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opencc-zeroDec 2011View details →

Data from: Body size evolution on islands: are adult size variations in tiger snakes a non-adaptive consequence of selection on birth size?

Mean adult size has been used as the traditional measure of body size to explain trends of insular gigantism and dwarfism in a wide array of taxa. However, patterns of variation in body size at birth have received surprisingly little attention, leaving open the possibility that adult body-size differences are nonadaptive consequences of selection acting on neonate body size. Here I used an empirical and correlative approach to test this hypothesis in a mosaic of 12 island and mainland snake populations in Australia. Data collected on 597 adult and 1,084 neonate tiger snakes showed that (1) both adult and neonate mean body sizes varied strongly across populations; (2) prey diversity and size convincingly explained birth-size variations: birth size—notably, gape size—correlated with prey size; (3) neonate snout-vent length was significantly correlated with neonate gape size; and (4) neonate snout-vent length was significantly correlated with adult snout-vent length. Postnatal growth rates recorded under common-garden conditions differed across populations and were correlated with mean prey size. These data collectively suggest that (1) prey size is the main driver for the evolution of body size at birth in gape-limited predators, (2) adult size variations may reflect selective forces acting on earlier life stages, and (3) adult size variations may also reflect resource availability during ontogeny (notably, prey diversity).

opencc-zeroDec 2017View details →

Data from: Variation in age, body size, and reproductive traits among urban and rural amphibian populations

Although amphibians use human-created habitats in urban landscapes, few studies have investigated the quality of these habitats. To assess habitat quality of stormwater management ponds and adjacent urban uplands forwood frogs (Lithobates sylvaticus) and American toads (Anaxyrus americanus), we compared life history characteristics between populations breeding across an urbanization gradient. Specifically, we compared body size, ages of breeding adults, and female reproductive investment among urban, suburban, and rural populations in Baltimore County, Maryland, USA. Although there was variation in age at maturity among populations, ages of breeding adults did not differ among urban, suburban, and rural areas. Maternal body size strongly influenced reproductive investment in both species, but relationships did not vary among urban, suburban, and rural populations. Adult wood frogs and American toads from more urbanized landscapes were significantly smaller at age than conspecifics from rural landscapes; the magnitude of differences was similar across adult age classes. Our results suggest that in the urban and rural landscapes that we studied, adult habitats are similar in quality, but either larval or juvenile habitats may be of lower quality in urban areas.

opencc-zeroJan 2024View details →

Supplementary material 1 from: Tanaka S (2024) Geographic variation in body size of the migratory locust Locusta migratoria (Orthoptera, Acrididae): Masaki's cline and phase polyphenism. Journal of Orthoptera Research 33(1): 27-40. https://doi.org/10.3897/jor.33.107242

Supplementary material 1 from: Tanaka S (2024) Geographic variation in body size of the migratory locust Locusta migratoria (Orthoptera, Acrididae): Masaki's cline and phase polyphenism. Journal of Orthoptera Research 33(1): 27-40. https://doi.org/10.3897/jor.33.107242

opencc-zeroAug 2022View details →

Data from 'Convergent patterns of body size variation in distinct parasite taxa with convergent life cycles'

Aim: Interspecific variation among metazoans often follows a latitudinal pattern, with species at higher latitudes being larger-bodied than related species from lower latitudes (Bergmann's rule). For parasitic species, body sizes within any higher taxon often correlate with the body sizes of their hosts (Harrison's rule). Whether temperature-driven latitudinal effects or host-driven resource constraints act independently or additively to shape interspecific variation in parasite body sizes remains unknown. We use a comparative approach to test the effects of latitude and host body size on parasite body sizes in two taxa of parasitic worms showing convergent life cycles. Location: Global. Time period: Contemporary. Major taxa studied: Hairworms (Nematomorpha) and mermithids (Nematoda) parasitic in arthropods. Methods: With 223 records for mermithids and 258 for nematomorphs worldwide, we used linear mixed effects models to test the effects of latitude and host body size on parasite length, intraspecific length variation, parasite egg diameter, and variation in egg diameter. Further, we modelled parasite length with local mean annual temperature as predictor instead of latitude, as a direct test of underlying mechanisms. All models took into account host and parasite taxonomic structure within the datasets. Results: For both taxa, host body size was clearly the main determinant of parasite body length, with neither latitude nor local temperature (annual mean or range) having an effect. No predictor affected intraspecific length variation, whereas egg diameter was positively associated with parasite length and variation in egg diameter was negatively associated with latitude. Main conclusions: Our results support a strong role for host traits in shaping the evolution of parasite body sizes (Harrison's rule), but no role for latitude (Bergmann's rule), even though these parasites infect ectothermic hosts. At a mechanistic level, the evolutionary driving force of external temperature on parasite physiology seems to be eclipsed by the availability of resources from the host.

opencc-zeroFeb 2022View details →

Impact of landscape fragmentation and climate change on body size variation of bumblebees during the last century

Body size is a key parameter of organism fitness. While the impact of climate change on body size has received increasing attention, the long-term consequences of landscape fragmentation are still poorly known. These two major global threats may potentially induce opposite trends: the decrease of body size in warmer environments (e.g. individuals developing faster) or the selection of larger individuals in fragmented habitats (e.g. large individuals more capable of reaching distant patches). We assessed the relationship between temperature and landscape fragmentation with mean body size during the last century, within four European regions (Austria, Belgium, England and above the Arctic circle in Scandinavia) and among queens of five bumblebee species. At the regional scale, we first analysed the variation over time of body size and the two hypothesised drivers, temperature and landscape fragmentation. Then, at the local landscape scale, we tested whether body size varied according to these drivers irrespective of the region. At the regional level, we observed a statistically clear increase of queen body size corresponding to an increase of landscape fragmentation (i.e. in Belgium and England). There was no increase of size when fragmentation did not increase (i.e. in Austria and above the Arctic Circle). Temperature also increased through time in all regions. At the local landscape scale, we found that all species were impacted by changes in both climate and landscape fragmentation but show different trends. The body size of the two largest species significantly increased at landscape level with higher fragmentation while body size of the two smallest species decreased with higher fragmentation. We highlight that, in a context of global changes, landscape fragmentation can also be a major driver of body size clines. Depending on the dispersal abilities of species, larger species could be positively selected for and overcome landscape fragmentation.

opencc-zeroDec 2014View details →

Data from: Population variation reveals independent selection towards small body size in Chinese Debao pony

Body size, one of the most important quantitative traits under evolutionary scrutiny, varies considerably among species and among populations within species. Revealing the genetic basis underlying this variation is very important, particularly in humans where there is a close relationship with diseases and in domestic animals as the selective patterns are associated with improvements in production traits. The Debao pony is a horse breed with small body size that is unique to China; however, it is unknown whether the size-related candidate genes identified in Western breeds also account for the small body size of the Debao pony. Here, we compared individual horses from the Debao population with other two Chinese horse populations using SNPs identified with the Equine SNP 65 Bead Chip. The previously reported size-related candidate gene HMGA2 showed a significant signature for selection, consistent with its role observed in human populations. More interestingly, we found a candidate gene TBX3, which had not been observed in previous studies on horse body size that displayed the highest differentiation and most significant association, and thus likely is the dominating factor for the small stature of the Debao pony. Further comparison between the Debao pony and other breeds of horses from around the world demonstrated that TBX3 was selected independently in the Debao pony, suggesting that there were multiple origins of small stature in the horse.

Figure 4 in Body size variation in a lineage of spur-thighed tortoises (Testudo graeca whitei) contrasts with that expected from the species level

Figure 4. Differences in body size (Straight Carapace Length; SCL) observed between the Testudo graeca whitei ranges in North Africa and SE Spain. The violin plot represents these differences, with its width indicating the frequency of a particular body size.

Figure 2 in Body size variation in a lineage of spur-thighed tortoises (Testudo graeca whitei) contrasts with that expected from the species level

Figure 2. Density contour plot illustrating the environmental conditions inhabited by Testudo graeca whitei in North Africa (pink dots) and SE Spain (green dots). The analysis considered two bioclimatic variables from WorldClim, namely Annual Precipitation and Annual Mean Temperature (BIO1 and BIO12). The total range of T. g. whitei was defined based on the minimum convex polygon, which encompasses all the previously sampled specimens, as outlined in Anadón et al. (2015). The color scale indicates frequency of occurrence, with lighter colors denoting more frequent bioclimate conditions. Site numbers are referenced in supplementary table S1.

Figure 6 in Body size variation in a lineage of spur-thighed tortoises (Testudo graeca whitei) contrasts with that expected from the species level

Figure 6. Effect of latitude on the adult size (Straight Carapace Length; SCL) of Testudo graeca whitei. N = 119 and N =

Figure 1 in Body size variation in a lineage of spur-thighed tortoises (Testudo graeca whitei) contrasts with that expected from the species level

Figure 1. Sampling of Testudo graeca whitei in North Africa and SE Spain according to the present-day map (1980-2016)

opencc-zeroJul 2021View details →

Phenotypic variation in male Calopteryx splendens damselflies: The role of wing pigmentation and body size in thermoregulation

For an ectothermic insect, its color and size are important determinants of body temperature: dark colors absorb heat more efficiently, while larger bodies require more heat to reach a certain temperature. These dark colors are expressed using melanin, which has been intimately linked with an insect's thermoregulatory capabilities. Melanin is also linked with immune defense and is often used as a secondary sexual character in insects. There is a potential trade-off situation between thermoregulatory capabilities, immune defence and secondary sexual characters, all of which use melanin. Some Calopteryx damselflies, such as Calopteryx splendens, have melanin-based wing pigmentation that is sexually selected and drives intra- and interspecific territorial aggressions. Our goal was to experimentally study how the wing pigmentation and body size of C. splendens males affect their thermoregulation and especially their ability to become active after being cooled down. Our results are in line with our hypotheses showing that (i) individuals with larger wing spots had significantly faster activation times than those with smaller wing spots, and (ii) individuals with larger body size had significantly slower activation times than those with smaller body size. Both variables showed an interaction and thus are important in damselfly warm up and activation. We discuss the role wing pigmentation and thermoregulation can have on the behavioral patterns observed in Calopteryx species.

opennotspecifiedJun 2010View details →

Figure 2 in Geographic variation in body size and sexual size dimorphism in the giant spiny frog Paa spinosa (David, 1875) (Anura: Ranoidae)

Figure 2. The sexual size dimorphism (SSD) ratio of five populations. SSD ratio = mean body size of the male/mean body size of the female.

opennotspecifiedJun 2010View details →

Figure 1 in Geographic variation in body size and sexual size dimorphism in the giant spiny frog Paa spinosa (David, 1875) (Anura: Ranoidae)

Figure 1. Map of South China showing localities where Paa spinosa was sampled for analyses of geographic variation in body size. Names of sampling localities and geographic coordinates are as follows: JH: JinHua (29°32′ N, 119°33′ E). LS: LiShui (28°27′ N, 119°54′ E). PJ: Pingjiang (28°72′ N, 113°58′ E). JGS: JinGangshan (26°34′ N, 114°10′ E). YS: YangShan (24°48′ N, 112°63′ E).

opencc-zeroAug 2021View details →

The chicken pan-genome reveals gene content variation and a promoter region deletion in IGF2BP1 affecting body size

Domestication and breeding have reshaped the genomic architecture of chicken, but the retention and loss of genomic elements during these evolutionary processes remain unclear. We present the first chicken pan-genome constructed using 664 individuals, which identified an additional ∼66.5 Mb sequences that are absent from the reference genome (GRCg6a). The constructed pan-genome encoded 20,491 predicated protein-coding genes, of which higher expression level are observed in conserved genes relative to dispensable genes. Presence/absence variation (PAV) analyses demonstrated that gene PAV in chicken was shaped by selection, genetic drift, and hybridization. PAV-based GWAS identified numerous candidate mutations related to growth, carcass composition, meat quality, or physiological traits. Among them, a deletion in the promoter region of IGF2BP1 affecting chicken body size is reported, which is supported by functional studies and extra samples. This is the first time to report the causal variant of chicken body size QTL located at chromosome 27 which was repeatedly reported. Therefore, the chicken pan-genome is a useful resource for biological discovery and breeding. It improves our understanding of chicken genome diversity and provides materials to unveil the evolution history of chicken domestication.

opennotspecifiedJun 2017View details →

Fig. 2 in Ground Beetle (Coleoptera: Carabidae) Diversity and Body-Size Variation in Four Land Use Types in a Mountainous Area Near Beijing, China

Fig. 2. Non-linear two-dimensional scaling of carabid samples based on Euclidean distance. a) All carabids in 2011, b) all carabids in 2012, c) large carabids in 2011, d) large carabids in 2012. WI = walnut-chrysanthemum intercropping system; WM = walnut monoculture system; F = temperate deciduous forest; M: alpine meadow.

opennotspecifiedJun 2017View details →

Fig. 1 in Ground Beetle (Coleoptera: Carabidae) Diversity and Body-Size Variation in Four Land Use Types in a Mountainous Area Near Beijing, China

Fig. 1. Activity-abundance and species richness of Carabidae in four habitats in a mountainous area near Beijing, China in 2011 and 2012. a) Activity-abundance of all carabids (2011: F = 2.82, p = 0.08; 2012: F = 2.58, p = 0.10), b) Chao1 index for all carabids (2011: F = 0.96, p = 0.44; 2012: F = 6.32, p <0.01), c) Activity-abundance of large carabids (2011: F = 0.87, p = 0.50; 2012: F = 6.35, p <0.01), d) Chao1 index for large carabids (2011: F = 0.98, p = 0.04; 2012: F = 2.08, p = 0.16) WI = walnut-chrysanthemum intercropping system; WM = walnut monoculture system; F = temperate deciduous forest; M = alpine meadow. Bars within each year of each graph with the same letter above the standard error bar are not significantly different (p> 0.05).

Figure 5 in Phylogeny explains better than ecology or body size the variation of the first lower molar in didelphid marsupials

Figure 5: Graphics of the three factors analyzed in variation partitioning analyses to illustrate both their individual contribution for explaining shape variance. (a) lnCS; (b) phylogeny; and (c) habitat and their interacting components (d, e, f, g). (A) females; (B) males.

Figure 4 in Phylogeny explains better than ecology or body size the variation of the first lower molar in didelphid marsupials

Figure 4: Shape deformations related to the first molar (m1). Deformation grids of the predicted shape of m1 for females (A) from the minimum (left, 0.090), medium (center, 0.785), and maximum (right, 1.568); males (B) from the minimum (left, 0.065), medium (center, 0.732), and maximum (right, 1.498) values of natural logtransformed centroid size (body size). Deformation grids related to habitat for females (C) and males (D) from the most terrestrial/semiaquatic (left) to the most arboreal (right).

Figure 3 in Phylogeny explains better than ecology or body size the variation of the first lower molar in didelphid marsupials

Figure 3: Scatter plot of relative warp (RW1 and RW2). Transformation grids visualize shape deformations relative to the mean at the positive and negative extremes of RW axes. (A) body size of females; (B) body size of males; (C) habitat of females; (D) habitat of males; (E) lineages of females; (F) lineages of males. Body sizes classified according to Paglia et al. (2012) and subfamilies/tribes according to Voss and Jansa (2009). Subtitles: see in Supplementary Appendix 1.

Figure 1 in Phylogeny explains better than ecology or body size the variation of the first lower molar in didelphid marsupials

Figure 1: Position of the six landmarks on the occlusal view of the first lower molar (m1) in a specimen of MetachirUS nUdicaUdatUS, and tooth nomenclature used in the study.