Latitudinal variation in snowshoe hare (Lepus americanus) body mass: a test of Bergmann’s rule

2020 ◽  
Vol 98 (2) ◽  
pp. 88-95 ◽  
Author(s):  
Laura C. Gigliotti ◽  
Nathan D. Berg ◽  
Rudy Boonstra ◽  
Shawn M. Cleveland ◽  
Duane R. Diefenbach ◽  
...  
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Snow Depth ◽  
Large Body ◽  
Geographic Location ◽  
Growing Season ◽  
Lepus Americanus ◽  
Bergmann’S Rule ◽  
Bergmann's Rule ◽  
The North

The relationship between body size and latitude has been the focus of dozens of studies across many species. However, results of testing Bergmann’s rule — that organisms in colder climates or at higher latitudes possess larger body sizes — have been inconsistent across studies. We investigated whether snowshoe hares (Lepus americanus Erxleben, 1777) follow Bergmann’s rule by investigating differences in body mass using data from six published studies and from data of 755 individual hares captured from 10 populations across North America covering 26° of north latitude. We also explored alternative hypotheses related to variation in hare body mass, including winter severity, length of growing season, elevation, and snow depth. We found body mass of hares varied throughout their range, but the drivers of body mass differed based on geographic location. In northern populations, females followed Bergmann’s rule, whereas males did not. In northern populations, male mass was related to mean snow depth. In contrast, in southern populations, body mass of both sexes was related to length of the growing season. These differences likely represent variation in the drivers of selection. Specifically, in the north, a large body size is beneficial to conserve heat because of low winter temperatures, whereas in the south, it is likely due to increased food supply associated with longer growing seasons.

scholarly journals The Elevation does not strongly influence interspecific variation in body size of small Tropical endotherms

2020 ◽  
Vol 68 (4) ◽  
Author(s):  
Oscar E. Murillo-García ◽  
Maria E. De la vega ◽  
Katherine Pérez-Castillo
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Environmental Changes ◽  
Large Body ◽  
Interspecific Variation ◽  
Bergmann’S Rule ◽  
Distribution Data ◽  
Bergmann's Rule ◽  
Altitudinal Distribution ◽  
Altitudinal Gradients

Introduction: Body size is an essential trait for endotherms to face the physiological requirements of cold, so there is a tendency to large body size at high altitudes and latitudes, known as Bergmann's rule. However, the validity of this ecomorphological rule to small-bodied endotherms across altitudinal gradients is poorly known. Objective: To understand the effects of environmental variation on body size, we assessed whether interspecific variation in body size of small tropical endotherms follows Bergmann's rule along tropical altitudinal gradients. Methods: We compiled data on elevational ranges and body masses for 133 species of hummingbirds of Colombia. We then assessed the association between body mass and mid-point of the altitudinal distribution using phylogenetic generalized least squares (PGLS) analyses under different evolutionary models. Results: We found a decelerating rate of evolution for body size since the Early Burst model of evolution provided a better fit to body mass data. For elevational range, we found a slow and constant rate since Pagel's lambda model provided a better fit to the mid-point of the altitudinal distribution data. Besides, phylogenetic regression analysis indicated that body mass and the altitudinal range of hummingbirds are associated through the phylogeny, with a positive but slight association (R2= 0.036). Conclusions: We found that body mass and altitude of hummingbirds are positively related, which is in agreement with expectations under Bergmann's rule. However, this association was weaker than expected for small and non-passerine birds like hummingbirds. Thus, our results suggest that environmental changes across altitudinal gradients do not strongly influence body mass in small tropical endotherms as hummingbirds.

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.

Latitudinal variation in body size in Fejervarya limnocharis supports the inverse of Bergmann’s rule

2018 ◽  
Vol 68 (2) ◽  
pp. 113-128 ◽  
Author(s):  
Qiao Liu ◽  
Hao Feng ◽  
Long Jin ◽  
Zhi Ping Mi ◽  
Zhao Min Zhou ◽  
...  
Keyword(s):  
Body Size ◽  
Environmental Temperature ◽  
Growing Season ◽  
Climatic Conditions ◽  
Latitudinal Variation ◽  
Bergmann’S Rule ◽  
Bergmann's Rule ◽  
Low Latitude ◽  
Fejervarya Limnocharis

AbstractBergmann’s rule states that within a species of endotherms smaller individuals are found in warmer conditions, which is consistent for nearly all endotherms, while in ectotherms body size patterns are less consistent. As ectothermic vertebrates, the morphology of amphibians is likely impacted by climatic conditions. Here, we examined latitudinal variation in body size in the ranid frog,Fejervarya limnocharis, based on literature and our own data on mean body size of 3637 individuals from 50 populations and average age of 2873 individuals from 40 populations in China. The results showed that body size was positively correlated with environmental temperature, but not with precipitation. Body size was negatively correlated with latitude among populations in this species, which supported the inverse of Bergmann’s rule. Our findings suggest that a larger body size in low-latitude populations is associated with a longer growing season related to the higher environmental temperature.

Oligo-Miocene climate change and mammal body-size evolution in the northwest United States: a test of Bergmann's Rule

Paleobiology ◽  
10.1666/13006 ◽  
2013 ◽  
Vol 39 (4) ◽  
pp. 648-661 ◽  
Author(s):  
John D. Orcutt ◽  
Samantha S. B. Hopkins
Keyword(s):  
United States ◽  
Body Size ◽  
Body Mass ◽  
Global Climate ◽  
Climatic Conditions ◽  
Bergmann’S Rule ◽  
Bergmann's Rule ◽  
Complex Interactions ◽  
Size Evolution ◽  
Body Size Evolution

Whether or not climate plays a causal role in mammal body-size evolution is one of the longest-standing debates in ecology. Bergmann's Rule, the longest-standing modeladdressing this topic, posits that geographic body-mass patterns are driven by temperature, whereas subsequent research has suggested that other ecological variables, particularly precipitation and seasonality, may be the major drivers of body-size evolution. While paleoecological data provide a unique and crucial perspective on this debate, paleontological tests of Bergmann's rule and its corollaries have been scarce. We present a study of body-size evolution in three ecologically distinct families of mammal (equids, canids, and sciurids) during the Oligo-Miocene of the northwest United States, an ideal natural laboratory for such studies because of its rich fossil and paleoclimatic records. Body-size trends are different in all three groups, and in no case is a significant relationship observed between body size and any climatic variable, counter to what has been observed in modern ecosystems. We suggest that for most of the Cenozoic, at least in the Northwest, body mass has not been driven by any one climatic factor but instead has been the product of complex interactions between organisms and their environments, though the nature of these interactions varies from taxon to taxon. The relationship that exists between climate and body size in many groups of modern mammals, therefore, is the exception to the rule and may be the product of an exceptionally cool and volatile global climate. As anthropogenic global warming continues and ushers in climatic conditions more comparable to earlier intervals of the Cenozoic than to the modern day, models of corresponding biotic variables such as body size may lose predictive power if they do not incorporate paleoecological data.

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.

An interspecific test of Bergmann's rule reveals inconsistent body size patterns across several lineages of water beetles (Coleoptera: Dytiscidae)

2018 ◽  
Vol 44 (2) ◽  
pp. 249-254 ◽  
Author(s):  
Susana Pallarés ◽  
Michele Lai ◽  
Pedro Abellán ◽  
Ignacio Ribera ◽  
David Sánchez-Fernández
Keyword(s):  
Body Size ◽  
Bergmann’S Rule ◽  
Bergmann's Rule ◽  
Water Beetles

Biogeographical effects on body mass of native Australian and introduced mice, Pseudomys hermannsburgensis and Mus domesticus: an inquiry into Bergmann's Rule

2008 ◽  
Vol 56 (6) ◽  
pp. 423 ◽  
Author(s):  
Sean Tomlinson ◽  
Philip C. Withers
Keyword(s):  
Ambient Temperature ◽  
Body Mass ◽  
Rainfall Variability ◽  
Negative Influence ◽  
Bergmann’S Rule ◽  
Annual Rainfall ◽  
Maximum Temperature ◽  
Mus Domesticus ◽  
Arid Areas ◽  
Bergmann's Rule

We investigated interactions of body mass with geographical location, and five climatic measures for two Australian rodents, the native Australian sandy inland mouse (Pseudomys hermannsburgensis) and the introduced house mouse (Mus domesticus). Correlation and regression analyses identified interactions of body mass with latitude, longitude, average highest maximum and lowest minimum temperatures, average annual rainfall, rainfall variability, and aridity. There was a significant correlation of body mass with latitude and longitude for Mus domesticus and P. hermannsburgensis. House mice were heavier in the south and east, and sandy inland mice were heavier in the north and east. M. domesticus conforms to Bergmann’s Rule, while P. hermannsburgensis does not. Maximum temperature, aridity and rainfall variability significantly influenced body mass of M. domesticus, which was heavier at cooler maxima, in less arid areas, and in areas of greater rainfall variability. Only aridity significantly influenced body mass of P. hermannsburgensis, which was heavier in more arid areas. Temperature did not interact significantly with body mass. After accounting for climatic variables, there was still a significant relationship between the residuals of body mass with locality for both species, with a negative influence of latitude and a positive influence of longitude in both; the latitudinal interaction for both species was converse to Bergmann’s Rule. We suggest that latitude, ambient temperature and other selection pressures (such as aridity or productivity) can act in opposing directions, and speculate that the influence of other factors, such as food availability or sociality, may be more important than latitude or ambient temperature.

Bergmann’s rule for Neomys fodiens in the middle of the distribution range

2014 ◽  
Vol 9 (12) ◽  
pp. 1147-1154 ◽  
Author(s):  
Linas Balčiauskas ◽  
Laima Balčiauskienė ◽  
Uudo Timm
Keyword(s):  
Body Size ◽  
The Body ◽  
Distribution Range ◽  
Bergmann’S Rule ◽  
Bergmann's Rule ◽  
Range Analysis ◽  
Skull Size ◽  
Skull Measurements ◽  
The Brain ◽  
Neomys Fodiens

AbstractThe body size of Palearctic Sorex shrews decreases at higher latitudes, and as such the Bergmann’s rule does not work. However, no analysis has ever been done for water shrew (Neomys fodiens) in the middle of distribution range. Analysis of available literature data showed that some body and skull measurements of N. fodiens are negatively correlated to latitude. Measurements of 158 water shrews from Estonia and Lithuania were also analyzed with respect to the short scale latitudinal pattern. We found that populations are separated (Wilk’s lambda = 0.363, p<0.0001). Differences are related to PC1 (skull size), explaining 49.80% of the variance and PC2 (body size), explaining 10.06% of the variance. Estonian shrews are smaller in their body and skull (most differences significant) and their skulls are relatively shorter and wider in the area of the brain case. Thus, the negative correlation of body and skull size to latitude in N. fodiens is applicable even over quite short latitudinal distances. Further analysis of diagnostic characters between N. fodiens and N. anomalus is required.

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