scholarly journals High moon brightness and low ambient temperatures affect sloth predation by harpy eagles

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9756 ◽  
Author(s):  
Everton B.P. de Miranda ◽  
Caio F. Kenup ◽  
Edwin Campbell-Thompson ◽  
Felix H. Vargas ◽  
Angel Muela ◽  
...  
Keyword(s):  
Body Temperature ◽  
Tropical Forests ◽  
Life Histories ◽  
Prey Species ◽  
Core Body Temperature ◽  
Climatic Conditions ◽  
Seasonal Effects ◽  
Top Down ◽  
Predator Prey ◽  
Ambient Temperatures

Background Climate plays a key role in the life histories of tropical vertebrates. However, tropical forests are only weakly seasonal compared with temperate and boreal regions. For species with limited ability to control core body temperature, even mild climatic variation can determine major behavioural outcomes, such as foraging and predator avoidance. In tropical forests, sloths are the arboreal vertebrate attaining the greatest biomass density, but their capacity to regulate body temperature is limited, relying on behavioural adaptations to thermoregulate. Sloths are largely or strictly nocturnal, and depend on crypsis to avoid predation. The harpy eagle (Harpia harpyja) is a sloth-specialist and exerts strong top-down control over its prey species. Yet the role of environmental variables on the regulation of predator–prey interactions between sloths and harpy eagles are unknown. The harpy eagle is considered Near Threatened. This motivated a comprehensive effort to reintroduce this species into parts of Mesoamerica. This effort incidentally enabled us to understand the prey profile of harpy eagles over multiple seasons. Methods Our study was conducted between 2003 and 2009 at Soberanía National Park, Panamá. Telemetered harpy eagles were seen hunting and feeding on individual prey species. For each predation event, field assistants systematically recorded the species killed. We analysed the effects of climatic conditions and vegetation phenology on the prey species profile of harpy eagles using generalised linear mixed models. Results Here we show that sloth predation by harpy eagles was negatively affected by nocturnal ambient light (i.e. bright moonshine) and positively affected by seasonally cool temperatures. We suggest that the first ensured low detectability conditions for sloths foraging at night and the second posed a thermally unsuitable climate that forced sloths to forage under riskier daylight. We showed that even moderate seasonal variation in temperature can influence the relationship between a keystone tropical forest predator and a dominant prey item. Therefore, predator–prey ecology in the tropics can be modulated by subtle changes in environmental conditions. The seasonal effects shown here suggest important demographic consequences for sloths, which are under top-down regulation from harpy eagle predation, perhaps limiting their geographic distribution at higher latitudes.

The population dynamics of bite-sized predators: prey dependence, territoriality, and mobility

2018 ◽  
Author(s):  
Xavier Lambin
Keyword(s):  
Prey Species ◽  
Top Down ◽  
Predator Prey ◽  
Biological Barrier ◽  
Reciprocal Interactions ◽  
Demographic Rates ◽  
Risk Of Predation ◽  
Increased Risk ◽  
Rodent Prey ◽  
Small Mustelids

The dependency of mustelid demographic rates on prey abundance has the potential to cause a strong coupling between predator-prey populations. Data on mustelid dynamics show that such strong reciprocal interactions only materialise in some restricted conditions. Bite-size mustelid predators searching for scarce, depleted prey expose themselves to increased risk of predation by larger predators of small mammal that are themselves searching for similar prey species. As voles or muskrats become scarcer, weasels and mink searching for prey over larger areas become increasingly exposed to intra-guild predation, unless they operate in a habitat refuge such as the sub-nivean space. Where larger predators are sufficiently abundant or exert year-round predation pressure on small mustelids, their impact on mustelids may impose biological barrier to dispersal that are sufficient to weaken the coupling between small mustelids and their rodent prey, and thus impose a degree of top down limitation on mustelids.

Pre-deployment Heat Acclimatization Guidelines for Disaster Responders

2015 ◽  
Vol 31 (1) ◽  
pp. 85-89 ◽  
Author(s):  
Matt B. Brearley
Keyword(s):  
Body Temperature ◽  
Physical Training ◽  
Perceived Exertion ◽  
Core Body Temperature ◽  
Training Session ◽  
Sudden Onset ◽  
Heat Acclimatization ◽  
Publication Type ◽  
Tropical Regions ◽  
Ambient Temperatures

AbstractIntroductionMinimal preparation time is a feature of responding to sudden onset disasters. While equipment and supplies are prepared for deployment at short notice, less is known of the physical preparation of medical responders. With many disaster-prone areas classified as tropical regions, there is potential for responders to endure a combination of high ambient temperatures and relative humidity during deployment. Heat acclimatization, defined as the physiological and perceptual adaptations to frequent elevations of core body temperature (Tc), is a key strategy to improve tolerance of hot conditions by medical responders.MethodsPre-deployment heat acclimatization guidelines were developed based upon the duration of physical training and the subjective rate of perceived exertion (session RPE). An objective of individual training sessions was the perception of body temperature as warm to hot. The guidelines were implemented for Team Bravo (2nd rotation) of the Australian Medical Assistance Team (AusMAT) deployed to Tacloban, Philippines following Typhoon Haiyan in November 2013. The guidelines were distributed electronically five to seven days prior to deployment and were followed by a consultation. A group training session in hot conditions was undertaken prior to departure.ResultsThe AusMAT responders to utilize the guidelines were based in cool or temperate climates that required extra layers of clothing, training during warmer parts of the days, or warm indoor conditions to achieve session objectives. Responders reported the guidelines were simple to use, applicable to their varied training regimens, and had improved their confidence to work in the heat despite not completing the entire 14 day period.ConclusionThe pre-deployment heat acclimatization guidelines provided AusMAT responders the ability to quantify their physical training and promoted physiological adaptations to maximize health, safety, and performance during deployment. While maintaining year-round heat acclimatization is considered essential for medical responders, these guidelines may facilitate beneficial adaptations once notified of deployment.BrearleyMB. Pre-deployment heat acclimatization guidelines for disaster responders. Prehosp Disaster Med. 2016;31(1):85–89.

scholarly journals Cooling Interventions Among Agricultural Workers: A Pilot Study

2020 ◽  
pp. 216507992097652
Author(s):  
Roxana Chicas ◽  
Nezahualcoyotl Xiuhtecutli ◽  
Lisa Elon ◽  
Madeleine K. Scammell ◽  
Kyle Steenland ◽  
...  
Keyword(s):  
Body Temperature ◽  
Core Body Temperature ◽  
Heat Exposure ◽  
The United States ◽  
Agricultural Workers ◽  
Control Group ◽  
Temperature Threshold ◽  
Convenience Sample ◽  
Ambient Temperatures ◽  
Core Body

Background Adverse health effects among agricultural workers due to chronic heat exposure have been characterized in the literature as not only due to high ambient temperatures but also due to intensive manual labor in hot and humid conditions. The aim of this study was to use biomonitoring equipment to examine the effectiveness of selected cooling devices at preventing agricultural workers from exceeding the core body temperature threshold of 38.0°C (Tc38) and attenuating heat-related illness symptoms. Methods A convenience sample of 84 agricultural workers in Florida was randomized to one of four groups: (a) no intervention, clothing as usual; (b) cooling bandana; (c) cooling vest; and (d) both the cooling bandana and cooling vest. Biomonitoring equipment worn by the participants included core body temperature monitor and an accelerometer to capture physical activity. Findings A total of 78 agricultural workers completed one intervention workday trial. Compared with the control group, the bandana group had lower odds of exceeding Tc38 (odds ratio [OR] = 0.7, 90% confidence interval [CI] = [0.2, 3.2]) and the vest group had higher odds of exceeding Tc38 (OR = 1.8, 90% CI = [0.4, 7.9]). The simultaneous use of cooling vest and bandana showed an effect little different from the control group (OR = 1.3, 90% CI = [0.3, 5.6]). Conclusion/Application to Practice This is the first field-based study to examine cooling intervention among agricultural workers in the United States using biomonitoring equipment. This study found that using a bandana while working in a hot agricultural environment has the potential to be protective against exceeding the recommended Tc38 threshold.

scholarly journals Combined stimuli of cold, hypoxia, and dehydration status on body temperature in rats: a pilot study with practical implications for humans

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Tadashi Uno ◽  
Tatsuya Hasegawa ◽  
Masahiro Horiuchi
Keyword(s):  
Body Temperature ◽  
Environmental Conditions ◽  
Multiple Stressors ◽  
Core Body Temperature ◽  
Area Under The Curve ◽  
Ambient Temperatures ◽  
Hypoxic Conditions ◽  
Loss Index ◽  
Core Body ◽  
Heat Loss Index

Abstract Objective As human thermoregulatory responses to maintain core body temperature (Tcore) under multiple stressors such as cold, hypoxia, and dehydration (e.g., exposure to high-altitude) are varied, the combined effects of cold, hypoxia, and dehydration status on Tcore in rats were investigated. The following environmental conditions were constructed: (1) thermoneutral (24 °C) or cold (10 °C), (2) normoxia (21% O2) or hypoxia (12% O2), and (3) euhydration or dehydration (48 h water deprivation), resulted in eight environmental conditions [2 ambient temperatures (Ta) × 2 oxygen levels × 2 hydration statuses)]. Each condition lasted for 24 h. Results Normoxic conditions irrespective of hypoxia or dehydration did not strongly decrease the area under the curve (AUC) in Tcore during the 24 period, whereas, hypoxic conditions caused greater decreases in the AUC in Tcore, which was accentuated with cold and dehydration (Ta × O2 × hydration, P = 0.040 by three-way ANOVA). In contrast, multiple stressors (Ta × O2 × hydration or Ta × O2 or O2 × hydration or Ta × hydration) did not affect locomotor activity counts (all P > 0.05), but a significant simple main effect for O2 and Ta was observed (P < 0.001). Heat loss index was not affected by all environmental conditions (all P > 0.05). In conclusion, decreases in Tcore were most affected by multiple environmental stressors such as cold, hypoxia, and dehydration.

Effects of 6-hydroxydopamine and pimozide on temperature maintenance by the chicken

1980 ◽  
Vol 239 (3) ◽  
pp. R296-R302
Author(s):  
D. L. Rowe-Murphy ◽  
A. van Tienhoven ◽  
N. R. Scott ◽  
P. E. Hillman ◽  
C. L. Wood ◽  
...  
Keyword(s):  
Body Temperature ◽  
Core Body Temperature ◽  
Control Treatment ◽  
Noradrenergic System ◽  
Ambient Temperatures ◽  
Drug Treatments ◽  
Lower Maximum ◽  
6 Hydroxydopamine ◽  
Core Body

Intraventricular implants of pimozide in adult white leghorn hens were used to block dopamine (DA) receptors, and 6-hydroxydopamine (6-OHDA) was injected intraventricularly to destroy the noradrenergic system locally. The hens were exposed to ambient temperatures of 5 and 35 degrees C, and their core temperature was measured. One hundred micrograms of 6-OHDA significantly reduced the norepinephrine (NE) but not the DA content of the hypothalamus and reduced the uptake of [3H]NE but not of [3H]DA by synaptosomes in vitro. Neither of the drug treatments nor their combination affected average core body temperature (Tb) at either 5 or 35 degrees C. Pimozide treatment caused a lower maximum Tb at 35 degrees C and a higher maximum Tb at 5 degrees C than the control treatment. No evidence was obtained that 6-OHDA treatment affected body temperature regulation. It is concluded that neither the DA nor the NE system is essential for normal temperature maintenance in the hen exposed to either 5 or 35 degrees C.

scholarly journals Temperature gradients in trailers and changes in broiler rectal and core body temperature during winter transportation in Saskatchewan

2010 ◽  
Vol 90 (3) ◽  
pp. 321-330 ◽  
Author(s):  
T D Knezacek ◽  
A A Olkowski ◽  
P J Kettlewell ◽  
M A Mitchell ◽  
H L Classen
Keyword(s):  
Body Temperature ◽  
Core Body Temperature ◽  
Cold Weather ◽  
Heterogeneous Distribution ◽  
Ambient Temperatures ◽  
Temperature Recording ◽  
Data Loggers ◽  
Before And After ◽  
Transportation Times ◽  
Core Body

Temperature conditions inside commercial trailers transporting market-age broilers during four winter journeys were measured, and changes in the rectal and core body temperature of birds were quantified. Pre-selected modules were equipped with data loggers recording temperature every 72 s. Rectal temperatures were taken from eight birds in each of four modules immediately before and after each trip, and two or three birds, with temperature recording implants, were placed in each of two selected modules. Temperature heterogeneity was found among modules on all loads with average crate temperatures ranging from 10.9 to 30.7, 8.9 to 28.1, 2.5 to 26.1 and -0.7 to 16.5°C for transportation times of 191, 193, 178 and 18 min and ambient temperatures of -7.1, -27.1, -28.2 and -18.4°C, respectively. Wet birds, condensation and frost provided evidence for moisture accumulation during transportation. Body temperature recordings indicated the potential for the development of both hypothermia and hyperthermia, showing that cold stress can occur near air inlets and heat stress in poorly ventilated areas. Passive ventilation inside trailers resulted in crate temperatures 17.7 to 55.2°C above outside temperature. Mortality ranged from 0.7 to 1.4% but several deaths occurred during lairage, prior to processing. A heterogeneous distribution of airflow resulted in undesirable temperate and humidity conditions for some birds. Key words: Broiler, transportation, temperature gradient, mortality, cold weather

Core body temperature is not a valid parameter to follow the reproductive cycle in female marmoset monkey (Callithrix jacchus)

2013 ◽  
Vol 121 (10) ◽  
Author(s):  
K Hoffmann ◽  
J König ◽  
K Eildermann ◽  
E Fuchs ◽  
R Behr ◽  
...  
Keyword(s):  
Body Temperature ◽  
Reproductive Cycle ◽  
Core Body Temperature ◽  
Callithrix Jacchus ◽  
Marmoset Monkey ◽  
Core Body

Core body temperature changes after sauna exposition in healthy subjects

2012 ◽  
Vol 26 (2) ◽  
Author(s):  
Joanna Pawlak ◽  
Paweł Zalewski ◽  
Jacek J. Klawe ◽  
Monika Zawadka ◽  
Anna Bitner ◽  
...  
Keyword(s):  
Body Temperature ◽  
Healthy Subjects ◽  
Core Body Temperature ◽  
Temperature Changes ◽  
Core Body
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