Journal of thermal biology最新文献_第5页

Divergent physiological and life-history responses to temperature acclimation in two soil free-living nematodes 两种土壤自由生活线虫对温度驯化的不同生理和生活史响应

IF 2.9 2区生物学 Q2 BIOLOGY

Journal of thermal biology

Pub Date : 2026-01-08 DOI: 10.1016/j.jtherbio.2026.104373

Ziqing Kang , Shan Sun , Leilei Lu , Huijun Li , Teng Li , Huixin Li

Climate warming significantly impacts the diversity and abundance of animals, including soil-dwelling species that play crucial roles in soil ecosystems. Understanding their response to temperature variations is crucial for comprehending their adaptative strategies to climate warming. However, most studies have primarily focused on aboveground animals, often neglecting those in soil. Our study examined the acclimation of two species of soil free-living nematodes, Acrobeloides sp. and Distolabrellus veechi, to cool and warm temperatures, focusing on their physiological (mass-specific routine metabolic rate, head swing frequency) and life-history (body size, reproduction, lifespan) responses. We also investigated maternal effects on offspring development and hatching success of these two nematodes. Our results revealed that warm acclimation increased the body size and head swing frequency of Acrobeloides, shortened its egg-laying period and lifespan, but did not alter its mass-specific routine metabolic rate or brood size. In contrast, warm acclimation increased both body size and brood size of D. veechi, decreased its mass-specific routine metabolic rate and head swing frequency, and shortened its egg-laying period and lifespan. Both nematode species modulated their offspring's acclimation to the maternal acclimation temperature to varying degrees through maternal effects. To our knowledge, this study is among the first to show that soil free-living nematodes can adjust their life-history strategies in response to temperature changes, highlighting the diversity of thermal responses in soil animals and providing a basis for understanding their adaptive strategies and ecological consequences under climate warming.

气候变暖显著影响动物的多样性和丰度，包括在土壤生态系统中发挥关键作用的土壤栖息物种。了解它们对温度变化的反应对于理解它们对气候变暖的适应策略至关重要。然而，大多数研究主要集中在地上的动物身上，往往忽视了土壤中的动物。本研究研究了两种土壤自由生活线虫（Acrobeloides sp.）和veechi Distolabrellus veechi)对低温和温暖环境的适应，重点研究了它们的生理（质量特异性常规代谢率、头部摆动频率）和生活史（体型、繁殖、寿命）反应。我们还研究了母体对这两种线虫后代发育和孵化成功的影响。结果表明，温驯化增加了棘球蜂的体型和摇头频率，缩短了其产卵期和寿命，但没有改变棘球蜂的质量代谢率和产卵量。温驯化使黄颡鱼体尺和产卵量增加，降低了黄颡鱼的质量常规代谢率和摇头频率，缩短了黄颡鱼的产卵期和寿命。两种线虫都通过母体效应不同程度地调节其后代对母体驯化温度的适应。据我们所知，这项研究是第一个表明土壤自由生活的线虫可以根据温度变化调整其生活史策略的研究之一，突出了土壤动物热响应的多样性，并为了解气候变暖下它们的适应策略和生态后果提供了基础。

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引用次数: 0

Spermidine ameliorates heat stress-induced testicular dysfunction in mice 亚精胺改善小鼠热应激性睾丸功能障碍。

IF 2.9 2区生物学 Q2 BIOLOGY

Journal of thermal biology

Pub Date : 2026-01-01 DOI: 10.1016/j.jtherbio.2025.104366

Shuqi Zou , Tao Sun , Shengqin Zang , Bo Pan , Jianpeng Qin , Can Wang , Kunlin Du , Yaozong Wei , Ao Ning , Xiangyi Chen , Jiangfeng Ye , Yuee Gao , Qiuxia Liang , Guozhi Yu , Tianzeng Song , Kai Yang , Guangbin Zhou

While the adverse effects of heat stress on male fertility are well-established, the development of targeted intervention strategies remains a critical research gap. Spermidine, a naturally occurring polyamine in plants and animals, exhibits diverse biological functions including potential antioxidant and autophagy-modulating properties. However, its protective role in spermatogenesis under heat stress conditions requires further investigation. This study aimed to determine whether spermidine mitigates heat stress-induced spermatogenic dysfunction through antioxidant effects or autophagy regulation. Our findings revealed that 14 days post-heat exposure (Day 0 to anaesthetization), testis-to-body significantly decreased, accompanied by increased seminiferous tubule damage and reduced germ cell layers. Heat stress altered the expression of key genes involved in the testicular antioxidant-related genes (SOD1, SOD2, Nrf2), autophagy-related genes (ATG4, PINK1), mitochondrial biogenesis-related genes (DNM1L, Sirt1, Pgc-1α, Tfam), apoptosis-related genes (Bax, Bcl2, Caspase 3, Caspase 9). Additionally, while testosterone levels increased, sperm motility, sperm concentration, and cleavage rates declined, with a concomitant rise in sperm abnormalities. Notably, intraperitoneal administration of 5 mg/kg spermidine effectively counteracted these detrimental effects. These results highlight spermidine's potential as a therapeutic agent for testicular damage due to heat stress.

虽然热应激对男性生育能力的不利影响已经确立，但有针对性的干预策略的发展仍然是一个关键的研究空白。亚精胺是一种天然存在于动植物体内的多胺，具有多种生物功能，包括潜在的抗氧化和自噬调节特性。然而，其在热应激条件下对精子发生的保护作用有待进一步研究。本研究旨在确定亚精胺是否通过抗氧化作用或自噬调节来减轻热应激诱导的生精功能障碍。我们的研究结果显示，热暴露后14天（麻醉第0天），睾丸对身体的影响显著降低，同时伴有精管损伤增加和生殖细胞层数减少。热应激改变了睾丸抗氧化相关基因（SOD1、SOD2、Nrf2）、自噬相关基因（ATG4、PINK1）、线粒体生物发生相关基因（DNM1L、Sirt1、Pgc-1α、Tfam）、凋亡相关基因（Bax、Bcl2、Caspase 3、Caspase 9）的表达。此外，当睾酮水平升高时，精子活力、精子浓度和卵裂率下降，精子异常率随之上升。值得注意的是，腹腔注射5mg /kg亚精胺可有效抵消这些有害影响。这些结果突出了亚精胺作为热应激引起的睾丸损伤治疗剂的潜力。

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引用次数: 0

Evaluating antenna configurations for improved microwave therapy outcomes in liver tumors enhanced with magnetic nanoparticles 评估天线配置对磁性纳米颗粒增强肝肿瘤微波治疗效果的改善

IF 2.9 2区生物学 Q2 BIOLOGY

Journal of thermal biology

Pub Date : 2026-01-01 DOI: 10.1016/j.jtherbio.2025.104365

Soheil S. Fakhradini, Mehdi Mosharaf-Dehkordi, Hossein Ahmadikia

The effects of geometric parameters on microwave thermal therapy, enhanced with magnetic nanoparticles, for liver cancer are investigated. Using finite element analysis and considering various tumor diameters ranging from 20 to 40 mm, the number and placement of antenna slots, antenna positioning, and slot spacing were evaluated to improve treatment efficacy. Numerical results indicate that three-slot antennas provide superior performance by generating uniform electromagnetic field that reduces collateral damage, whereas five-slot configurations increased healthy tissue necrosis by up to 124 % for smaller tumors. Moreover, slot spacing has a negligible effect in nanoparticle-enhanced treatments, as the nanoparticles dominated heat distribution. Positioning the antenna tip at the tumor's edge can reduce treatment times and side effects, limiting healthy tissue damage by 21–79 %, depending on tumor size and offset. For tumors of diameters larger than 35 mm, positioning effects diminish, as necrosis volume stabilized across different placements. Compared to a 25 mm tumor, the 20 mm tumor showed that 67 % of the increase in necrosis volume was due to healthy tissue damage, even though the treated tumor volume was 95 % larger. This efficiency can be improved with tumor size; for a 40 mm tumor, the increase in healthy tissue necrosis was only 27 %, despite the tumor being 49 % larger. The location of gap also played a role, smaller gaps near the antenna tip improve tumor coverage and reduce side effects, but variations in gap location had minimal impact on healthy tissue necrosis. These results demonstrate that appropriate geometric configurations in microwave thermal therapy can enhance tumor ablation while minimizing collateral damage, particularly for larger tumors.

研究了几何参数对磁性纳米颗粒增强微波热治疗肝癌的影响。采用有限元分析方法，考虑肿瘤直径在20 ~ 40 mm范围内，对天线槽数、放置位置、天线定位、槽间距进行评估，以提高治疗效果。数值结果表明，三槽天线通过产生均匀的电磁场来减少附带损伤，从而提供了优越的性能，而对于较小的肿瘤，五槽天线的配置可使健康组织坏死增加高达124%。此外，在纳米颗粒增强处理中，槽间距的影响可以忽略不计，因为纳米颗粒主导了热分布。将天线尖端放置在肿瘤边缘可以减少治疗时间和副作用，将健康组织损伤限制在21 - 79%，具体取决于肿瘤大小和偏移量。对于直径大于35mm的肿瘤，定位效果减弱，因为不同位置的坏死体积稳定。与25mm肿瘤相比，20mm肿瘤显示67%的坏死体积增加是由于健康组织损伤，尽管治疗后的肿瘤体积增加了95%。这种效率可以随着肿瘤的大小而提高；对于40mm的肿瘤，尽管肿瘤增大了49%，但健康组织坏死仅增加了27%。间隙的位置也发挥了作用，天线尖端附近较小的间隙可以改善肿瘤覆盖范围并减少副作用，但间隙位置的变化对健康组织坏死的影响最小。这些结果表明，微波热治疗中适当的几何结构可以增强肿瘤消融，同时最大限度地减少附带损伤，特别是对于较大的肿瘤。

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引用次数: 0

Genetic and phenotypic insights into thermal load and racing performance of Quarter Horses 四分之一马的热负荷和比赛表现的遗传和表型分析。

IF 2.9 2区生物学 Q2 BIOLOGY

Journal of thermal biology

Pub Date : 2025-12-29 DOI: 10.1016/j.jtherbio.2025.104362

Mário L. Santana , Annaiza B. Bignardi , Ricardo A.S. Faria , Josineudson A.II.V. Silva

Thermal load is a major welfare and performance concern for athletic horses, as physical exertion increases internal heat production. Although several phenotypic strategies have been developed to mitigate its effects, the genetic basis of thermal tolerance in horses remains largely unexplored. This study aimed to (1) evaluate the influence of thermal indices on the racing performance of Brazilian Quarter Horses, and (2) investigate the genetic basis of thermal tolerance through the estimation of genetic parameters across temperature gradients. We analyzed 21,857 racing-time (RT) records from 5542 horses competing between 1984 and 2016 in Sorocaba, São Paulo, Brazil, a region with a mild subtropical climate. The performance of Quarter Horses improved at higher air temperatures and thermal indices, as races were held within their thermal comfort zone. Among all environmental variables, the average air temperature over the four days preceding each race (T4) explained the greatest proportion of variation in RT. A reaction norm model was applied to RT using T4 as the environmental descriptor. Both thermotolerant and heat-sensitive genotypes were identified. Heritability and additive genetic variance varied along the temperature scale, revealing heterogeneity in genetic control. A negative genetic correlation between intercept and slope indicated a trade-off between overall performance and heat tolerance. Genetic trends showed that selection for faster racing times was associated with reduced tolerance to higher thermal load in Quarter Horses. Therefore, future breeding strategies should explicitly integrate thermotolerance to maintain performance under increasingly challenging climatic conditions.

热负荷是运动马的主要福利和表现问题，因为体力消耗会增加内部产热。尽管已经开发了几种表型策略来减轻其影响，但马耐热性的遗传基础仍未得到很大程度的探索。本研究旨在(1)评估热指标对巴西四分之一马比赛表现的影响；(2)通过估计不同温度梯度的遗传参数来研究热耐受性的遗传基础。我们分析了1984年至2016年在巴西圣保罗索罗卡巴（soocaba）比赛的5542匹马的21857个比赛时间（RT）记录，这是一个亚热带气候温和的地区。四分之一马的表现在较高的气温和热指数下有所改善，因为比赛是在它们的热舒适区举行的。在所有环境变量中，每场比赛前4天的平均气温（T4）解释了RT变化的最大比例。将T4作为环境描述符应用于RT的反应范数模型。鉴定出耐热型和热敏型两种基因型。遗传力和加性遗传方差沿温度尺度变化，表明遗传控制存在异质性。截距和斜率之间呈负相关，表明综合性能与耐热性之间存在权衡关系。遗传趋势表明，选择更快的比赛时间与四分之一马对更高热负荷的耐受性降低有关。因此，未来的育种策略应明确整合耐热性，以在日益严峻的气候条件下保持性能。

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引用次数: 0

Taurine alleviates heat stress-induced intestinal injury by inhibiting ROS-mediated endoplasmic reticulum stress in mice 牛磺酸通过抑制ros介导的内质网应激减轻小鼠热应激诱导的肠道损伤

IF 2.9 2区生物学 Q2 BIOLOGY

Journal of thermal biology

Pub Date : 2025-12-24 DOI: 10.1016/j.jtherbio.2025.104363

Xixi Ren, Zhiqing Huang, Gang Jia, Hua Zhao, Xiaoling Chen

Heat stress (HS) induces intestinal injury in animals, but the underlying mechanisms are unknown. This study aimed to investigate the protective effect of taurine (TAU) on intestinal injury induced by heat stress. The heat stress model was established by maintaining mice in a constant temperature and humidity environment (41 ± 1 °C, relative humidity 50 %–60 %), with core body temperature reaching 42 °C. In the experimental design, we supplemented different doses (100, 200, and 400 mg/kg) of TAU to the mice's basal diet, while setting up two positive control groups that received intraperitoneal injections of N-acetyl-L-cysteine (NAC) and 4-phenylbutyric acid (4-PBA), respectively. The findings revealed that heat stress led to a significant upregulation of intestinal heat shock protein 70 protein expression along with higher serum corticosterone in mice. Heat stress impaired intestinal morphology, downregulated tight junction protein gene expression and increased intestinal permeability. Simultaneously, heat stress significantly decreased intestinal antioxidant capacity, caused mitochondrial dysfunction, increased the content of inflammatory cytokines and promoted apoptosis, resulting in excessive accumulation of reactive oxygen species (ROS) and triggering endoplasmic reticulum stress. However, dietary supplementation with TAU alleviated these heat stress-induced effects, and similar results were also obtained with NAC and 4-PBA. Together, TAU could inhibit the accumulation of ROS and endoplasmic reticulum stress by enhancing intestinal antioxidant capacity, decreased inflammatory responses and apoptosis, which may exert its protective effect against heat stress-induced intestinal injury.

热应激（HS）可引起动物肠道损伤，但其机制尚不清楚。本研究旨在探讨牛磺酸（TAU）对热应激引起的肠道损伤的保护作用。将小鼠置于恒温恒湿环境（41±1℃，相对湿度50% - 60%），核心体温达到42℃，建立热应激模型。在实验设计中，我们在小鼠基础日粮中添加不同剂量（100、200和400 mg/kg）的TAU，同时建立两个阳性对照组，分别腹腔注射n -乙酰- l-半胱氨酸（NAC）和4-苯基丁酸（4-PBA）。结果表明，热应激导致小鼠肠道热休克蛋白70蛋白表达显著上调，血清皮质酮水平升高。热应激损伤肠道形态，下调紧密连接蛋白基因表达，增加肠道通透性。同时，热应激显著降低肠道抗氧化能力，引起线粒体功能障碍，增加炎症细胞因子含量，促进细胞凋亡，导致活性氧（ROS）过度积累，引发内质网应激。然而，在饮食中添加TAU可以缓解这些热应激诱导的影响，NAC和4-PBA也可以获得类似的结果。TAU通过增强肠道抗氧化能力，减少炎症反应和细胞凋亡，抑制ROS的积累和内质网应激，可能对热应激引起的肠道损伤发挥保护作用。

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引用次数: 0

High mountains are more than cold peaks: Diverse thermal availability for an endemic lizard 高山不仅仅是寒冷的山峰：对一种特有的蜥蜴来说，不同的热可利用性

IF 2.9 2区生物学 Q2 BIOLOGY

Journal of thermal biology

Pub Date : 2025-12-23 DOI: 10.1016/j.jtherbio.2025.104367

Guadalupe López Juri , José M. Sánchez , Rafael A. Lara-Reséndiz , Sergio Naretto

引用次数: 0

The effects of improving barn cooling on the behaviour, physiological responses, gene expression, and milk yield of dairy cows 改善牲口棚降温对奶牛行为、生理反应、基因表达和产奶量的影响

IF 2.9 2区生物学 Q2 BIOLOGY

Journal of thermal biology

Pub Date : 2025-12-23 DOI: 10.1016/j.jtherbio.2025.104364

Viktor Jurkovich , Szilvia Szalai , Zsóka Várhidi , Szilvia Kusza , Zoltán Bagi , Lilla Bodrogi , Blanka Dávid , Mária Kovács-Weber , Róbert Kővágó , Mikolt Bakony , Péter Hejel

Heat stress poses a significant challenge for dairy cows, particularly in warm climates, as it hampers their physiology, behaviour, and milk production. This study evaluated the effectiveness of a modern barn cooling system equipped with temperature-dependent fans in alleviating heat stress and enhancing cow welfare and productivity. The research was conducted on a large-scale Holstein Friesian dairy farm, comparing two high-yielding groups of around 100 cows each. The experimental group was housed in a barn with newly installed louvered, temperature-dependent circulation fans (providing high airspeed), while the control group remained in a barn with box ventilators (low airspeed). Data were collected over four three-day sampling periods during the summer. Environmental conditions were monitored using data loggers that recorded temperature and humidity, enabling calculation of the temperature-humidity index (THI). Cow body temperature was measured intravaginally. Additionally, time spent lying, eating, and ruminating was also tracked. Daily milk yields were obtained from the farm's database. Blood samples were also taken for gene expression measurements. Results indicated that THI values in both barns frequently surpassed the heat stress threshold (THI >68), yet air velocity in the experimental barn was notably higher (1.5–2.5 m/s) than in the control barn (0.2–0.5 m/s). Cows in the cooled barn showed significantly lower body temperatures in three of four periods. While lying time did not vary significantly, eating time increased in the experimental group later in the study. Moreover, milk yield was approximately 3 L/day higher (p < 0.05) in the experimental group. Enhanced ventilation led to complex changes in gene expression patterns, suggesting dynamic cellular responses to improved environmental conditions. These outcomes indicate that improved ventilation effectively reduces heat stress and supports better health, feeding behaviour, and milk production in dairy cows.

热应激对奶牛构成了重大挑战，特别是在温暖的气候中，因为它会影响它们的生理、行为和产奶量。本研究评估了配备温度依赖风扇的现代牛舍冷却系统在缓解热应激和提高奶牛福利和生产力方面的有效性。这项研究是在一个大型荷斯坦弗里西亚奶牛场进行的，比较了两个高产组，每个组约100头奶牛。实验组被安置在一个装有新安装的百叶、温度依赖循环风扇的谷仓里（提供高空速），而对照组则被安置在一个装有箱形通风机的谷仓里（低空速）。数据是在夏季四个为期三天的采样期收集的。使用记录温度和湿度的数据记录仪监测环境条件，从而计算温湿度指数（THI）。阴道内测量奶牛体温。此外，撒谎、进食和沉思的时间也被追踪。每日产奶量从农场的数据库中获取。血液样本也被用于基因表达测量。结果表明，两个仓的THI值都经常超过热应力阈值（THI >68），但实验仓的空气速度（1.5 ~ 2.5 m/s）明显高于对照仓（0.2 ~ 0.5 m/s）。在降温的牛棚里，奶牛的体温在四个时期中的三个时期明显降低。虽然躺着的时间没有显著变化，但在研究后期，实验组的进食时间增加了。另外，试验组产奶量比对照组高约3 L/d （p < 0.05）。增强的通风导致基因表达模式的复杂变化，表明对改善的环境条件的动态细胞反应。这些结果表明，改善通风可以有效地减少热应激，并有助于奶牛的健康、摄食行为和产奶量。

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引用次数: 0

Using drone-based infrared thermography for monitoring vital signs in dolphins 利用无人机红外热像仪监测海豚的生命体征

IF 2.9 2区生物学 Q2 BIOLOGY

Journal of thermal biology

Pub Date : 2025-12-16 DOI: 10.1016/j.jtherbio.2025.104353

Charlie White , Andrew P. Colefax , Guido J. Parra

Monitoring wild animal health is essential for assessing environmental threats. Physiological parameters such as body temperature and respiration rate provide critical insights into an animal's condition but collecting these from free-ranging species is challenging. This study validated drone-based infrared thermography (drone-IRT) as a non-invasive method for estimating dolphin vital signs, evaluating its accuracy, reliability, and practical application. Using a multirotor drone with an integrated thermal camera, we obtained thermographic images of 14 common bottlenose dolphins (Tursiops truncatus) under human care. Flights were conducted in Austral summer and winter at heights of 5 m–30 m, with the camera angled at 0° (zenith) and 50° pitch. Dolphins were either swimming freely or beached. From thermal images, we extracted temperatures based on the heat received from the blowhole, body, and dorsal fin, along with respiration rate estimates. Close-range IRT reference temperatures and environmental variables were recorded throughout each flight. Robust linear mixed-effects models assessed the influence of flight and environmental variables on measurement accuracy and precision. Spearman's rank correlation evaluated the relationship between drone-IRT blowhole temperature and rectal temperature. Drone-IRT measurements closely matched close-range IRT reference values. The most reliable temperature estimates occurred at a combined 10 m and a 0° angle (accuracy: −0.19 °C – 0.08 °C, precision: −0.07 °C – 0.08 °C). The most accurate respiration rate estimates were obtained at 10 m while dolphins swam freely. A weak negative correlation was found between blowhole and rectal temperatures (r = −0.19). This study demonstrates that drone-IRT is a reliable, non-invasive method for monitoring dolphins' surface temperature and respiration rates, but not rectal temperature.

监测野生动物健康对于评估环境威胁至关重要。体温和呼吸速率等生理参数为了解动物状况提供了关键的信息，但从自由放养的物种中收集这些数据是具有挑战性的。本研究验证了基于无人机的红外热像仪（drone-IRT）作为一种非侵入性的海豚生命体征评估方法，评估了其准确性、可靠性和实际应用。利用集成热像仪的多旋翼无人机，获得了人类照料下14只普通宽吻海豚（Tursiops truncatus）的热像图。飞行在南方夏季和冬季进行，高度为5米至30米，相机角度为0°（天顶）和50°俯仰。海豚要么在自由地游泳，要么在海滩上搁浅。从热图像中，我们根据从气孔、身体和背鳍接收的热量以及呼吸速率估计提取温度。近距离IRT参考温度和环境变量在每次飞行中都被记录下来。鲁棒线性混合效应模型评估了飞行和环境变量对测量精度和精度的影响。Spearman等级相关评价了无人机- irt喷气孔温度与直肠温度之间的关系。无人机IRT测量值与近距离IRT参考值非常匹配。最可靠的温度估计发生在10米和0°角（精度：- 0.19°C - 0.08°C，精度：- 0.07°C - 0.08°C）。最准确的呼吸速率估计是在海豚自由游泳时在10米处获得的。气孔温度与直肠温度呈弱负相关（r = - 0.19）。这项研究表明，无人机irt是一种可靠的，非侵入性的方法，用于监测海豚的表面温度和呼吸速率，但不是直肠温度。

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引用次数: 0

Extra food buffers thermoregulatory costs during early development but does not reduce heatwave-induced mortality in nestlings of a cavity-nesting raptor 额外的食物缓冲了早期发育过程中的体温调节成本，但并不能降低穴居猛禽雏鸟因热浪引起的死亡率

IF 2.9 2区生物学 Q2 BIOLOGY

Journal of thermal biology

Pub Date : 2025-12-16 DOI: 10.1016/j.jtherbio.2025.104361

Alejandro Corregidor-Castro , Alessandro Berlusconi , Erica Figus , Anna Kyriakopoulou , Jacopo G. Cecere , Michelangelo Morganti , Diego Rubolini , Andrea Pilastro , Andrea Romano

Global climate change is increasing both average temperatures and the occurrence of extreme weather events, such as heatwaves. These changes pose major challenges for wildlife, especially during vulnerable life stages. In altricial bird species, nest-bound offspring are particularly susceptible to thermal stress due to limited behavioural thermoregulation, where high nest temperatures can impair development and induce elevated mortality, particularly when exceeding critical thresholds. We experimentally manipulated nest temperature and food availability in lesser kestrels (Falco naumanni) rearing their nestlings in nest boxes to investigate whether compensatory feeding offsets the negative effects of high nest temperatures on offspring size and pre-fledging survival. Nestlings were reared under three conditions: control (high nest temperatures), shaded (reduced temperature), and food-supplemented (high temperature with extra food). While parental provisioning rates did not differ among experimental groups, nestlings in food-supplemented boxes showed greater body size than control nestlings, despite similar thermal exposure, and matched the size of nestlings in shaded boxes. This indicates that increased food can buffer the energetic costs of thermoregulation under elevated, but non-lethal, temperatures. Mortality during development did not differ significantly among groups, as temperatures remained below critical thresholds. However, during a naturally occurring heatwave, mortality in control and food-supplemented nests was similarly high (∼40 %), whereas it was very limited in shaded nest boxes (∼4 %). These results suggest that food supplementation cannot prevent heatwave-induced mortality, likely caused by hyperthermia rather than starvation/dehydration. Nest microclimate may thus play a key role in mitigating the negative impacts of intense heatwaves in avian species.

全球气候变化正在增加平均气温和极端天气事件的发生，如热浪。这些变化对野生动物构成了重大挑战，特别是在脆弱的生命阶段。在晚育鸟类中，由于有限的行为体温调节，巢内的后代特别容易受到热应激的影响，巢内的高温会损害发育并导致死亡率升高，特别是在超过临界阈值时。为了研究补偿性喂养是否能抵消高巢温度对雏鸟大小和雏鸟成活率的负面影响，对在巢箱中饲养雏鸟的小红隼（Falco naumanni）进行了调节巢温和食物供应的实验。雏鸟在三种条件下饲养：对照（巢温高）、遮荫（温度降低）和食物补充（高温加额外食物）。虽然各组间的亲代供给率没有差异，但在热暴露相似的情况下，食物补充箱中的雏鸟比对照组雏鸟的体型更大，并且与阴影箱中的雏鸟的体型相匹配。这表明，在升高但非致命的温度下，增加食物可以缓冲体温调节的能量消耗。由于温度保持在临界阈值以下，各组之间发育期间的死亡率没有显著差异。然而，在自然发生的热浪期间，对照巢和食物补充巢的死亡率同样高（~ 40%），而在阴暗的巢箱中，死亡率非常有限（~ 4%）。这些结果表明，食物补充不能防止热浪引起的死亡，可能是由高温而不是饥饿/脱水引起的。因此，巢微气候可能在减轻强烈热浪对鸟类的负面影响方面发挥关键作用。

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引用次数: 0

Thermal ecology and embryonic development in black caiman’s (Melanosuchus niger, Spix 1758) 黑凯门鳄（Melanosuchus niger, Spix 1758）的热生态与胚胎发育。

IF 2.9 2区生物学 Q2 BIOLOGY

Journal of thermal biology

Pub Date : 2025-12-15 DOI: 10.1016/j.jtherbio.2025.104357

Helena Gurjão Pinheiro Do Val , Luiza Figueiredo Passos , Joilson Medeiros de Barros , Grahame Webb , Marcos Eduardo Coutinho

The black caiman (Melanosuchus niger, Spix, 1825) is a crocodilian species endemic to the Amazon biome, that nests within a defined nesting season bridging the local dry and wet seasons. Eggs are deposited in a mound of fresh and old vegetation, but little is known about the thermal relations of M. niger nests and their influence on embryo development rates and total incubation time. We present data for 7 wild nests from the southwestern Brazilian Amazon, gathered in 2019 and 2024. The mean incubation period from laying to hatching was 77.1 ± 8.3 days (SD; range 71.3–93.8 days). Nest temperatures were subject to daily cycling and baseline shifts over time, and had an overall mean of 31.6 ± 1.65 °C (range 27.2 °C–35.9 °C). The nests insulate and buffer the eggs against ambient temperature extremes. Mean nest temperature increases with nest size, and precipitation causes baseline declines in temperature. High nest temperatures (33.6 ± 1.39 °C) in one nest disrupted normal embryo development, and may have affected another. Embryo development rates within 6 nests, and their interactions with nest temperatures, survival to hatching and development time between laying and hatching are investigated. Based on nest temperatures we consider it likely that the M. niger nests we studied would have produced hatchlings with a female bias but could not confirm it.

黑凯门鳄（Melanosuchus niger, Spix, 1825）是一种亚马逊生物群系特有的鳄鱼物种，它们在一个确定的筑巢季节筑巢，连接当地的干湿季节。卵沉积在一堆新鲜和古老的植被中，但对黑乳杆菌巢穴的热关系及其对胚胎发育率和总孵化时间的影响知之甚少。我们展示了2019年和2024年在巴西亚马逊西南部收集的7个野生巢穴的数据。产蛋至孵化平均潜伏期为77.1±8.3天（SD；范围71.3 ~ 93.8天）。巢内温度受每日循环和基线随时间变化的影响，总体平均值为31.6±1.65°C（范围27.2°C-35.9°C）。巢将蛋与外界极端温度隔绝，并起到缓冲作用。巢的平均温度随着巢的大小而增加，而降水导致温度基线下降。一个巢的高温（33.6±1.39°C）破坏了正常的胚胎发育，并可能影响到另一个巢。研究了6个巢内的胚胎发育率及其与巢内温度、孵化存活率和孵化间发育时间的相互作用。根据巢温，我们认为我们所研究的黑乳杆菌巢可能会产生雌性偏向的幼雏，但无法证实这一点。

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