Ecological constraints to match field and preferred temperatures in lizards Tropidurus catalanensis (Squamata; Tropiduridae).

We compared microhabitat and body temperatures in the field with thermal preferences of Tropidurus catalanensis to investigate if they match or diverge as demonstration respectively of suitability or poor-quality of the thermal environment. As T. catalanensis is subjected to variable thermal conditions along its distribution and may be jeopardized by the climate change, we measured its thermal preferences after exposure to milder (17 °C-27 °C) and warmer (22 °C-32 °C) thermal conditions to evaluate acclimatory responses and tolerances and vulnerabilities to warming. Field body temperatures tended to be similar to minimum preferred body temperatures, and microhabitat and body temperatures in the field were cooler in the remaining comparisons with thermal preferences [preferred (Tpref), set-point range (Tset), minimum preferred (Tpref_min) and maximum preferred (Tpref_max) body temperatures], suggesting there was a constraint to warming up in nature. The minimum preferred body temperatures may be a threshold separating proper functioning from markedly noxious impacts due to progressive impairment by the cooling. Difficulties to warm and keep suitable body temperatures may jeopardize overall ecophysiological and behavioral processes with implications for maintenance, fitness, and survival. The constraints to warm may impact T. catalanensis differently depending on its body size and its properties of heat conservation (thermal inertia). Smaller and larger T. catalanensis may respectively cool down easier and have difficulties to warm up, being jeopardized by the constraints due to the cold. The warmer preferred body temperatures coupled with the cooler microhabitats and bodies in nature complicate to anticipate how individuals will respond to climate change, but the acclimation to the warmer temperatures led six of them to death, suggesting they had limited tolerance to heat and would be vulnerable to global warming.

Development of a Bayesian based adaptive optimisation algorithm for the thermostat settings in agile open plan offices.

The development of a Bayesian based adaptive optimisation algorithm for optimising the indoor thermostat settings in a large agile open plan office is presented. Occupant expressions of thermal dissatisfaction and indoor environmental conditions were collected using densely-placed devices over a period of approximately 19 months. A logistic regression model was employed to identify the optimal settings, using regression coefficients that were estimated using Bayesian inference. A series of optimisation scenarios with and without considering the temporal variations of occupant thermal preferences and the spatial deviation of the indoor conditions was designed and implemented to evaluate their potential benefit in terms of overall occupant thermal dissatisfaction reduction. We developed two metrics that were tailored to quantify the overall reduction of thermal dissatisfaction when using optimal air temperature and PMV thermostat settings. These two metrics represented the average reduction of overall indoor thermal dissatisfaction each time a thermostat value was updated. The results showed that it was useful to consider the temporal variations of occupant thermal preferences to reduce the overall occupant thermal dissatisfaction in the office, and that using the same approach on individual zones within the open plan office would lead to further improvements. The case study demonstrated that the optimal adaptive temperature and PMV thermostat settings led to an overall thermal dissatisfaction reduction of 1.47% and 1.21% in the whole office, respectively (as opposed to 0.25% and 0.19% when single fixed temperature-based and PMV-based thermostat settings were used). By applying the proposed adaptive optimisation algorithm on individual zones in the office, the occupant thermal dissatisfaction reductions ranged from 0.88% to 5.17% for PMV-based settings, and from 1.20% to 5.19% for temperature-based settings.

Exploring the effects of warming seas by using the optimal and pejus temperatures of the embryo of three Octopoda species in the Gulf of Mexico.

Using data related to thermal optimal and pejus of the embryos of Octopus americanus from Brazil and O. insularis and O. maya from Mexico, this study aimed to project the potential distribution areas in the Gulf of Mexico and predict distribution shifts under different Representative Concentration Pathway scenarios (RCP 6 and 8.5) for the years 2050 and 2100. The different thermal tolerances elicited different responses to current and future scenarios. In this sense, O. insularis and O. maya thermal niches stretch from the Caribbean to Florida. Nevertheless, O. insularis may inhabit warmer areas than O. maya. Surprisingly, no area was considered thermally habitable for O. americanus, which could have been associated with the use of data of populations thermally adapted to temperate conditions south of Brazil. According to models, a warming scenario would cause a restriction of the available thermal niche of O. maya, while O. insularis could expand under RCP 6 scenarios. This restriction was more substantial in the RCP 8.5 scenario. Nevertheless, under the RCP 8.5 scenario, the temperature in 2100 may negatively affect even O. insularis, the species most thermal tolerant. If our results are accurate, the fishing yield of O. insularis will increase in the future, replacing the heavily exploited O. maya in the coasts of the southern Gulf of Mexico. Regarding O. americanus, no inference might be made until thermal tolerances of locally adapted populations can be studied.

Thermal preferences of bird schistosome snail hosts increase the risk of swimmer's itch.

Ambient temperature strongly affects host parasite interactions, especially when both are ectothermic. Bird schistosomes, which cercariae are known as agents of swimmer's itch and their snail hosts can be a good example of this phenomenon. The snails of these parasites play the key role, as the source of harmful larvae. Cercarial dermatitis is noted even in areas when prevalence of parasites in snail populations is very low. The main question is what adaptation in snail-fluke association can lead to a sufficient number of cercariae causing swimmer's itch in lake water? The influence of ambient temperature on snail survival and cercarial production as well as the thermal preferences of two host species naturally infected with bird schistosomes were studied. The 24-h preferences of Lymnaea stagnalis infected with Trichobilharzia szidati, and Planorbarius corneus infected with Bilharziella polonica were recorded using an oblong thermal gradient set (OTGS). Both cercariae releasing hosts of bird schistosomes preferred a significantly lower temperature than non-infected snails. Additionally, at a higher temperature, the survival of snail hosts was shortened as a result of the increase in daily cercarial expulsion. An especially interesting result concerns the release of a significantly larger total cercariae number by L. stagnalis at lower than at higher temperatures. These data indicate that preferences of infected snails to low temperature microhabitats can increase host survival and parasite success, as well as affecting the increase in the number of invasive larvae in the environment increasing the risk of swimmer's itch.

Adaptive seasonal shifts in the thermal preferences of the lizard Iberolacerta galani (Squamata, Lacertidae).

The León rock lizard, Iberolacerta galani, lives in isolated mountains of Spain. We studied the seasonal changes in the thermal biology of I. galani between spring and summer. We calculated precision, accuracy and effectiveness of thermoregulation and the habitat thermal quality for spring, and compared with the values of summer. In addition, we studied how the shift in the thermal preferences of lizards would contribute to achieve a higher effectiveness of thermoregulation. Thermal preferences of León rock lizards are among the lowest in lacertids, and are also very narrow, maintaining the narrowness among seasons. As for summer (27.90-29.70°C, mean value =28.76°C), the thermal preferences of I. galani are also low in spring (29.60-31.10°C, mean value =30.38°C), supporting the idea that this species is adapted to cold environments. The habitat thermal quality is lower in spring (10.99°C) than in summer (9.36°C), while the effectiveness of thermoregulation is higher in spring (0.92) than in summer (0.80). We found that the seasonal shift in thermal preferences contributes significantly to enhance the effectiveness of thermoregulation in both seasons, more in spring (0.45°C) than in summer (0.16°C). Because I. galani inhabits isolated mountains, where the activity period is reduced from April to October, we hypothesize that the observed adaptation of the thermal preferences, which enhance thermoregulation to a larger extent in spring, may evolved to maximize performance during the reproductive season.

Comparative energetics and thermal responses to feeding in allied Agkistrodon snakes with contrasting diet and habitat use.

Variation in animal responses to feeding can be attributed to a variety of ecological factors, including foraging mode and dietary specialization. Specialization often favors species that have traits for exploiting food resources that are rare and that are not commonly shared by dietary generalists. We investigated physiological and behavioral responses to feeding between two snake species with different degrees of mammal feeding specialization: Agkistrodon contortrix (copperheads; a terrestrial species in which adults feed almost exclusively on mammals) and Agkistrodon piscivorus (cottonmouths; a semi-aquatic species feeding less on mammals and primarily on ectothermic prey). We measured metabolic rates (at 20, 25, and 30 °C) and body temperature (Tb) selection of snakes both pre- and post-feeding. Following the consumption of rodent meals, post-feeding energy use was higher in A. piscivorus than A. contortrix at both 25 and 30 °C. After feeding, A. piscivorus maintained body temperatures that were 3-4 °C higher, whereas A. contortrix remained within 1 °C of their pre-feeding Tb. Our results support the contention that dietary specialization leads to potential energetic advantages and that generalist species may change their behavior to offset energy used to digest prey.

The underestimated role of temperature-oxygen relationship in large-scale studies on size-to-temperature response.

The observation that ectotherm size decreases with increasing temperature (temperature-size rule; TSR) has been widely supported. This phenomenon intrigues researchers because neither its adaptive role nor the conditions under which it is realized are well defined. In light of recent theoretical and empirical studies, oxygen availability is an important candidate for understanding the adaptive role behind TSR. However, this hypothesis is still undervalued in TSR studies at the geographical level. We reanalyzed previously published data about the TSR pattern in diatoms sampled from Icelandic geothermal streams, which concluded that diatoms were an exception to the TSR. Our goal was to incorporate oxygen as a factor in the analysis and to examine whether this approach would change the results. Specifically, we expected that the strength of size response to cold temperatures would be different than the strength of response to hot temperatures, where the oxygen limitation is strongest. By conducting a regression analysis for size response at the community level, we found that diatoms from cold, well-oxygenated streams showed no size-to-temperature response, those from intermediate temperature and oxygen conditions showed reverse TSR, and diatoms from warm, poorly oxygenated streams showed significant TSR. We also distinguished the roles of oxygen and nutrition in TSR. Oxygen is a driving factor, while nutrition is an important factor that should be controlled for. Our results show that if the geographical or global patterns of TSR are to be understood, oxygen should be included in the studies. This argument is important especially for predicting the size response of ectotherms facing climate warming.

Occurrence data may provide unreliable thermal preferences and breadth of species.

Accurate information on the thermal preference and specialization of species is needed to understand and predict species geographical range size and vulnerability to climate change. Here we estimate the position and breadth of species within thermal gradients based on the shape of the response curve of species abundance to temperature. The objective of the study is to compare the measurements of this approach based on abundance data with those of the classical approach using species' occurrence data. The relationship between species' relative abundance and minimum winter temperature of 106 bird species wintering in the Iberian Peninsula is modeled at 100 Km2 resolution with quadratic logistic regressions. From these models we calculated the preferred temperature of species as the temperature at which the abundance is maximized, and the thermal breadth of species as the relative area under the temperature-abundance curve. We also estimated the thermal preferences and breadth of species as the average temperature and temperature range of the UTM cells in which the species are present. The abundance-temperature response curves reveal that birds prefer higher temperatures to overwinter, and are more thermally selective, than is measured by the classical approach. Moreover, response curves detect a higher inter-specific variability in both thermal preferences and thermal breadth of species. As occurrence data gives the same weight to cells with one or many individuals, the average temperature of the cells in which the species is present roughly reflects the average temperature in the region of study and not the environmental preferences of species.