scholarly journals To be small and dark is advantageous for gaining heat in mezquite lizards, Sceloporus grammicus (Squamata: Phrynosomatidae)

2020 ◽  
Vol 132 (1) ◽  
pp. 93-103
Author(s):  
Juan Carlos González-Morales ◽  
Jimena Rivera-Rea ◽  
Gregorio Moreno-Rueda ◽  
Elizabeth Bastiaans ◽  
Héctor Díaz-Albiter ◽  
...  
Keyword(s):  
Body Size ◽  
High Altitude ◽  
Heating Rate ◽  
Small Body ◽  
Individual Performance ◽  
Lizard Species ◽  
Heat Gain ◽  
Thermal Environments ◽  
Sceloporus Grammicus ◽  
Thermal Melanism

Abstract Body temperature is important in determining individual performance in ectotherms such as lizards. Environmental temperature decreases with increasing altitude, but nevertheless many lizards inhabit high-altitude environments. The ‘thermal melanism hypothesis’ proposes that a dark dorsal coloration enables darker individuals to heat up faster because they absorb more solar radiation and thus being darker may be advantageous in cold habitats. The aim of the present study is to evaluate how heating rate, cooling rate and net heat gain vary with body size and dorsal skin coloration in Sceloporus grammicus lizards along an altitudinal gradient. We measured these traits multiple times in the same individuals with a radiation heat source and spectrophotometry under laboratory conditions. Our results showed that S. grammicus lizards are smaller and darker at high elevations than at low elevations. In addition, the smallest and darkest lizards showed the greatest heating rate and net heat gain. Therefore, in S. grammicus, we suggest that small body size and dark dorsal coloration provide thermoregulatory benefits in high-altitude environments. Hence, this study supports the thermal melanism hypothesis in a lizard species under varied thermal environments.

Size-dependent heating rates determine the spatial and temporal distribution of small-bodied lizards

2007 ◽  
Vol 28 (3) ◽  
pp. 347-356 ◽  
Author(s):  
János Török ◽  
Gábor Herczeg ◽  
Zoltán Korsós
Keyword(s):  
Body Size ◽  
Heating Rate ◽  
Time Budget ◽  
Activity Patterns ◽  
Temporal Distribution ◽  
Spatial And Temporal Distribution ◽  
Seasonal Activity ◽  
Heating Rates ◽  
Lizard Species ◽  
Joint Effects

AbstractThe rate of heat exchange with the environment is of obvious importance in determining the time budget of behavioural thermoregulation in ectotherms. In small reptiles, heating rate depends mainly on their physical characteristics. We analysed the effect of body size, and the possible joint effects originating from shape and colour differences on heating rate in three small-bodied (0.15-20 g) sympatric lizard species. Heating rate was strongly influenced by body size, while no joint effects with the two other factors were detected. We found that the increase in heating rate with decreasing body size accelerated dramatically below a body weight of 2-3 g. We also analysed associations between body size, seasonal activity patterns and thermal characteristics of the sites where lizards were encountered in the field. Differently sized lizards occurred in thermally different sites and differed in their seasonal activity patterns, both within and among species. Smaller (<2-3 g) lizards occurred in cooler sites and exhibited very low activity during summer. Our results suggest that body size has a considerable influence on the spatial and temporal distribution of extremely small lizards in environments subject to a danger of overheating.

Comparative thermal ecology of the high-altitude lizard Sceloporus grammicus on the eastern slope of the Iztaccihuatl Volcano, Puebla, Mexico

1995 ◽  
Vol 73 (12) ◽  
pp. 2184-2191 ◽  
Author(s):  
Julio A. Lemos-Espinal ◽  
Royce E. Ballinger
Keyword(s):  
High Altitude ◽  
Thermal Environment ◽  
High Elevation ◽  
Thermal Ecology ◽  
Body Temperatures ◽  
Thermoregulatory Behavior ◽  
Thermal Environments ◽  
Sceloporus Grammicus ◽  
Study Sites ◽  
Similar Body

We studied the thermal ecology of Sceloporus grammicus occurring in very different thermal environments at 3700 and 4400 m elevation on the Iztaccihuatl Volcano, Mexico. Despite differences in the thermal environment between study sites, individual lizards maintained similar active body temperatures (around 31.5 °C). Similar body temperatures at the two study sites probably result in differences in the cost of the thermoregulatory behavior. Lizards at the high-altitude site, an open area with few predators or competitors, presumably incur a lower thermoregulatory cost than those at the low-altitude site, which has a considerable number of shaded spots and more predators and competitors. Lizards at the low-elevation site showed a greater resistance to high temperatures than those at the high-elevation site. Physiological acclimatization to higher environmental temperatures at low elevation is likely to explain the greater heat tolerance. Freezing tolerance, thermoregulatory behavior, and low energy requirements permit S. grammicus to survive at high altitudes.

scholarly journals Assessment of the Growth and Reproductive Performance of Cloned Pietrain Boars

Animals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2053
Author(s):  
Junsong Shi ◽  
Baohua Tan ◽  
Lvhua Luo ◽  
Zicong Li ◽  
Linjun Hong ◽  
...  
Keyword(s):  
Growth Rate ◽  
Body Size ◽  
Growth Performance ◽  
Reproductive Performance ◽  
Semen Quality ◽  
Small Body ◽  
Economic Benefits ◽  
Large Animal ◽  
Significant Difference ◽  
F1 Progeny

How to maximize the use of the genetic merits of the high-ranking boars (also called superior ones) is a considerable question in the pig breeding industry, considering the money and time spent on selection. Somatic cell nuclear transfer (SCNT) is one of the potential ways to answer the question, which can be applied to produce clones with genetic resources of superior boar for the production of commercial pigs. For practical application, it is essential to investigate whether the clones and their progeny keep behaving better than the “normal boars”, considering that in vitro culture and transfer manipulation would cause a series of harmful effects to the development of clones. In this study, 59,061 cloned embryos were transferred into 250 recipient sows to produce the clones of superior Pietrain boars. The growth performance of 12 clones and 36 non-clones and the semen quality of 19 clones and 28 non-clones were compared. The reproductive performance of 21 clones and 25 non-clones were also tested. Furthermore, we made a comparison in the growth performance between 466 progeny of the clones and 822 progeny of the non-clones. Our results showed that no significant difference in semen quality and reproductive performance was observed between the clones and the non-clones, although the clones grew slower and exhibited smaller body size than the non-clones. The F1 progeny of the clones showed a greater growth rate than the non-clones. Our results demonstrated through the large animal population showed that SCNT manipulation resulted in a low growth rate and small body size, but the clones could normally produce F1 progeny with excellent growth traits to bring more economic benefits. Therefore, SCNT could be effective in enlarging the merit genetics of the superior boars and increasing the economic benefits in pig reproduction and breeding.

scholarly journals Independent evolution towards larger body size in the distinctive Faroe Island mice

2021 ◽  
Author(s):  
Ricardo Wilches ◽  
William H Beluch ◽  
Ellen McConnell ◽  
Diethard Tautz ◽  
Yingguang Frank Chan
Keyword(s):  
Body Size ◽  
Meta Analysis ◽  
Small Body ◽  
Laboratory Mouse ◽  
Large Body ◽  
Natural Populations ◽  
Size Variation ◽  
Phenotypic Traits ◽  
Island Population ◽  
Multiple Loci

Abstract Most phenotypic traits in nature involve the collective action of many genes. Traits that evolve repeatedly are particularly useful for understanding how selection may act on changing trait values. In mice, large body size has evolved repeatedly on islands and under artificial selection in the laboratory. Identifying the loci and genes involved in this process may shed light on the evolution of complex, polygenic traits. Here, we have mapped the genetic basis of body size variation by making a genetic cross between mice from the Faroe Islands, which are among the largest and most distinctive natural populations of mice in the world, and a laboratory mouse strain selected for small body size, SM/J. Using this F2 intercross of 841 animals, we have identified 111 loci controlling various aspects of body size, weight and growth hormone levels. By comparing against other studies, including the use of a joint meta-analysis, we found that the loci involved in the evolution of large size in the Faroese mice were largely independent from those of a different island population or other laboratory strains. We hypothesize that colonization bottleneck, historical hybridization, or the redundancy between multiple loci have resulted in the Faroese mice achieving an outwardly similar phenotype through a distinct evolutionary path.

A new species of the highland frog genus Holoaden (Amphibia, Strabomantidae) from cloud forests of southeastern Brazil

Zootaxa ◽  
2013 ◽  
Vol 3599 (2) ◽  
pp. 178-188 ◽  
Author(s):  
ITAMAR A. MARTINS ◽  
HUSSAM ZAHER
Keyword(s):  
New Species ◽  
Body Size ◽  
High Altitude ◽  
Ventral Surface ◽  
Sao Paulo ◽  
Southeastern Brazil ◽  
São Paulo ◽  
Cloud Forests ◽  
Serra Do Mar ◽  
A New Species

A new species of the genus Holoaden is described from the Atlantic forest of the state of São Paulo, Brazil, being restricted to primary or slightly disturbed high altitude cloud forests along the northeastern portion of the Serra do Mar. The typelocality is determined as Estação Ecológica de Bananal, in the Municipality of Bananal, State of São Paulo, Brazil. The new species is characterized by its moderate body size (female 42.6–44.2 mm SVL; male 37.2–38.5 mm SVL) with long and slender limbs, a head wider than long, a highly glandular dorsum, covered by well developed macroglands that extend to the internasal region, thigh and tibia, and an intense dark brown dorsal coloration and dark grey ventral surface.

scholarly journals Adaptive significance of small body size under poor socio-economic conditions in southern Peru

1973 ◽  
Vol 39 (2) ◽  
pp. 255-261 ◽  
Author(s):  
A. Roberto Frisancho ◽  
Jorge Sanchez ◽  
Danilo Pallardel ◽  
Lizandro Yanez
Keyword(s):  
Body Size ◽  
Small Body ◽  
Adaptive Significance ◽  
Economic Conditions ◽  
Small Body Size ◽  
Southern Peru

Decline of Cane Toad, Bufo-Marinus, Populations - Status of Urban Toads

1986 ◽  
Vol 13 (4) ◽  
pp. 597 ◽  
Author(s):  
WJ Freeland ◽  
BLJ Delvinquier ◽  
B Bonnin
Keyword(s):  
Body Size ◽  
Urban Population ◽  
Small Body ◽  
Rural Populations ◽  
Small Body Size ◽  
High Food ◽  
Cane Toad ◽  
Water Shortages ◽  
Toad Bufo ◽  
Low Rate

Cane toads from an urban population in Townsville, Qld, exhibit poor body condition and small body size, as do toads in populations around Townsville which have declined in numbers. The small body size and poor condition are associated with a high food intake and a low rate of parasitism. The results suggest that decline of rural populations is not a product of parasitism, or food and or water shortages related to unusually adverse seasonal conditions. Populations of cane toads around Townsville declined more than 3 years before this study.

scholarly journals Genetic testing of dogs predicts problem behaviors in clinical and nonclinical samples

2020 ◽  
Author(s):  
Isain Zapata ◽  
M. Leanne Lilly ◽  
Meghan E. Herron ◽  
James A. Serpell ◽  
Carlos E. Alvarez
Keyword(s):  
Body Size ◽  
Problem Behaviors ◽  
Small Body ◽  
Community Sample ◽  
Large Body ◽  
Second Phase ◽  
Logistic Regression Models ◽  
Individual Level ◽  
Increased Risk ◽  
Phenotype Data

AbstractVery little is known about the etiology of personality and psychiatric disorders. Because the core neurobiology of many such traits is evolutionarily conserved, dogs present a powerful model. We previously reported genome scans of breed averages of ten traits related to fear, anxiety, aggression and social behavior in multiple cohorts of pedigree dogs. As a second phase of that discovery, here we tested the ability of markers at 13 of those loci to predict canine behavior in a community sample of 397 pedigree and mixed-breed dogs with individual-level genotype and phenotype data. We found support for all markers and loci. By including 122 dogs with veterinary behavioral diagnoses in our cohort, we were able to identify eight loci associated with those diagnoses. Logistic regression models showed subsets of those loci could predict behavioral diagnoses. We corroborated our previous findings that small body size is associated with many problem behaviors and large body size is associated with increased trainability. Children in the home were associated with anxiety traits; illness and other animals in the home with coprophagia; working-dog status with increased energy and separation-related problems; and competitive dogs with increased aggression directed at familiar dogs, but reduced fear directed at humans and unfamiliar dogs. Compared to other dogs, Pit Bull-type dogs were not defined by a set of our markers and were not more aggressive; but they were strongly associated with pulling on the leash. Using severity-threshold models, Pit Bull-type dogs showed reduced risk of owner-directed aggression (75th quantile) and increased risk of dog-directed fear (95th quantile). Our findings have broad utility, including for clinical and breeding purposes, but we caution that thorough understanding is necessary for their interpretation and use.

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