Journal of thermal biology最新文献

The elytron is a hard, intricately patterned exoskeleton of beetles with multiple functions: wing cover, protection from predators and the environment, as well as thermal insulation and heat dissipation. Owing to the complex shape and internal structure spanning millimeters, microns and nanoscales it is difficult to measure and analyze the thermal properties of elytra. Here, we describe a thermal imaging, phase-sensitive (lock-in) technique to assess minute temperature differences and their dependence on elytral anatomy. This is achieved by periodically heating the elytra with a laser while synchronously detecting the emitted thermal radiation with an infrared camera. In this way, the thermal noise was strongly suppressed, revealing small thermal variations along the elytra. Hoplia argentea (Poda, 1761) (Coleoptera: Scarabaeidae: Melolonthinae) was used as a case study, and we were able to relate temperature variation to underlying structures (e.g., wing scales or lacunae). The disclosed technique may be applied to study many thermal processes in insects and other species.

Human sleep is strongly influenced by thermoregulatory and circadian processes, both of which are challenged in polar environments characterized by continuous daylight, low ambient temperatures, and high variability in solar radiation. This study examined how thermal and photic conditions modulate sleep architecture and autonomic function during the 2025 Czech Antarctic Expedition at James Ross Island. Ten expedition members were continuously monitored using validated wearable sensors that recorded sleep stages, heart rate, and respiratory rate across pre-expedition, Antarctic, and post-expedition phases. Environmental variables, including air temperature, relative humidity, and global radiation, were concurrently logged indoors and outdoors. Linear mixed-effects models revealed that the Antarctic phase was associated with a significant increase in slow-wave sleep (17.8 ± 4.1% pre-expedition vs. 20.2 ± 4.3% during expedition, p<0.001) and a decrease in light sleep (p=0.002). Higher outdoor temperatures predicted a greater proportion of deep sleep (β=2.00, p<0.001), and lower humidity was associated with increased deep sleep (β=-1.04, p=0.046). The resting heart rate rose during the expedition and then declined significantly afterward, indicating autonomic recovery. These findings suggest that human sleep exhibits adaptive reorganization under combined thermal and photic stress, with enhanced slow-wave sleep supporting physiological restoration in cold, high-variability environments. The results provide novel evidence of thermoregulatory coupling between environmental conditions, sleep architecture, and autonomic balance in situ.

The flat-tailed horned lizard (Phrynosoma mcallii), endemic to the Sonoran Desert, is a highly specialized ectotherm inhabiting sandy dunes with extreme summer temperatures (up to 49 °C) and very low annual precipitation. Listed as Threatened under Mexico's red list and Near Threatened by the IUCN, this species faces increasing risks from climate change. Despite its ecological importance, our understanding of how thermal and hydric constraints shape its current and future distribution remains limited. We assessed the vulnerability of this species using hybrid ecophysiological ensemble models integrating 193 curated occurrence records, voluntary thermal limits (with sensitivity analyses), bioclimatic variables, and three modeling algorithms (GLM, MARS, and RF). Layers of activity hours (ha) and thermal restriction hours (hr) were generated for current and projected conditions (2070, SSP5-8.5). Currently, ha ranges from 3.36 to 7.75h and is projected to increase to 6.14-10.6h by 2070, expanding activity opportunities. However, hr increases from 0 to 1.25h to values approaching 3.2h at the landscape scale, with hr within suitable habitat reaching ∼2.5h and approaching extinction thresholds (>3.85h). Predictive models, driven primarily by ha (importance = 0.357) and precipitation of the warmest quarter (Bio18 = 0.312), project a 17.1% increase in suitable habitat (from 40,304 to 47,192 km²), but with 30.6% losses (12,322 km²) across the US-Mexico transboundary region (northern Sonora, southern Arizona) and limited gains in coastal microhabitats of California and Baja California. Stable refugia cover 26,872 km², with potential colonization areas spanning 20,541 km². When soil texture was incorporated as an edaphic constraint, a substantial fraction of projected suitable and colonization areas was excluded, highlighting the importance of sandy substrate availability. Ecological specialization, low dispersal capacity, and anthropogenic fragmentation amplify vulnerability to local extirpation. Conservation of P. mcallii requires coordinated binational monitoring, preservation of active dune systems, and ecological corridors to connect climatic refugia and mitigate thermal impacts.