Cost of foraging in the subterranean rodent Ctenomys talarum: effect of soil hardness

2006 ◽  
Vol 84 (5) ◽  
pp. 661-667 ◽  
Author(s):  
Facundo Luna ◽  
C. Daniel Antinuchi
Keyword(s):  
Thermal Environment ◽  
Subterranean Rodents ◽  
Subterranean Rodent ◽  
Thomomys Bottae ◽  
Soil Hardness ◽  
Ctenomys Talarum ◽  
The Cost ◽  
Access To Food ◽  
The Relationship ◽  
Subterranean Species

Subterranean burrows provide inhabitants with shelter, a relatively stable thermal environment, and potentially access to food resources. However, one cost of living in such burrows is the energetically expensive mode of locomotion. Soil hardness and the physiological capabilities of animals are likely important factors that affect the cost of burrow construction, and hence, distribution of burrows. We assessed the effect of soil hardness on the cost of digging by captive individual Ctenomys talarum Thomas, 1898 in soft soils. Digging metabolic rate (DMR) was higher in harder soil than in softer soil (408.30 ± 51.35 mL O2·h–1 vs. 267.59 ± 20.97 mL O2·h–1, respectively). In C. talarum, a higher soil hardness augments DMR by increasing, in terms of the cost of burrowing model, the costs of shearing and of pushing the removed soil. Additionally, these costs differ between C. talarum and other subterranean species (e.g., Thomomys bottae (Eydoux and Gervais, 1836)), depending on soil hardness and digging mode. Thus, the relationship between digging cost and soil hardness appears to be one of the most important factors that affect burrowing efficiency in subterranean rodents.

Bite force and jaw biomechanics in the subterranean rodent Talas tuco-tuco (Ctenomys talarum) (Caviomorpha: Octodontoidea)

2011 ◽  
Vol 89 (4) ◽  
pp. 334-342 ◽  
Author(s):  
Federico Becerra ◽  
Alejandra Echeverría ◽  
Aldo Iván Vassallo ◽  
Adrià Casinos
Keyword(s):  
Cross Section ◽  
Force Transducer ◽  
Bite Force ◽  
Adult Males ◽  
Subterranean Rodent ◽  
Soil Hardness ◽  
Ctenomys Talarum ◽  
Adductor Muscles ◽  
Typical Habitat

The Talas tuco-tuco ( Ctenomys talarum Thomas, 1898) is a South American subterranean rodent that digs using both forelimbs and incisors, the latter being used when animals face hard soils and fibrous roots. In this rodent, the incisors are also used during intermale competition for mates. Bite forces were measured on wild females (n = 21) and males (n = 21) (both adult and young individuals) using a force transducer. Bite force was significantly higher in adult males than in females (32 vs. 27 N, respectively). Bite forces calculated on the physiological cross-section of jaw adductor muscles in dissected specimens were slightly higher than in vivo measurements. Regressions against body mass showed that bite force scaled with positive allometry, with slopes of 0.89 (females) and 0.99 (males). No significant differences were observed, neither in the slope nor in the y intercept of both sexes’ equations; therefore intersexual differences in bite forces observed in adults should mainly be due to size dimorphism. Considering that soil hardness of C. talarum’s typical habitat averages 100 N/cm2, and taking into account incisor’s cross-section, it was assessed that the pressure exerted by jaw adductor muscles at the incisors level is three times higher than that required for soil penetration.

Familiarity and mating behavior in the subterranean rodent Ctenomys talarum (tuco-tuco)

2007 ◽  
Vol 85 (9) ◽  
pp. 944-955 ◽  
Author(s):  
Roxana R. Zenuto ◽  
Candelaria Estavillo ◽  
María Sol Fanjul
Keyword(s):  
Mating Behavior ◽  
Mate Selection ◽  
Individual Recognition ◽  
Scent Mark ◽  
Subterranean Rodents ◽  
Subterranean Rodent ◽  
Odor Cues ◽  
Mating Costs ◽  
Neighbor Recognition ◽  
Ctenomys Talarum

Biological odors that convey cues regarding individual identity are known to alter mating behavior in some rodents. Deposition of chemical signals by males on the substrate could give females information about their neighbors’ identity and allow familiarization with their odors. This study tested whether familiarization of females with conspecific male odors affects mating behavior in Ctenomys talarum Thomas, 1898, facilitating mating as a consequence of a decrease in aggressive behavior and an increase in sexual behavior. Tuco-tucos are solitary subterranean rodents that occupy and defend adjacent burrows. Both sexes usually scent-mark burrow openings, providing odor signals to neighbors during their aboveground patrolling and foraging activities. Hence, familiarity by odor cues may represent an important mechanism that mediates neighbor recognition and probably mate selection. In this study, familiarity was established by housing females with male odors for 8 days. In C. talarum, individual recognition by olfactory cues may reduce mating costs when pairing with neighbors, since females showed low aggression towards familiar males and copulations were not repeated in consecutive days. Females that were not exposed to male odors were more aggressive, but surprisingly these pairs copulated repeatedly.

Digging energetics in the South American rodent Ctenomys talarum (Rodentia, Ctenomyidae)

2002 ◽  
Vol 80 (12) ◽  
pp. 2144-2149 ◽  
Author(s):  
Facundo Luna ◽  
C Daniel Antinuchi ◽  
Cristina Busch
Keyword(s):  
Metabolic Rate ◽  
Energy Cost ◽  
Resting Metabolic Rate ◽  
Energetic Cost ◽  
Soil Conditions ◽  
Natural Soil ◽  
Subterranean Rodents ◽  
South American ◽  
Ctenomys Talarum ◽  
The Cost

Ctenomys is the most speciose among subterranean rodents. There are few studies on energetics of Ctenomys, and none of them have focused on the energetics of digging. The present study aims to quantify the energetic cost of burrowing in Ctenomys talarum in natural soil conditions and to compare the energetics data with those reported for other subterranean rodents. Digging metabolic rate (DMR) in gravelly sand for C. talarum was 337.4 ± 65.9 mL O2·h–1 (mean ± SD). No differences in DMR were detected between sexes. Moreover, DMR was 295.9% of resting metabolic rate. In terms of a cost of burrowing model, the mass of soil removed per distance burrowed (Msoil) in gravelly sand was 44.5 ± 6.7 g·cm–1. Coefficients of the equation that related the energy cost of constructing a burrow segment of length S and Msoil(Eseg/Msoil) were Ks = 0.33 ± 0.32 J·g–1, which is the energy cost of shearing 1 g of soil, and Kp = 0.0055 ± 0.0042 J·g–1·cm–1, which is the energy cost of pushing 1 g of soil 100 cm. Regarding the cost of burrowing model, our data showed that C. talarum has the lowest DMR in gravelly sand among unrelated subterranean rodents analyzed. Moreover, despite C. talarum feeding aboveground, the foraging economics was similar that of to other rodents.

The Awareness Level of the Safety and Health of the Operational Level

2017 ◽  
Vol 3 (1) ◽  
pp. 42
Author(s):  
Roshanira Che Mohd Noor ◽  
Nur Atiqah Rochin Demong
Keyword(s):  
Health And Safety ◽  
Health Conditions ◽  
Effective Strategies ◽  
Operational Level ◽  
Safety And Health ◽  
Health Factors ◽  
The Cost ◽  
The Relationship ◽  
Awareness Level

Providing a safe and healthy workplace is one of the most effective strategies in for holding down the cost of doing construction business. It was a part of the overall management system to facilitate themanagement of the occupational health and safety risk that are associated with the business of the organization. Factors affected the awareness level inclusive of safety and health conditions, dangerous working area, long wait care and services and lack of emergency communication werethe contributed factors to the awareness level for the operational level. Total of 122 incidents happened at Telekom Malaysia Berhad as compared to year 2015 only 86 cases. Thus, the main objective of this study was to determine the relationship between safety and health factors and the awareness level among operational workers.The determination of this research was to increase the awareness level among the operational level workerswho committing to safety and health environment.

Pound Wise and Penny Foolish? Weight Loss and The Dynamics of Health Care Spending

2011 ◽  
Vol 14 (2) ◽  
Author(s):  
Thomas G Koch
Keyword(s):  
Weight Loss ◽  
Cost Savings ◽  
Cost Effective ◽  
Economic Consequences ◽  
Health Care Spending ◽  
Order Of Magnitude ◽  
Dynamic Measures ◽  
The Cost ◽  
The Impact ◽  
The Relationship

Current estimates of obesity costs ignore the impact of future weight loss and gain, and may either over or underestimate economic consequences of weight loss. In light of this, I construct static and dynamic measures of medical costs associated with body mass index (BMI), to be balanced against the cost of one-time interventions. This study finds that ignoring the implications of weight loss and gain over time overstates the medical-cost savings of such interventions by an order of magnitude. When the relationship between spending and age is allowed to vary, weight-loss attempts appear to be cost-effective starting and ending with middle age. Some interventions recently proven to decrease weight may also be cost-effective.

Marginal assessment of the cost and benefits of aphasia treatment: Evidence from community-based telerehabilitation treatment for aphasia

2021 ◽  
pp. 1357633X2098277
Author(s):  
Molly Jacobs ◽  
Patrick M Briley ◽  
Heather Harris Wright ◽  
Charles Ellis
Keyword(s):  
Cost Effectiveness ◽  
Economies Of Scale ◽  
Reference Group ◽  
Unit Cost ◽  
Community Based ◽  
Face To Face ◽  
Conduction Aphasia ◽  
Aphasia Treatment ◽  
The Cost ◽  
The Relationship

Introduction Few studies have reported information related to the cost-effectiveness of traditional face-to-face treatments for aphasia. The emergence and demand for telepractice approaches to aphasia treatment has resulted in an urgent need to understand the costs and cost-benefits of this approach. Methods Eighteen stroke survivors with aphasia completed community-based aphasia telerehabilitation treatment, utilizing the Language-Oriented Treatment (LOT) delivered via Webex videoconferencing program. Marginal benefits to treatment were calculated as the change in Western Aphasia Battery-Revised (WAB-R) score pre- and post-treatment and marginal cost of treatment was calculated as the relationship between change in WAB-R aphasia quotient (AQ) and the average cost per treatment. Controlling for demographic variables, Bayesian estimation evaluated the primary contributors to WAB-R change and assessed cost-effectiveness of treatment by aphasia type. Results Thirteen out of 18 participants experienced significant improvement in WAB-R AQ following telerehabilitation delivered therapy. Compared to anomic aphasia (reference group), those with conduction aphasia had relatively similar levels of improvement whereas those with Broca’s aphasia had smaller improvement. Those with global aphasia had the largest improvement. Each one-point of improvement cost between US$89 and US$864 for those who improved (mean = US$200) depending on aphasia type/severity. Discussion Individuals with severe aphasia may have the greatest gains per unit cost from treatment. Both improvement magnitude and the cost per unit of improvement were driven by aphasia type, severity and race. Economies of scale to aphasia treatment–cost may be minimized by treating a variety of types of aphasia at various levels of severity.

Relationship among social tactics, job embeddedness, and affective commitment in newcomers: the moderating effect of workplace spirituality

2021 ◽  
pp. 1-21
Author(s):  
Hsien-Long Huang ◽  
Li-Keng Cheng ◽  
Pi-Chuan Sun ◽  
Yi Shiuan Jiang ◽  
Hsin Hua Lin
Keyword(s):  
Work Experience ◽  
Affective Commitment ◽  
Human Resources Management ◽  
Workplace Spirituality ◽  
Job Embeddedness ◽  
Moderating Effect ◽  
Empirical Examination ◽  
Employee Survey ◽  
The Cost ◽  
The Relationship

Abstract The cost of recruitment and training of newcomers can be a burden for enterprises, causing adverse effects on human resources management. Although much research has addressed employee turnover, less attention has been paid to methods of improving the retention of new hires. This study is an empirical examination of the increase in predictive strength of antecedents of affective commitment for comparing newcomers’ workplace spirituality. The results of an employee survey completed by 237 newcomers with under two years of work experience indicate that socialization tactics have a direct impact on job embeddedness, which in turn has a direct effect on affective commitment. Workplace spirituality has a significant moderating effect on the relationship between socialization tactics and job embeddedness. Also, workplace spirituality has a significant moderating effect on the relationship between job embeddedness and affective commitment.

scholarly journals Searching for signatures of positive selection in cytochrome b gene associated with subterranean lifestyle in fast-evolving arvicolines (Arvicolinae, Cricetidae, Rodentia)

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Olga V. Bondareva ◽  
Nadezhda A. Potapova ◽  
Kirill A. Konovalov ◽  
Tatyana V. Petrova ◽  
Natalia I. Abramson
Keyword(s):  
Amino Acid ◽  
Oxidative Phosphorylation ◽  
Adaptive Evolution ◽  
Complex Structure ◽  
Subterranean Rodents ◽  
Amino Acid Sequence Variation ◽  
Tertiary Protein Structure ◽  
Metabolic Performance ◽  
The Impact ◽  
Subterranean Species

Abstract Background Mitochondrial genes encode proteins involved in oxidative phosphorylation. Variations in lifestyle and ecological niche can be directly reflected in metabolic performance. Subterranean rodents represent a good model for testing hypotheses on adaptive evolution driven by important ecological shifts. Voles and lemmings of the subfamily Arvicolinae (Rodentia: Cricetidae) provide a good example for studies of adaptive radiation. This is the youngest group within the order Rodentia showing the fastest rates of diversification, including the transition to the subterranean lifestyle in several phylogenetically independent lineages. Results We evaluated the signatures of selection in the mitochondrial cytochrome b (cytB) gene in 62 Arvicolinae species characterized by either subterranean or surface-dwelling lifestyle by assessing amino acid sequence variation, exploring the functional consequences of the observed variation in the tertiary protein structure, and estimating selection pressure. Our analysis revealed that: (1) three of the convergent amino acid substitutions were found among phylogenetically distant subterranean species and (2) these substitutions may have an influence on the protein complex structure, (3) cytB showed an increased ω and evidence of relaxed selection in subterranean lineages, relative to non-subterranean, and (4) eight protein domains possess increased nonsynonymous substitutions ratio in subterranean species. Conclusions Our study provides insights into the adaptive evolution of the cytochrome b gene in the Arvicolinae subfamily and its potential implications in the molecular mechanism of adaptation. We present a framework for future characterizations of the impact of specific mutations on the function, physiology, and interactions of the mtDNA-encoded proteins involved in oxidative phosphorylation.

Sign in / Sign up

Export Citation Format

Share Document