Pub Date : 2026-02-01Epub Date: 2026-01-21DOI: 10.1016/j.jtherbio.2026.104384
Mustafa Kibar , Ramazan Erkmen , Ertuğrul Kul , İbrahim Aytekin
This study aimed to determine the relationships between the HSP70 g.1117G > A gene and some milk production traits such as daily milk yield (DMY), conductivity (Cond), milking time (MT) and activity (Act) in Holstein-Friesian dairy cattle. Blood samples from the coccygeal vein of 203 Holstein-Friesian cows in different lactations were collected. The population, with A and G allele frequencies of 0.2365 and 0.7635 and AA, AG, GG genotype frequencies of 0.089, 0.295, and 0.616, was not in Hardy-Weinberg equilibrium (P < 0.01). The lowest DMY was in the THI<65 group, while the highest was in the 65≤THI<68 and THI≥68 groups. Regarding temperature-humidity index (THI), the lowest MT and Act values were recorded in the THI<65 group, while the highest were in the THI≥68 group. For DMY and Cond, the highest values were in AG and the lowest were in AA genotype cattle (P < 0.01). Regarding MT, the highest values were observed in the AA and AG, with the lowest in GG genotypes (P < 0.01). For Act, AG and GG genotypes showed the highest values, while AA had the lowest (P < 0.01). As a result, the G allele (sensitive to heat stress) could be beneficial for both increasing DMY and reducing MT. However, the threshold values for the THI should be re-evaluated based on the effectiveness of the cooling systems used and the specific conditions of the farm.
{"title":"Novel significant associations between temperature-humidity index and HSP70 g.1117G>A with milk yield traits of Holstein-Friesian cows reared in semi-arid regions","authors":"Mustafa Kibar , Ramazan Erkmen , Ertuğrul Kul , İbrahim Aytekin","doi":"10.1016/j.jtherbio.2026.104384","DOIUrl":"10.1016/j.jtherbio.2026.104384","url":null,"abstract":"<div><div>This study aimed to determine the relationships between the HSP70 g.1117G > A gene and some milk production traits such as daily milk yield (DMY), conductivity (Cond), milking time (MT) and activity (Act) in Holstein-Friesian dairy cattle. Blood samples from the coccygeal vein of 203 Holstein-Friesian cows in different lactations were collected. The population, with A and G allele frequencies of 0.2365 and 0.7635 and AA, AG, GG genotype frequencies of 0.089, 0.295, and 0.616, was not in Hardy-Weinberg equilibrium (P < 0.01). The lowest DMY was in the THI<65 group, while the highest was in the 65≤THI<68 and THI≥68 groups. Regarding temperature-humidity index (THI), the lowest MT and Act values were recorded in the THI<65 group, while the highest were in the THI≥68 group. For DMY and Cond, the highest values were in AG and the lowest were in AA genotype cattle (P < 0.01). Regarding MT, the highest values were observed in the AA and AG, with the lowest in GG genotypes (P < 0.01). For Act, AG and GG genotypes showed the highest values, while AA had the lowest (P < 0.01). As a result, the G allele (sensitive to heat stress) could be beneficial for both increasing DMY and reducing MT. However, the threshold values for the THI should be re-evaluated based on the effectiveness of the cooling systems used and the specific conditions of the farm.</div></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"136 ","pages":"Article 104384"},"PeriodicalIF":2.9,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146024131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01Epub Date: 2026-01-10DOI: 10.1016/j.jtherbio.2026.104374
Marcelo T. Andrade , Matheus M.S. Nunes-Leite , Rúbio S. Bruzzi , Carlos H. Souza , João P. Uendeles-Pinto , Nathan B. Amarante de Sá , Thiago T. Mendes , Luciano S. Prado , Cândido C. Coimbra , Danusa D. Soares , Samuel P. Wanner
Endurance performance is regulated by integrated physiological, perceptual, and behavioral mechanisms, and is markedly impaired by environmental heat stress. However, how heat stress influences this multifaceted regulation of performance merits further investigation. This study aimed to identify predictors of mean and final km paces during a laboratory-based run in hot conditions. We analyzed 75 records from recreational athletes who ran 10 km as fast as possible at 33 °C. The independent variables included maximal oxygen uptake (VO2MAX), whole-body sweat loss, fan-generated airflow, wet-bulb globe temperature (WBGT), change in core temperature (ΔTCORE: entire exercise and its first five km), heart rate (HR), rating of perceived exertion (RPE), pacing strategy, biological sex, thermal comfort, the core-to-skin temperature difference, and percentage change in body mass (Δ% body mass). These independent variables were selected a priori based on theoretical models that explain pacing regulation in an integrative manner. The dependent variables were the mean and final km paces (min/km), and predictors were analyzed using hierarchical multiple linear regression. Mean pace was best predicted by air velocity (β = −0.494), ΔTCORE (β = −0.456), VO2MAX (β = −0.387), WBGT (β = 0.294), ΔTCORE 0–5 km (β = 0.323), and Δ% body mass (β = −0.191), with the model explaining 54.3 % of the dependent variable's variance. Final km pace was best predicted by the adoption of a negative-split pacing strategy (β = 0.387), followed by HR (β = −0.206) and RPE (β = −0.188), with the model explaining 30.3 % of the dependent variable's variance. The current findings reinforce the notion that the regulation of mean and final km paces integrates physiological, environmental, behavioral, and perceptual mechanisms. Our findings also indicate that interventions to improve athletes' performance in hot conditions should combine aerobic fitness development, early TCORE control, optimized airflow and hydration, and RPE-guided conservative/negative-split pacing.
{"title":"Environmental, physiological, perceptual, and behavioral predictors of mean and final km paces during a laboratory-based self-paced 10 km run in hot conditions","authors":"Marcelo T. Andrade , Matheus M.S. Nunes-Leite , Rúbio S. Bruzzi , Carlos H. Souza , João P. Uendeles-Pinto , Nathan B. Amarante de Sá , Thiago T. Mendes , Luciano S. Prado , Cândido C. Coimbra , Danusa D. Soares , Samuel P. Wanner","doi":"10.1016/j.jtherbio.2026.104374","DOIUrl":"10.1016/j.jtherbio.2026.104374","url":null,"abstract":"<div><div>Endurance performance is regulated by integrated physiological, perceptual, and behavioral mechanisms, and is markedly impaired by environmental heat stress. However, how heat stress influences this multifaceted regulation of performance merits further investigation. This study aimed to identify predictors of mean and final km paces during a laboratory-based run in hot conditions. We analyzed 75 records from recreational athletes who ran 10 km as fast as possible at 33 °C. The independent variables included maximal oxygen uptake (VO<sub>2MAX</sub>), whole-body sweat loss, fan-generated airflow, wet-bulb globe temperature (WBGT), change in core temperature (ΔT<sub>CORE</sub>: entire exercise and its first five km), heart rate (HR), rating of perceived exertion (RPE), pacing strategy, biological sex, thermal comfort, the core-to-skin temperature difference, and percentage change in body mass (Δ% body mass). These independent variables were selected a priori based on theoretical models that explain pacing regulation in an integrative manner. The dependent variables were the mean and final km paces (min/km), and predictors were analyzed using hierarchical multiple linear regression. Mean pace was best predicted by air velocity (β = −0.494), ΔT<sub>CORE</sub> (β = −0.456), VO<sub>2MAX</sub> (β = −0.387), WBGT (β = 0.294), ΔT<sub>CORE</sub> 0–5 km (β = 0.323), and Δ% body mass (β = −0.191), with the model explaining 54.3 % of the dependent variable's variance. Final km pace was best predicted by the adoption of a negative-split pacing strategy (β = 0.387), followed by HR (β = −0.206) and RPE (β = −0.188), with the model explaining 30.3 % of the dependent variable's variance. The current findings reinforce the notion that the regulation of mean and final km paces integrates physiological, environmental, behavioral, and perceptual mechanisms. Our findings also indicate that interventions to improve athletes' performance in hot conditions should combine aerobic fitness development, early T<sub>CORE</sub> control, optimized airflow and hydration, and RPE-guided conservative/negative-split pacing.</div></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"136 ","pages":"Article 104374"},"PeriodicalIF":2.9,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146018904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01Epub Date: 2026-01-10DOI: 10.1016/j.jtherbio.2026.104371
Xiang-Yang Xu , Xin Kang , Meng-Meng Liu , Shu-Qi Zhang , Sai-Nan Dong , Xiao-Wen Jiang , Wen-Hui Yu
Heat stress constitutes a severe risk to the health of poultry, not only damaging intestinal health, but also reducing antioxidant defenses and weakening the immune response. Exogenous melatonin can enhance the antioxidant capacity of heat-stressed chicks through the cecal microbiota, and reduce the inflammatory response and intestinal barrier damage. 21-day-old Hy-Line brown chicks were divided into control group, heat stress group, and three groups receiving different doses of melatonin (0.5, 1.0, 2.0 mg/kg). Except for the control group (22 ± 2 °C from 00:00 to 24:00 daily), all other groups were exposed to a high-temperature environment (34 ± 2 °C, from 08:00 to 18:00 daily) for 21 consecutive days. The results showed that heat stress significantly decreased final body weight of chicks, increased serum MDA, IL-1β, IL-6, TNF-α, D-LA and DAO levels, decreased GSH-Px, CAT and SOD activities, and decreased jejunal and ileal villus height/crypt depth (VH/CD), cecal Firmicutes/Bacteroidetes (F/B) ratio and Lactobacillus abundance. Exogenous melatonin reversed these changes, and 1.0 mg/kg was the most effective. It included the recovery of antioxidant enzyme activity, the decrease of serum inflammatory factors, D-LA and DAO, the up-regulation of VH/CD and tight junction genes (CLDN1, OCLN, TJP1, MUC2) in jejunum and ileum, the increase of cecal F/B ratio and the enrichment of Lactobacillus. Network pharmacology and molecular docking identified the core targets of anti-oxidation and anti-inflammation. Melatonin reduced heat stress-induced intestinal injury by reducing inflammation and oxidative stress.
{"title":"Exploring the protective mechanism of exogenous melatonin on intestine of heat-stressed chicks based on network pharmacology and intestinal microbiota analysis","authors":"Xiang-Yang Xu , Xin Kang , Meng-Meng Liu , Shu-Qi Zhang , Sai-Nan Dong , Xiao-Wen Jiang , Wen-Hui Yu","doi":"10.1016/j.jtherbio.2026.104371","DOIUrl":"10.1016/j.jtherbio.2026.104371","url":null,"abstract":"<div><div>Heat stress constitutes a severe risk to the health of poultry, not only damaging intestinal health, but also reducing antioxidant defenses and weakening the immune response. Exogenous melatonin can enhance the antioxidant capacity of heat-stressed chicks through the cecal microbiota, and reduce the inflammatory response and intestinal barrier damage. 21-day-old Hy-Line brown chicks were divided into control group, heat stress group, and three groups receiving different doses of melatonin (0.5, 1.0, 2.0 mg/kg). Except for the control group (22 ± 2 °C from 00:00 to 24:00 daily), all other groups were exposed to a high-temperature environment (34 ± 2 °C, from 08:00 to 18:00 daily) for 21 consecutive days. The results showed that heat stress significantly decreased final body weight of chicks, increased serum MDA, IL-1β, IL-6, TNF-α, D-LA and DAO levels, decreased GSH-Px, CAT and SOD activities, and decreased jejunal and ileal villus height/crypt depth (VH/CD), cecal Firmicutes/Bacteroidetes (F/B) ratio and Lactobacillus abundance. Exogenous melatonin reversed these changes, and 1.0 mg/kg was the most effective. It included the recovery of antioxidant enzyme activity, the decrease of serum inflammatory factors, D-LA and DAO, the up-regulation of VH/CD and tight junction genes (CLDN1, OCLN, TJP1, MUC2) in jejunum and ileum, the increase of cecal F/B ratio and the enrichment of Lactobacillus. Network pharmacology and molecular docking identified the core targets of anti-oxidation and anti-inflammation. Melatonin reduced heat stress-induced intestinal injury by reducing inflammation and oxidative stress.</div></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"136 ","pages":"Article 104371"},"PeriodicalIF":2.9,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145966546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01Epub Date: 2026-02-06DOI: 10.1016/j.jtherbio.2026.104395
Helena Gurjão Pinheiro Do Val , Luiza Figueiredo Passos , Joilson Medeiros de Barros , Grahame Webb , Marcos Eduardo Coutinho
{"title":"Corrigendum to “Thermal ecology and embryonic development in black caiman’s (Melanosuchus niger, Spix 1758)” [J. Therm. Biol. (2026) 104357]","authors":"Helena Gurjão Pinheiro Do Val , Luiza Figueiredo Passos , Joilson Medeiros de Barros , Grahame Webb , Marcos Eduardo Coutinho","doi":"10.1016/j.jtherbio.2026.104395","DOIUrl":"10.1016/j.jtherbio.2026.104395","url":null,"abstract":"","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"136 ","pages":"Article 104395"},"PeriodicalIF":2.9,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146132271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01Epub Date: 2026-02-17DOI: 10.1016/j.jtherbio.2026.104427
Chuang Liu , Yunfei Sun , Zhigang Yang , Yongxu Cheng
Procambarus clarkii, widely farmed in rice-crayfish systems, is vulnerable to high-temperature stress during summer. This study aimed to investigate its physiological and metabolic responses to acute heat stress. Subadult crayfish (13.72 ± 1.91 g) were exposed to 33 °C for 96 h (21 °C as control), and samples of gill, hepatopancreas, and muscle tissues were collected at 6, 12, 24, 48, and 96 h. Histological changes were observed using paraffin sectioning, while metabolic enzyme activities, substrate levels, and lipid metabolism-related gene expression were analyzed. The 96-h upper incipient lethal temperature (UILT50) was determined to be 34.5 °C. Elevated temperatures significantly increased oxygen consumption, ammonia excretion, and overall metabolic rate, although the oxygen-to-nitrogen ratio remained stable. After 96 h of heat exposure, gill tissues showed reduced hemocytes, distorted filaments, and epithelial damage. In the hepatopancreas, B cell numbers increased and lipid droplets in R cells decreased. Energy metabolism shifted over time: during early stress (0-48 h), glucose was the primary energy source, with glycolysis as the main pathway; during later stress (48-96 h), lipid catabolism became dominant. Adipose triglyceride lipase (ATGL), rather than hormone-sensitive lipase (HSL), played a key role in lipid mobilization. These findings suggest that acute heat stress disrupts respiratory metabolism, damages key tissues, and drives a shift in energy strategy from carbohydrates to lipids in P. clarkii.
{"title":"Effects of acute high-temperature stress on respiratory metabolism, tissue structure, and glycolipid metabolism in subadult Procambarus clarkii","authors":"Chuang Liu , Yunfei Sun , Zhigang Yang , Yongxu Cheng","doi":"10.1016/j.jtherbio.2026.104427","DOIUrl":"10.1016/j.jtherbio.2026.104427","url":null,"abstract":"<div><div><em>Procambarus clarkii</em>, widely farmed in rice-crayfish systems, is vulnerable to high-temperature stress during summer. This study aimed to investigate its physiological and metabolic responses to acute heat stress. Subadult crayfish (13.72 ± 1.91 g) were exposed to 33 °C for 96 h (21 °C as control), and samples of gill, hepatopancreas, and muscle tissues were collected at 6, 12, 24, 48, and 96 h. Histological changes were observed using paraffin sectioning, while metabolic enzyme activities, substrate levels, and lipid metabolism-related gene expression were analyzed. The 96-h upper incipient lethal temperature (UILT<sub>50</sub>) was determined to be 34.5 °C. Elevated temperatures significantly increased oxygen consumption, ammonia excretion, and overall metabolic rate, although the oxygen-to-nitrogen ratio remained stable. After 96 h of heat exposure, gill tissues showed reduced hemocytes, distorted filaments, and epithelial damage. In the hepatopancreas, B cell numbers increased and lipid droplets in R cells decreased. Energy metabolism shifted over time: during early stress (0-48 h), glucose was the primary energy source, with glycolysis as the main pathway; during later stress (48-96 h), lipid catabolism became dominant. Adipose triglyceride lipase (ATGL), rather than hormone-sensitive lipase (HSL), played a key role in lipid mobilization. These findings suggest that acute heat stress disrupts respiratory metabolism, damages key tissues, and drives a shift in energy strategy from carbohydrates to lipids in <em>P. clarkii</em>.</div></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"136 ","pages":"Article 104427"},"PeriodicalIF":2.9,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146258552","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Heat stress (HS) significantly challenges dairy cattle, affecting their immune function, endocrine responses, and thermoregulation. This study investigated cytokine responses, hormonal changes, and body surface temperature variations in 12 indigenous Sahiwal (SW) and 12 crossbred Karan Fries (KF) cows reared under hot-dry (HD; THI = 77.75) and hot-humid (HH; THI = 81.48) seasons. Plasma concentrations of Interleukin-6 (IL-10), tumor necrosis factor-α (TNF-α), Interleukin-6 (IL-6), Interleukin-1β (IL- 1β), cortisol, triiodothyronine (T3), and thyroxine (T4) were analysed using ELISA, while body surface temperatures were measured using infrared thermography (IRT). Significant (P < 0.05) variations were observed between breeds and across the two seasons. Higher TNF-α, IL-6, IL-1β, and cortisol levels were observed under HH compared to HD seasons. TNF-α levels increased significantly (P < 0.05) by 31.76% in SW and 36.47% in KF cows, while cortisol levels rose by 44.41% and 47.42%, respectively, from the HD to HH season. In contrast, T3 and T4 levels declined significantly (P < 0.05) by 25.60% and 36.42%, respectively, under HH seasons, with a greater reduction observed in KF cows. Body surface temperatures were significantly (P < 0.05) higher in KF cows across all measured regions, with eye temperature exhibiting a strong correlation with TNF-α (r = 0.88, P < 0.01) and cortisol (r = 0.78, P < 0.01). These findings highlighted the heightened susceptibility of crossbred cows to HS and also provided important new insights into some stress indicators in native and crossbred cows, which could be integrated into farming systems under hot conditions.
{"title":"Effect of hot-dry and hot-humid seasons on the plasma cytokines, hormones, and body surface temperatures in lactating indigenous (Sahiwal) and crossbred (Karan Fries) cows raised in tropical climates","authors":"Manisha Choudhary , Aarti Kamboj , Pritam Pal , Bagavathi M , Animesh Patel , Pankaj Suman , Ajay Kumar Dang","doi":"10.1016/j.jtherbio.2026.104405","DOIUrl":"10.1016/j.jtherbio.2026.104405","url":null,"abstract":"<div><div>Heat stress (HS) significantly challenges dairy cattle, affecting their immune function, endocrine responses, and thermoregulation. This study investigated cytokine responses, hormonal changes, and body surface temperature variations in 12 indigenous Sahiwal (SW) and 12 crossbred Karan Fries (KF) cows reared under hot-dry (HD; THI = 77.75) and hot-humid (HH; THI = 81.48) seasons. Plasma concentrations of Interleukin-6 (IL-10), tumor necrosis factor-α (TNF-α), Interleukin-6 (IL-6), Interleukin-1β (IL- 1β), cortisol, triiodothyronine (T3), and thyroxine (T4) were analysed using ELISA, while body surface temperatures were measured using infrared thermography (IRT). Significant (P < 0.05) variations were observed between breeds and across the two seasons. Higher TNF-α, IL-6, IL-1β, and cortisol levels were observed under HH compared to HD seasons. TNF-α levels increased significantly (P < 0.05) by 31.76% in SW and 36.47% in KF cows, while cortisol levels rose by 44.41% and 47.42%, respectively, from the HD to HH season. In contrast, T3 and T4 levels declined significantly (P < 0.05) by 25.60% and 36.42%, respectively, under HH seasons, with a greater reduction observed in KF cows. Body surface temperatures were significantly (P < 0.05) higher in KF cows across all measured regions, with eye temperature exhibiting a strong correlation with TNF-α (r = 0.88, P < 0.01) and cortisol (r = 0.78, P < 0.01). These findings highlighted the heightened susceptibility of crossbred cows to HS and also provided important new insights into some stress indicators in native and crossbred cows, which could be integrated into farming systems under hot conditions.</div></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"136 ","pages":"Article 104405"},"PeriodicalIF":2.9,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146165649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01Epub Date: 2026-01-19DOI: 10.1016/j.jtherbio.2026.104381
Katherine A. Travis , Caleb M. McKinney , Evan P. Tanner , Ashley M. Tanner , Fidel Hernández , Leonard A. Brennan , David G. Hewitt , Humberto L. Perotto-Baldivieso , Ryan S. Luna , R. Dwayne Elmore , John McLaughlin
Animal space use is structured by a combination of biotic and abiotic factors, often resulting in disparity of useable space across gradients of these conditions. Animals experience two fundamentally different environments across the diel cycle, as diurnal and nocturnal periods contain different conditions around which animals must partition their space use. This partitioning is partially a consequence of animals needing to meet different demands across the diel cycle. Abiotic conditions can interact with biotic pressures to cause animals to respond differently to compounding pressures such as thermal stress between the diurnal and nocturnal periods. The chestnut-bellied scaled quail (Callipepla squamata var. castanogastris) is a shrubland-obligate subspecies of scaled quail within the Tamaulipan thornscrub biotic province that has faced population declines in recent decades. Our objectives were to examine the space use of GPS-tagged chestnut-bellied scaled quail at two sites in South Texas (one stable and one declining population) and to predict how habitat suitability shifts across the diel cycle. Additionally, we determined how changes in habitat suitability may be impacted by ambient temperature as well as landscape configuration. While diurnal and nocturnal environmental suitability overlap was relatively high at most temperatures (Schoener's D: 0.67–0.81 [stable site]; 0.70–0.87 [declining site]), we found that overlap decreased by 15 % (stable population site) and 22 % (declining population site) when ambient temperatures reached the upper limit of the species' thermoneutral zone (35 °C). This decrease in environmental suitability overlap occurred at relatively cooler temperatures at the declining population site (32.2°C–35.0 °C) than at the stable population site (35.0°C–37.8 °C). Our results indicate that relatively small changes in temperature can affect habitat suitability across the diel cycle. Understanding disparity in diurnal and nocturnal space use, and the possible consequences of this divergence, is increasingly important in a warming and more anthropogenically altered environment.
{"title":"In the heat of the night: Temperature and vegetation structure disparity in habitat suitability for scaled quail","authors":"Katherine A. Travis , Caleb M. McKinney , Evan P. Tanner , Ashley M. Tanner , Fidel Hernández , Leonard A. Brennan , David G. Hewitt , Humberto L. Perotto-Baldivieso , Ryan S. Luna , R. Dwayne Elmore , John McLaughlin","doi":"10.1016/j.jtherbio.2026.104381","DOIUrl":"10.1016/j.jtherbio.2026.104381","url":null,"abstract":"<div><div>Animal space use is structured by a combination of biotic and abiotic factors, often resulting in disparity of useable space across gradients of these conditions. Animals experience two fundamentally different environments across the diel cycle, as diurnal and nocturnal periods contain different conditions around which animals must partition their space use. This partitioning is partially a consequence of animals needing to meet different demands across the diel cycle. Abiotic conditions can interact with biotic pressures to cause animals to respond differently to compounding pressures such as thermal stress between the diurnal and nocturnal periods. The chestnut-bellied scaled quail (<em>Callipepla squamata</em> var. <em>castanogastris</em>) is a shrubland-obligate subspecies of scaled quail within the Tamaulipan thornscrub biotic province that has faced population declines in recent decades. Our objectives were to examine the space use of GPS-tagged chestnut-bellied scaled quail at two sites in South Texas (one stable and one declining population) and to predict how habitat suitability shifts across the diel cycle. Additionally, we determined how changes in habitat suitability may be impacted by ambient temperature as well as landscape configuration. While diurnal and nocturnal environmental suitability overlap was relatively high at most temperatures (Schoener's <em>D</em>: 0.67–0.81 [stable site]; 0.70–0.87 [declining site]), we found that overlap decreased by 15 % (stable population site) and 22 % (declining population site) when ambient temperatures reached the upper limit of the species' thermoneutral zone (35 °C). This decrease in environmental suitability overlap occurred at relatively cooler temperatures at the declining population site (32.2°C–35.0 °C) than at the stable population site (35.0°C–37.8 °C). Our results indicate that relatively small changes in temperature can affect habitat suitability across the diel cycle. Understanding disparity in diurnal and nocturnal space use, and the possible consequences of this divergence, is increasingly important in a warming and more anthropogenically altered environment.</div></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"136 ","pages":"Article 104381"},"PeriodicalIF":2.9,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146052991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01Epub Date: 2026-01-20DOI: 10.1016/j.jtherbio.2026.104385
Shahar Dubiner
Endothermy is an important trait in the biology of several (extant and extinct) groups of amniotes. Despite its distinct benefits, it is an extremely expensive trait, and the drivers for its emergence and evolutionary success are debated. I offer a hypothesis complementary to current theories, linking endotherms’ capacity for thermogenesis with the need to increase body temperature during pathogen infection (“fever”, present in both endotherms and ectotherms). I do not propose this as a primary driver of endothermy; rather, the emergence of efficient fever prevented the secondary loss of endothermy. After endothermy has evolved in a given lineage, the stabler host temperature, coupled with higher direct transmission due to incubation and parental care, would lead to the propagation and specialization of pathogens in the population. Hence, although ectothermy carries no inherent disadvantage, reverting from endothermy to ectothermy faces the obstacle of an already-high pathogen load. Reduced heat production would increase the gap from normal to fever temperature, impairing the reliability of the response and increasing its cost, when pathogen load in the population is already higher and more specialized as enabled by endothermy. This factor may be enough to outweigh selective pressures against the energetic cost of endothermy. This hypothesis, though anecdotally supported by the intriguing fact that endothermy is very rarely lost (and is often retained even when homeothermy is not), is merely a conceptual framework and must be tested further.
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Pub Date : 2026-02-01Epub Date: 2026-01-22DOI: 10.1016/j.jtherbio.2026.104401
R. Allan , H.T. Hurst , B. Akin , N. Liles , J. Dickson , J. Knill-Jones , J. Sinclair , S. Dillon , S.J. Hesketh , C. Mawhinney
Background
Studies of cold-dwelling humans show lower bone mineral density (BMD) and greater age-related bone loss. While cold exposure is regularly used for analgesic purposes, prolonged use may unintentionally exacerbate symptoms it aims to treat.
Objective
To evaluate human evidence on the effects of cold exposure upon markers of bone health.
Methods
This scoping review followed the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines. OVID (MEDLINE, EMBASE), Elsevier (ScienceDirect, Scopus), and PubMED databases were searched using the terms (“Cold temperature” OR “cryotherapy” OR “Hydrotherapy” OR “Cold stress”) AND (“Bone Matrix” OR “Bone mineral density” OR “bone formation” OR “bone remodelling” OR Osteogenesis). Inclusion criteria were: (1) cold exposure or application in humans; (2) measurement of bone health or turnover markers; and (3) original research or case reports.
Results
Searches resulted in 2372 articles, yielding a final pool of 13 articles for inclusion after screening. Several cooling methods were used, predominantly cold air (n = 6), cooling vests (n = 4), sleeping in cold rooms (n = 1), β3 agonist coupled with cooling pads (n = 1) and ice water swimming (n = 3). Markers of bone health were assessed, with BMD shown to increase following cryotherapy, and having a positive correlation with brown adipose tissue. Papers returned suggest a neutral or positive response in factors that enhance osteoblast differentiation (irisin, insulin-like growth factor-1 [IGF-1], meteorin-like protein [METRNL]), which fails to translate directly into improved bone formation (procollagen 1 N-terminal propeptide [P1NP], osteocalcin).
Conclusion
Cold exposure might dampen bone resorption mechanisms (beta isomerised C terminal telopeptide of type 1 collagen [β-CTX]) but not others (receptor activator of nuclear factor κ B [RANK], RANK ligand [RANKL], interleukin-6 [IL-6]). Hormonal markers of bone remodelling (thyroid stimulating hormone [TSH], parathyroid hormone [PTH], triiodothyronine [T3]) also showed contrasting effects. As such, the limited data does not allow for clear conclusions.
{"title":"The influence of cold temperature exposure on markers of bone health in humans: A scoping review","authors":"R. Allan , H.T. Hurst , B. Akin , N. Liles , J. Dickson , J. Knill-Jones , J. Sinclair , S. Dillon , S.J. Hesketh , C. Mawhinney","doi":"10.1016/j.jtherbio.2026.104401","DOIUrl":"10.1016/j.jtherbio.2026.104401","url":null,"abstract":"<div><h3>Background</h3><div>Studies of cold-dwelling humans show lower bone mineral density (BMD) and greater age-related bone loss. While cold exposure is regularly used for analgesic purposes, prolonged use may unintentionally exacerbate symptoms it aims to treat.</div></div><div><h3>Objective</h3><div>To evaluate human evidence on the effects of cold exposure upon markers of bone health.</div></div><div><h3>Methods</h3><div>This scoping review followed the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines. OVID (MEDLINE, EMBASE), Elsevier (ScienceDirect, Scopus), and PubMED databases were searched using the terms (“Cold temperature” OR “cryotherapy” OR “Hydrotherapy” OR “Cold stress”) AND (“Bone Matrix” OR “Bone mineral density” OR “bone formation” OR “bone remodelling” OR Osteogenesis). Inclusion criteria were: (1) cold exposure or application in humans; (2) measurement of bone health or turnover markers; and (3) original research or case reports.</div></div><div><h3>Results</h3><div>Searches resulted in 2372 articles, yielding a final pool of 13 articles for inclusion after screening. Several cooling methods were used, predominantly cold air (n = 6), cooling vests (n = 4), sleeping in cold rooms (n = 1), β3 agonist coupled with cooling pads (n = 1) and ice water swimming (n = 3). Markers of bone health were assessed, with BMD shown to increase following cryotherapy, and having a positive correlation with brown adipose tissue. Papers returned suggest a neutral or positive response in factors that enhance osteoblast differentiation (irisin, insulin-like growth factor-1 [IGF-1], meteorin-like protein [METRNL]), which fails to translate directly into improved bone formation (procollagen 1 N-terminal propeptide [P1NP], osteocalcin).</div></div><div><h3>Conclusion</h3><div>Cold exposure might dampen bone resorption mechanisms (beta isomerised C terminal telopeptide of type 1 collagen [β-CTX]) but not others (receptor activator of nuclear factor <em>κ</em> B [RANK], RANK ligand [RANKL], interleukin-6 [IL-6]). Hormonal markers of bone remodelling (thyroid stimulating hormone [TSH], parathyroid hormone [PTH], triiodothyronine [T3]) also showed contrasting effects. As such, the limited data does not allow for clear conclusions.</div></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"136 ","pages":"Article 104401"},"PeriodicalIF":2.9,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146078899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01Epub Date: 2026-02-11DOI: 10.1016/j.jtherbio.2026.104414
Julio Cruz-Vila , Alexandre Mestre , Lucía Villarroya-Villalba , Alex Martínez , Francesc Mesquita-Joanes
Temporary ponds experience wide variation in their physical and chemical conditions, including changes in temperature and salinity, two critical factors strongly affecting aquatic life metabolism. Although ostracods are common in these habitats, little is known on the combined effects of temperature and salt content on their metabolic rates. Here, we compared the oxygen consumption rates of two cosmopolitan ostracods common in temporary ponds: Eucypris virens, which mostly grows dense populations during winter-spring in temperate climates, and Heterocypris incongruens, mostly considered a spring-summer inhabitant in the same habitats. We performed respirometry experiments combining five different temperatures (5-25 °C) and six salinities (0.1-10 PSU), and quantified their combined effects on mass-specific oxygen consumption rates of both species. According to the Metabolic Cold Adaptation (MCA) hypothesis, we expected differences in metabolic rate associated with their different phenologies, with the winter species showing a higher rate at the same temperature. We observed significant effects of temperature and salinity with no interaction between them on the oxygen consumption rates of both species, and confirmed that the winter species had higher energetic demands at all the temperatures tested, as predicted by MCA. Furthermore, significant interaction effects between species and salinity were consistent with their different salinity tolerances. These results provide support for MCA in ostracods and call for further experimental work with a wider range of conditions to better evaluate variation in ostracod metabolic responses at more extreme values of salinity and temperature.
{"title":"Oxygen uptake in two temporary pond ostracods (Crustacea: Ostracoda) in response to different temperatures and salt contents: testing the Metabolic Cold Adaptation hypothesis","authors":"Julio Cruz-Vila , Alexandre Mestre , Lucía Villarroya-Villalba , Alex Martínez , Francesc Mesquita-Joanes","doi":"10.1016/j.jtherbio.2026.104414","DOIUrl":"10.1016/j.jtherbio.2026.104414","url":null,"abstract":"<div><div>Temporary ponds experience wide variation in their physical and chemical conditions, including changes in temperature and salinity, two critical factors strongly affecting aquatic life metabolism. Although ostracods are common in these habitats, little is known on the combined effects of temperature and salt content on their metabolic rates. Here, we compared the oxygen consumption rates of two cosmopolitan ostracods common in temporary ponds: <em>Eucypris virens</em>, which mostly grows dense populations during winter-spring in temperate climates, and <em>Heterocypris incongruens</em>, mostly considered a spring-summer inhabitant in the same habitats. We performed respirometry experiments combining five different temperatures (5-25 °C) and six salinities (0.1-10 PSU), and quantified their combined effects on mass-specific oxygen consumption rates of both species. According to the Metabolic Cold Adaptation (MCA) hypothesis, we expected differences in metabolic rate associated with their different phenologies, with the winter species showing a higher rate at the same temperature. We observed significant effects of temperature and salinity with no interaction between them on the oxygen consumption rates of both species, and confirmed that the winter species had higher energetic demands at all the temperatures tested, as predicted by MCA. Furthermore, significant interaction effects between species and salinity were consistent with their different salinity tolerances. These results provide support for MCA in ostracods and call for further experimental work with a wider range of conditions to better evaluate variation in ostracod metabolic responses at more extreme values of salinity and temperature.</div></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"136 ","pages":"Article 104414"},"PeriodicalIF":2.9,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146202096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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