scholarly journals Comparison of Static and Dynamic Assays When Quantifying Thermal Plasticity of Drosophilids

Insects ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 537
Author(s):  
Christian Winther Bak ◽  
Simon Bahrndorff ◽  
Natasja Krog Noer ◽  
Lisa Bjerregaard Jørgensen ◽  
Johannes Overgaard ◽  
...  
Keyword(s):  
Critical Temperature ◽  
Constant Temperature ◽  
Heat Tolerance ◽  
Thermal Tolerance ◽  
Physiological Trait ◽  
Thermal Plasticity ◽  
Heat Hardening ◽  
Temperature Interaction ◽  
Dynamic Assay ◽  
Species Specific

Numerous assays are used to quantify thermal tolerance of arthropods including dynamic ramping and static knockdown assays. The dynamic assay measures a critical temperature while the animal is gradually heated, whereas the static assay measures the time to knockdown at a constant temperature. Previous studies indicate that heat tolerance measured by both assays can be reconciled using the time × temperature interaction from “thermal tolerance landscapes” (TTLs) in unhardened animals. To investigate if this relationship remains true within hardened animals, we use a static assay to assess the effect of heat hardening treatments on heat tolerance in 10 Drosophila species. Using this TTL approach and data from the static heat knockdown experiments, we model the expected change in dynamic heat knockdown temperature (CTmax: temperature at which flies enter coma) and compare these predictions to empirical measurements of CTmax. We find that heat tolerance and hardening capacity are highly species specific and that the two assays report similar and consistent responses to heat hardening. Tested assays are therefore likely to measure the same underlying physiological trait and provide directly comparable estimates of heat tolerance. Regardless of this compliance, we discuss why and when static or dynamic assays may be more appropriate to investigate ectotherm heat tolerance.

scholarly journals Limited plasticity in thermally tolerant ectotherm populations: evidence for a trade-off

2021 ◽  
Vol 288 (1958) ◽  
pp. 20210765
Author(s):  
Jordanna M. Barley ◽  
Brian S. Cheng ◽  
Matthew Sasaki ◽  
Sarah Gignoux-Wolfsohn ◽  
Cynthia G. Hays ◽  
...  
Keyword(s):  
Climate Change ◽  
Heat Tolerance ◽  
Thermal Tolerance ◽  
Meta Analysis ◽  
Strong Support ◽  
Thermal Acclimation ◽  
Species Variation ◽  
Trade Off ◽  
Temperature Changes ◽  
Thermal Plasticity

Many species face extinction risks owing to climate change, and there is an urgent need to identify which species' populations will be most vulnerable. Plasticity in heat tolerance, which includes acclimation or hardening, occurs when prior exposure to a warmer temperature changes an organism's upper thermal limit. The capacity for thermal acclimation could provide protection against warming, but prior work has found few generalizable patterns to explain variation in this trait. Here, we report the results of, to our knowledge, the first meta-analysis to examine within-species variation in thermal plasticity, using results from 20 studies (19 species) that quantified thermal acclimation capacities across 78 populations. We used meta-regression to evaluate two leading hypotheses. The climate variability hypothesis predicts that populations from more thermally variable habitats will have greater plasticity, while the trade-off hypothesis predicts that populations with the lowest heat tolerance will have the greatest plasticity. Our analysis indicates strong support for the trade-off hypothesis because populations with greater thermal tolerance had reduced plasticity. These results advance our understanding of variation in populations' susceptibility to climate change and imply that populations with the highest thermal tolerance may have limited phenotypic plasticity to adjust to ongoing climate warming.

scholarly journals Using naturally occurring climate resilient corals to construct bleaching-resistant nurseries

2019 ◽  
Vol 116 (21) ◽  
pp. 10586-10591 ◽  
Author(s):  
Megan K. Morikawa ◽  
Stephen R. Palumbi
Keyword(s):  
Heat Tolerance ◽  
Thermal Tolerance ◽  
American Samoa ◽  
Bleaching Event ◽  
Lower Growth ◽  
Experimental Heat ◽  
Naturally Occurring ◽  
Nursery Stock ◽  
Heat Tolerant ◽  
Species Specific

Ecological restoration of forests, meadows, reefs, or other foundational ecosystems during climate change depends on the discovery and use of individuals able to withstand future conditions. For coral reefs, climate-tolerant corals might not remain tolerant in different environments because of widespread environmental adjustment of coral physiology and symbionts. Here, we test if parent corals retain their heat tolerance in nursery settings, if simple proxies predict successful colonies, and if heat-tolerant corals suffer lower growth or survival in normal settings. Before the 2015 natural bleaching event in American Samoa, we set out 800 coral fragments from 80 colonies of four species selected by prior tests to have a range of intraspecific natural heat tolerance. After the event, nursery stock from heat-tolerant parents showed two to three times less bleaching across species than nursery stock from less tolerant parents. They also retained higher individual genetic diversity through the bleaching event than did less heat-tolerant corals. The three best proxies for thermal tolerance were response to experimental heat stress, location on the reef, and thermal microclimate. Molecular biomarkers were also predictive but were highly species specific. Colony genotype and symbiont genus played a similarly strong role in predicting bleaching. Combined, our results show that selecting for host and symbiont resilience produced a multispecies coral nursery that withstood multiple bleaching events, that proxies for thermal tolerance in restoration can work across species and be inexpensive, and that different coral clones within species reacted very differently to bleaching.

scholarly journals Rapid induction of the heat hardening response in an Arctic insect

2019 ◽  
Vol 15 (10) ◽  
pp. 20190613 ◽  
Author(s):  
Mathias Hamann Sørensen ◽  
Torsten Nygaard Kristensen ◽  
Jannik Mørk Skovgaard Lauritzen ◽  
Natasja Krog Noer ◽  
Toke Thomas Høye ◽  
...  
Keyword(s):  
Heat Tolerance ◽  
Climate Changes ◽  
Extreme Temperature ◽  
Short Term ◽  
Rapid Induction ◽  
Thermal Plasticity ◽  
Thermal Maximum ◽  
Short Term Exposure ◽  
Heat Hardening ◽  
Increase Heat Resistance

The ability to cope with increasing and more variable temperatures, due to predicted climate changes, through plastic and/or evolutionary responses will be crucial for the persistence of Arctic species. Here, we investigate plasticity of heat tolerance of the Greenlandic seed bug Nysius groenlandicus, which inhabits areas with widely fluctuating temperatures. We test the heat tolerance and hardening capacity (plasticity) of N. groenlandicus using both static (heat knock down time, HKDT) and dynamic (critical thermal maximum, CT max ) assays. We find that N. groenlandicus is able to tolerate short-term exposure to temperatures up to almost 50°C and that it can quickly increase heat resistance following heat hardening. Furthermore, we find that this hardening response is reversible within hours after hardening. These findings contrast with common observations from temperate and tropical insects and suggest high thermal plasticity in some Arctic insects which enables them to cope with extreme temperature variability in their habitats.

Membrane lipid metabolism, heat shock response, and energy costs mediate the interaction between acclimatization and heat hardening response

2021 ◽  
Author(s):  
Wenyi Zhang ◽  
Yunwei Dong
Keyword(s):  
Thermal Stress ◽  
Lipid Metabolism ◽  
Heat Shock ◽  
Thermal Tolerance ◽  
Global Climate ◽  
Membrane Lipid ◽  
Maximum Temperature ◽  
Energy Costs ◽  
Thermal Plasticity ◽  
Heat Hardening

Thermal plasticity on different timescales, including acclimation/acclimatization and heat hardening response – a rapid adjustment for thermal tolerance after nonlethal thermal stress, can interact to improve the resilience of organisms to thermal stress. However, little is known about physiological mechanisms mediating this interaction. To investigate underpinnings of heat hardening responses after acclimatization in warm seasons, we measured thermal tolerance plasticity, compared transcriptomic and metabolomic changes after heat hardening at 33 or 37oC followed by recovery of 3 h or 24 h in an intertidal bivalve Sinonovacula constricta. Clams showed explicit heat hardening responses after acclimatization in a warm season. The higher inducing temperature (37oC) caused less effective heat hardening effects than the inducing temperature that was closer to the seasonal maximum temperature (33oC). Metabolomic analysis highlighted the elevated contents of glyceropholipids in all heat-hardened clams, which may help to maintain the structure and function of the membrane. Heat shock proteins (HSPs) tended to be up-regulated after heat hardening at 37oC but not at 33oC, indicating that there was no complete dependency of heat hardening effects on up-regulated HSPs. Enhanced energy metabolism and decreased energy reserves were observed after heat hardening at 37oC, suggesting more energy costs during exposure to a higher inducing temperature which may restrict heat hardening effects. These results highlighted the mediating role of membrane lipid metabolism, heat shock responses, and energy costs in the interaction between heat hardening response and seasonal acclimatization, and benefit the mechanistic understanding of evolutionary change and thermal plasticity during global climate change.

scholarly journals Interactions between developmental and adult acclimation have distinct consequences for heat-tolerance and heat-stress recovery

2021 ◽  
Author(s):  
Quentin Willot ◽  
Ben Loos ◽  
John S. Terblanche
Keyword(s):  
Heat Stress ◽  
Heat Tolerance ◽  
Thermal Tolerance ◽  
Climatic Conditions ◽  
Distinct Pattern ◽  
Recovery Rates ◽  
Relative Contribution ◽  
Heat Hardening ◽  
Full Factorial Experimental Design ◽  
Post Stress

Developmental and adult thermal acclimation can have distinct, even opposite, effects on adult heat resistance in ectotherms. Yet, their relative contribution to heat-hardiness of ectotherms remains unclear despite the broad ecological implications thereof. Furthermore, the deterministic relationship between heat-knockdown and recovery from heat stress is poorly understood but significant for establishing causal links between climate variability and population dynamics. Here, using D. melanogaster in a full-factorial experimental design, we assess flies heat-tolerance in static stress assays, and document how developmental and adult acclimation interact with a distinct pattern to promote survival to heat-stress in adults. We show that warmer adult acclimation is the initial factor enhancing survival to constant stressful high temperatures in flies, but also that the interaction between adult and developmental acclimation becomes gradually more important to ensure survival as the stress persists. This provides an important framework revealing the dynamic interplay between these two forms of acclimation, that ultimately enhance thermal tolerance as a function of stress duration. Furthermore, by investigating recovery rates post-stress, we also show that the process of heat-hardening and recovery post heat knockdown are likely to be based on set of (at least partially) divergent mechanisms. This could bear ecological significance as a tradeoff may exist between increasing thermal tolerance and maximizing recovery rates post-stress, constraining population responses when exposed to variable and stressful climatic conditions.

scholarly journals Basal tolerance to heat and cold exposure of the spotted wing drosophila,Drosophila suzukii

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3112 ◽  
Author(s):  
Thomas Enriquez ◽  
Hervé Colinet
Keyword(s):  
High Temperatures ◽  
Heat Tolerance ◽  
Thermal Tolerance ◽  
Abiotic Factors ◽  
Methodological Approach ◽  
Spotted Wing Drosophila ◽  
Basic Knowledge ◽  
Drosophila Suzukii ◽  
Cold Tolerant ◽  
C 30

The spotted wing Drosophila,Drosophila suzukii, is a new pest in Europe and America which causes severe damages, mostly to stone fruit crops. Temperature and humidity are among the most important abiotic factors governing insect development and fitness. In many situations, temperature can become stressful thus compromising survival. The ability to cope with thermal stress depends on basal level of thermal tolerance. Basic knowledge on temperature-dependent mortality ofD. suzukiiis essential to facilitate management of this pest. The objective of the present study was to investigateD. suzukiibasal cold and heat tolerance. Adults and pupae were subjected to six low temperatures (−5–7.5 °C) and seven high temperatures (30–37 °C) for various durations, and survival-time-temperature relationships were investigated. Data showed that males were globally more cold tolerant than females. At temperature above 5 °C, adult cold mortality became minor even after prolonged exposures (e.g., only 20% mortality after one month at 7.5 °C). Heat tolerance of males was lower than that of females at the highest tested temperatures (34, 35 and 37 °C). Pupae appeared much less cold tolerant than adults at all temperatures (e.g., Lt50at 5° C: 4–5 d for adultsvs.21 h for pupae). Pupae were more heat tolerant than adults at the most extreme high temperatures (e.g., Lt50at 37 °C: 30 min for adultsvs.4 h for pupae). The pupal thermal tolerance was further investigated under lowvs.high humidity. Low relative humidity did not affect pupal cold survival, but it reduced survival under heat stress. Overall, this study shows that survival ofD. suzukiiunder heat and cold conditions can vary with stress intensity, duration, humidity, sex and stage, and the methodological approach used here, which was based on thermal tolerance landscapes, provides a comprehensive description ofD. suzukiithermal tolerance and limits.

scholarly journals Thermal tolerance patterns across latitude and elevation

2019 ◽  
Vol 374 (1778) ◽  
pp. 20190036 ◽  
Author(s):  
Jennifer Sunday ◽  
Joanne M. Bennett ◽  
Piero Calosi ◽  
Susana Clusella-Trullas ◽  
Sarah Gravel ◽  
...  
Keyword(s):  
Cold Tolerance ◽  
Heat Tolerance ◽  
Thermal Tolerance ◽  
Large Scale ◽  
Global Climate ◽  
Climate Extremes ◽  
Species Traits ◽  
Acclimation Temperature ◽  
Tolerance Limits ◽  
Thermal Limits

Linking variation in species' traits to large-scale environmental gradients can lend insight into the evolutionary processes that have shaped functional diversity and future responses to environmental change. Here, we ask how heat and cold tolerance vary as a function of latitude, elevation and climate extremes, using an extensive global dataset of ectotherm and endotherm thermal tolerance limits, while accounting for methodological variation in acclimation temperature, ramping rate and duration of exposure among studies. We show that previously reported relationships between thermal limits and latitude in ectotherms are robust to variation in methods. Heat tolerance of terrestrial ectotherms declined marginally towards higher latitudes and did not vary with elevation, whereas heat tolerance of freshwater and marine ectotherms declined more steeply with latitude. By contrast, cold tolerance limits declined steeply with latitude in marine, intertidal, freshwater and terrestrial ectotherms, and towards higher elevations on land. In all realms, both upper and lower thermal tolerance limits increased with extreme daily temperature, suggesting that different experienced climate extremes across realms explain the patterns, as predicted under the Climate Extremes Hypothesis . Statistically accounting for methodological variation in acclimation temperature, ramping rate and exposure duration improved model fits, and increased slopes with extreme ambient temperature. Our results suggest that fundamentally different patterns of thermal limits found among the earth's realms may be largely explained by differences in episodic thermal extremes among realms, updating global macrophysiological ‘rules’. This article is part of the theme issue ‘Physiological diversity, biodiversity patterns and global climate change: testing key hypotheses involving temperature and oxygen’.

Species-specific differences in thermal tolerance may define susceptibility to intracellular acidosis in reef corals

2015 ◽  
Vol 162 (3) ◽  
pp. 717-723 ◽  
Author(s):  
Emma M. Gibbin ◽  
Hollie M. Putnam ◽  
Ruth D. Gates ◽  
Matthew R. Nitschke ◽  
Simon K. Davy
Keyword(s):  
Thermal Tolerance ◽  
Intracellular Acidosis ◽  
Reef Corals ◽  
Species Specific

Acute exposure to sublethal doses of neonicotinoid insecticides increases heat tolerance in honey bees

2020 ◽  
Author(s):  
Victor H. Gonzalez ◽  
John M. Hranitz ◽  
Mercedes B. McGonigle ◽  
Rachel E. Manweiler ◽  
Deborah R. Smith ◽  
...  
Keyword(s):  
High Temperatures ◽  
Heat Tolerance ◽  
Honey Bees ◽  
Thermal Tolerance ◽  
Survival Rates ◽  
Acute Exposure ◽  
Control Group ◽  
Colony Losses ◽  
Neonicotinoid Insecticides ◽  
Sublethal Doses

AbstractThe European honey bee, Apis mellifera L., is the single most valuable managed pollinator in the world. Poor colony health or unusually high colony losses of managed honey bees result from myriad stressors, which are more harmful in combination. Climate change is expected to accentuate the effects of these stressors, but the physiological and behavioral responses of honey bees to high temperatures while under simultaneous pressure of one or more stressors remains largely unknown. Here we test the hypothesis that exposure to acute, sublethal doses of neonicotinoid insecticides reduce thermal tolerance in honey bees. We administered to bees oral doses of imidacloprid and acetamiprid at 1/5, 1/20, and 1/100 of LD50 and measured their heat tolerance 4 h post-feeding, using both dynamic and static protocols. Contrary to our expectations, acute exposure to sublethal doses of both pesticides resulted in higher thermal tolerance and greater survival rates of bees. Bees that ingested the higher doses of pesticides displayed a critical thermal maximum from 2 °C to 4 °C greater than that of the control group, and a reduction in mortality from 69% to 96%. Our study suggests a resilience of honey bees to high temperatures when other stressors are present, which is consistent with studies in other insects. We discuss the implications of these results and hypothesize that this compensatory effect is likely due to induction of heat shock proteins by the insecticides, which provides temporary protection from extremely high temperatures.

scholarly journals Thermal Tolerance of Fruit-Feeding Butterflies (Lepidoptera: Nymphalidae) in Contrasting Mountaintop Environments

Insects ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 278 ◽  
Author(s):  
Vanessa Diniz e Silva ◽  
Marina Vale Beirão ◽  
Danon Clemes Cardoso
Keyword(s):  
Climate Change ◽  
Critical Temperature ◽  
Thermal Tolerance ◽  
Global Climate ◽  
Campo Rupestre ◽  
Temperature Dependent ◽  
Physiological Constraints ◽  
Resistant Species ◽  
Complicated Task ◽  
Forest Islands

Ectothermic organisms, such as insects, are highly temperature dependent and are good models for studies that predict organisms’ responses to global climate change. Predicting how climate change may affect species distributions is a complicated task. However, it is possible to estimate species’ physiological constraints through maximum critical temperature, which may indicate if the species can tolerate new climates. Butterflies are useful organisms for studies of thermal tolerance. We tested if species have different thermal tolerances and if different habitats influence the thermal tolerance of the butterflies present in Brazil’s campo rupestre (open areas) and forest islands (shaded areas). A total of 394 fruit-feeding butterflies, comprising 45 species, were tested. The results separated the species into two statistically different groups: the resistant species with maximum critical temperature of 53.8 ± 7.4 °C, and the non-resistant species with maximum critical temperature of 48.2 ± 7.4 °C. The species of butterflies displayed differences in maximum critical temperature between the campo rupestre and forest islands that can be related to the two distinct habitats, but this did not correlate phylogenetically. Species from the forest islands were also divided into two groups, “resistant” and “non-resistant”, probably due to the heterogeneity of the habitat; the forest islands have a canopy, and in the understory, there are shaded and sunny areas. Species from forest islands, especially species that displayed lower thermal tolerance, may be more susceptible to global warming.

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