Impacts of thermal limitation on thermoregulatory behaviour and reproductive success in a lizard

2015 ◽  
Vol 63 (4) ◽  
pp. 225 ◽  
Author(s):  
Jennifer E. Halstead ◽  
Lisa E. Schwanz
Keyword(s):  
Reproductive Success ◽  
Thermal Environment ◽  
Thermal Conditions ◽  
Egg Laying ◽  
Warm Climate ◽  
Lethal Temperatures ◽  
Amphibolurus Muricatus ◽  
Thermoregulatory Behaviour ◽  
Insight Into ◽  
Thermal Limitation

Climatic variation can impact populations of ectotherms by altering reproduction, development, and survival. While a warm climate can provide additional thermal opportunities for ectotherms, excessively warm conditions can restrict activity in avoidance of lethal temperatures. However, ectotherms are not necessarily passive to thermal conditions, and often employ flexible thermoregulatory behaviour to accommodate environmental variation. Here, we examine whether the Australian jacky dragon lizard, Amphibolurus muricatus, can compensate for reduced basking opportunity by basking with greater intensity, and how the thermal environment influences reproductive success in females. Overall, there was no compelling evidence for compensatory thermoregulatory behaviour in response to reduced basking opportunity. Moreover, females with reduced thermal opportunities did not produce eggs, although reproductive success was quite low for both groups, so additional factors may have limited reproduction in the colony. This study allows insight into the links between climate and population persistence in wild animals by providing crucial and rare data on how thermal environment impacts reproduction in an egg-laying lizard.

scholarly journals Plasticity of preferred body temperatures as means of coping with climate change?

2011 ◽  
Vol 8 (2) ◽  
pp. 262-265 ◽  
Author(s):  
Lumír Gvoždík
Keyword(s):  
Climate Change ◽  
Adaptive Capacity ◽  
Thermal Environment ◽  
Global Climate ◽  
Thermal Conditions ◽  
Body Temperatures ◽  
Widespread Occurrence ◽  
The Impact ◽  
Thermoregulatory Behaviour

Thermoregulatory behaviour represents an important component of ectotherm non-genetic adaptive capacity that mitigates the impact of ongoing climate change. The buffering role of behavioural thermoregulation has been attributed solely to the ability to maintain near optimal body temperature for sufficiently extended periods under altered thermal conditions. The widespread occurrence of plastic modification of target temperatures that an ectotherm aims to achieve (preferred body temperatures) has been largely overlooked. I argue that plasticity of target temperatures may significantly contribute to an ectotherm's adaptive capacity. Its contribution to population persistence depends on both the effectiveness of acute thermoregulatory adjustments (reactivity) in buffering selection pressures in a changing thermal environment, and the total costs of thermoregulation (i.e. reactivity and plasticity) in a given environment. The direction and magnitude of plastic shifts in preferred body temperatures can be incorporated into mechanistic models, to improve predictions of the impact of global climate change on ectotherm populations.

scholarly journals Behavioural adaptations in egg laying ancestors facilitate evolutionary transitions to live birth

2021 ◽  
Author(s):  
Amanda K. Pettersen ◽  
Nathalie Feiner ◽  
Daniel W.A. Noble ◽  
Geoffrey M. While ◽  
Charlie K. Cornwallis ◽  
...  
Keyword(s):  
Live Birth ◽  
Phylogenetic Analyses ◽  
Thermal Conditions ◽  
Egg Laying ◽  
Significant Feature ◽  
Evolutionary Transitions ◽  
Egg Retention ◽  
Key Innovation ◽  
Gravid Females ◽  
Thermoregulatory Behaviour

AbstractLive birth is a key innovation that has evolved from egg laying over 100 times in reptiles. One significant feature in this transition is the thermal conditions experienced by developing embryos. Adult lizards and snakes often have preferred body temperatures that can be lethal to developing embryos and should prevent egg retention: how has viviparity repeatedly evolved in the face of this pervasive mismatch? Here we resolve this paradox by conducting phylogenetic analyses using data on thermal preference from 224 species. Thermal mismatches between mothers and offspring are widespread but resolved by gravid females behaviourally down-regulating their body temperature towards the thermal optimum of embryos. Importantly, this thermoregulatory behaviour evolved in ancestral egg-laying species before the evolutionary emergence of live birth. Maternal thermoregulatory behaviour therefore bypasses constraints imposed by a slowly evolving thermal physiology and is likely to have been a key requirement for repeated transitions to live birth.

scholarly journals Thermal Condition and Air Quality Investigation in Commercial Airliner Cabins

2021 ◽  
Vol 13 (13) ◽  
pp. 7047
Author(s):  
Nu Yu ◽  
Yao Zhang ◽  
Mengya Zhang ◽  
Haifeng Li
Keyword(s):  
Air Quality ◽  
Occupational Safety ◽  
Thermal Environment ◽  
Thermal Conditions ◽  
Pressure Change ◽  
Health Administration ◽  
Exposure Limit ◽  
Safety And Health ◽  
The Us ◽  
Carbon Dioxide Co2

Cabin air quality and thermal conditions have a direct impact on passenger and flight crew’s health and comfort. In this study, in-cabin thermal environment and particulate matter (PM) exposures were investigated in four China domestic flights. The mean and standard deviation of the in-cabin carbon dioxide (CO2) concentrations in two tested flights are 1440 ± 111 ppm. The measured maximum in-cabin carbon monoxide (CO) concentration is 1.2 ppm, which is under the US Occupational Safety and Health Administration (OSHA) permissible exposure limit of 10 ppm. The tested relative humidity ranges from 13.8% to 67.0% with an average of 31.7%. The cabin pressure change rates at the end of the climbing stages and the beginning of the descending stages are close to 10 hPa·min−1, which might induce the uncomfortable feeling of passengers and crew members. PM mass concentrations were measured on four flights. The results show that PM concentrations decreased after the aircraft cabin door closed and were affected by severe turbulences. The highest in-cabin PM concentrations were observed in the oldest aircraft with an age of 13.2 years, and the waiting phase in this aircraft generated the highest exposures.

Breeding biology of the Critically Endangered Tahiti MonarchPomarea nigra, a bird with a low productivity

2017 ◽  
Vol 28 (4) ◽  
pp. 606-619 ◽  
Author(s):  
CAROLINE BLANVILLAIN ◽  
THOMAS GHESTEMME ◽  
TEHANI WITHERS ◽  
MARK O’BRIEN
Keyword(s):  
Reproductive Success ◽  
French Polynesia ◽  
Egg Laying ◽  
Breeding Biology ◽  
Critically Endangered ◽  
Tropical Island ◽  
Island Endemics ◽  
Nest Activity ◽  
Considerable Length ◽  
One Year

SummaryWe studied the breeding biology of Tahiti MonarchPomarea nigra, a ‘Critically Endangered’ forest bird endemic to Tahiti (French Polynesia). Nest activity was monitored from 1998 to 2002, and again from 2008 to 2015. During these 12 years, only 2–13 breeding pairs per year produced hatchlings. Egg-laying occurred all year, but usually increased between August and January, peaking around November. Of the 200 nests monitored, 33 (16%) were abandoned shortly after construction, 71 had an egg laid immediately after the nest were completed (34 %) and 96 nests (46 %) had a pre-incubation phase of 18.9 ± 1.9 days (3–62 days;n= 47 nests), during which the birds visited the nest on an irregular basis. Half (49 of 96) of these nests were abandoned before an egg was laid, with incubation subsequently commencing at the remaining nests (n= 47). Although both sexes incubated for an average of 13.6 ± 0.3 days (range 13–15), the female usually spent more time incubating than the male. Only one young per nest was ever observed. The average nestling phase was 15.5 ± 0.7 days (range 13 to 20 days). Parents continue to feed the young after fledging for 74 ± 4.7 days (range 42–174). As with many tropical island endemics, the Tahiti Monarch has low reproductive productivity as indicated by the fact that: 1) only 56% of pairs attempt to lay an egg in any one year, 2) most pairs attempt only one brood per year and 3) the considerable length of the nesting and fledging phases. Because of its low productivity, maximising the reproductive success of the Tahiti Monarch is essential to secure its recovery.

Female, but not male, agonistic behaviour is associated with male reproductive success in stable bluebanded goby (Lythrypnus dalli) hierarchies

Behaviour ◽  
2014 ◽  
Vol 151 (10) ◽  
pp. 1367-1387 ◽  
Author(s):  
Tessa K. Solomon-Lane ◽  
Madelyne C. Willis ◽  
Devaleena S. Pradhan ◽  
Matthew S. Grober
Keyword(s):  
Reproductive Success ◽  
Egg Laying ◽  
Dominant Male ◽  
Male Reproductive Success ◽  
Agonistic Behaviour ◽  
Social Species ◽  
Evolution Of Sociality ◽  
Lythrypnus Dalli ◽  
Linear Hierarchies ◽  
Substantial Control

In many social species, there are important connections between social behaviour and reproduction that provide critical insights into the evolution of sociality. In this study, we describe associations between agonistic behaviour and male reproductive success in stable social groups of bluebanded gobies (Lythrypnus dalli). This highly social, sex-changing species forms linear hierarchies of a dominant male and multiple subordinate females. Males reproduce with each female in the harem and care for the eggs. Since aggression tends to be associated with reduced reproduction in social hierarchies, we hypothesized that males in groups with high rates of aggression would fertilise fewer eggs. We also hypothesized that a male’s agonistic behaviour would be associated with his reproductive success. Dominants often exert substantial control over their harem, including control over subordinate reproduction. To address these hypotheses, we quantified egg laying/fertilisation over 13 days and observed agonistic behaviour. We show that there was a significant, negative association between male reproductive success and the total rate agonistic interactions by a group. While no male behaviours were associated with the quantity of eggs fertilised, female agonistic behaviour may be central to male reproductive success. We identified a set of models approximating male reproductive success that included three female behaviours: aggression by the highest-ranking female and approaches by the lowest-ranking female were negatively associated with the quantity of eggs fertilised by males in their groups, but the efficiency with which the middle-ranking female displaced others was positively associated with this measure. These data provide a first step in elucidating the behavioural mechanisms that are associated with L. dalli reproductive success.

scholarly journals Field Study Of A Radiant Heating System For Sleep Thermal Comfort And Potential Energy Saving

2021 ◽  
Author(s):  
Christopher L. K. Wang
Keyword(s):  
Potential Energy ◽  
Thermal Comfort ◽  
Energy Saving ◽  
Energy Savings ◽  
Thermal Environment ◽  
Residential Buildings ◽  
Thermal Conditions ◽  
Heating System ◽  
The Body ◽  
Radiant Temperature

As sleep is unconscious, the traditional definition of thermal comfort with conscious judgment does not apply. In this thesis sleep thermal comfort is defined as the thermal condition which enables sleep to most efficiently rejuvenate the body and mind. A comfort model was developed to stimulate the respective thermal environment required to achieve the desired body thermal conditions and a new infrared sphere method was developed to measure mean radiant temperature. Existing heating conditions according to building code conditions during sleeping hours was calculated to likely overheat a sleeping person and allowed energy saving potential by reducing nighttime heating set points. Experimenting with existing radiantly and forced air heated residential buildings, it was confirmed that thermal environment was too hot for comfortable sleep and that the infrared sphere method shows promise. With the site data, potential energy savings were calculated and around 10% of energy consumption reduction may be achieved during peak heating.

scholarly journals The smell of success: Reproductive success related to rub behavior in brown bears

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0247964
Author(s):  
Andrea T. Morehouse ◽  
Anne E. Loosen ◽  
Tabitha A. Graves ◽  
Mark S. Boyce
Keyword(s):  
Reproductive Success ◽  
Ursus Arctos ◽  
Scent Marking ◽  
Brown Bear ◽  
Parentage Analysis ◽  
Fitness Component ◽  
Brown Bears ◽  
Male And Female ◽  
Rubbing Behavior ◽  
Insight Into

Several species of bears are known to rub deliberately against trees and other objects, but little is known about why bears rub. Patterns in rubbing behavior of male and female brown bears (Ursus arctos) suggest that scent marking via rubbing functions to communicate among potential mates or competitors. Using DNA from bear hairs collected from rub objects in southwestern Alberta from 2011–2014 and existing DNA datasets from Montana and southeastern British Columbia, we determined sex and individual identity of each bear detected. Using these data, we completed a parentage analysis. From the parentage analysis and detection data, we determined the number of offspring, mates, unique rub objects where an individual was detected, and sampling occasions during which an individual was detected for each brown bear identified through our sampling methods. Using a Poisson regression, we found a positive relationship between bear rubbing behavior and reproductive success; both male and female bears with a greater number of mates and a greater number of offspring were detected at more rub objects and during more occasions. Our results suggest a fitness component to bear rubbing, indicate that rubbing is adaptive, and provide insight into a poorly understood behaviour.

Some evidence of a time-varying thermal perception

2021 ◽  
pp. 1420326X2110345
Author(s):  
Marika Vellei ◽  
William O’Brien ◽  
Simon Martinez ◽  
Jérôme Le Dréau
Keyword(s):  
Thermal Comfort ◽  
Energy Savings ◽  
Thermal Environment ◽  
Thermal Conditions ◽  
Time Of Day ◽  
Time Varying ◽  
Thermal Perception ◽  
Indoor Thermal Environment ◽  
Human Circadian Rhythm ◽  
Comfort Criteria

Recent research suggests that a time-varying indoor thermal environment can lead to energy savings and contribute to boost buildings' energy flexibility. However, thermal comfort standardization has so far considered thermal comfort criteria as constant throughout the day. In general, very little attention has been given to the ‘ time of day' variable in the context of thermal comfort research. In this paper, we show some evidence of a time-varying thermal perception by using: (1) data from about 10,000 connected Canadian thermostats made available as part of the ‘ Donate Your Data' dataset and (2) about 22,000 samples of complete (objective + ‘ right-here-right-now' subjective) thermal comfort field data from the ASHRAE I and SCATs datasets. We observe that occupants prefer colder thermal conditions at 14:00 and progressively warmer ones in the rest of the day, indistinctively in the morning and evening. Neutral temperature differences between 08:00 and 14:00 and 14:00 and 20:00 are estimated to be of the order of 2°C. We hypothesize that the human circadian rhythm is the cause of this difference. Nevertheless, the results of this study are only based on observational data. Thermal comfort experiments in controlled environmental chambers are required to confirm these findings and to better elucidate the effects of light and circadian timing and their interaction on thermal perception.

Analysis of the influence of cooling jets on the wind and thermal environment in football stadiums in hot climates

2019 ◽  
Vol 41 (5) ◽  
pp. 561-585 ◽  
Author(s):  
Fangliang Zhong ◽  
John K Calautit ◽  
Ben R Hughes
Keyword(s):  
Energy Consumption ◽  
Thermal Comfort ◽  
Air Conditioning ◽  
Thermal Environment ◽  
Thermal Conditions ◽  
Optimized Design ◽  
Outdoor Temperature ◽  
World Cup ◽  
Wind Environment ◽  
The Spectator

After winning the bid of the FIFA’s World Cup 2022, Qatar is facing the greatest challenges in terms of minimizing substantial energy consumptions for air-conditioning of stadiums and maintaining aero-thermal comfort for both players and spectators inside stadiums. This paper presents the results of temperature distributions and wind environment of the original stadium under the hot-humid climate and improvements on them for optimized scenarios of cooling jets. A combined computational fluid dynamics and building energy simulation approach was used to analyse the cooling performance and energy consumption per match of cooling air jets for 10 scenarios with different supply velocities, supply temperatures and locations of jets. The optimal scenario is to employ vertical jets above the upper tiers at supply temperature of 20°C and velocities of 2–12 m/s, integrated with horizontal jets of the same temperature at the lower tiers with 4 m/s and around the pitch with 7 m/s. This scenario can maintain the spectator tiers at an average temperature of 22°C and reduce the maximum predicted percentage of dissatisfied of thermal comfort from the original 100% to 63% for the pitch and 19% for the tiers, respectively. In terms of the energy consumption for the air-conditioning system per match, compared with one of the 2010 South Africa World Cup stadiums Royal Bafokeng stadium which consumed approximately 22.8 MWh energy for air-conditioning in winter (highest outdoor temperature 24.4°C), the maximum energy consumption of the optimal scenario in November (highest outdoor temperature 34.2°C) can reach 108 MWh. In addition, the spectator zones with scenario 8 have the potential to be resilient to the seasonal change of outdoor temperature if slight modifications of the supply velocities and precise temperature control on the spectator zones are applied. Moreover, the configurations presented in this paper can be used as a foundation of jets arrangement for future stadium retrofits in the hot climates. Practical application: This study assesses the aero-thermal conditions of a case study stadium under the hot climate of Qatar and explores the potential of applying cooling jets with different supply velocities, supply temperatures and their locations on the enhancement of both thermal and wind environment of spectator tiers and pitch. The assessment of the original stadium indicates that the ascending curved roof structure impedes the fresh air entering into the stadium and results in an asymmetric temperature distribution on the spectator tiers. The optimized design suggests a combination of vertical jets under the roof and both three arrays of horizontal jets at lower tiers and around pitch for future stadium optimizations in hot climates. It also recommends enhancing the thermal conditions on the pitch by optimizing the velocity of horizontal jets around the pitch. Moreover, the future design of the exact stadiums to be resilient to the seasonal changing outdoor temperature can be implemented based on scenario 8.

Latrophilin mediates insecticides susceptibility and fecundity through two carboxylesterases, esterase4 and esterase6, in Tribolium castaneum

2019 ◽  
Vol 109 (4) ◽  
pp. 534-543 ◽  
Author(s):  
L. Wei ◽  
S. Gao ◽  
W. Xiong ◽  
J. Liu ◽  
J. Mao ◽  
...  
Keyword(s):  
Tribolium Castaneum ◽  
Molecular Mechanisms ◽  
Vital Role ◽  
Egg Laying ◽  
Egg Hatching ◽  
Compensatory Response ◽  
Physiological Processes ◽  
Similar Phenotype ◽  
G Protein Coupled ◽  
Insight Into

AbstractLatrophilin (LPH) is known as an adhesion G-protein-coupled receptor which involved in multiple physiological processes in organisms. Previous studies showed that lph not only involved the susceptibility to anticholinesterase insecticides but also affected fecundity in Tribolium castaneum. However, its regulatory mechanisms in these biological processes are still not clear. Here, we identified two potential downstream carboxylesterase (cce) genes of Tclph, esterase4 and esterase6, and further characterized their interactions with Tclph. After treatment of T. castaneum larvae with carbofuran or dichlorvos insecticides, the transcript levels of Tcest4 and Tcest6 were significantly induced from 12 to 72 h. RNAi against Tcest4 or Tcest6 led to the higher mortality compared with the controls after the insecticides treatment, suggesting that these two genes play a vital role in detoxification of insecticides in T. castaneum. Furthermore, with insecticides exposure to Tclph knockdown beetles, the expression of Tcest4 was upregulated but Tcest6 was downregulated, indicating that beetles existed a compensatory response against the insecticides. Additionally, RNAi of Tcest6 resulted in 43% reductions in female egg laying and completely inhibited egg hatching, which showed the similar phenotype as that of Tclph knockdown. These results indicated that Tclph affected fecundity by positively regulating Tcest6 expression. Our findings will provide a new insight into the molecular mechanisms of Tclph involved in physiological functions in T. castaneum.

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