Stougaardskaarup1599

Temperature strongly drives physiological and ecological processes in ectotherms. While many species rely on behavioural thermoregulation to avoid thermal extremes, others build structures (nests) that confer a shelter against climate variability and extremes. However, the microclimate inside nests remains unknown for most insects. We investigated the thermal environment inside the nest of a temperate winter-developing insect species, the pine processionary moth (PPM), Thaumetopoea pityocampa. Gregarious larvae collectively build a silken nest at the beginning of the cold season. We tested the hypothesis that it provides a warmer microenvironment to larvae. First, we monitored temperature inside different types of nests varying in the number of larvae inside. Overall, nest temperature was positively correlated to global radiation and air temperature. At noon, when global radiation was maximal, nest temperature exceeded air temperature by up to 11.2-16.5 °C depending on nest type. In addition, thermal gradients of amplitude from 6.85 to 15.5 °C were observed within nests, the upper part being the warmest. Second, we developed a biophysical model to predict temperature inside PPM nests based on heat transfer equations and to explain this important temperature excess. A simple model version accurately predicted experimental measurements, confirming that nest temperature is driven mainly by radiation load. Finally, the model showed that nest temperature increases at the same rate as air temperature change. We conclude that some pest insects already live in warm microclimates by building their own sheltering nest. This effect should be considered when studying the impact of climate change on phenology and distribution.Substantial increases in global temperature are projected for the coming decades due to climate change. Considering that temperature has a strong influence on insect voltinism (i.e., number of generations per year), climate change may affect the population growth of insects, with potential consequences for food production. The southern armyworm, Spodoptera eridania, is a multivoltine species native to the American tropics that causes severe damage to several crops. In this context, this study evaluated the impacts of climate change on the voltinism of S. eridania in southern Brazil. Current and future daily temperature data were combined with non-linear and degree-day models to estimate the voltinism of this pest. Under current climate conditions, the voltinism of S. eridania ranged from 2.9 to 9.2 generations, with fewer cohorts in colder regions and more in warmer ones. A higher number of generations was predicted for the future climate scenarios evaluated, reaching up to 12.1 annual generations in certain regions by 2070. Most of the variation in voltinism was explained by location (87.7%) and by the interaction between location and mathematical model (3.0%). The degree-day model estimated an increase in the number of generations in the entire study area, while the non-linear model predicted a decrease in voltinism in the warmer regions under future climate change scenarios. Given these differences between the predictions provided by degree-day and non-linear models, the selection of the best method to be used in climate change studies should be carried out carefully, considering how species respond to temperature. A considerable increase in the number of generations of S. eridania was projected for most of the study area under the climate change scenarios evaluated, suggesting a possible rise in pest incidence levels in the coming decades.High ambient temperature has potential influence on oxidative stress, or systemic inflammation affecting poultry production and immune status of chickens. Heat stress (HS) induces intestinal inflammation and increases susceptibility of harmful pathogens, such as Salmonella and Escherichia coli. Intestinal inflammation is a common result of body immune dysfunction. Therefore, we designed an experiment to analyze the effects of 35 ± 2 °C HS on salmonella infection in chickens through regulation of the immune responses. 40 broiler chickens were randomly divided into 4 groups control group, heat stress (HS) group, salmonella typhimurium (ST) group and model group (heat stress + salmonella typhimurium, HS + ST). Birds in HS and model group were treated with 35 ± 2 °C heat stress 6 h a day and for 14 continuous days. Then, ST and model group birds were orally administrated with 1 mL ST inoculum (109 cfu/mL). Chickens were sacrificed at the 4th day after ST administration and ileum tissues were measured. We observed that heat stress decreased ileum TNF-α and IL-1β protein expressions. Concomitantly heat stress decreased NLRP3 and Caspase-1 protein levels. The protein expressions of p-NF-κB-p65 and p-IκB-α in ileum. Heat stress also inhibited IFN-α, p-IRF3 and p-TBK1, showing a deficiency in the HS + ST group birds. Together, the present data suggested that heat stress suppressed intestinal immune activity in chickens infected by salmonella typhimurium, as observed by the decrease of immune cytokines levels, which regulated by NF-κB-NLRP3 signaling pathway.The present study was aimed to assess the effect of temperatures on egg incubation, growth, standard metabolic rate (SMR), and thermal tolerance of a near threatened Himalayan hill stream chocolate mahseer (Neolissochilus hexagonolepis). For the hatching study, eggs were incubated in four temperatures (17, 20, 23, and 26 °C). The total hatching and free-swimming larvae percentage were higher at 23 °C (p less then 0.05). Experiment I (for validation of the CTmax method) was carried out by incubating eggs at 17 °C and 23 °C. The CTmax was estimated in response to different warming rates (1-18°C h-1), acclimation temperatures (17 and 23°C), and the age of fishes (8, 15, 35 dph). The results suggested that a warming rate of 18°C h-1 could be used for the thermal tolerance study of yolk-sac larvae (8 dph) and 35 dph larvae, but for free-swimming larvae (15 dph) up to 3°C h-1 is suitable. Experiment II (for growth, SMR and thermal tolerance) was carried by acclimatizing 15 dph larvae in five temperatures (15, 19, 23, 27, and 31 °C) for 60 days. The mean growth rate increased with the increase in temperature from 15°C to 27°C (1.30-3.58% day-1) and decreased at 31°C. The mean SMR of the chocolate mahseer in the above acclimation temperatures was ranged from 1.14 ± 0.36 to 2.81 ± 0.15 μgO2h-1mg-1 and were significantly different (p less then 0.01). The Q10 with the SMR of the fish suggested the preferred temperature ranged between 23 and 27 °C, and the optimum temperature for growth (ToptG) was estimated to be 25 °C. Chocolate mahseer is an eurythermal species which is advantageous for aquaculture practices due to its wide thermal tolerance zone (411.68°C2 in 15 to 31 °C acclimation temperature range) and high ARR values (0.49 - 0.54).The neuroendocrine hormone melatonin and molecular chaperones (heat shock proteins) are evolutionarily conserved molecules that play an important role in protecting organisms from abiotic and biotic stressors. Environmental temperature and seasonality modulates immunity which impacts the overall health of animals. Most studies in relation to thermal stress are based on animals inhabiting temperate zones however, the substantial effect of climatic stress on tropical animals is less explored. Therefore, in this study we focused on the immunosuppressive effect of cold environment on a seasonally breeding tropical rodent and highlighted the importance of melatonin and HSF-1/Hsp-70 in regulating immunity. Animals were exposed to different temperatures with or without melatonin treatment. Our results suggest that, low temperature elicited cold-associated stress in animals marked by reduced body weight, decreased TLC/LC count in the blood and increased corticosterone production which was central to all immune alterations. Cold temperature also increased the oxidative stress which further induced apoptosis in the immune cells and activated stress response molecular chaperones HSF-1/HSP-70. Exogenous melatonin treatment not only ameliorated cold-induced immune suppression but also upregulated the expression of HSF-1 and HSP-70 in the immune cells thereby preventing protein unfolding and cell death. Thus, we conclude that melatonin and molecular chaperones synergistically alleviated immune suppression and could emerge as a promising combination therapy to target temperature stress in animals while boosting immunity.Given the global temperature anomalies observed in recent years, knowing the temperature preferences of ectotherms is very important. Rhapontigenin The purpose of this study was to determine the final preferred temperature (FPT) and the preferred temperature (PT) range in non-acclimated animals in comparison with acclimated animals, as well as with data obtained by the gravitational method using the example of Cladocera Daphnia longispina. For the first time, the FPT in D. longispina was determined by the "acute" and gravitational methods (18.4 and 18.8 ± 1.7 °C, respectively). We showed that it is possible to calculate the PT range from the standard deviations and/or confidence intervals of PT linear regression that cross the line of equality. The range of PT for acclimated D. longispina obtained by the "acute" method was 17.5-19.4 °C and 16-22 °C as calculated by the gravitational method. The ranges of pejus (7-15 and 23-24 °C) and avoided (3-6 and 25-27 °C) temperatures were also determined. The possibility of using the "acute" method for determining FPT in animals selected from natural habitats without prior acclimation has been shown.Although climate warming can increase both mean temperature and its variability, it is often the effects of climate warming on short periods of extreme temperatures that are expected to have particularly large physiological and ecological consequences. Understanding the vulnerability of organisms at various latitudes to climate extremes is thus critical for understanding warming effects on regional biodiversity conservation and ecosystem management. While previous studies have shown that thermal responses depend on temperature regimes that organisms have previously experienced, this issue has not been considered much when comparing the effects of temperature extremes at different latitudes. To fill this gap, here we manipulated different combinations of amplitude and duration of daily high temperature extremes to simulate conditions at different latitudes. We tested the effects of those regimes on life-history traits and fitness of a globally-distributed aphid species, Rhopalosiphum padi. We compared our results with previous studies to better understand the extent to which these regimes affect conclusions based on comparisons under different mean temperatures. As a consequence of asymmetrical thermal performance curves, we hypothesized that the temperature regimes with higher daily maximum temperatures at higher latitudes would cause strong negative effects. Our results showed that these regimes with thermal extremes caused substantial decreases in life-history traits and fitness relative to the predictions from different mean temperatures. Specifically, the regime with higher daily maximum temperature reflecting a higher mid-latitude location had larger impacts on development, reproduction and population fitness than the regime representing a lower mid-latitude location. These findings have implications for understanding the vulnerability of organisms across latitudes to increasingly frequent extreme heat events under ongoing climate warming.