Geographical clines in the size of the herb field mouse (Apodemus uralensis)

Abstract

Patterns of body size variation along geographical gradients have long been searched for and generalized into eco‐geographical rules. However, no rodent species has yet been analyzed in relation to the 3 dimensions of latitude, longitude and altitude. We analyzed geographical clines and dimorphism of body and skull size in the herb field mouse (Apodemus uralensis) across the species range, based on field data and on data from the literature. Sexual dimorphism in adult A. uralensis was not expressed at a large scale, while local patterns were inconsistent. Age‐dependent size changes were most expressed in adult individuals: most characters of adults exceeded in size those of subadults, while subadult–juvenile size differences were only significant in body weight and length, zygomatic skull width, length of cranial diastema and breadth of braincase. Despite central morphological niches along the clines being separated, A. uralensis populations showed a high degree of size overlap in morphological space. We found the species to be characterized by high size variability, with the largest individuals inhabiting the eastern and southern edges of the distribution range. Tail, hind foot and ear lengths were largest in the southern part of the range, in agreement with Allen's rule. The main measurements that we analyzed, namely body mass, zygomatic skull width and condylobasal skull length, show the presence of 3 clines in the size of adult A. uralensis: (i) a decreasing south–north cline, opposing Bergmann's rule; (ii) an increasing west–east cline, in accordance with Murphy's rule; and (iii) an increasing altitudinal cline.

Challenging ecogeographical rules: Phenotypic variation in the Mountain Treeshrew (Tupaia montana) along tropical elevational gradients

“…Ear and hindfoot length did not follow this rule, since the former remained constant, and the latter increased with elevation (although differences were found among mountains). Allen's rule has previously been supported for relative tail length in Xeric Four-striped Grass Rat (Rhabdomys pumilio) across elevation; and Virginia opossums (Didelphis virginiana), Herb Field mice (Apodemus uralensis), and Long-tailed macaques (Macaca fascicularis) across latitude; but not for South African Mouse shrews (Myosorex varius) or Soft-furred Tree mice (Typhlomys cinereus) across elevation, or fossorial Southern African Pouched mice (Saccostomus campestris) across latitude [3,7,26,[62][63][64]. Interestingly, tail length seems to exhibit a stronger relationship than ear or hindfoot length with elevation [3] and latitude [65,66].…”

Geographical variation of organ size in Andrew’s toad (Bufo andrewsi)

“…The theory of phenotypic plasticity states that organisms change their morphology and physiological function as an adaptive response to environmental conditions (Stearns, 1989;Clifton et al, 2020;Peng et al, 2022). Phenotypic plasticity in morphological and physiological traits is a common phenomenon across animal taxa (Tucker and Horvath, 1973;Hammond et al, 1999;Piersma et al, 1999;Naya et al, 2009;Zhong et al, 2017;Balciauskas et al, 2020;Donihue et al, 2021;Huang et al, 2021;Liang et al, 2021;Zamora-camacho, 2021;Zedda et al, 2021;Giacomini et al, 2022;Hinds et al, 2022). Organ's size can reflect the traits of structures with certain morphology and independent physiological functions within an organism, and it' variation also Zhu et al 10.3389/fevo.2022.972942 undergo certain adaptations to respond to environmental changes (Hammond et al, 2001;Chen et al, 2021;Jiang et al, 2022a).…”

Testis Size Variation and Its Environmental Correlates in Andrew’s Toad (Bufo andrewsi)

“…Life-history theory predicts that trade-offs between current reproductive investments and future reproductive success and/or survival enable an organism to cope with environmental changes [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ]. This inevitable trade-off is reflected by testis size, a dominant measure of reproductive investment in males, varying extensively within and between species [ 8 , 9 , 10 , 11 ].…”