  
Ecological Factors ◽  
Taxonomic Composition ◽  
Latitudinal Gradients ◽  
Size Segregation ◽  
Biogeographic Patterns ◽  
Diversity Gradient

Abstract Intertidal communities’ composition and diversity usually exhibit strong changes in relation to environmental gradients at different biogeographical scales. This study represents the first comprehensive diversity and composition description of polyplacophoran assemblages along the Peruvian Province (SE Pacific, 12°S–39°S), as a model system for ecological latitudinal gradients. A total of 4,775 chitons from 21 species were collected on twelve localities along the Peruvian Province. This sampling allowed us to quantitatively estimate the relative abundance of the species in this assemblage, and to test whether chitons conform to elementary predictions of major biogeographic patterns such as a latitudinal diversity gradient. We found that the species composition supported the division of the province into three ecoregional faunal groups (i.e. Humboldtian, Central Chile, and Araucanian). Though chiton diversity did not follow a clear latitudinal gradient, changes in species composition were dominated by smaller scale variability in salinity and temperature. Body size significantly differed by ecoregions and species, indicating latitudinal size-structure assamblages. In some localities body size ratios differed from a random assemblage, evidencing competition at local scale. Changes in composition between ecoregions influence body size structure, and their overlapping produce vertical size segregation, suggesting that competition coupled with environmental conditions structure these assemblages.

scholarly journals Photoperiod and Relationship with Body Mass and Size in Bumblebee, Bombus terrestris L. (Hymenoptera: Apidae) Workers

1970 ◽  
Vol 46 (4) ◽  
pp. 447-450 ◽  
Author(s):  
MR Amin ◽  
YJ Kwon
Keyword(s):  
Body Size ◽  
Key Words ◽  
Body Mass ◽  
Large Scale ◽  
Bombus Terrestris ◽  
The Body ◽  
Crop Pollination ◽  
Greenhouse Crops ◽  
Photoperiodic Condition ◽  
Wet Masses

Bombus terrestris L. appears to be a promising and cosmopolitan bumblebee species for pollination of greenhouse crops and its demand for large scale rearing. For effective crop pollination, colonies with optimal body sized workers are essential because generally larger bees visit more flowers per unit time. The body size is correlated with flexible development and growth in a changing environment. This study explored the effect of different photoperiodic regimes i.e., L0:D24, L8:D16, L16:D8 and L24:D0 in regulation of the body mass and size of bumblebee workers during the stages of larval, pupal and adult eclosion. The results showed that wet masses of larvae, pupae and adult ranged from 144.2 ± 7.6 to 198.7 ± 11.7, 398.3 ± 16.0 to 464.7 ± 9.3 and 224.8 ± 9.3 to 274.7 ± 7.0 mg, respectively whereas their dry masses were 47.7 ± 4.8 to 63.7 ± 5.4, 176.7 ± 6.7 to 204.7 ± 5.6 and 62.8 ± 3.0 to 78.7 ± 2.1 mg, respectively. The length of wing and tibae were observed 8.14 ± 0.82 to 8.47 ± 0.73 and 4.30 ± 0.51 to 4.47 ± 0.32 mm, respectively. The L0:D24 photoperiodic condition produced heavier larvae, pupae and adult workers with larger wings and tibiae and worker's body size and mass decreased significantly when the bees were reared under L16:D8 and L24:D0 conditions. Key words: Bumblebee; Body mass and size; Photoperiod DOI: http://dx.doi.org/10.3329/bjsir.v46i4.9589 BJSIR 2011; 46(4): 447-450

scholarly journals Environmental drivers of body size in North American bats

2021 ◽  
Author(s):  
Jesse M Alston ◽  
Douglas A Keinath ◽  
Craig K.R. Willis ◽  
Cori L Lausen ◽  
Joy M O'Keefe ◽  
...  
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Resource Availability ◽  
Net Primary Productivity ◽  
Bergmann’S Rule ◽  
Environmental Drivers ◽  
Mean Annual Temperature ◽  
Bergmann's Rule ◽  
Bayesian Hierarchical ◽  
Spatio Temporal

Bergmann's Rule--which posits that larger animals live in colder areas--is thought to influence variation in body size within species across space and time, but evidence for this claim is mixed. We tested four competing hypotheses for spatio-temporal variation in body size within bat species during the past two decades across North America. Bayesian hierarchical models revealed that spatial variation in body mass was most strongly (and negatively) correlated with mean annual temperature, supporting the heat conservation hypothesis (historically believed to underlie Bergmann's Rule). Across time, variation in body mass was most strongly (and positively) correlated with net primary productivity, supporting the resource availability hypothesis. Climate change could influence body size in animals through both changes in mean annual temperature and in resource availability. Rapid reductions in body size associated with increasing temperatures have occurred in short-lived, fecund species, but such reductions likely transpire more slowly in longer-lived species.

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 Morphological determinants of jumping performance in the Iberian green frog

2019 ◽  
Vol 66 (4) ◽  
pp. 417-424
Author(s):  
Gregorio Moreno-Rueda ◽  
Abelardo Requena-Blanco ◽  
Francisco J Zamora-Camacho ◽  
Mar Comas ◽  
Guillem Pascual
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Fluctuating Asymmetry ◽  
Hind Limb ◽  
Limb Length ◽  
Age Classes ◽  
Jumping Performance ◽  
Hind Limbs ◽  
Selective Forces ◽  
Pelophylax Perezi

Abstract Predation is one of the main selective forces in nature, frequently selecting potential prey for developing escape strategies. Escape ability is typically influenced by several morphological parameters, such as morphology of the locomotor appendices, muscular capacity, body mass, or fluctuating asymmetry, and may differ between sexes and age classes. In this study, we tested the relationship among these variables and jumping performance in 712 Iberian green frogs Pelophylax perezi from an urban population. The results suggest that the main determinant of jumping capacity was body size (explaining 48% of variance). Larger frogs jumped farther, but jumping performance reached an asymptote for the largest frogs. Once controlled by structural body size, the heaviest frogs jumped shorter distances, suggesting a trade-off between fat storage and jumping performance. Relative hind limb length also determined a small but significant percentage of variance (2.4%) in jumping performance—that is, the longer the hind limbs, the greater the jumping capacity. Juveniles had relatively shorter and less muscular hind limbs than adults (for a given body size), and their jumping performance was poorer. In our study population, the hind limbs of the frogs were very symmetrical, and we found no effect of fluctuating asymmetry on jumping performance. Therefore, our study provides evidence that jumping performance in frogs is not only affected by body size, but also by body mass and hind limb length, and differ between age classes.

scholarly journals Influence of temperature on the larval development of the edible crab, Cancer pagurus

2009 ◽  
Vol 89 (4) ◽  
pp. 753-759 ◽  
Author(s):  
Monika Weiss ◽  
Sven Thatje ◽  
Olaf Heilmayer ◽  
Klaus Anger ◽  
Thomas Brey ◽  
...  
Keyword(s):  
Larval Development ◽  
Body Mass ◽  
Large Scale ◽  
Citrate Synthase ◽  
C:N Ratio ◽  
Intraspecific Variability ◽  
Larval Body ◽  
Influence Of Temperature ◽  
Cancer Pagurus ◽  
Influence Of Temperature On

The influence of temperature on larval survival and development was studied in the edible crab, Cancer pagurus, from a population off the island of Helgoland, North Sea. In rearing experiments conducted at six different temperatures (6°, 10°, 14°, 15°, 18° and 24°C), zoeal development was only completed at 14° and 15°C. Instar duration of the Zoea I was negatively correlated with temperature. A model relating larval body mass to temperature and developmental time suggests that successful larval development is possible within a narrow temperature range (14° ± 3°C) only. This temperature optimum coincides with the highest citrate synthase activity found at 14°C. A comparison for intraspecific variability among freshly hatched zoeae from different females (CW 13–17 cm, N = 8) revealed that both body mass and elemental composition varied significantly. Initial larval dry weight ranged from 12.1 to 17.9 μg/individual, the carbon content from 4.6 to 5.8 μg/individual, nitrogen from 1.1 to 1.3 μg/individual, and the C:N ratio from 4.1 to 4.4. A narrow larval temperature tolerance range of C. pagurus as well as the indication of intraspecific variability in female energy allocation into eggs may indicate a potential vulnerability of this species to climate change. Large-scale studies on the ecological and physiological resilience potential of this commercially fished predator are needed.

scholarly journals Ontogeny of body size and shape of Antarctic and subantarctic fur seals

2007 ◽  
Vol 85 (12) ◽  
pp. 1275-1285 ◽  
Author(s):  
Sebastián P. Luque ◽  
Edward H. Miller ◽  
John P.Y. Arnould ◽  
Magaly Chambellant ◽  
Christophe Guinet
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Morphological Traits ◽  
Body Shape ◽  
Size And Shape ◽  
Fur Seals ◽  
Fur Seal ◽  
Adult Body ◽  
Weaning Age ◽  
Lactation Duration

Pre- and post-weaning functional demands on body size and shape of mammals are often in conflict, especially in species where weaning involves a change of habitat. Compared with long lactations, brief lactations are expected to be associated with fast rates of development and attainment of adult traits. We describe allometry and growth for several morphological traits in two closely related fur seal species with large differences in lactation duration at a sympatric site. Longitudinal data were collected from Antarctic ( Arctocephalus gazella (Peters, 1875); 120 d lactation) and subantarctic ( Arctocephalus tropicalis (Gray, 1872); 300 d lactation) fur seals. Body mass was similar in neonates of both species, but A. gazella neonates were longer, less voluminous, and had larger foreflippers. The species were similar in rate of preweaning growth in body mass, but growth rates of linear variables were faster for A. gazella pups. Consequently, neonatal differences in body shape increased over lactation, and A. gazella pups approached adult body shape faster than did A. tropicalis pups. Our results indicate that preweaning growth is associated with significant changes in body shape, involving the acquisition of a longer, more slender body with larger foreflippers in A. gazella. These differences suggest that A. gazella pups are physically more mature at approximately 100 d of age (close to weaning age) than A. tropicalis pups of the same age.

Genetic and morphological diversity of the cosmopolitan chaetognath Pseudosagitta maxima (Conant, 1896) in the Atlantic Ocean and its relationship with the congeneric species

2017 ◽  
Vol 74 (7) ◽  
pp. 1875-1884 ◽  
Author(s):  
Dmitry N. Kulagin ◽  
Tatiana V. Neretina
Keyword(s):  
Atlantic Ocean ◽  
Large Scale ◽  
Phylogenetic Analyses ◽  
Morphological Diversity ◽  
Maturity Stage ◽  
Congeneric Species ◽  
Morphological Examination ◽  
Posterior Teeth ◽  
Biogeographic Patterns ◽  
True Diversity

Abstract Until recently many oceanic zooplankton species have been considered as cosmopolitan organisms. At present it became evident that some of them comprise many distinct molecular operational taxonomic units (MOTUs) that often are regarded as cryptic species. As they can significantly change our perceptions of large-scale biogeographic patterns, it is important to characterize the true diversity within common and ecologically important groups. We have analysed the molecular and morphological diversity of the cosmopolitan mesopelagic chaetognath Pseudosagitta maxima throughout the Atlantic Ocean from 60° S to 85° N and its position within the genus Pseudosagitta. Three distinct mitochondrial clades within P. maxima were revealed with phylogenetic analyses (Maximum Likelihood, Bayesian Inference) and were geographically separated. The subsequent analyses of nuclear markers (H3, ITS1) have shown that P. maxima most likely comprises two distinct MOTUs, tropical and bipolar, that also have some morphological differences. The latter MOTU consists of two genetically slightly divergent populations: southern and northern. The morphological examination allowed the determination of a character (type of hook coloration) that accurately distinguishes juveniles of the P. maxima complex from the other congeneric species. Molecular data have shown that evolutionary P. lyra and P. gazellae are more closely related to each other than to P. maxima. Number of hooks, number of anterior and posterior teeth and the arrangement of ova in the ovary were proposed to be the most useful morphological characters to distinguish between tropical and bipolar MOTUs within the P. maxima complex. The first three characters should be determined for each maturity stage separately.

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