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1.
The body size of an animal is probably its most important functional trait. For arthropods, environmental drivers of body size variation are still poorly documented and understood, especially in tropical regions. We use a unique dataset for two species‐rich, phylogenetically independent moth taxa (Lepidoptera: Geometridae; Arctiinae), collected along an extensive tropical elevational gradient in Costa Rica, to investigate the correlates and possible causes of body‐size variation. We studied 15 047 specimens (794 species) of Geometridae and 4167 specimens (308 species) of Arctiinae to test the following hypotheses: 1) body size increases with decreasing ambient temperature, as predicted by the temperature–size rule; 2) body size increases with increasing rainfall and primary productivity, as predicted from considerations of starvation resistance; and 3) body size scales allometrically with wing area, as elevation increases, such that wing loading (the ratio of body size to wing area) decreases with increasing elevation to compensate for lower air density. To test these hypotheses, we examined forewing length as a proxy for body size in relation to ambient temperature, rainfall, vegetation index and elevation as explanatory variables in linear and polynomial spatial regression models. We analysed our data separately for males and females using two principal approaches: mean forewing length of species at each site, and mean forewing length of complete local assemblages, weighted by abundance. Body size consistently increased with elevation in both taxa, both approaches, both sexes, and also within species. Temperature was the best predictor for this pattern (–0.98 < r < –0.74), whereas body size was uncorrelated or weakly correlated with rainfall and enhanced vegetation index. Wing loading increased with elevation. Our results support the temperature–size rule as an important mechanism for body size variation in arthropods along tropical elevational gradients, whereas starvation resistance and optimization of flight mechanics seem to be of minor importance. 相似文献
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Georgina L. Adams Doris E. Pichler Eileen J. Cox Eoin J. O'Gorman Alex Seeney Guy Woodward Daniel C. Reuman 《Global Change Biology》2013,19(11):3540-3552
Climate warming has been linked to an apparent general decrease in body sizes of ectotherms, both across and within taxa, especially in aquatic systems. Smaller body size in warmer geographical regions has also been widely observed. Since body size is a fundamental determinant of many biological attributes, climate‐warming‐related changes in size could ripple across multiple levels of ecological organization. Some recent studies have questioned the ubiquity of temperature–size rules, however, and certain widespread and abundant taxa, such as diatoms, may be important exceptions. We tested the hypothesis that diatoms are smaller at warmer temperatures using a system of geothermally heated streams. There was no consistent relationship between size and temperature at either the population or community level. These field data provide important counterexamples to both James’ and Bergmann's temperature–size rules, respectively, undermining the widely held assumption that warming favours the small. This study provides compelling new evidence that diatoms are an important exception to temperature–size rules for three reasons: (i) we use many more species than prior work; (ii) we examine both community and species levels of organization simultaneously; (iii) we work in a natural system with a wide temperature gradient but minimal variation in other factors, to achieve robust tests of hypotheses without relying on laboratory setups, which have limited realism. In addition, we show that interspecific effects were a bigger contributor to whole‐community size differences, and are probably more ecologically important than more commonly studied intraspecific effects. These findings highlight the need for multispecies approaches in future studies of climate warming and body size. 相似文献
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David Samuel Johnson Cynthia Crowley Katherine Longmire James Nelson Bethany Williams Serina Wittyngham 《Ecology and evolution》2019,9(24):14489-14497
Bergmann's rule predicts that organisms at higher latitudes are larger than ones at lower latitudes. Here, we examine the body size pattern of the Atlantic marsh fiddler crab, Minuca pugnax (formerly Uca pugnax), from salt marshes on the east coast of the United States across 12 degrees of latitude. We found that M. pugnax followed Bergmann's rule and that, on average, crab carapace width increased by 0.5 mm per degree of latitude. Minuca pugnax body size also followed the temperature–size rule with body size inversely related to mean water temperature. Because an organism's size influences its impact on an ecosystem, and M. pugnax is an ecosystem engineer that affects marsh functioning, the larger crabs at higher latitudes may have greater per‐capita impacts on salt marshes than the smaller crabs at lower latitudes. 相似文献
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Ongoing climate change affects various aspects of an animal's life, with important effects on distribution range and phenology. The relationship between global warming and body size changes in mammals and birds has been widely studied, with most findings indicating a decline in body size over time. Nevertheless, little data exist on similar size change patterns of invertebrates in general and insects in particular, and it is unclear whether insects should decrease in size or not with climate warming. We measured over 4000 beetle specimens, belonging to 29 beetle species in 8 families, collected in Israel during the last 100 years. The sampled species are all herbivorous. We examined whether beetle body size had changed over the years, while also investigating the relationships between body size and annual temperature, precipitation, net primary productivity (NPP) at the collection site and collection month. None of the environmental variables, including the collection year, was correlated with the size of most of the studied beetle species, while there were strong interactions of all variables with species. Our results, though mostly negative, suggest that the effect of climate change on insect body size is species‐specific and by no means a general macro‐ecological rule. They also suggest that the intrapopulation variance in body size of insects collected as adults in the field is large enough to conceal intersite environmental effects on body size, such as the effect of temperature and NPP. 相似文献
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Animal body size commonly shows a relationship with latitude to the degree that this phenomenon is one of the few ‘rules’ discussed in evolutionary ecology: Bergmann's rule. Although exaggerated secondary sexual traits frequently exhibit interesting relationships with body size (allometries) and are expected to evolve rapidly in response to environmental variation, the way in which allometry might interact with latitude has not been addressed. We present data showing latitudinal variation in body size and weapon allometry for the New Zealand giraffe weevil (Lasiorhynchus barbicornis). Males display an extremely elongated rostrum used as a weapon during fights for access to females. Consistent with Bergmann's rule, mean body size increased with latitude. More interestingly, weapon allometry also varied with latitude, such that lower latitude populations exhibited steeper allometric slopes between weapon and body size. To our knowledge, this is the first study to document a latitudinal cline in weapon allometry and is therefore a novel contribution to the collective work on Bergmann's rule and secondary sexual trait variation. 相似文献
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Amy E. Arnett Nicholas J. Gotelli 《Evolution; international journal of organic evolution》1999,53(4):1180-1188
In eastern North America, body size of the larval ant lion Myrmeleon immaculatus increases from south to north, following Bergmann's rule. We used a common-garden experiment and a reciprocal-transplant experiment to evaluate the effects of food and temperature on ant lion growth, body size, and survivorship. In the laboratory common-garden experiment, first-instar larvae from two southern (Georgia, South Carolina) and two northern (Connecticut, Rhode Island) populations were reared in incubators under high- and low-food and high- and low-temperature regimes. For all populations, high food increased final body mass and growth rate and decreased development time. Growth rates were higher at low temperatures, but temperature did not affect larval or adult body mass. Survivorship was highest in high-food and low-temperature treatments. Across all food and temperature treatments, northern populations exhibited a larger final body mass, shorter development time, faster growth rate, and greater survivorship than did southern populations. Results were similar for a field reciprocal-transplant experiment of third-instar larvae between populations in Connecticut and Oklahoma: Connecticut larvae grew faster than Oklahoma larvae, regardless of transplant site. Conversely, larvae transplanted to Oklahoma grew faster than larvae transplanted to Connecticut, regardless of population source. These results suggest that variation in food availability, not temperature, may account for differences in growth and body size of northern and southern ant lions. Although northern larvae grew faster and reached a larger body size in both experiments, northern environments should suppress growth because of reduced food availability and a limited growing season. This study provides the first example of countergradient selection causing Bergmann's rule in an ectotherm. 相似文献
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Ulrich Sommer Kalista H. Peter Savvas Genitsaris Maria Moustaka‐Gouni 《Biological reviews of the Cambridge Philosophical Society》2017,92(2):1011-1026
Global warming has revitalized interest in the relationship between body size and temperature, proposed by Bergmann's rule 150 years ago, one of the oldest manifestations of a ‘biogeography of traits’. We review biogeographic evidence, results from clonal cultures and recent micro‐ and mesocosm experiments with naturally mixed phytoplankton communities regarding the response of phytoplankton body size to temperature, either as a single factor or in combination with other factors such as grazing, nutrient limitation, and ocean acidification. Where possible, we also focus on the comparison between intraspecific size shifts and size shifts resulting from changes in species composition. Taken together, biogeographic evidence, community‐level experiments and single‐species experiments indicate that phytoplankton average cell sizes tend to become smaller in warmer waters, although temperature is not necessarily the proximate environmental factor driving size shifts. Indirect effects via nutrient supply and grazing are important and often dominate. In a substantial proportion of field studies, resource availability is seen as the only factor of relevance. Interspecific size effects are greater than intraspecific effects. Direct temperature effects tend to be exacerbated by indirect ones, if warming leads to intensified nutrient limitation or copepod grazing while ocean acidification tends to counteract the temperature effect on cell size in non‐calcifying phytoplankton. We discuss the implications of the temperature‐related size trends in a global‐warming context, based on known functional traits associated with phytoplankton size. These are a higher affinity for nutrients of smaller cells, highest maximal growth rates of moderately small phytoplankton (ca. 102 µm3), size‐related sensitivities for different types of grazers, and impacts on sinking rates. For a phytoplankton community increasingly dominated by smaller algae we predict that: (i) a higher proportion of primary production will be respired within the microbial food web; (ii) a smaller share of primary production will be channeled to the classic phytoplankton – crustacean zooplankton – fish food chain, thus leading to decreased ecological efficiency from a fish‐production point of view; (iii) a smaller share of primary production will be exported through sedimentation, thus leading to decreased efficiency of the biological carbon pump. 相似文献
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Shai Meiri Tamar Dayan Daniel Simberloff Richard Grenyer 《Proceedings. Biological sciences / The Royal Society》2009,276(1661):1469-1476
Evolutionary biologists have long been fascinated by both the ways in which species respond to ecological conditions at the edges of their geographic ranges and the way that species'' body sizes evolve across their ranges. Surprisingly, though, the relationship between these two phenomena is rarely studied. Here, we examine whether carnivore body size changes from the interior of their geographic range towards the range edges. We find that within species, body size often varies strongly with distance from the range edge. However, there is no general tendency across species for size to be either larger or smaller towards the edge. There is some evidence that the smallest guild members increase in size towards their range edges, but results for the largest guild members are equivocal. Whether individuals vary in relation to the distance from the range edges often depends on the way edge and interior are defined. Neither geographic range size nor absolute body size influences the tendency of size to vary with distance from the range edge. Therefore, we suggest that the frequent significant association between body size and the position of individuals along the edge-core continuum reflects the prevalence of geographic size variation and that the distance to range edge per se does not influence size evolution in a consistent way. 相似文献
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Bergmann's rule describes the macroecological pattern of increasing body size in response to higher latitudes and elevations. This pattern is extensively documented in endothermic vertebrates, within and among species; however, studies involving ectotherms are less common and suggest no consistent pattern for amphibians and reptiles. Moreover, adaptive traits, such as epidermal features like scales, have not been widely examined in conjunction with Bergmann's rule, even though these traits affect physiological processes, such as thermoregulation, which are hypothesized as underlying mechanisms for the pattern. Here, we investigate how scale characters correlate with elevation among 122 New World pitviper species, representing 15 genera. We found a contra‐Bergmann's pattern, where body size is smaller at higher elevations. This pattern was mainly driven by the presence of small‐bodied clades at high elevations and large‐bodied clades at low elevations, emphasizing the importance of taxonomic scope in studying macroecological patterns. Within a subset of speciose clades, we found that only Crotalus demonstrated a significant negative relationship between body size and elevation, perhaps because of its wide elevational range. In addition, we found a positive correlation between scale counts and body size but no independent effect of elevation on scale numbers. Our study increases our knowledge of Bergmann's rule in reptiles by specifically examining characters of squamation and suggests a need to reexamine macroecological patterns for this group. 相似文献
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Although we know there is considerable variation in gut microbial composition within host species, little is known about how this variation is shaped and why such variation exists. In humans, obesity is associated with the relative abundance of two dominant bacterial phyla: an increase in the proportion of Firmicutes and a decrease in the proportion of Bacteroidetes. As there is evidence that humans have adapted to colder climates by increasing their body mass (e.g. Bergmann''s rule), we tested whether Firmicutes increase and Bacteroidetes decrease with latitude, using 1020 healthy individuals drawn from 23 populations and six published studies. We found a positive correlation between Firmicutes and latitude and a negative correlation between Bacteroidetes and latitude. The overall pattern appears robust to sex, age and bacterial detection methods. Comparisons between African Americans and native Africans and between European Americans and native Europeans suggest no evidence of host genotype explaining the observed patterns. The variation of gut microbial composition described here is consistent with the pattern expected by Bergmann''s rule. This surprising link between large-scale geography and human gut microbial composition merits further investigation. 相似文献
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Stillwell RC Moya-Laraño J Fox CW 《Evolution; international journal of organic evolution》2008,62(10):2534-2544
Body size of many animals increases with increasing latitude, a phenomenon known as Bergmann's rule (Bergmann clines). Latitudinal gradients in mean temperature are frequently assumed to be the underlying cause of this pattern because temperature covaries systematically with latitude, but whether and how temperature mediates selection on body size is unclear. To test the hypothesis that the \"relative\" advantage of being larger is greatest at cooler temperatures we compare the fitness of replicate lines of the seed beetle, Stator limbatus, for which body size was manipulated via artificial selection (\"Large,\"Control,\" and \"Small\" lines), when raised at low (22 degrees C) and high (34 degrees C) temperatures. Large-bodied beetles (Large lines) took the longest to develop but had the highest lifetime fecundity, and highest fitness (r(C)), at both low and high temperatures. However, the relative difference between the Large and Small lines did not change with temperature (replicate 2) or was greatest at high temperature (replicate 1), contrary to the prediction that the fitness advantage of being large relative to being small will decline with increasing temperature. Our results are consistent with two previous studies of this seed beetle, but inconsistent with prior studies that suggest that temperature-mediated selection on body size is a major contributor to the production of Bergmann clines. We conclude that other environmental and ecological variables that covary with latitude are more likely to produce the gradient in natural selection responsible for generating Bergmann clines. 相似文献
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Cowgill LW Eleazer CD Auerbach BM Temple DH Okazaki K 《American journal of physical anthropology》2012,148(4):557-570
While ecogeographic variation in adult human body proportions has been extensively explored, relatively less attention has been paid to the effect of Bergmann's and Allen's rules on human body shape during growth. The relationship between climate and immature body form is particularly important, as immature mortality is high, mechanisms of thermoregulation differ between young and mature humans, and immature body proportions fluctuate due to basic parameters of growth. This study explores changes in immature ecogeographic body proportions via analyses of anthropometric data from children included in Eveleth and Tanner's (1976) Worldwide Variation in Human Growth, as well as limb proportion measurements in eight different skeletal samples. Moderate to strong correlations exist between climatic data and immature stature, weight, BMI, and bi-iliac breadth; these relationships are as strong, if not stronger, in immature individuals as they are in adults. Correlations between climate and trunk height relative to stature are weak or nonexistent. Altitude also has significant effects on immature body form, with children from higher altitudes displaying smaller statures and lower body weights. Brachial and crural indices remain constant over the course of growth and display consistent, moderate correlations with latitude across ontogeny that are just as high as those detected in adults. The results of this study suggest that while some features of immature body form, such as bi-iliac breadth and intralimb indices, are strongly dictated by ecogeographic principles, other characteristics of immature body proportions are influenced by intrinsic and extrinsic factors such as nutrition and basic constraints of growth. 相似文献
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Progressive body‐size dwarfing of animal populations is predicted under chronic mortality stress, such as that inflicted by human harvesting. However, empirical support for such declines in body size due to elevated mortality is lacking. In fact, the size of three macropodid species ─ the two grey kangaroo species, Macropus fuliginosus and M. giganteus, and the Red‐necked Wallaby, M. rufogriseus ─ appears to have increased since European settlement in Australia, despite these species being subjected to size‐selective harvesting over this period. To test whether this unexpected trend also characterises other species, we sought evidence of human‐induced body‐size changes in the two most widely distributed kangaroo species, the Euro Macropus robustus and Red Kangaroo M. rufus, from the late 19th Century onwards. Spatial autoregressive models controlling for age, sex and island effects were first used to identify environmental predictors of body size and to evaluate multi‐causal explanations for spatial body‐size patterns. Primary productivity emerged as the key driver of body size in both species, while heat conservation was supported as a further mechanism explaining the large body size of M. robustus in cold climatic regions. After controlling for these environmental factors, we find that the size of M. rufus has been stable over time and limited support for a small increase in the size of M. robustus. Hence, there is no empirical evidence that contemporary size‐selective harvesting has reduced body size in these species. Rather, the latter result supports the possibility that pasture improvement and/or dingo control (and associated reduction in predation pressure) facilitated body‐size increases following European settlement in Australia. 相似文献
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Danilo Russo;Gareth Jones;Adriano Martinoli;Damiano G. Preatoni;Martina Spada;Andrea Pereswiet-Soltan;Luca Cistrone; 《Ecology and evolution》2024,14(2):e10872
Animal size, a trait sensitive to spatial and temporal variables, is a key element in ecological and evolutionary dynamics. In the context of climate change, there is evidence that some bat species are increasing their body size via phenotypic responses to higher temperatures at maternity roosts. To test the generality of this response, we conducted a >20-year study examining body size changes in 15 bat species in Italy, analysing data from 4393 individual bats captured since 1995. In addition to examining the temporal effect, we considered the potential influence of sexual dimorphism and, where relevant, included latitude and altitude as potential drivers of body size change. Contrary to initial predictions of a widespread increase in size, our findings challenge this assumption, revealing a nuanced interplay of factors contributing to the complexity of bat body size dynamics. Specifically, only three species (Myotis daubentonii, Nyctalus leisleri, and Pipistrellus pygmaeus) out of the 15 exhibited a discernible increase in body size over the studied period, prompting a reassessment of bats as reliable indicators of climate change based on alterations in body size. Our investigation into influencing factors highlighted the significance of temperature-related variables, with latitude and altitude emerging as crucial drivers. In some cases, this mirrored patterns consistent with Bergmann's rule, revealing larger bats recorded at progressively higher latitudes (Plecotus auritus, Myotis mystacinus, and Miniopterus schreibersii) or altitudes (Pipistrellus kuhlii). We also observed a clear sexual dimorphism effect in most species, with females consistently larger than males. The observed increase in size over time in three species suggests the occurrence of phenotypic plasticity, raising questions about potential long-term selective pressures on larger individuals. The unresolved question of whether temperature-related changes in body size reflect microevolutionary processes or phenotypic plastic responses adds further complexity to our understanding of body size patterns in bats over time and space. 相似文献
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The importance of phylogenetic scale in tests of Bergmann's and Rapoport's rules: lessons from a clade of South American lizards 总被引：1，自引：0，他引：1
We tested for the occurrence of Bergmann's rule, the pattern of increasing body size with latitude, and Rapoport's rule, the positive relationship between geographical range size and latitude, in 34 lineages of Liolaemus lizards that occupy arid regions of the Andean foothills. We tested the climatic-variability hypothesis (CVH) by examining the relationship between thermal tolerance breadth and distribution. Each of these analyses was performed varying the level of phylogenetic inclusiveness. Bergmann's rule and the CVH were supported, but Rapoport's rule was not. More variance in the data for Bergmann's rule and the CVH was explained using species belonging to the L. boulengeri series rather than all species, and inclusion of multiple outgroups tended to obscure these macroecological patterns. Evidence for Bergmann's rule and the predicted patterns from the CVH remained after application of phylogenetic comparative methods, indicating a greater role of ecological processes rather than phylogeny in shaping the current species distributions of these lizards. 相似文献
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Jack V. Johnson Catherine Finn Jacinta Guirguis Luke E. B. Goodyear Lilly P. Harvey Ryan Magee Santiago Ron Daniel Pincheira-Donoso 《Global Ecology and Biogeography》2023,32(8):1311-1322