Phenotypic plasticity in evolutionary rescue experiments

Population persistence in a new and stressful environment can be influenced by the plastic phenotypic responses of individuals to this environment, and by the genetic evolution of plasticity itself. This process has recently been investigated theoretically, but testing the quantitative predictions in the wild is challenging because (i) there are usually not enough population replicates to deal with the stochasticity of the evolutionary process, (ii) environmental conditions are not controlled, and (iii) measuring selection and the inheritance of traits affecting fitness is difficult in natural populations. As an alternative, predictions from theory can be tested in the laboratory with controlled experiments. To illustrate the feasibility of this approach, we briefly review the literature on the experimental evolution of plasticity, and on evolutionary rescue in the laboratory, paying particular attention to differences and similarities between microbes and multicellular eukaryotes. We then highlight a set of questions that could be addressed using this framework, which would enable testing the robustness of theoretical predictions, and provide new insights into areas that have received little theoretical attention to date.

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Evolution of polygenic traits under global vs local adaptation

Genetics ◽

10.1093/genetics/iyab134 ◽

2022 ◽

Vol 220 (1) ◽

Author(s):

Sam Yeaman

Keyword(s):

Local Adaptation ◽

Complex Traits ◽

Genetic Architecture ◽

Population Genomics ◽

Natural Populations ◽

Evolutionary Process ◽

Frequency Effect ◽

Theoretical Predictions ◽

Using Data ◽

And Migration

Abstract Observations about the number, frequency, effect size, and genomic distribution of alleles associated with complex traits must be interpreted in light of evolutionary process. These characteristics, which constitute a trait’s genetic architecture, can dramatically affect evolutionary outcomes in applications from agriculture to medicine, and can provide a window into how evolution works. Here, I review theoretical predictions about the evolution of genetic architecture under spatially homogeneous, global adaptation as compared with spatially heterogeneous, local adaptation. Due to the tension between divergent selection and migration, local adaptation can favor “concentrated” genetic architectures that are enriched for alleles of larger effect, clustered in a smaller number of genomic regions, relative to expectations under global adaptation. However, the evolution of such architectures may be limited by many factors, including the genotypic redundancy of the trait, mutation rate, and temporal variability of environment. I review the circumstances in which predictions differ for global vs local adaptation and discuss where progress can be made in testing hypotheses using data from natural populations and lab experiments. As the field of comparative population genomics expands in scope, differences in architecture among traits and species will provide insights into how evolution works, and such differences must be interpreted in light of which kind of selection has been operating.

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Constraints on plastic responses to climate variation in red deer

Biology Letters ◽

10.1098/rsbl.2005.0352 ◽

2005 ◽

Vol 1 (4) ◽

pp. 457-460 ◽

Cited By ~ 36

Author(s):

Daniel H Nussey ◽

Tim H Clutton-Brock ◽

Steve D Albon ◽

Josephine Pemberton ◽

Loeske E.B Kruuk

Keyword(s):

Life History Traits ◽

Red Deer ◽

Natural Populations ◽

Spring Temperature ◽

Ecological Conditions ◽

In The Wild ◽

Additional Level ◽

Plastic Responses ◽

Phenotypic Responses

Influences of climate on life history traits in natural populations are well documented. However, the implications of between-individual variation in phenotypic plasticity underlying observed trait–environment relationships are rarely considered due to the large, long-term datasets required for such analysis. Studies typically present correlations of annual trait means with climate or assume that individual phenotypic responses are constant. Here, we examine this additional level of variation and show that, in a red deer population on the Isle of Rum, Scotland, changes in climate generate changes in phenotype only amongst individuals who have experienced favourable ecological conditions. Examination of relationships between offspring birth weight and spring temperature within the lifetimes of individual females revealed that the tendency to respond to climate declined as the population density experienced early in life increased. The presence of such systematic variation in individual plasticity is rarely documented in the wild, and has important implications for our understanding of the environmental dependencies of traits under varying ecological conditions.

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On the mod resc Model and the Evolution of Wolbachia Compatibility Types

Genetics ◽

10.1093/genetics/159.4.1415 ◽

2001 ◽

Vol 159 (4) ◽

pp. 1415-1422 ◽

Cited By ~ 1

Author(s):

Sylvain Charlat ◽

Claire Calmet ◽

Hervé Merçot

Keyword(s):

Cytoplasmic Incompatibility ◽

Natural Populations ◽

Evolutionary Process ◽

Embryonic Mortality ◽

Step Process ◽

Zygote Development ◽

Specific Manner

Abstract Cytoplasmic incompatibility (CI) is induced by the endocellular bacterium Wolbachia. It results in an embryonic mortality occurring when infected males mate with uninfected females. The mechanism involved is currently unknown, but the mod resc model allows interpretation of all observations made so far. It postulates the existence of two bacterial functions: modification (mod) and rescue (resc). The mod function acts in the males' germline, before Wolbachia are shed from maturing sperm. If sperm is affected by mod, zygote development will fail unless resc is expressed in the egg. Interestingly, CI is also observed in crosses between infected males and infected females when the two partners bear different Wolbachia strains, demonstrating that mod and resc interact in a specific manner: Two Wolbachia strains are compatible with each other only if they harbor the same compatibility type. Here we focus on the evolutionary process involved in the emergence of new compatibility types from ancestral ones. We argue that new compatibility types are likely to evolve under a wider range of conditions than previously thought, through a two-step process. First, new mod variants can arise by mutation and spread by drift. This is possible because mod is expressed in males and Wolbachia is transmitted by females. Second, once such a mod variant achieves a certain frequency, it can create the conditions for the deterministic invasion of a new resc variant, allowing the invasion of a new mod resc pair. Furthermore, we show that a stable polymorphism might be maintained in natural populations, allowing the long-term existence of “suicidal” Wolbachia strains.

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An ecological explanation for hyperallometric scaling of reproduction

10.1101/2021.03.12.435090 ◽

2021 ◽

Author(s):

Tomos Potter ◽

Anja Felmy

Keyword(s):

Body Size ◽

Reproductive Output ◽

Resource Competition ◽

Natural Populations ◽

Scaling Exponent ◽

Wild Populations ◽

Wet Season ◽

Size Dependent ◽

In The Wild ◽

The Relationship

AbstractIn wild populations, large individuals have disproportionately higher reproductive output than smaller individuals. We suggest an ecological explanation for this observation: asymmetry within populations in rates of resource assimilation, where greater assimilation causes both increased reproduction and body size. We assessed how the relationship between size and reproduction differs between wild and lab-reared Trinidadian guppies. We show that (i) reproduction increased disproportionately with body size in the wild but not in the lab, where effects of resource competition were eliminated; (ii) in the wild, the scaling exponent was greatest during the wet season, when resource competition is strongest; and (iii) detection of hyperallometric scaling of reproduction is inevitable if individual differences in assimilation are ignored. We propose that variation among individuals in assimilation – caused by size-dependent resource competition, niche expansion, and chance – can explain patterns of hyperallometric scaling of reproduction in natural populations.

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A sink host allows a specialist herbivore to persist in a seasonal source

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2021.1604 ◽

2021 ◽

Vol 288 (1958) ◽

pp. 20211604

Author(s):

Alicja Laska ◽

Sara Magalhães ◽

Mariusz Lewandowski ◽

Ewa Puchalska ◽

Kamila Karpicka-Ignatowska ◽

...

Keyword(s):

Experimental Evolution ◽

Laboratory Experiments ◽

Field Observations ◽

Stepping Stones ◽

Specialist Herbivore ◽

Negative Growth Rate ◽

Evolutionary Rescue ◽

Main Host ◽

Negative Growth

In seasonal environments, sinks that are more persistent than sources may serve as temporal stepping stones for specialists. However, this possibility has to our knowledge, not been demonstrated to date, as such environments are thought to select for generalists, and the role of sinks, both in the field and in the laboratory, is difficult to document. Here, we used laboratory experiments to show that herbivorous arthropods associated with seasonally absent main (source) habitats can endure on a suboptimal (sink) host for several generations, albeit with a negative growth rate. Additionally, they dispersed towards this host less often than towards the main host and accepted it less often than the main host. Finally, repeated experimental evolution attempts revealed no adaptation to the suboptimal host. Nevertheless, field observations showed that arthropods are found in suboptimal habitats when the main habitat is unavailable. Together, these results show that evolutionary rescue in the suboptimal habitat is not possible. Instead, the sink habitat functions as a temporal stepping stone, allowing for the persistence of a specialist when the source habitat is gone.

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The sources of sex differences in aging in annual fishes

10.1101/2020.08.25.266411 ◽

2020 ◽

Author(s):

Martin Reichard ◽

Radim Blažek ◽

Jakub Žák ◽

Petr Kačer ◽

Oldřich Tomášek ◽

...

Keyword(s):

Sex Differences ◽

Social Environment ◽

Social Factors ◽

Environmental Conditions ◽

Natural Populations ◽

Experimental Results ◽

Survival Difference ◽

Captive Populations ◽

Baseline Mortality ◽

In The Wild

AbstractSex differences in lifespan and aging are widespread among animals, with males usually the shorter-lived sex. Despite extensive research interest, it is unclear how lifespan differences between the sexes are modulated by genetic, environmental and social factors. We combined comparative data from natural populations of annual killifishes with experimental results on replicated captive populations, showing that females consistently outlived males in the wild. This sex-specific survival difference persisted in social environment only in two most aggressive species, and ceased completely when social and physical contacts were prevented. Demographically, neither an earlier start nor faster rate of aging accounted for shorter male lifespans, but increased baseline mortality and the lack of mortality deceleration in the oldest age shortened male lifespan. The sexes did not differ in any measure of functional aging we recorded. Overall, we demonstrate that sex differences in lifespan and aging may be ameliorated by modulating social and environmental conditions.

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REPRODUCTION IN CAGE POPULATIONS OF A POLYMORPHISM REGULARLY OBSERVED IN THE NATURAL POPULATIONS OF DROSOPHILA MELANOGASTER IN FRANCE

Genetics ◽

10.1093/genetics/88.4.755 ◽

1978 ◽

Vol 88 (4) ◽

pp. 755-759

Author(s):

Annie Fleuriet

Keyword(s):

Drosophila Melanogaster ◽

Natural Populations ◽

Rate Of Return ◽

Rapid Rate ◽

Experimental Conditions ◽

Co2 Sensitivity ◽

In The Wild ◽

Strong Forces

ABSTRACT Polymorphism for both alleles of a gene ref(2)P, which is a usual trait of French natural populations of Drosophila melanogaster, can be reproduced in experimental conditions. ref(2)P is a gene for resistance to the hereditary, noncontagious Rhabdovirus α, responsible for CO2 sensitivity in Drosophila melanogaster. The equilibrium frequencies observed in cages are the same as in the wild, whether α virus is present or not. The rapid rate of return to these equilibrium frequencies indicates that strong forces, which remain to be determined, are responsible for the maintenance of this polymorphism.

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Ploidy frequencies in plants with ploidy heterogeneity: fitting a general gametic model to empirical population data

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2012.2387 ◽

2013 ◽

Vol 280 (1751) ◽

pp. 20122387 ◽

Cited By ~ 19

Author(s):

Jan Suda ◽

Tomáš Herben

Keyword(s):

Natural Populations ◽

Evolutionary Process ◽

Optimization Procedure ◽

Population Data ◽

Unreduced Gametes ◽

Unreduced Gamete ◽

Model Parameters ◽

Main Mode ◽

Ploidy Levels ◽

Polyploid Formation

Genome duplication (polyploidy) is a recurrent evolutionary process in plants, often conferring instant reproductive isolation and thus potentially leading to speciation. Outcome of the process is often seen in the field as different cytotypes co-occur in many plant populations. Failure of meiotic reduction during gametogenesis is widely acknowledged to be the main mode of polyploid formation. To get insight into its role in the dynamics of polyploidy generation under natural conditions, and coexistence of several ploidy levels, we developed a general gametic model for diploid–polyploid systems. This model predicts equilibrium ploidy frequencies as functions of several parameters, namely the unreduced gamete proportions and fertilities of higher ploidy plants. We used data on field ploidy frequencies for 39 presumably autopolyploid plant species/populations to infer numerical values of the model parameters (either analytically or using an optimization procedure). With the exception of a few species, the model fit was very high. The estimated proportions of unreduced gametes (median of 0.0089) matched published estimates well. Our results imply that conditions for cytotype coexistence in natural populations are likely to be less restrictive than previously assumed. In addition, rather simple models show sufficiently rich behaviour to explain the prevalence of polyploids among flowering plants.

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Captive Hill Mynah Gracula religiosa breeding success: potential for bird conservation in Thailand?

Bird Conservation International ◽

10.1017/s0959270905000651 ◽

2005 ◽

Vol 15 (4) ◽

pp. 327-335 ◽

Cited By ~ 3

Author(s):

MANEE ARCHAWARANON

Keyword(s):

Captive Breeding ◽

Natural Populations ◽

Reproductive Behaviour ◽

Free Access ◽

Bird Conservation ◽

Species Survival ◽

Conservation Problem ◽

In Captivity ◽

In The Wild ◽

Nest Materials

Hill Mynah Gracula religiosa is one of the most popular bird pets worldwide due to its ability to mimic diverse sounds, especially human speech. However, Mynahs have rarely been bred in captivity, so nestlings from natural populations are in large demand, resulting in many populations being threatened with extinction. Both subspecies in Thailand, intermedia and religiosa, are costly and desired in the pet market. Captive breeding is one of the most practical strategies to solve a conservation problem of this nature and this report describes a success in breeding Hill Mynahs in captivity. Mated pairs were given free access to food, nest-cavities and nest materials. Reproductive behaviour in captivity was not different from that in the wild, with the exception that breeding occurred throughout the year, even during the non-breeding season for wild populations. Although there are doubts concerning the reintroduction of captive-bred birds and whether successful Hill Mynah breeding in captivity is an economically competitive alternative to poaching, it ensures species survival in captivity as the risk of extinction increases.

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Captive-bred Atlantic salmon released into the wild have fewer offspring than wild-bred fish and decrease population productivity

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2020.1671 ◽

2020 ◽

Vol 287 (1937) ◽

pp. 20201671

Author(s):

Ronan James O'Sullivan ◽

Tutku Aykanat ◽

Susan E. Johnston ◽

Ger Rogan ◽

Russell Poole ◽

...

Keyword(s):

Atlantic Salmon ◽

Natural Populations ◽

Mixed Population ◽

Lifetime Reproductive Success ◽

Wild Relative ◽

Offspring Survival ◽

Wild Populations ◽

Annual Productivity ◽

In The Wild ◽

Analyse Data

The release of captive-bred animals into the wild is commonly practised to restore or supplement wild populations but comes with a suite of ecological and genetic consequences. Vast numbers of hatchery-reared fish are released annually, ostensibly to restore/enhance wild populations or provide greater angling returns. While previous studies have shown that captive-bred fish perform poorly in the wild relative to wild-bred conspecifics, few have measured individual lifetime reproductive success (LRS) and how this affects population productivity. Here, we analyse data on Atlantic salmon from an intensely studied catchment into which varying numbers of captive-bred fish have escaped/been released and potentially bred over several decades. Using a molecular pedigree, we demonstrate that, on average, the LRS of captive-bred individuals was only 36% that of wild-bred individuals. A significant LRS difference remained after excluding individuals that left no surviving offspring, some of which might have simply failed to spawn, consistent with transgenerational effects on offspring survival. The annual productivity of the mixed population (wild-bred plus captive-bred) was lower in years where captive-bred fish comprised a greater fraction of potential spawners. These results bolster previous empirical and theoretical findings that intentional stocking, or non-intentional escapees, threaten, rather than enhance, recipient natural populations.

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