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Phenotypically plastic responses to predation risk are temperature dependent

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Predicting how organisms respond to climate change requires that we understand the temperature dependence of fitness in relevant ecological contexts (e.g., with or without predation risk). Predation risk often induces changes to life history traits that are themselves temperature dependent. We explore how perceived predation risk and temperature interact to determine fitness (indicated by the intrinsic rate of increase, r) through changes to its underlying components (net reproductive rate, generation time, and survival) in Daphnia magna. We exposed Daphnia to predation cues from dragonfly naiads early, late, or throughout their ontogeny. Predation risk increased r differentially across temperatures and depending on the timing of exposure to predation cues. The timing of predation risk likewise altered the temperature-dependent response of T and R0. Daphnia at hotter temperatures responded to predation risk by increasing r through a combination of increased R0 and decreased T that together countered an increase in mortality rate. However, only D. magna that experienced predation cues early in ontogeny showed elevated r at colder temperatures. These results highlight the fact that phenotypically plastic responses of life history traits to predation risk can be strongly temperature dependent.
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Oecologia (2019) 191:709–719
Phenotypically plastic responses topredation risk are temperature
ThomasM.Luhring1,2 · JannaM.Vavra1· ClaytonE.Cressler1· JohnP.DeLong1
Received: 7 September 2018 / Accepted: 30 September 2019 / Published online: 10 October 2019
© Springer-Verlag GmbH Germany, part of Springer Nature 2019
Predicting how organisms respond to climate change requires that we understand the temperature dependence of fitness in
relevant ecological contexts (e.g., with or without predation risk). Predation risk often induces changes to life history traits
that are themselves temperature dependent. We explore how perceived predation risk and temperature interact to determine
fitness (indicated by the intrinsic rate of increase, r) through changes to its underlying components (net reproductive rate,
generation time, and survival) in Daphnia magna. We exposed Daphnia to predation cues from dragonfly naiads early,
late, or throughout their ontogeny. Predation risk increased r differentially across temperatures and depending on the tim-
ing of exposure to predation cues. The timing of predation risk likewise altered the temperature-dependent response of T
and R0. Daphnia at hotter temperatures responded to predation risk by increasing r through a combination of increased R0
and decreased T that together countered an increase in mortality rate. However, only D. magna that experienced predation
cues early in ontogeny showed elevated r at colder temperatures. These results highlight the fact that phenotypically plastic
responses of life history traits to predation risk can be strongly temperature dependent.
Keywords Climate change· Fecundity· Life history· Mortality· Reproduction· Survivorship
Global climate change is leaving an indelible mark on the
ecology of organisms worldwide (Walther etal. 2002;
Parmesan 2006; Poloczanska etal. 2013). Organisms can
respond to climate change through rapid evolutionary and/
or developmental changes in morphology, behavior, and life
history (Reale etal. 2003; Knies etal. 2006, 2009; Charman-
tier etal. 2008; Angilletta etal. 2010; Anderson etal. 2012;
Charmantier and Gienapp 2014; Tseng and O’Connor 2015;
Seebacher etal. 2015; Padfield etal. 2016; Schaum etal.
2017). Furthermore, changing thermal regimes associated
with climate change influence virtually all aspects of natural
systems, because biological processes are dominated by the
effects of temperature (Ernest etal. 2003; Brown etal. 2004;
Kerkhoff etal. 2005; Kingsolver 2009; DeLong etal. 2017).
While the temperature dependence of fitness is of interest
for projecting the effects of climate change (Deutsch etal.
2008; Vasseur etal. 2014; Sinclair etal. 2016), the traits
that determine fitness occur within the context of natural
food webs and are simultaneously altered and constrained
by temperature and other factors (e.g., predation, allocation
trade-offs) (Luhring etal. 2018).
Predation and predation risk strongly influence prey evo-
lution, development, morphology, behavior, and life history
(Reznick and Endler 1982; Lima and Dill 1990; Stibor 1992;
Van Buskirk and Schmidt 2000; Benard 2004; Lind and
Cresswell 2005; Grigaltchik etal. 2012, 2016; Seebacher
and Grigaltchik 2015; Tseng and O’Connor 2015; Luhring
etal. 2016). Furthermore, predators shape prey demography
and dynamics through both the lethal effects of predation
and the effects of predation risk on prey behavior and phe-
notypes (Pangle etal. 2007; Creel and Christianson 2008;
Communicated by Scott D Peacor.
Electronic supplementary material The online version of this
article (https :// 2-019-04523 -9) contains
supplementary material, which is available to authorized users.
* Thomas M. Luhring
1 School ofBiological Sciences, University ofNebraska-
Lincoln, 410 Manter Hall, Lincoln, NE68588, USA
2 Present Address: Department ofBiological Sciences, Wichita
State University, 1845 Fairmount Street, Wichita, KS67260,
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
... How biotic stressors such as predation risk can alter the physiology of prey species and further modulate their sensitivity to warming remain a major gap of knowledge. Few studies have investigated the effect of predator cues on zooplankton under elevated temperatures (e.g., Luhring et al., 2019;Meyer et al., 2017;Tseng and O'Connor, 2015). In freshwater ecosystems, Meyer et al. (2017) showed that effects of predators (Cyclops kolensis) on the abundance of prey animals (Gastropus stylifer and Keratella cochlearis and copepod nauplii) are independent of temperatures. ...
... FPC was thaw before using. Effects of predator cues on prey animals remain after freezing (Luhring et al., 2019). ...
... Furthermore, the presence of the non-consumptive predation risk, while showed a higher performance of P. incisus under control temperature, doubled negative effects of MHW on the lifetime nauplii production. While effects of elevated temperatures and predation threats on copepods have been two central themes in ecological research for decades, the interactive effects of both stressors on prey species have rarely been investigated (Luhring et al., 2019;Meyer et al., 2017;Tseng and O'Connor, 2015). Our study provides evidence on how predator cues may substantially exaggerate negative effects of MHWs on tropical copepods. ...
Mangroves and lagoons are spawning and nursery grounds of marine fish. These ecosystems are increasingly exposed to episodes of extreme temperatures from marine heatwaves (MHWs). However, it is unknown how MHW effects may interact with those of predators to affect the fitness of prey species in these ecosystems. To address the issue, we exposed the calanoid copepod Pseudodiaptomus incisus to a simulated MHW and with/without the presence of fish predator cues (FPC). The size at maturity, clutch size, hatching success, lifetime nauplii and faecal pellet production, and the adult lifespan were determined. All fitness parameters of P. incisus were lower under MHW. Remarkably, nauplii production was reduced 80%, and adult lifespan was shortened 50%, respectively. Overall, FPC increased the size at maturity and hatching at both temperatures. FPC also increased clutch size, nauplii and faecal pellet production in the control temperature, but decreased all three parameters under MHW. These results suggest that FPC may increase the vulnerability of P. incisus to MHWs by lowering reproductive success and reducing grazing rate. Our study sheds light on how interactive effects between biotic and abiotic factors may shape the vulnerability of marine copepods in mangroves and lagoons of tropical regions.
... adaptations may be reduced or constrained when responding to multiple stressors (Luhring, Vavra, Cressler, & DeLong, 2019). ...
... For example, populations of Paramecium aurelia exposed to predation show a more rapid increase in growth as temperature increases and a more rapid decline as temperatures decrease than populations not exposed to predation (Luhring & DeLong, 2016). Similarly, Daphnia magna show changes in body size, population growth rate, and life-history traits in response to predation risk (Luhring, Vavra, Cressler, & DeLong, 2018;Luhring et al., 2019;Tseng, Bernhardt, & Chila, 2019), and bacteriophage presence alters TPCs in the bacterium Pseudomonas fluorescens (Padfield, Castledine, & Buckling, 2019). ...
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Abstract The effects of climate change—such as increased temperature variability and novel predators—rarely happen in isolation, but it is unclear how organisms cope with multiple stressors simultaneously. To explore this, we grew replicate Paramecium caudatum populations in either constant or variable temperatures and exposed half to predation. We then fit thermal performance curves (TPCs) of intrinsic growth rate (rmax) for each replicate population (N = 12) across seven temperatures (10°C–38°C). TPCs of P. caudatum exposed to both temperature variability and predation responded only to one or the other (but not both), resulting in unpredictable outcomes. These changes in TPCs were accompanied by changes in cell morphology. Although cell volume was conserved across treatments, cells became narrower in response to temperature variability and rounder in response to predation. Our findings suggest that predation and temperature variability produce conflicting pressures on both thermal performance and cell morphology. Lastly, we found a strong correlation between changes in cell morphology and TPC parameters in response to predation, suggesting that responses to opposing selective pressures could be constrained by trade‐offs. Our results shed new light on how environmental and ecological pressures interact to elicit changes in characteristics at both the individual and population levels. We further suggest that morphological responses to interactive environmental forces may modulate population‐level responses, making prediction of long‐term responses to environmental change challenging.
... Life-history trait evolution can be complex due to the variety of selective pressures that can be encountered (Schluter and Mcphail, 1992). Selective pressures rarely occur independently, with individuals being far more likely to face several interlinking selective pressures at once (Luhring et al., 2019). This can have complex influences on life-history traits (Bandara et al., 2019). ...
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Trade-offs between life-history traits offset the energetic costs of maintaining fitness in complex environments. Ceratitis species have been recorded to have long lifespans, which may have evolved in response to seasonal resource fluctuation. It is thus likely that reproductive patterns have evolved concomitantly as part of the trade-off between lifespan and reproduction. In this study, we investigated how reproductive patterns differ between Ceratitis cosyra (Walker) and Ceratitis capitata (Wiedemann; Diptera: Tephritidae), two species with different average and maximum lifespans. Females of both species were mated and patterns of female survival, fecundity, remating and sperm storage were tested. Ceratitis cosyra had a higher rate of survival and a lower fecundity when compared with the shorter-lived C. capitata, suggesting that both species exhibit a trade-off between lifespan and reproduction. Both species showed a similar and consistent willingness to remate, despite declines in sperm storage, suggesting that sperm alone does not fully inhibit remating. As expected, C. cosyra transferred high numbers of sperm during the first mating. However, sperm stores declined unexpectedly by 14 days. This indicates that males might transfer large ejaculates as a nuptial gift, that females then later degrade as a source of nutrients. Large declines in sperm storage may also indicate that females discard excess sperm stores due to the toxicity involved with storing sperm. These results do not suggest that patterns of sperm storage and remating align with lifespan and resource seasonality in these species, but a wider range of species needs to be assessed to better understand variation in Ceratitis mating systems.
... Temperature is one of the main abiotic factors influencing the potential of natural enemies to suppress pests (Zamani et al. 2006;Sarnevesht et al. 2018;Su et al. 2018;Lin et al. 2019, Luhring et al. 2019), but its effects may differ between different predator species. Little is known about the functional response of H. axyridis towards the two walnut aphid species above at different temperatures, although this information is requisite to establishing an effective biological control strategy using H. axyridis. ...
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Background: The walnut aphid species Chromaphis juglandicola Kalt. and Panaphis juglandis (Goeze) are destructive insect pests. Harmonia axyridis (Pall.) (Coleoptera: Coccinellidae) is the main predatory insect with a wide geographical distribution. The feeding behavior of the predator against the two different aphid species might influence bio-control efficacy in walnut orchards. Main body: Functional response of H. axyridis to various densities of the two aphid species was examined under temperatures ranging from 15 to 30 °C. The results showed that functional responses of H. axyridis towards C. juglandicola or P. juglandis fitted well with the Holling-II equation within the range of 15–30 °C. A greater biomass of aphids was consumed when the temperature increased from 15 to 30 °C. The predation efficacy of H. axyridis against C. juglandicola was greater than against P. juglandis, and the searching efficiency of H. axyridis against C. juglandicola was more effective than against P. juglandis. Moreover, predation rates against both aphid species decreased with increasing the H. axyridis density. Conclusion: This study showed that H. axyridis was an effective predator against the two walnut aphids. Increasing temperature (15–30 °C) increased prey consumption. Interference between individuals from increasing predator density had a negative impact on predation rate against the two aphid species.
... Biological effects of global warming may not be simple emergent functions of biochemical kinetics, but may depend critically on the ecological context. As a result, predicting biological and ecological effects of global warming becomes complicated (also see Tseng and O'Connor, 2015;Lau and terHorst, 2020;Luhring et al., 2019;Tseng et al., 2019;Truong et al., 2020). As shown in our study, warming may increase the metabolic rates of small juveniles more than that of large adult amphipods in springs with fish predators, but do the opposite in springs without fish. ...
According to the metabolic theory of ecology, metabolic rate, an important indicator of the pace of life, varies with body mass and temperature as a result of internal physical constraints. However, various ecological factors may also affect metabolic rate and its scaling with body mass. Although reports of such effects on metabolic scaling usually focus on single factors, the possibility of significant interactive effects between multiple factors requires further study. In this study, we show that the effect of temperature on the ontogenetic scaling of resting metabolic rate of the freshwater amphipod Gammarus minus depends critically on habitat differences in predation regime. Increasing temperature tends to cause decreases in the metabolic scaling exponent (slope) in population samples from springs with fish predators, but increases in population samples from springs without fish. Accordingly, the temperature sensitivity of metabolic rate is not only size-specific, but also its relationship to body size shifts dramatically in response to fish predators. We hypothesize that the dampened effect of temperature on the metabolic rate of large adults in springs with fish, and of small juveniles in springs without fish are adaptive evolutionary responses to differences in the relative mortality risk of adults and juveniles in springs with versus without fish predators. Our results demonstrate a complex interaction among metabolic rate, body mass, temperature and predation regime. The intraspecific scaling of metabolic rate with body mass and temperature is not merely the result of physical constraints related to internal body design and biochemical kinetics, but rather is ecologically sensitive and evolutionarily malleable.
... However, phenotypically plastic effects of predators or their cues on the body mass scaling of metabolic rate and the temperature dependence of these effects have not been explored. Although interactive effects of temperature and predators on prey phenotypes have been reported for some physiological, behavioural and life-history traits [23][24][25][26][27][28][29][30][31], this has not been explored for metabolic scaling. ...
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A common belief is that body mass scaling of metabolic rate results chiefly from intrinsic body-design constraints. However, several studies have shown that multiple ecological factors affect metabolic scaling. The mechanistic basis of these effects is largely unknown. Here, we explore whether abiotic and biotic environmental factors have interactive effects on metabolic scaling. To address this question, we studied the simultaneous effects of temperature and predator cues on the ontogenetic metabolic scaling of amphipod crustaceans inhabiting two different aquatic ecosystems, a freshwater spring and a saltwater lagoon. We assessed effects of phenotypic plasticity on metabolic scaling by exposing amphipods in the laboratory to water with and without fish cues at multiple temperatures. Temperature interacts significantly with predator cues to affect metabolic scaling. Our results suggest that metabolic scaling is highly malleable in response to short-term acclimation. The interactive effects of temperature and predators show the importance of studying effects of global warming in realistic ecological contexts.
... Second, interactions between various anti-predator responses by prey (e.g., changes in their rates of feeding, metabolism, growth, reproduction and behavioral activity: see e.g., [13,23,24,38,44,45,48,49,130,163]), and reciprocal effects of these responses on the vulnerability of prey to predation should be investigated (following [24,61,164]). Third, effects of other environmental factors (e.g., temperature, habitat, parasites, and food quantity and quality) on prey responses to predator risk deserve further attention (see e.g., [6,38,43,58,116,119,120,[165][166][167][168][169][170][171][172][173][174][175][176][177]). Fourth, the relative roles of evolutionary adaptation and phenotypically plastic acclimation involved in prey responses to predators require elucidation (see e.g., [13,48,166,168,[178][179][180]). ...
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Little is known about how predators or their cues affect the acquisition and allocation of energy throughout the ontogeny of prey organisms. To address this question, we have been comparing the ontogenetic body-mass scaling of various traits related to energy intake and use between populations of a keystone amphipod crustacean inhabiting freshwater springs, with versus without fish predators. In this progress report, we analyze new and previously reported data to develop a synthetic picture of how the presence/absence of fish predators affects the scaling of food assimilation, fat content, metabolism, growth and reproduction in populations of Gammarus minus located in central Pennsylvania (USA). Our analysis reveals two major clusters of ‘symmorphic allometry’ (parallel scaling relationships) for traits related to somatic versus reproductive investment. In the presence of fish predators, the scaling exponents for somatic traits tend to decrease, whereas those for reproductive traits tend to increase. This divergence of scaling exponents reflects an intensified trade-off between somatic and reproductive investments resulting from low adult survival in the face of size-selective predation. Our results indicate the value of an integrated view of the ontogenetic size-specific energetics of organisms and its response to both top-down (predation) and bottom-up (resource supply) effects.
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Rhyzobius lophanthae Blaisdell (Coleoptera: Coccinellidae) kabuklubitlerin avcısı olarak bilinmektedir. Çalışmada türlerin daha verimli olduğu optimum sıcaklık değerinin belirlenmesi amaçlanmıştır. Bu çalışmada 14, 16, 18, 20, 22, 24, 26, 28, 30 ve 32 °C, %60 orantılı nem ve uzun gün aydınlatmalı iklim koşullarında R. lophanthae'nin yaşam çizelgesi parametreleri Euler-Lotka eşitliğine göre RmStat-3 kullanılarak hesaplanmıştır. 26, 28 ve 30 °C elde edilen sonuçlara göre Kalıtsal üreme yeteneği (rm) 0.120, 0.142, 0.132 dişi/dişi/gün olarak hesaplanırken, Net üreme gücü (R0) 56.883, 80.944, 31.149 dişi/dişi/döl olarak hesaplanmıştır. Ortalama döl süresi (T0) sırasıyla 33.801, 30.866, 25.978 gün olmuştur. Toplam üreme oranı (GRR) 177.779, 303.751, 105.751 yumurta/dişi olarak hesaplanmıştır. Çalışmada laboratuvar koşullarında R. lophanthae'nin etkinliği için 28 °C’nin optimum sıcaklık olduğu sonucuna varılmıştır. Elde edilen sonuçlara göre avcılar ve zararlıların çevresel koşullardaki etkileşimleri hakkında daha fazla çalışmaya ihtiyaç duyulduğu gözlenmiştir.
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The purple scale predator, Rhyzobius lophanthae Blaisdell (Coleoptera: Coccinellidae) is known as coccidophagous ladybird predator, and effective against scales’ insects. The present study aimed to evaluate the optimum temperature for the species to be more efficient. In this study, the life table parameters of R. lophanthae were determined on different temperatures at 4, 16, 18, 20, 22, 24, 26, 28, 30 and 32 °C and 60% RH, by calculations using RmStat-3 software according to Euler-Lotka equation. The results showed that the intrinsic rates of increase (r m ) were 0.016, 0.022, 0.030, 0.052, 0.056, 0.068, 0.120, 0.142, 0.132, 0.021 females/females/day, respectively, while the net reproductive rates (R 0 ) were 7.082, 9.514, 11.960, 50.906, 54.150, 49.525, 56.883, 80.944, 31.149, 1.882 females/females/generation, respectively. The mean generation times (T 0 ) were 125.966, 104.602, 84.009, 75.742, 71.511, 57.568, 33.801, 30.866, 25.978, 30.759 days, respectively. Total productivity rates (GRR) were 34.865, 39.210, 48.216, 201.990, 209.469, 166.207, 177.779, 303.751, 105.751, 12.622 egg/female, respectively. The study concluded that 26-30 °C was the optimum temperature range for the efficient role of R. lophanthae under laboratory conditions. From the results, it is still needed to do more studies on the interactions of pests, predators with environmental conditions.
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Although life histories are shaped by temperature and predation, their joint influence on the interdependence of life‐history traits is poorly understood. Shifts in one life‐history trait often necessitate shifts in another—structured in some cases by trade‐offs—leading to differing life‐history strategies among environments. The offspring size–number trade‐off connects three traits whereby a constant reproductive allocation (R) constrains how the number (O) and size (S) of offspring change. Increasing temperature and size‐independent predation decrease size at and time to reproduction which can lower R through reduced time for resource accrual or size‐constrained fecundity. We investigated how O, S, and R in a clonal population of Daphnia magna change across their first three clutches with temperature and size‐independent predation risk. Early in ontogeny, increased temperature moved O and S along a trade‐off curve (constant R) toward fewer larger offspring. Later in ontogeny, increased temperature reduced R in the no‐predator treatment through disproportionate decreases in O relative to S. In the predation treatment, R likewise decreased at warmer temperatures but to a lesser degree and more readily traded off S for O whereby the third clutch showed a constant allocation strategy of O versus S with decreasing R. Ontogenetic shifts in S and O rotated in a counterclockwise fashion as temperature increased and more drastically under risk of predation. These results show that predation risk can alter the temperature dependence of traits and their interactions through trade‐offs. Temperature and predation risk have interactive effects on the offspring size–number trade‐off through its underlying constraint (reproductive investment). Thus understanding life‐history responses to environmental change in natural systems requires integrated approaches that incorporate multiple linked traits and the constraints that tether them to one another.
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Extinction rates are predicted to rise exponentially under climate warming, but many of these predictions ignore physiological and behavioral plasticity that might buffer species from extinction. We evaluated the potential for physiological acclimatization and behavioral avoidance of poor climatic conditions to lower extinction risk under climate change in the global hotspot of salamander diversity, a region currently predicted to lose most of the salamander habitat due to warming. Our approach integrated experimental physiology and behavior into a mechanistic species distribution model to predict extinction risk based on an individual's capacity to maintain energy balance with and without plasticity. We assessed the sensitivity of extinction risk to body size, behavioral strategies, limitations on energy intake, and physiological acclimatization of water loss and metabolic rate. The field and laboratory experiments indicated that salamanders readily acclimatize water loss rates and metabolic rates in ways that could maintain positive energy balance. Projections with plasticity reduced extinction risk by 72% under climate warming, especially in the core of their range. Further analyses revealed that juveniles might experience the greatest physiological stress under climate warming, but we identified specific physiological adaptations or plastic responses that could minimize the lethal physiological stress imposed on juveniles. We conclude that incorporating plasticity fundamentally alters ecological predictions under climate change by reducing extinction risk in the hotspot of salamander diversity.
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Synopsis: The mean and variance of environmental temperature are changing as a consequence of human activities. Ectotherms are sensitive to these temperature changes in the short term, typically displaying a unimodal response of most biological rates to temperature (thermal performance curves; TPCs). Many organisms, however, may acclimate or evolve in response to new temperature regimes. In particular, population growth rate TPCs (r TPCs) reflect the ability to maintain positive growth under a range of temperatures, and therefore shifts in r TPCs due to acclimation are fundamental to our understanding of how ectotherms will respond to changes in climate. Here, we derive a model for r TPCs rooted in temperature dependent metabolic rate (through enzyme kinetics and activity). We then use this model to interpret the effects of acclimation to different temperatures on r TPCs of the protist Paramecium bursaria. Intermediate acclimation temperatures generally resulted in higher upper critical thermal limits, thermal optima, maximum population growth rate, and the area under the TPC. Lower critical thermal limits increased linearly with acclimation temperature, causing a decrease in thermal breadth with increased acclimation temperature. Thus, rather than showing improved performance at the acclimation temperature, P. bursaria appeared to pay a price at all temperatures for acclimating to higher temperatures. The fits of our data to our model also suggest that changes in the structure and function of metabolic enzymes may underlie the changes in the TPCs. Specifically, our results suggest that both the delta heat capacity and delta enthalpy of formation of metabolic enzymes may have increased with acclimation. Since these two factors are correlated across acclimation temperatures, our data also suggest potential trade-offs that may constrain changes in TPCs.
The sensitivity of metabolic rate to temperature constrains the climate in which ectotherms can function, yet the temperature dependence of metabolic rate may evolve in response to biotic and abiotic factors. We compiled a dataset on the temperature dependence of metabolic rate for heterotrophic ectotherms from studies that show a peak in metabolic rate at an optimal temperature (i.e. that describe the thermal performance curve for metabolic rate). We found that peak metabolic rates were lower in aquatic than terrestrial habitats and increased with body mass, latitude and the optimal temperature. In addition, the optimal temperature decreased with latitude. These results support competing hypotheses about metabolic rate adaptation, with hotter being better in the tropics but colder being better towards the poles. Moreover, our results suggest that the temperature dependence of metabolic rate is more complex than previously suggested.
Environmental variability is ubiquitous, but its effects on populations are not fully understood or predictable. Recent attention has focused on how rapid evolution can impact ecological dynamics via adaptive trait change. However, the impact of trait change arising from plastic responses has received less attention, and is often assumed to optimize performance and unfold on a separate, faster timescale than ecological dynamics. Challenging these assumptions, we propose that gradual plasticity is important for ecological dynamics, and present a study of the plastic responses of the freshwater green algae Chlamydomonas reinhardtii as it acclimates to temperature changes. First, we show that C. reinhardtii's gradual acclimation responses can both enhance and suppress its performance after a perturbation, depending on its prior thermal history. Second, we demonstrate that where conventional approaches fail to predict the population dynamics of C. reinhardtii exposed to temperature fluctuations, a new model of gradual acclimation succeeds. Finally, using high-resolution data, we show that phytoplankton in lake ecosystems can experience thermal variation sufficient to make acclimation relevant. These results challenge prevailing assumptions about plasticity's interactions with ecological dynamics. Amidst the current emphasis on rapid evolution, it is critical that we also develop predictive methods accounting for plasticity.