scholarly journals Plasticity of Performance Curves in Ectotherms: Individual Variation Modulates Population Responses to Environmental Change

2021 ◽  
Vol 12 ◽  
Author(s):  
Frank Seebacher ◽  
Alexander G. Little
Keyword(s):  
Temperature Change ◽  
Developmental Plasticity ◽  
Swimming Performance ◽  
Random Order ◽  
Population Variation ◽  
Published Data ◽  
Population Responses ◽  
Trade Offs ◽  
Temperature Regimes ◽  
Performance Curves

Many ectothermic animals can respond to changes in their environment by altering the sensitivities of physiological rates, given sufficient time to do so. In other words, thermal acclimation and developmental plasticity can shift thermal performance curves so that performance may be completely or partially buffered against the effects of environmental temperature changes. Plastic responses can thereby increase the resilience to temperature change. However, there may be pronounced differences between individuals in their capacity for plasticity, and these differences are not necessarily reflected in population means. In a bet-hedging strategy, only a subsection of the population may persist under environmental conditions that favour either plasticity or fixed phenotypes. Thus, experimental approaches that measure means across individuals can not necessarily predict population responses to temperature change. Here, we collated published data of 608 mosquitofish (Gambusia holbrooki) each acclimated twice, to a cool and a warm temperature in random order, to model how diversity in individual capacity for plasticity can affect populations under different temperature regimes. The persistence of both plastic and fixed phenotypes indicates that on average, neither phenotype is selectively more advantageous. Fish with low acclimation capacity had greater maximal swimming performance in warm conditions, but their performance decreased to a greater extent with decreasing temperature in variable environments. In contrast, the performance of fish with high acclimation capacity decreased to a lesser extent with a decrease in temperature. Hence, even though fish with low acclimation capacity had greater maximal performance, high acclimation capacity may be advantageous when ecologically relevant behaviour requires submaximal locomotor performance. Trade-offs, developmental effects and the advantages of plastic phenotypes together are likely to explain the observed population variation.

scholarly journals Divergence and constraint in the thermal sensitivity of aquatic insect swimming performance

2020 ◽  
Vol 66 (5) ◽  
pp. 555-564 ◽  
Author(s):  
Alisha A Shah ◽  
Eva M S Bacmeister ◽  
Juan G Rubalcaba ◽  
Cameron K Ghalambor
Keyword(s):  
Aquatic Insects ◽  
Environmental Temperature ◽  
Swimming Performance ◽  
Thermal Sensitivity ◽  
Aquatic Insect ◽  
Tropical Species ◽  
Swimming Velocity ◽  
Evolutionary Divergence ◽  
Trade Offs ◽  
Performance Curves

Abstract Environmental temperature variation may play a significant role in the adaptive evolutionary divergence of ectotherm thermal performance curves (TPCs). However, divergence in TPCs may also be constrained due to various causes. Here, we measured TPCs for swimming velocity of temperate and tropical mayflies (Family: Baetidae) and their stonefly predators (Family: Perlidae) from different elevations. We predicted that differences in seasonal climatic regimes would drive divergence in TPCs between temperate and tropical species. Stable tropical temperatures should favor the evolution of “specialists” that perform well across a narrow range of temperatures. Seasonally, variable temperatures in temperate zones, however, should favor “generalists” that perform well across a broad range of temperatures. In phylogenetically paired comparisons of mayflies and stoneflies, swimming speed was generally unaffected by experimental temperature and did not differ among populations between latitudes, suggesting a maintenance of performance breadth across elevation and latitude. An exception was found between temperate and tropical mayflies at low elevation where climatic differences between latitudes are large. In addition, TPCs did not differ between mayflies and their stonefly predators, except at tropical low elevation. Our results indicate that divergence in TPCs may be constrained in aquatic insects except under the most different thermal regimes, perhaps because of trade-offs that reduce thermal sensitivity and increase performance breadth.

Hormones and Behavior

2019 ◽  
pp. 11-26
Author(s):  
Maren N. Vitousek ◽  
Laura A. Schoenle
Keyword(s):  
Life History ◽  
Life Histories ◽  
Life History Traits ◽  
Developmental Plasticity ◽  
Endocrine System ◽  
Phenotypic Traits ◽  
Social Environments ◽  
Trade Offs ◽  
And Behavior

Hormones mediate the expression of life history traits—phenotypic traits that contribute to lifetime fitness (i.e., reproductive timing, growth rate, number and size of offspring). The endocrine system shapes phenotype by organizing tissues during developmental periods and by activating changes in behavior, physiology, and morphology in response to varying physical and social environments. Because hormones can simultaneously regulate many traits (hormonal pleiotropy), they are important mediators of life history trade-offs among growth, reproduction, and survival. This chapter reviews the role of hormones in shaping life histories with an emphasis on developmental plasticity and reversible flexibility in endocrine and life history traits. It also discusses the advantages of studying hormone–behavior interactions from an evolutionary perspective. Recent research in evolutionary endocrinology has provided insight into the heritability of endocrine traits, how selection on hormone systems may influence the evolution of life histories, and the role of hormonal pleiotropy in driving or constraining evolution.

Should I stay or should I go? Complex environments influence the developmental plasticity of flight capacity and flight-related trade-offs

2019 ◽  
Vol 128 (1) ◽  
pp. 59-69 ◽  
Author(s):  
Jordan R Glass ◽  
Zachary R Stahlschmidt
Keyword(s):  
Life History ◽  
Food Availability ◽  
Life History Traits ◽  
Developmental Plasticity ◽  
Temperature Variability ◽  
Field Cricket ◽  
Valuable Insight ◽  
Complex Environments ◽  
Trade Offs ◽  
Flight Capacity

Abstract Complex environments, characterized by co-varying factors (e.g. temperature and food availability) may cause animals to invest resources differentially into fitness-related traits. Thus, experiments manipulating multiple environmental factors concurrently provide valuable insight into the role of the environment in shaping not only important traits (e.g. dispersal capacity or reproduction), but also trait–trait interactions (e.g. trade-offs between traits). We used a multi-factorial design to manipulate variation in temperature (constant 28 °C vs. 28 ± 5 °C daily cycle) and food availability (unlimited vs. intermittent access) throughout development in the sand field cricket (Gryllus firmus). Using a univariate approach, we found that temperature variability and unlimited food availability promoted survival, development, growth, body size and/or reproductive investment. Using principal components as indices of resource allocation strategy, we found that temperature variability and unlimited food reduced investment into flight capacity in females. Thus, we detected a sex-specific trade-off between flight and other life-history traits that was developmentally plastic in response to variation in temperature and food availability. We develop an experimental and statistical framework to reveal shifts in correlative patterns of investment into different life-history traits. This approach can be applied to a range of biological systems to investigate how environmental complexity influences traits and trait trade-offs.

scholarly journals Carpogenic Germinability of Diverse Sclerotinia sclerotiorum Populations Within the Southwestern Australian Grain Belt

Plant Disease ◽  
2020 ◽  
Vol 104 (11) ◽  
pp. 2891-2897
Author(s):  
Pippa J. Michael ◽  
King Yin Lui ◽  
Linda L. Thomson ◽  
Katia Stefanova ◽  
Sarita J. Bennett
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Temperature Fluctuations ◽  
Sclerotinia Stem Rot ◽  
Dark Cycle ◽  
Diurnal Temperature ◽  
Population Responses ◽  
Carpogenic Germination ◽  
Southwestern Australia ◽  
Temperature Regimes ◽  
Mycelial Compatibility

Sclerotinia stem rot, caused by the necrotrophic plant pathogen Sclerotinia sclerotiorum (Lib.) de Bary, is a major disease of canola and pulses in Australia. Current disease management relies greatly on cultural and chemical means of control. Timing of fungicide applications remains a challenge, because efficacy is dependent on accurate prediction of ascospore release and presence on the plant. The aims of this study were to determine the optimal temperature for carpogenic germination of S. sclerotiorum populations sampled from canola and lupin fields in southwestern Australia and characterize diversity using mycelial compatibility groupings (MCGs). Sclerotia were collected from four diseased canola and one diseased lupin field from across southwestern Australia. Forty sclerotia from each population were incubated at four alternating temperatures of 30/15, 20/15, 20/4, and 15/4°C (12-h/12-h light/dark cycle) and assessed every 2 to 3 days for a 180-day period. MCG groupings for populations were characterized using 12 reference isolates. Results indicated the time to initial carpogenic germination decreased as diurnal temperature fluctuations decreased, with a fluctuation of 5°C (20/15°C) having the most rapid initial germination followed by 11°C (15/4°C) followed by 16°C (20/4°C). Optimal germination temperature for all five populations was 20/15°C; however, population responses to other diurnal temperature regimes varied considerably. No germination was observed at 30/15°C. MCG results indicate extensive diversity within and between populations, with at least 40% of sclerotia within each population unable to be characterized. We suggest that this diversity has enabled S. sclerotiorum populations to adapt to varying environmental conditions within southwestern Australia.

scholarly journals Divergence and ontogenetic coupling of larval behaviour and thermal reaction norms in three closely related butterflies

2010 ◽  
Vol 278 (1703) ◽  
pp. 313-320 ◽  
Author(s):  
David Berger ◽  
Magne Friberg ◽  
Karl Gotthard
Keyword(s):  
Developmental Plasticity ◽  
Larval Growth ◽  
State Dependence ◽  
Reaction Norm ◽  
Thermal Reaction ◽  
Reaction Norms ◽  
Feeding Strategies ◽  
Species Differentiation ◽  
Larval Behaviour ◽  
Trade Offs

Genetic trade-offs such as between generalist–specialist strategies can be masked by changes in compensatory processes involving energy allocation and acquisition which regulation depends on the state of the individual and its ecological surroundings. Failure to account for such state dependence may thus lead to misconceptions about the trade-off structure and nature of constraints governing reaction norm evolution. Using three closely related butterflies, we first show that foraging behaviours differ between species and change remarkably throughout ontogeny causing corresponding differences in the thermal niches experienced by the foraging larvae. We further predicted that thermal reaction norms for larval growth rate would show state-dependent variation throughout development as a result of selection for optimizing feeding strategies in the respective foraging niches of young and old larvae. We found substantial developmental plasticity in reaction norms that was species-specific and reflected the different ontogenetic niche shifts. Any conclusions regarding constraints on performance curves or species-differentiation in thermal physiology depend on when reaction norms were measured. This demonstrates that standardized estimates at single points in development, or in general, allow variation in only one ecological dimension, may sometimes provide incomplete information on reaction norm constraints.

Benefits of fidelity: does host specialization impact nematode parasite life history and fecundity?

Parasitology ◽  
2013 ◽  
Vol 140 (5) ◽  
pp. 587-597 ◽  
Author(s):  
J. KOPRIVNIKAR ◽  
H. S. RANDHAWA
Keyword(s):  
Life History ◽  
Host Specificity ◽  
Egg Size ◽  
Host Specialization ◽  
Published Data ◽  
Female Size ◽  
Patent Period ◽  
Trade Offs ◽  
Evolutionary Level ◽  
Host Parasite

SUMMARYThe range of hosts used by a parasite is influenced by macro-evolutionary processes (host switching, host–parasite co-evolution), as well as ‘encounter filters’ and ‘compatibility filters’ at the micro-evolutionary level driven by host/parasite ecology and physiology. Host specialization is hypothesized to result in trade-offs with aspects of parasite life history (e.g. reproductive output), but these have not been well studied. We used previously published data to create models examining general relationships among host specificity and important aspects of life history and reproduction for nematodes parasitizing animals. Our results indicate no general trade-off between host specificity and the average pre-patent period (time to first reproduction), female size, egg size, or fecundity of these nematodes. However, female size was positively related to egg size, fecundity, and pre-patent period. Host compatibility may thus not be the primary determinant of specificity in these parasitic nematodes if there are few apparent trade-offs with reproduction, but rather, the encounter opportunities for new host species at the micro-evolutionary level, and other processes at the macro-evolutionary level (i.e. phylogeny). Because host specificity is recognized as a key factor determining the spread of parasitic diseases understanding factors limiting host use are essential to predict future changes in parasite range and occurrence.

scholarly journals Variation at range margins across multiple spatial scales: environmental temperature, population genetics and metabolomic phenotype

2009 ◽  
Vol 276 (1661) ◽  
pp. 1495-1506 ◽  
Author(s):  
William E Kunin ◽  
Philippine Vergeer ◽  
Tanaka Kenta ◽  
Matthew P Davey ◽  
Terry Burke ◽  
...  
Keyword(s):  
Spatial Scales ◽  
Physical Distance ◽  
Population Variation ◽  
Regional Patterns ◽  
Range Margin ◽  
Arabidopsis Lyrata ◽  
Perennial Plant ◽  
Temperature Regimes ◽  
Population Structures ◽  
Genetic Profiles

Range margins are spatially complex, with environmental, genetic and phenotypic variations occurring across a range of spatial scales. We examine variation in temperature, genes and metabolomic profiles within and between populations of the subalpine perennial plant Arabidopsis lyrata ssp. petraea from across its northwest European range. Our surveys cover a gradient of fragmentation from largely continuous populations in Iceland, through more fragmented Scandinavian populations, to increasingly widely scattered populations at the range margin in Scotland, Wales and Ireland. Temperature regimes vary substantially within some populations, but within-population variation represents a larger fraction of genetic and especially metabolomic variances. Both physical distance and temperature differences between sites are found to be associated with genetic profiles, but not metabolomic profiles, and no relationship was found between genetic and metabolomic population structures in any region. Genetic similarity between plants within populations is the highest in the fragmented populations at the range margin, but differentiation across space is the highest there as well, suggesting that regional patterns of genetic diversity may be scale dependent.

scholarly journals Developmental plasticity evolved according to specialist–generalist trade-offs in experimental populations of Drosophila melanogaster

2016 ◽  
Vol 12 (7) ◽  
pp. 20160379 ◽  
Author(s):  
Jacqueline Le Vinh Thuy ◽  
John M. VandenBrooks ◽  
Michael J. Angilletta
Keyword(s):  
Drosophila Melanogaster ◽  
Developmental Plasticity ◽  
Evolutionary Patterns ◽  
Trade Offs ◽  
Experimental Populations ◽  
Fluctuating Temperatures

We studied the evolution of developmental plasticity in populations of Drosophila melanogaster that evolved at either constant or fluctuating temperatures. Consistent with theory, genotypes that evolved at a constant 16°C or 25°C performed best when raised and tested at that temperature. Genotypes that evolved at fluctuating temperatures performed well at either temperature, but only when raised and tested at the same temperature. Our results confirm evolutionary patterns predicted by theory, including a loss of plasticity and a benefit of specialization in constant environments.

Periodic and Resident Components in Communities of Atlantic Fishes

1971 ◽  
Vol 28 (7) ◽  
pp. 935-946 ◽  
Author(s):  
A. V. Tyler
Keyword(s):  
Temperature Fluctuation ◽  
Published Data ◽  
Regular Component ◽  
Component Structure ◽  
Fourth Group ◽  
Temperature Regimes ◽  
Passamaquoddy Bay ◽  
Periodic Components ◽  
Small Periodic

From trawling at least monthly on a station in Passamaquoddy Bay, N.B., four groups of species were distinguished. One group of species was present on station during winter only, another group in summer only, and a third group was present throughout the year. A fourth group of species was present only occasionally. This type of temporal component structure was found in previously published data for stations with similar habitat but at different latitudes and different temperature regimes. With increased annual temperature fluctuation by locality, there were proportionately more species in the periodic components and fewer in the regular component. Comparable tropical communities had very small periodic components.

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