The Temporal Dimension of Plant-Soil Microbe Interactions: Mechanisms Promoting Feedback between Generations
The American Naturalist, Ahead of Print. (Source: The American Naturalist)
Source: The American Naturalist - July 22, 2021 Category: Zoology Authors: Po-Ju Ke Jonathan M. Levine Source Type: research

Evolution of Anisogamy in Organisms with Parthenogenetic Gametes
The American Naturalist, Ahead of Print. (Source: The American Naturalist)
Source: The American Naturalist - July 21, 2021 Category: Zoology Authors: Jussi Lehtonen Yusuke Horinouchi Tatsuya Togashi Geoff A. Parker Source Type: research

Sexual Dichromatism Is Decoupled from Diversification over Deep Time in Fishes
Am Nat. 2021 Aug;198(2):232-252. doi: 10.1086/715114. Epub 2021 Jun 7.ABSTRACTAbstractSexually selected traits have long been thought to drive diversification, but support for this hypothesis has been persistently controversial. In fishes, sexually dimorphic coloration is associated with assortative mating and speciation among closely related species, as shown in classic studies. However, it is unclear whether these results can generalize to explain diversity patterns across ray-finned fishes, which contain the majority of vertebrate species and 96% of fishes. Here, we use phylogenetic approaches to test for an association...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Elizabeth Christina Miller Sarah L Mesnick John J Wiens Source Type: research

On Male Harm: How It Is Measured and How It Evolves in Different Environments
Am Nat. 2021 Aug;198(2):219-231. doi: 10.1086/715038. Epub 2021 Jun 10.ABSTRACTAbstractMales can harm the females that they interact with, but populations and species widely vary in the occurrence and extent of harm. We consider the merits and limitations of two common approaches to investigating male harm and apply these to an experimental study of divergence in harm. Different physical environments can affect how the sexes interact, causing plastic and/or evolved changes in harm. If harmful male phenotypes are less likely to evolve in situations where females have more control over sexual interactions, populations evolvi...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Li Yun Aneil F Agrawal Howard D Rundle Source Type: research

Resistance Correlations Influence Infection by Foreign Pathogens
We present models describing the genetic basis for assessing resistance relationships between endemic and foreign pathogens and for quantifying infection probabilities on foreign pathogen introduction. We show that even when the foreign pathogen has a lower average infection ability than the endemic pathogen, infection outcomes are determined by the sign and strength of the regression of the host's genetic variation in infection rates by a foreign pathogen on variation in infection rates by an endemic pathogen as well as by resistance allele frequencies. Given that preinvasion equilibria of resistance are determined by fac...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Noah Lerner Victoria Luizzi Janis Antonovics Emily Bruns Michael E Hood Source Type: research

Individual-Level Memory Is Sufficient to Create Spatial Segregation among Neighboring Colonies of Central Place Foragers
Am Nat. 2021 Aug;198(2):E37-E52. doi: 10.1086/715014. Epub 2021 Jun 24.ABSTRACTAbstractCentral place foragers often segregate in space, even without signs of direct agonistic interactions. Using parsimonious individual-based simulations, we show that for species with spatial cognitive abilities, individual-level memory of resource availability can be sufficient to cause spatial segregation in the foraging ranges of colonial animals. The shapes of the foraging distributions are governed by commuting costs, the emerging distribution of depleted resources, and the fidelity of foragers to their colonies. When colony fidelity i...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Geert Aarts Evert Mul John Fieberg Sophie Brasseur Jan A van Gils Jason Matthiopoulos Louise Riotte-Lambert Source Type: research

Coevolutionary Arms Races and the Conditions for the Maintenance of Mutualism
Am Nat. 2021 Aug;198(2):195-205. doi: 10.1086/714274. Epub 2021 May 27.ABSTRACTAbstractEmpirical evidence suggests that coevolutionary arms races between flowering plants and their pollinators can occur in wild populations. In extreme cases, trait escalation may result in evolutionary switching from mutualism to parasitism. However, theoretical approaches to studying coevolution typically assume fixed types of ecological interactions and ignore the evolution of absolute fitness. Here, we introduce a novel approach to track the evolution of absolute fitness as a framework to determine when escalatory coevolution results in ...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Bob Week Scott L Nuismer Source Type: research

Nested versus Independent Sampling: Solving the Mystery of Contradictory Species-Area Relationships
Am Nat. 2021 Aug;198(2):268-277. doi: 10.1086/715143. Epub 2021 Jun 14.ABSTRACTAbstractSpecies-area relationships (SARs) describe how the number of species increases with the size of the area surveyed. They usually take the form of a power law on regional spatial scales. A metareview of empirical data has shown that the exponent of the power law is larger on average when the areas are sampled in a nested manner, compared with sampling of isolated areas such as islands or nature reserves of different sizes. Because this finding contradicts ecological reasoning, we performed computer simulations of three qualitatively differ...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Johannes Reinhard Barbara Drossel Source Type: research

The Context-Dependent Effects of Host Competence, Competition, and Pathogen Transmission Mode on Disease Prevalence
Am Nat. 2021 Aug;198(2):179-194. doi: 10.1086/715110. Epub 2021 Jun 4.ABSTRACTAbstractBiodiversity in communities is changing globally, including the gain and loss of host species in host-pathogen communities. Increased host diversity can cause infection prevalence in a focal host to increase (amplification) or decrease (dilution). However, it is unclear what general rules govern the context-dependent effects, in part because theories for pathogens with different transmission modes have developed largely independently. Using a two-host model, we explore how the pathogen transmission mode and characteristics of a second hos...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Michael H Cortez Meghan A Duffy Source Type: research

A New Diploid Parthenogenetic Whiptail Lizard from Sonora, Mexico, Is the "Missing Link" in the Evolutionary Transition to Polyploidy
Am Nat. 2021 Aug;198(2):295-309. doi: 10.1086/715056. Epub 2021 Jun 4.ABSTRACTAbstractTransitions between sexual and unisexual reproductive modes have significant consequences for the evolutionary trajectories of species. These transitions have occurred numerous times in vertebrates and are frequently mediated by hybridization events. Triploid unisexual vertebrates are thought to arise through hybridization between individuals of a diploid unisexual lineage and a sexual species, although additional evidence that confirms this mechanism is needed in numerous groups. North American whiptail lizards (Aspidoscelis) are notable...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Anthony J Barley Tod W Reeder Adri án Nieto-Montes de Oca Charles J Cole Robert C Thomson Source Type: research

Differences in Thermal Tolerance between Parental Species Could Fuel Thermal Adaptation in Hybrid Wood Ants
Am Nat. 2021 Aug;198(2):278-294. doi: 10.1086/715012. Epub 2021 Jun 3.ABSTRACTAbstractGenetic variability is essential for adaptation and could be acquired via hybridization with a closely related lineage. We use ants to investigate thermal adaptation and the link between temperature and genetic variation arising from hybridization. We test for differences in cold and heat tolerance between Finnish Formica polyctena and Formica aquilonia wood ants and their naturally occurring hybrids. Using workers, we find that the parental individuals differ in both cold and heat tolerances and express thermal limits that reflect their ...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Raphael Martin-Roy Elisa Nyg ård Pierre Nouhaud Jonna Kulmuni Source Type: research

Alternative States in Plant Communities Driven by a Life-History Trade-Off and Demographic Stochasticity
Am Nat. 2021 Aug;198(2):E27-E36. doi: 10.1086/714418. Epub 2021 Jun 1.ABSTRACTAbstractLife-history trade-offs among species are major drivers of community assembly. Most studies investigate how trade-offs promote deterministic coexistence of species. It remains unclear how trade-offs may instead promote historically contingent exclusion of species, where species dominance is affected by initial abundances, causing alternative community states via priority effects. Focusing on the establishment-longevity trade-off, in which high longevity is associated with low competitive ability during establishment, we study the transien...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Niv DeMalach Nadav Shnerb Tadashi Fukami Source Type: research

Emergent Shapes of Trait-Based Competition Functions from Resource-Based Models: A Gaussian Is Not Normal in Plant Communities
Am Nat. 2021 Aug;198(2):253-267. doi: 10.1086/714868. Epub 2021 Jun 4.ABSTRACTAbstractIn community ecology, it is widely assumed that organisms with similar traits compete more intensely with one another for resources. This assumption is often encoded into theory and empirical tests via a unimodal competition function, which predicts that per capita competitive effect declines with separation in traits. Yet it remains unknown how well this function represents the true effect of traits on competitive outcomes, especially for long-lived plant communities, where lifetime fitness is difficult to estimate. Here, we evaluate the...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Daniel S Falster Georges Kunstler Richard G FitzJohn Mark Westoby Source Type: research

Editorial Expression of Concern
Am Nat. 2021 Aug;198(2):313-316. doi: 10.1086/714867. Epub 2021 Jun 1.NO ABSTRACTPMID:34260876 | DOI:10.1086/714867 (Source: The American Naturalist)
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Daniel I Bolnick Jeremy W Fox Florence D ébarre Emma I Dietrich Steve M Phelps Alex Jordan Sorbus Torminalis Source Type: research

Correction
Am Nat. 2021 Aug;198(2):310-312. doi: 10.1086/714866. Epub 2021 Jun 1.NO ABSTRACTPMID:34260877 | DOI:10.1086/714866 (Source: The American Naturalist)
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Jonathan N Pruitt John J Stachowicz Andrew Sih Source Type: research

Sexual Dichromatism Is Decoupled from Diversification over Deep Time in Fishes
Am Nat. 2021 Aug;198(2):232-252. doi: 10.1086/715114. Epub 2021 Jun 7.ABSTRACTAbstractSexually selected traits have long been thought to drive diversification, but support for this hypothesis has been persistently controversial. In fishes, sexually dimorphic coloration is associated with assortative mating and speciation among closely related species, as shown in classic studies. However, it is unclear whether these results can generalize to explain diversity patterns across ray-finned fishes, which contain the majority of vertebrate species and 96% of fishes. Here, we use phylogenetic approaches to test for an association...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Elizabeth Christina Miller Sarah L Mesnick John J Wiens Source Type: research

On Male Harm: How It Is Measured and How It Evolves in Different Environments
Am Nat. 2021 Aug;198(2):219-231. doi: 10.1086/715038. Epub 2021 Jun 10.ABSTRACTAbstractMales can harm the females that they interact with, but populations and species widely vary in the occurrence and extent of harm. We consider the merits and limitations of two common approaches to investigating male harm and apply these to an experimental study of divergence in harm. Different physical environments can affect how the sexes interact, causing plastic and/or evolved changes in harm. If harmful male phenotypes are less likely to evolve in situations where females have more control over sexual interactions, populations evolvi...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Li Yun Aneil F Agrawal Howard D Rundle Source Type: research

Resistance Correlations Influence Infection by Foreign Pathogens
We present models describing the genetic basis for assessing resistance relationships between endemic and foreign pathogens and for quantifying infection probabilities on foreign pathogen introduction. We show that even when the foreign pathogen has a lower average infection ability than the endemic pathogen, infection outcomes are determined by the sign and strength of the regression of the host's genetic variation in infection rates by a foreign pathogen on variation in infection rates by an endemic pathogen as well as by resistance allele frequencies. Given that preinvasion equilibria of resistance are determined by fac...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Noah Lerner Victoria Luizzi Janis Antonovics Emily Bruns Michael E Hood Source Type: research

Individual-Level Memory Is Sufficient to Create Spatial Segregation among Neighboring Colonies of Central Place Foragers
Am Nat. 2021 Aug;198(2):E37-E52. doi: 10.1086/715014. Epub 2021 Jun 24.ABSTRACTAbstractCentral place foragers often segregate in space, even without signs of direct agonistic interactions. Using parsimonious individual-based simulations, we show that for species with spatial cognitive abilities, individual-level memory of resource availability can be sufficient to cause spatial segregation in the foraging ranges of colonial animals. The shapes of the foraging distributions are governed by commuting costs, the emerging distribution of depleted resources, and the fidelity of foragers to their colonies. When colony fidelity i...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Geert Aarts Evert Mul John Fieberg Sophie Brasseur Jan A van Gils Jason Matthiopoulos Louise Riotte-Lambert Source Type: research

Coevolutionary Arms Races and the Conditions for the Maintenance of Mutualism
Am Nat. 2021 Aug;198(2):195-205. doi: 10.1086/714274. Epub 2021 May 27.ABSTRACTAbstractEmpirical evidence suggests that coevolutionary arms races between flowering plants and their pollinators can occur in wild populations. In extreme cases, trait escalation may result in evolutionary switching from mutualism to parasitism. However, theoretical approaches to studying coevolution typically assume fixed types of ecological interactions and ignore the evolution of absolute fitness. Here, we introduce a novel approach to track the evolution of absolute fitness as a framework to determine when escalatory coevolution results in ...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Bob Week Scott L Nuismer Source Type: research

Nested versus Independent Sampling: Solving the Mystery of Contradictory Species-Area Relationships
Am Nat. 2021 Aug;198(2):268-277. doi: 10.1086/715143. Epub 2021 Jun 14.ABSTRACTAbstractSpecies-area relationships (SARs) describe how the number of species increases with the size of the area surveyed. They usually take the form of a power law on regional spatial scales. A metareview of empirical data has shown that the exponent of the power law is larger on average when the areas are sampled in a nested manner, compared with sampling of isolated areas such as islands or nature reserves of different sizes. Because this finding contradicts ecological reasoning, we performed computer simulations of three qualitatively differ...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Johannes Reinhard Barbara Drossel Source Type: research

The Context-Dependent Effects of Host Competence, Competition, and Pathogen Transmission Mode on Disease Prevalence
Am Nat. 2021 Aug;198(2):179-194. doi: 10.1086/715110. Epub 2021 Jun 4.ABSTRACTAbstractBiodiversity in communities is changing globally, including the gain and loss of host species in host-pathogen communities. Increased host diversity can cause infection prevalence in a focal host to increase (amplification) or decrease (dilution). However, it is unclear what general rules govern the context-dependent effects, in part because theories for pathogens with different transmission modes have developed largely independently. Using a two-host model, we explore how the pathogen transmission mode and characteristics of a second hos...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Michael H Cortez Meghan A Duffy Source Type: research

A New Diploid Parthenogenetic Whiptail Lizard from Sonora, Mexico, Is the "Missing Link" in the Evolutionary Transition to Polyploidy
Am Nat. 2021 Aug;198(2):295-309. doi: 10.1086/715056. Epub 2021 Jun 4.ABSTRACTAbstractTransitions between sexual and unisexual reproductive modes have significant consequences for the evolutionary trajectories of species. These transitions have occurred numerous times in vertebrates and are frequently mediated by hybridization events. Triploid unisexual vertebrates are thought to arise through hybridization between individuals of a diploid unisexual lineage and a sexual species, although additional evidence that confirms this mechanism is needed in numerous groups. North American whiptail lizards (Aspidoscelis) are notable...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Anthony J Barley Tod W Reeder Adri án Nieto-Montes de Oca Charles J Cole Robert C Thomson Source Type: research

Differences in Thermal Tolerance between Parental Species Could Fuel Thermal Adaptation in Hybrid Wood Ants
Am Nat. 2021 Aug;198(2):278-294. doi: 10.1086/715012. Epub 2021 Jun 3.ABSTRACTAbstractGenetic variability is essential for adaptation and could be acquired via hybridization with a closely related lineage. We use ants to investigate thermal adaptation and the link between temperature and genetic variation arising from hybridization. We test for differences in cold and heat tolerance between Finnish Formica polyctena and Formica aquilonia wood ants and their naturally occurring hybrids. Using workers, we find that the parental individuals differ in both cold and heat tolerances and express thermal limits that reflect their ...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Raphael Martin-Roy Elisa Nyg ård Pierre Nouhaud Jonna Kulmuni Source Type: research

Alternative States in Plant Communities Driven by a Life-History Trade-Off and Demographic Stochasticity
Am Nat. 2021 Aug;198(2):E27-E36. doi: 10.1086/714418. Epub 2021 Jun 1.ABSTRACTAbstractLife-history trade-offs among species are major drivers of community assembly. Most studies investigate how trade-offs promote deterministic coexistence of species. It remains unclear how trade-offs may instead promote historically contingent exclusion of species, where species dominance is affected by initial abundances, causing alternative community states via priority effects. Focusing on the establishment-longevity trade-off, in which high longevity is associated with low competitive ability during establishment, we study the transien...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Niv DeMalach Nadav Shnerb Tadashi Fukami Source Type: research

Emergent Shapes of Trait-Based Competition Functions from Resource-Based Models: A Gaussian Is Not Normal in Plant Communities
Am Nat. 2021 Aug;198(2):253-267. doi: 10.1086/714868. Epub 2021 Jun 4.ABSTRACTAbstractIn community ecology, it is widely assumed that organisms with similar traits compete more intensely with one another for resources. This assumption is often encoded into theory and empirical tests via a unimodal competition function, which predicts that per capita competitive effect declines with separation in traits. Yet it remains unknown how well this function represents the true effect of traits on competitive outcomes, especially for long-lived plant communities, where lifetime fitness is difficult to estimate. Here, we evaluate the...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Daniel S Falster Georges Kunstler Richard G FitzJohn Mark Westoby Source Type: research

Editorial Expression of Concern
Am Nat. 2021 Aug;198(2):313-316. doi: 10.1086/714867. Epub 2021 Jun 1.NO ABSTRACTPMID:34260876 | DOI:10.1086/714867 (Source: The American Naturalist)
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Daniel I Bolnick Jeremy W Fox Florence D ébarre Emma I Dietrich Steve M Phelps Alex Jordan Sorbus Torminalis Source Type: research

Correction
Am Nat. 2021 Aug;198(2):310-312. doi: 10.1086/714866. Epub 2021 Jun 1.NO ABSTRACTPMID:34260877 | DOI:10.1086/714866 (Source: The American Naturalist)
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Jonathan N Pruitt John J Stachowicz Andrew Sih Source Type: research

Sexual Dichromatism Is Decoupled from Diversification over Deep Time in Fishes
Am Nat. 2021 Aug;198(2):232-252. doi: 10.1086/715114. Epub 2021 Jun 7.ABSTRACTAbstractSexually selected traits have long been thought to drive diversification, but support for this hypothesis has been persistently controversial. In fishes, sexually dimorphic coloration is associated with assortative mating and speciation among closely related species, as shown in classic studies. However, it is unclear whether these results can generalize to explain diversity patterns across ray-finned fishes, which contain the majority of vertebrate species and 96% of fishes. Here, we use phylogenetic approaches to test for an association...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Elizabeth Christina Miller Sarah L Mesnick John J Wiens Source Type: research

On Male Harm: How It Is Measured and How It Evolves in Different Environments
Am Nat. 2021 Aug;198(2):219-231. doi: 10.1086/715038. Epub 2021 Jun 10.ABSTRACTAbstractMales can harm the females that they interact with, but populations and species widely vary in the occurrence and extent of harm. We consider the merits and limitations of two common approaches to investigating male harm and apply these to an experimental study of divergence in harm. Different physical environments can affect how the sexes interact, causing plastic and/or evolved changes in harm. If harmful male phenotypes are less likely to evolve in situations where females have more control over sexual interactions, populations evolvi...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Li Yun Aneil F Agrawal Howard D Rundle Source Type: research

Resistance Correlations Influence Infection by Foreign Pathogens
We present models describing the genetic basis for assessing resistance relationships between endemic and foreign pathogens and for quantifying infection probabilities on foreign pathogen introduction. We show that even when the foreign pathogen has a lower average infection ability than the endemic pathogen, infection outcomes are determined by the sign and strength of the regression of the host's genetic variation in infection rates by a foreign pathogen on variation in infection rates by an endemic pathogen as well as by resistance allele frequencies. Given that preinvasion equilibria of resistance are determined by fac...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Noah Lerner Victoria Luizzi Janis Antonovics Emily Bruns Michael E Hood Source Type: research

Individual-Level Memory Is Sufficient to Create Spatial Segregation among Neighboring Colonies of Central Place Foragers
Am Nat. 2021 Aug;198(2):E37-E52. doi: 10.1086/715014. Epub 2021 Jun 24.ABSTRACTAbstractCentral place foragers often segregate in space, even without signs of direct agonistic interactions. Using parsimonious individual-based simulations, we show that for species with spatial cognitive abilities, individual-level memory of resource availability can be sufficient to cause spatial segregation in the foraging ranges of colonial animals. The shapes of the foraging distributions are governed by commuting costs, the emerging distribution of depleted resources, and the fidelity of foragers to their colonies. When colony fidelity i...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Geert Aarts Evert Mul John Fieberg Sophie Brasseur Jan A van Gils Jason Matthiopoulos Louise Riotte-Lambert Source Type: research

Coevolutionary Arms Races and the Conditions for the Maintenance of Mutualism
Am Nat. 2021 Aug;198(2):195-205. doi: 10.1086/714274. Epub 2021 May 27.ABSTRACTAbstractEmpirical evidence suggests that coevolutionary arms races between flowering plants and their pollinators can occur in wild populations. In extreme cases, trait escalation may result in evolutionary switching from mutualism to parasitism. However, theoretical approaches to studying coevolution typically assume fixed types of ecological interactions and ignore the evolution of absolute fitness. Here, we introduce a novel approach to track the evolution of absolute fitness as a framework to determine when escalatory coevolution results in ...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Bob Week Scott L Nuismer Source Type: research

Nested versus Independent Sampling: Solving the Mystery of Contradictory Species-Area Relationships
Am Nat. 2021 Aug;198(2):268-277. doi: 10.1086/715143. Epub 2021 Jun 14.ABSTRACTAbstractSpecies-area relationships (SARs) describe how the number of species increases with the size of the area surveyed. They usually take the form of a power law on regional spatial scales. A metareview of empirical data has shown that the exponent of the power law is larger on average when the areas are sampled in a nested manner, compared with sampling of isolated areas such as islands or nature reserves of different sizes. Because this finding contradicts ecological reasoning, we performed computer simulations of three qualitatively differ...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Johannes Reinhard Barbara Drossel Source Type: research

The Context-Dependent Effects of Host Competence, Competition, and Pathogen Transmission Mode on Disease Prevalence
Am Nat. 2021 Aug;198(2):179-194. doi: 10.1086/715110. Epub 2021 Jun 4.ABSTRACTAbstractBiodiversity in communities is changing globally, including the gain and loss of host species in host-pathogen communities. Increased host diversity can cause infection prevalence in a focal host to increase (amplification) or decrease (dilution). However, it is unclear what general rules govern the context-dependent effects, in part because theories for pathogens with different transmission modes have developed largely independently. Using a two-host model, we explore how the pathogen transmission mode and characteristics of a second hos...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Michael H Cortez Meghan A Duffy Source Type: research

A New Diploid Parthenogenetic Whiptail Lizard from Sonora, Mexico, Is the "Missing Link" in the Evolutionary Transition to Polyploidy
Am Nat. 2021 Aug;198(2):295-309. doi: 10.1086/715056. Epub 2021 Jun 4.ABSTRACTAbstractTransitions between sexual and unisexual reproductive modes have significant consequences for the evolutionary trajectories of species. These transitions have occurred numerous times in vertebrates and are frequently mediated by hybridization events. Triploid unisexual vertebrates are thought to arise through hybridization between individuals of a diploid unisexual lineage and a sexual species, although additional evidence that confirms this mechanism is needed in numerous groups. North American whiptail lizards (Aspidoscelis) are notable...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Anthony J Barley Tod W Reeder Adri án Nieto-Montes de Oca Charles J Cole Robert C Thomson Source Type: research

Differences in Thermal Tolerance between Parental Species Could Fuel Thermal Adaptation in Hybrid Wood Ants
Am Nat. 2021 Aug;198(2):278-294. doi: 10.1086/715012. Epub 2021 Jun 3.ABSTRACTAbstractGenetic variability is essential for adaptation and could be acquired via hybridization with a closely related lineage. We use ants to investigate thermal adaptation and the link between temperature and genetic variation arising from hybridization. We test for differences in cold and heat tolerance between Finnish Formica polyctena and Formica aquilonia wood ants and their naturally occurring hybrids. Using workers, we find that the parental individuals differ in both cold and heat tolerances and express thermal limits that reflect their ...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Raphael Martin-Roy Elisa Nyg ård Pierre Nouhaud Jonna Kulmuni Source Type: research

Alternative States in Plant Communities Driven by a Life-History Trade-Off and Demographic Stochasticity
Am Nat. 2021 Aug;198(2):E27-E36. doi: 10.1086/714418. Epub 2021 Jun 1.ABSTRACTAbstractLife-history trade-offs among species are major drivers of community assembly. Most studies investigate how trade-offs promote deterministic coexistence of species. It remains unclear how trade-offs may instead promote historically contingent exclusion of species, where species dominance is affected by initial abundances, causing alternative community states via priority effects. Focusing on the establishment-longevity trade-off, in which high longevity is associated with low competitive ability during establishment, we study the transien...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Niv DeMalach Nadav Shnerb Tadashi Fukami Source Type: research

Emergent Shapes of Trait-Based Competition Functions from Resource-Based Models: A Gaussian Is Not Normal in Plant Communities
Am Nat. 2021 Aug;198(2):253-267. doi: 10.1086/714868. Epub 2021 Jun 4.ABSTRACTAbstractIn community ecology, it is widely assumed that organisms with similar traits compete more intensely with one another for resources. This assumption is often encoded into theory and empirical tests via a unimodal competition function, which predicts that per capita competitive effect declines with separation in traits. Yet it remains unknown how well this function represents the true effect of traits on competitive outcomes, especially for long-lived plant communities, where lifetime fitness is difficult to estimate. Here, we evaluate the...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Daniel S Falster Georges Kunstler Richard G FitzJohn Mark Westoby Source Type: research

Editorial Expression of Concern
Am Nat. 2021 Aug;198(2):313-316. doi: 10.1086/714867. Epub 2021 Jun 1.NO ABSTRACTPMID:34260876 | DOI:10.1086/714867 (Source: The American Naturalist)
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Daniel I Bolnick Jeremy W Fox Florence D ébarre Emma I Dietrich Steve M Phelps Alex Jordan Sorbus Torminalis Source Type: research

Correction
Am Nat. 2021 Aug;198(2):310-312. doi: 10.1086/714866. Epub 2021 Jun 1.NO ABSTRACTPMID:34260877 | DOI:10.1086/714866 (Source: The American Naturalist)
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Jonathan N Pruitt John J Stachowicz Andrew Sih Source Type: research

Sexual Dichromatism Is Decoupled from Diversification over Deep Time in Fishes
Am Nat. 2021 Aug;198(2):232-252. doi: 10.1086/715114. Epub 2021 Jun 7.ABSTRACTAbstractSexually selected traits have long been thought to drive diversification, but support for this hypothesis has been persistently controversial. In fishes, sexually dimorphic coloration is associated with assortative mating and speciation among closely related species, as shown in classic studies. However, it is unclear whether these results can generalize to explain diversity patterns across ray-finned fishes, which contain the majority of vertebrate species and 96% of fishes. Here, we use phylogenetic approaches to test for an association...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Elizabeth Christina Miller Sarah L Mesnick John J Wiens Source Type: research

On Male Harm: How It Is Measured and How It Evolves in Different Environments
Am Nat. 2021 Aug;198(2):219-231. doi: 10.1086/715038. Epub 2021 Jun 10.ABSTRACTAbstractMales can harm the females that they interact with, but populations and species widely vary in the occurrence and extent of harm. We consider the merits and limitations of two common approaches to investigating male harm and apply these to an experimental study of divergence in harm. Different physical environments can affect how the sexes interact, causing plastic and/or evolved changes in harm. If harmful male phenotypes are less likely to evolve in situations where females have more control over sexual interactions, populations evolvi...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Li Yun Aneil F Agrawal Howard D Rundle Source Type: research

Resistance Correlations Influence Infection by Foreign Pathogens
We present models describing the genetic basis for assessing resistance relationships between endemic and foreign pathogens and for quantifying infection probabilities on foreign pathogen introduction. We show that even when the foreign pathogen has a lower average infection ability than the endemic pathogen, infection outcomes are determined by the sign and strength of the regression of the host's genetic variation in infection rates by a foreign pathogen on variation in infection rates by an endemic pathogen as well as by resistance allele frequencies. Given that preinvasion equilibria of resistance are determined by fac...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Noah Lerner Victoria Luizzi Janis Antonovics Emily Bruns Michael E Hood Source Type: research

Individual-Level Memory Is Sufficient to Create Spatial Segregation among Neighboring Colonies of Central Place Foragers
Am Nat. 2021 Aug;198(2):E37-E52. doi: 10.1086/715014. Epub 2021 Jun 24.ABSTRACTAbstractCentral place foragers often segregate in space, even without signs of direct agonistic interactions. Using parsimonious individual-based simulations, we show that for species with spatial cognitive abilities, individual-level memory of resource availability can be sufficient to cause spatial segregation in the foraging ranges of colonial animals. The shapes of the foraging distributions are governed by commuting costs, the emerging distribution of depleted resources, and the fidelity of foragers to their colonies. When colony fidelity i...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Geert Aarts Evert Mul John Fieberg Sophie Brasseur Jan A van Gils Jason Matthiopoulos Louise Riotte-Lambert Source Type: research

Coevolutionary Arms Races and the Conditions for the Maintenance of Mutualism
Am Nat. 2021 Aug;198(2):195-205. doi: 10.1086/714274. Epub 2021 May 27.ABSTRACTAbstractEmpirical evidence suggests that coevolutionary arms races between flowering plants and their pollinators can occur in wild populations. In extreme cases, trait escalation may result in evolutionary switching from mutualism to parasitism. However, theoretical approaches to studying coevolution typically assume fixed types of ecological interactions and ignore the evolution of absolute fitness. Here, we introduce a novel approach to track the evolution of absolute fitness as a framework to determine when escalatory coevolution results in ...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Bob Week Scott L Nuismer Source Type: research

Nested versus Independent Sampling: Solving the Mystery of Contradictory Species-Area Relationships
Am Nat. 2021 Aug;198(2):268-277. doi: 10.1086/715143. Epub 2021 Jun 14.ABSTRACTAbstractSpecies-area relationships (SARs) describe how the number of species increases with the size of the area surveyed. They usually take the form of a power law on regional spatial scales. A metareview of empirical data has shown that the exponent of the power law is larger on average when the areas are sampled in a nested manner, compared with sampling of isolated areas such as islands or nature reserves of different sizes. Because this finding contradicts ecological reasoning, we performed computer simulations of three qualitatively differ...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Johannes Reinhard Barbara Drossel Source Type: research

The Context-Dependent Effects of Host Competence, Competition, and Pathogen Transmission Mode on Disease Prevalence
Am Nat. 2021 Aug;198(2):179-194. doi: 10.1086/715110. Epub 2021 Jun 4.ABSTRACTAbstractBiodiversity in communities is changing globally, including the gain and loss of host species in host-pathogen communities. Increased host diversity can cause infection prevalence in a focal host to increase (amplification) or decrease (dilution). However, it is unclear what general rules govern the context-dependent effects, in part because theories for pathogens with different transmission modes have developed largely independently. Using a two-host model, we explore how the pathogen transmission mode and characteristics of a second hos...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Michael H Cortez Meghan A Duffy Source Type: research

A New Diploid Parthenogenetic Whiptail Lizard from Sonora, Mexico, Is the "Missing Link" in the Evolutionary Transition to Polyploidy
Am Nat. 2021 Aug;198(2):295-309. doi: 10.1086/715056. Epub 2021 Jun 4.ABSTRACTAbstractTransitions between sexual and unisexual reproductive modes have significant consequences for the evolutionary trajectories of species. These transitions have occurred numerous times in vertebrates and are frequently mediated by hybridization events. Triploid unisexual vertebrates are thought to arise through hybridization between individuals of a diploid unisexual lineage and a sexual species, although additional evidence that confirms this mechanism is needed in numerous groups. North American whiptail lizards (Aspidoscelis) are notable...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Anthony J Barley Tod W Reeder Adri án Nieto-Montes de Oca Charles J Cole Robert C Thomson Source Type: research

Differences in Thermal Tolerance between Parental Species Could Fuel Thermal Adaptation in Hybrid Wood Ants
Am Nat. 2021 Aug;198(2):278-294. doi: 10.1086/715012. Epub 2021 Jun 3.ABSTRACTAbstractGenetic variability is essential for adaptation and could be acquired via hybridization with a closely related lineage. We use ants to investigate thermal adaptation and the link between temperature and genetic variation arising from hybridization. We test for differences in cold and heat tolerance between Finnish Formica polyctena and Formica aquilonia wood ants and their naturally occurring hybrids. Using workers, we find that the parental individuals differ in both cold and heat tolerances and express thermal limits that reflect their ...
Source: The American Naturalist - July 14, 2021 Category: Biology Authors: Raphael Martin-Roy Elisa Nyg ård Pierre Nouhaud Jonna Kulmuni Source Type: research