Within-species leaf size–number trade-offs in herbaceous angiosperms

Botany ◽  
2012 ◽  
Vol 90 (3) ◽  
pp. 223-235 ◽  
Author(s):  
Stephanie L. Scott ◽  
Lonnie W. Aarssen
Keyword(s):  
Natural Populations ◽  
Negative Relationship ◽  
Leaf Size ◽  
Dry Mass ◽  
Species Level ◽  
Trade Off ◽  
Plant Body ◽  
Trade Offs ◽  
Body Sizes ◽  
Plant Level

Leafing intensity—number of leaves produced per unit of supporting (nonleaf, aboveground) dry mass—determines the size of a plant’s “bud bank”, i.e., the number of axillary meristems per unit plant body or shoot size. This in turn determines the plant’s capacity for flexible and economic meristem deployment strategies as vegetative or reproductive structures. From recent research, it is now widely established that leafing intensity has a strong and isometrically negative relationship with individual leaf mass at the between-species level for both woody and herbaceous species. In the present study of 24 natural populations of herbaceous angiosperms, we show that these two traits also have a general trade-off relationship at the between-plant level within a species. Smaller resident reproductive (i.e., mature) plants generally produced smaller leaves, and plants with smaller leaves generally had higher leafing intensity, in most cases involving an isometric trade-off. For several species, however, the trade-off was allometric—i.e., plants with smaller leaves, which also had generally smaller body sizes, had generally greater than proportionally higher leafing intensity. This parallels results of an earlier study at the between-species level suggesting that, when plant body size is relatively small, there may be a premium—in terms of maximizing fitness—on relatively high leafing intensity. The latter, it is proposed, may function in maximizing the capacity for “reproductive economy”, i.e., successful reproduction despite intense size suppression owing to competition.

scholarly journals Conflicting functional effects of xylem pit structure relate to the growth-longevity trade-off in a conifer species

2019 ◽  
Vol 116 (30) ◽  
pp. 15282-15287 ◽  
Author(s):  
Beth Roskilly ◽  
Eric Keeling ◽  
Sharon Hood ◽  
Arnaud Giuggiola ◽  
Anna Sala
Keyword(s):  
Life History ◽  
Pinus Ponderosa ◽  
Growth Rates ◽  
Morphological Traits ◽  
Natural Populations ◽  
Negative Relationship ◽  
Multiple Traits ◽  
Conifer Species ◽  
Trade Off ◽  
Trade Offs

Consistent with a ubiquitous life history trade-off, trees exhibit a negative relationship between growth and longevity both among and within species. However, the mechanistic basis of this life history trade-off is not well understood. In addition to resource allocation conflicts among multiple traits, functional conflicts arising from individual morphological traits may also contribute to life history trade-offs. We hypothesized that conflicting functional effects of xylem structural traits contribute to the growth-longevity trade-off in trees. We tested this hypothesis by examining the extent to which xylem morphological traits (i.e., wood density, tracheid diameters, and pit structure) relate to growth rates and longevity in two natural populations of the conifer speciesPinus ponderosa. Hydraulic constraints arise as trees grow larger and xylem anatomical traits adjust to compensate. We disentangled the effects of size through ontogeny in individual trees and growth rates among trees on xylem traits by sampling each tree at multiple trunk diameters. We found that the oldest trees had slower lifetime growth rates compared with younger trees in the studied populations, indicating a growth-longevity trade-off. We further provide evidence that a single xylem trait, pit structure, with conflicting effects on xylem function (hydraulic safety and efficiency) relates to the growth-longevity trade-off in a conifer species. This study highlights that, in addition to trade-offs among multiple traits, functional constraints based on individual morphological traits like that of pit structure provide mechanistic insight into how and when life history trade-offs arise.

scholarly journals Warmer temperatures attenuate the classic offspring number and reproductive investment trade-off in the common lizard, Zootoca vivipara

2016 ◽  
Vol 12 (6) ◽  
pp. 20160101 ◽  
Author(s):  
Alexis Rutschmann ◽  
Donald B. Miles ◽  
Jean Clobert ◽  
Murielle Richard
Keyword(s):  
Life History ◽  
Environmental Conditions ◽  
Life History Traits ◽  
Natural Populations ◽  
Trade Off ◽  
Offspring Number ◽  
Common Lizard ◽  
Trade Offs ◽  
Zootoca Vivipara ◽  
The Common

Life-history traits involved in trade-offs are known to vary with environmental conditions. Here, we evaluate the response of the trade-off between ‘offspring number’ versus ‘energy invested per offspring’ to ambient temperature in 11 natural populations of the common lizard, Zootoca vivipara . We provide evidence at both the intra- and interpopulation levels that the trade-off is reduced with an increase in air temperature. If this effect enhances current individual fitness, it may lead to an accelerated pace of life in warmer environments and could ultimately increase adult mortality. In the context of global warming, our results advocate the need for more studies in natural populations to explore interactions between life-history traits' trade-offs and environmental conditions.

scholarly journals Phenotypic plasticity and diversity in insects

2010 ◽  
Vol 365 (1540) ◽  
pp. 593-603 ◽  
Author(s):  
Armin P. Moczek
Keyword(s):  
Gene Expression ◽  
Phenotypic Plasticity ◽  
Natural Populations ◽  
Evolutionary Developmental Biology ◽  
Life Cycles ◽  
Biological Organization ◽  
Trade Off ◽  
Evolutionary Innovation ◽  
Trade Offs ◽  
Evolutionary Trajectories

Phenotypic plasticity in general and polyphenic development in particular are thought to play important roles in organismal diversification and evolutionary innovation. Focusing on the evolutionary developmental biology of insects, and specifically that of horned beetles, I explore the avenues by which phenotypic plasticity and polyphenic development have mediated the origins of novelty and diversity. Specifically, I argue that phenotypic plasticity generates novel targets for evolutionary processes to act on, as well as brings about trade-offs during development and evolution, thereby diversifying evolutionary trajectories available to natural populations. Lastly, I examine the notion that in those cases in which phenotypic plasticity is underlain by modularity in gene expression, it results in a fundamental trade-off between degree of plasticity and mutation accumulation. On one hand, this trade-off limits the extent of plasticity that can be accommodated by modularity of gene expression. On the other hand, it causes genes whose expression is specific to rare environments to accumulate greater variation within species, providing the opportunity for faster divergence and diversification between species, compared with genes expressed across environments. Phenotypic plasticity therefore contributes to organismal diversification on a variety of levels of biological organization, thereby facilitating the evolution of novel traits, new species and complex life cycles.

scholarly journals Heat hardening in a pair of Anolis lizards: constraints, dynamics, and ecological consequences

2021 ◽  
pp. jeb.240994
Author(s):  
Sean W. Deery ◽  
Julie E. Rej ◽  
Daniel Haro ◽  
Alex. R. Gunderson
Keyword(s):  
Heat Shock ◽  
Heat Tolerance ◽  
Negative Relationship ◽  
Anolis Carolinensis ◽  
Biophysical Model ◽  
Published Data ◽  
Lizard Species ◽  
Trade Off ◽  
Trade Offs ◽  
Heat Hardening

Heat tolerance plasticity is predicted to be an important buffer against global warming. Nonetheless, basal heat tolerance often correlates negatively with tolerance plasticity (“Trade-off Hypothesis”), a constraint that could limit plasticity benefits. We tested the trade-off hypothesis at the individual level with respect to heat hardening in two lizard species, Anolis carolinensis and A. sagrei. Heat hardening is a rapid increase in heat tolerance after heat shock that is rarely measured in reptiles but is generally considered a first line of physiological defense against heat. We also employed a biophysical model of operative habitat temperatures to estimate the performance consequences of hardening under ecologically relevant conditions. Anolis carolinensis hardened by two hours post heat shock and maintained hardening for several hours. However, A. sagrei did not harden. Biophysical models showed that hardening in A. carolinensis reduces their overheating risk in the field. Therefore, while not all lizards heat harden, hardening has benefits for species that can. We initially found a negative relationship between basal tolerance and hardening within both species, consistent with the trade-off hypothesis. However, permutation analyses showed that the apparent trade-offs could not be differentiated from statistical artifact. We found the same result when we re-analyzed published data supporting the trade-off hypothesis in another lizard species. Our results show that false positives may be common when testing the trade-off hypothesis. Statistical approaches that account for this are critical to ensure that the hypothesis, which has broad implications for thermal adaptation and responses to warming, is assessed appropriately.

scholarly journals Heterotrophic eukaryotes show a slow-fast continuum, not a gleaner–exploiter trade-off

2020 ◽  
Vol 117 (40) ◽  
pp. 24893-24899
Author(s):  
Thomas Kiørboe ◽  
Mridul K. Thomas
Keyword(s):  
Positive Relationship ◽  
Ingestion Rate ◽  
Negative Relationship ◽  
Large Mammals ◽  
Ecological Processes ◽  
Trade Off ◽  
Trade Offs ◽  
Wide Range ◽  
Fast Gradient ◽  
Using Data

Gleaners and exploiters (opportunists) are organisms adapted to feeding in nutritionally poor and rich environments, respectively. A trade-off between these two strategies—a negative relationship between the rate at which organisms can acquire food and ingest it—is a critical assumption in many ecological models. Here, we evaluate evidence for this trade-off across a wide range of heterotrophic eukaryotes from unicellular nanoflagellates to large mammals belonging to both aquatic and terrestrial realms. Using data on the resource acquisition and ingestion rates in >500 species, we find no evidence of a trade-off across species. Instead, there is a positive relationship between maximum clearance rate and maximum ingestion rate. The positive relationship is not a result of lumping together diverse taxa; it holds within all subgroups of organisms we examined as well. Correcting for differences in body mass weakens but does not reverse the positive relationship, so this is not an artifact of size scaling either. Instead, this positive relationship represents a slow–fast gradient in the “pace of life” that overrides the expected gleaner–exploiter trade-off. Other trade-offs must therefore shape ecological processes, and investigating them may provide deeper insights into coexistence, competitive dynamics, and biodiversity patterns in nature. A plausible target for study is the well-documented trade-off between growth rate and predation avoidance, which can also drive the slow–fast gradient we observe here.

scholarly journals Consistency of demographic trade-offs across tropical forests

2021 ◽  
Author(s):  
Stephan Kambach ◽  
Richard Condit ◽  
Salomón Aguilar ◽  
Helge Bruelheide ◽  
Sarayudh Bunyavejchewin ◽  
...  
Keyword(s):  
Tropical Forest ◽  
Tropical Forests ◽  
Large Scale ◽  
Negative Relationship ◽  
Trade Off ◽  
Growth And Survival ◽  
Trade Offs ◽  
Tree Communities ◽  
Demographic Processes ◽  
Tropical Forest Dynamics

All species must balance their allocation to growth, survival and recruitment. Among trees, evolution has resulted in different strategies of partitioning resources to these key demographic processes, i.e. demographic trade-offs. It is unclear whether the same demographic trade-offs structure tropical forests worldwide. Here, we used data from 13 large-scale and long-term tropical forest plots to estimate the principal trade-offs in growth, survival, recruitment, and tree stature at each site. For ten sites, two trade-offs appeared repeatedly. One trade-off showed a negative relationship between growth and survival, i.e. the well-known fast−slow continuum. The second trade-off distinguished between tall-statured species and species with high recruitment rates, i.e. a stature−recruitment trade-off. Thus, the fast-slow continuum and tree stature are two independent dimensions structuring most tropical tree communities. Our discovery of the consistency of demographic trade-offs and strategies across forest types in three continents substantially improves our ability to predict tropical forest dynamics worldwide.

scholarly journals On being the right size: increased body size is associated with reduced telomere length under natural conditions

2015 ◽  
Vol 282 (1820) ◽  
pp. 20152331 ◽  
Author(s):  
Thor Harald Ringsby ◽  
Henrik Jensen ◽  
Henrik Pärn ◽  
Thomas Kvalnes ◽  
Winnie Boner ◽  
...  
Keyword(s):  
Body Size ◽  
Telomere Length ◽  
Natural Populations ◽  
Negative Relationship ◽  
House Sparrows ◽  
Selection Regime ◽  
Trade Offs ◽  
Length Changes ◽  
The Relationship ◽  
Telomere Dynamics

Evolution of body size is likely to involve trade-offs between body size, growth rate and longevity. Within species, larger body size is associated with faster growth and ageing, and reduced longevity, but the cellular processes driving these relationships are poorly understood. One mechanism that might play a key role in determining optimal body size is the relationship between body size and telomere dynamics. However, we know little about how telomere length is affected when selection for larger size is imposed in natural populations. We report here on the relationship between structural body size and telomere length in wild house sparrows at the beginning and end of a selection regime for larger parent size that was imposed for 4 years in an isolated population of house sparrows. A negative relationship between fledgling size and telomere length was present at the start of the selection; this was extended when fledgling size increased under the selection regime, demonstrating a persistent covariance between structural size and telomere length. Changes in telomere dynamics, either as a correlated trait or a consequence of larger size, could reduce potential longevity and the consequent trade-offs could thereby play an important role in the evolution of optimal body size.

scholarly journals The growth−survival and stature−recruitment  trade-offs structure the majority of tropical forests.

2021 ◽  
Author(s):  
Stephan Kambach ◽  
Richard Condit ◽  
Salomón Aguilar ◽  
Helge Bruelheide ◽  
Sarayudh Bunyavejchewin ◽  
...  
Keyword(s):  
Tropical Forest ◽  
Tropical Forests ◽  
Large Scale ◽  
Negative Relationship ◽  
Trade Off ◽  
Growth And Survival ◽  
Trade Offs ◽  
Tree Communities ◽  
Demographic Processes ◽  
Tropical Forest Dynamics

All species must balance their allocation to growth, survival and recruitment. Among trees, evolution has resulted in different strategies of partitioning resources to these key demographic processes, i.e. demographic trade-offs. It is unclear whether the same demographic trade-offs structure tropical forests worldwide. Here, we used data from 13 large-scale and long-term tropical forest plots to estimate the principal trade-offs in growth, survival, recruitment, and tree stature at each site. For ten sites, two trade-offs appeared repeatedly. One trade-off showed a negative relationship between growth and survival, i.e. the well-known fast−slow continuum. The second trade-off distinguished between tall-statured species and species with high recruitment rates, i.e. a stature−recruitment trade-off. Thus, the fast-slow continuum and tree stature are two independent dimensions structuring most tropical tree communities. Our discovery of the consistency of demographic trade-offs and strategies across forest types in three continents substantially improves our ability to predict tropical forest dynamics worldwide.

Plant population dynamics

2007 ◽  
Author(s):  
Michael J. Crawley
Keyword(s):  
Population Dynamics ◽  
Competitive Ability ◽  
Plant Population ◽  
Plant Population Dynamics ◽  
Trade Off ◽  
Trade Offs ◽  
Generation Times ◽  
High Death ◽  
Body Sizes ◽  
Rapid Generation

Plants exhibit an extraordinary range of sizes and generation times, from single-celled algae with body sizes of the order of 5 mm and generation times of the order of 1 day, to massive forest trees more than 50 m tall that can live for over 1000 years. Diatoms and trees have the virtue of being easy to count, so it is natural to seek to model the dynamics of changes in numbers. On the other hand, many herbaceous perennials (like clonal herbs or turf-forming grasses) are difficult or impossible to count, and for these plants it is natural to model the dynamics of fluctuation in biomass or proportional space occupancy. The theory of plant population dynamics is linked to the rest of plant biology through a series of fundamental trade-offs, reflecting the fact that individual plants are constrained in what they can do. There are important trade-offs in reproduction because a plant could produce many small seeds or a few large seeds, but it is not an option to produce many large seeds. Other trade-offs involve investment decisions: for instance a plant can invest in growth or defence and this leads to a trade-off between competitive ability and palatability to herbivores. Alternatively, high growth rate in full sun may trade-off against a high death rate in low light (the cost of shade tolerance). An important set of trade-offs involve competing demands for resource capture. Thus a plant could invest in its root system to forage for phosphorus, or in its shoot system to forage for light, but it cannot maximise investment in competitive ability for light and soil nutrients. Finally, there is an important trade-off between competition and colonization because good dispersers tend to be inferior competitors; this is exemplified by the r-K continuum where colonizers (r strategists) have a set of traits like rapid generation time, small seeds, wind dispersal, and high light requirements, whereas late successional species (K strategists) tend to live longer, produce fewer, larger seeds, and to have more shade-tolerant, slowergrowing juveniles. Underpinning the theory of plant population dynamics is the invasion criterion, which states that all persistent populations must exhibit the tendency to increase when rare.

scholarly journals Reproductive trade-offs of the estuarine copepod Eurytemora affinis under different thermal and haline regimes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Anissa Souissi ◽  
Jiang-Shiou Hwang ◽  
Sami Souissi
Keyword(s):  
Clutch Size ◽  
Egg Size ◽  
Abiotic Factors ◽  
Negative Relationship ◽  
Cold Temperature ◽  
Female Size ◽  
Eurytemora Affinis ◽  
Trade Off ◽  
Trade Offs ◽  
Higher Temperature

AbstractCopepod females invest a quantity of resources in their reproduction. Depending on several biotic and abiotic factors and their evolutionary history a trade-off can be commonly observed between producing a large number of smaller offspring or a small number of larger offspring. In this study, a multi-generational approach was applied to determine whether a trade-off between clutch size and egg size existed in the copepod Eurytemora affinis under different controlled conditions of temperature and salinity. This protocol was based on the follow-up of reproductive (Clutch Size ‘CS’, Egg Diameter ‘ED’) and morphological (Prosome Length ‘PL’) traits during several generations. Copepods were acclimated to cold (7 °C) and warm (20 °C) temperatures, and then their reproductive output was tested at the higher temperature of 24 °C. CS and ED were positively correlated to PL, so as a first step linear regressions between each reproductive trait and female PL were performed. The residuals from the regression lines of CS and ED with PL were calculated to remove the effect of female size. When the normalized data (residuals) of CS and ED plotted together a negative relationship between egg size and egg number revealed the existence of a trade-off. Copepod populations initially acclimated to cold temperature are commonly characterized by relatively smaller CS and larger ED. Conversely, warm temperature adapted females produced relatively larger CS and smaller ED. After transfer to a temperature of 24 °C, the ED did not change but the CS showed high variability indicating stressful conditions and no trade-off was observed. These observations suggest that E. affinis is able to modulate its reproduction depending on the encountered temperature. It seems that this copepod species can shift between a K- and an r-strategy in response to colder or warmer conditions. In a late winter-early spring like cold temperature, copepod females seem to invest more on offspring quality by producing relatively larger eggs. This ecological strategy ensures a high recruitment of the spring generation that is responsible for the strength of the maximum population size usually observed in late spring-early summer (May–June). To the contrary, at summer-like temperature, where the population density decreases significantly in the Seine estuary, copepod females seem to switch from K to r strategy by favoring offspring number compared to offspring size. Finally, the use of a higher temperature of 24 °C seems to disrupt the observed reproductive trade-off even after several generations. These results suggest that a switching between K- or r-strategy of E. affinis depends highly on temperature effects. The effect of salinity increase during a summer-like temperature of 20 °C as well as after transfer to 24 °C decreased PL and CS but the ED did not change significantly.

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