Individual Specialization and Multihost Epidemics: Disease Spread in Plant-Pollinator Networks
The American Naturalist, Ahead of Print. (Source: The American Naturalist)
Source: The American Naturalist - April 2, 2020 Category: Zoology Authors: Stephen P. Ellner Wee Hao Ng Christopher R. Myers Source Type: research

Vertical Transmission of a Nematode from Female Lizards to the Brains of Their Offspring
The American Naturalist, Ahead of Print. (Source: The American Naturalist)
Source: The American Naturalist - March 31, 2020 Category: Zoology Authors: Nathalie Feiner Sueli de Souza-Lima F átima Jorge Soraya Naem Fabien Aubret Tobias Uller Steven A. Nadler Source Type: research

Factors That Can Affect the Spatial Positioning of Large and Small Individuals in Clusters of Sit-and-Wait Predators.
Abstract Shadow competition, the interception of prey by sit-and-wait predators closest to the source of prey arrival, is prevalent in clusters of sit-and-wait predators. Peripheral positions in the cluster receive more prey and should thus be more frequently occupied. Models predicting spatial positioning in groups, however, usually ignore variability among group members. Here, I used a simulation model to determine conditions under which small and large sit-and-wait predators, which differ in their attack range, should differ in their spatial positions in the cluster. Small predators occupied peripheral position...
Source: The American Naturalist - March 30, 2020 Category: Biology Authors: Scharf I Tags: Am Nat Source Type: research

Maintenance of Fertility in the Face of Meiotic Drive.
Abstract Selfish genetic elements that gain a transmission advantage through the destruction of sperm have grave implications for drive male fertility. In the X-linked meiotic drive system (SR) of a stalk-eyed fly, we found that SR males have greatly enlarged testes and maintain high fertility despite the destruction of half of their sperm, even when challenged with fertilizing large numbers of females. Conversely, we observed reduced allocation of resources to the accessory glands that probably explains the lower mating frequency of SR males. Body size and eye span were also reduced, which are likely to impair vi...
Source: The American Naturalist - March 30, 2020 Category: Biology Authors: Meade L, Finnegan SR, Kad R, Fowler K, Pomiankowski A Tags: Am Nat Source Type: research

Body Size, Light Intensity, and Nutrient Supply Determine Plankton Stoichiometry in Mixotrophic Plankton Food Webs.
Abstract Trophic strategy determines stoichiometry of plankton. In general, heterotrophic zooplankton have lower and more stable C∶N and C∶P ratios than photoautotrophic phytoplankton, whereas mixotrophic protists, which consume prey and photosynthesize, have stoichiometry between zooplankton and phytoplankton. As trophic strategies change with cell size, body size may be a key trait influencing eukaryotic plankton stoichiometry. However, the relationship between body size and stoichiometry remains unclear. Here we measured plankton size-fractionated C∶N ratios under different intensities of light and nutrie...
Source: The American Naturalist - March 30, 2020 Category: Biology Authors: Ho PC, Chang CW, Shiah FK, Wang PL, Hsieh CH, Andersen KH Tags: Am Nat Source Type: research

Life-History Plasticity and Water-Use Trade-Offs Associated with Drought Resistance in a Clade of California Jewelflowers.
Abstract Water limitation is a primary driver of plant geographic distributions and individual plant fitness. Drought resistance is the ability to survive and reproduce despite limited water, and numerous studies have explored its physiological basis in plants. However, it is unclear how drought resistance and trade-offs associated with drought resistance evolve within plant clades. We quantified the relationship between water availability and fitness for 13 short-lived plant taxa in the Streptanthus clade that vary in their phenology and the availability of water in the environments where they occur. We derived t...
Source: The American Naturalist - March 30, 2020 Category: Biology Authors: Pearse IS, Aguilar JM, Strauss SY Tags: Am Nat Source Type: research

When Do Individuals Maximize Their Inclusive Fitness?
Abstract Adaptation is often described in behavioral ecology as individuals maximizing their inclusive fitness. Under what conditions does this hold, and how does this relate to the gene-centered perspective of adaptation? We unify and extend the literature on these questions to class-structured populations. We demonstrate that the maximization (in the best-response sense) of class-specific inclusive fitness obtains in uninvadable population states (meaning that all deviating mutants become extinct). This defines a genuine actor-centered perspective on adaptation. But this inclusive fitness is assigned to all bear...
Source: The American Naturalist - March 30, 2020 Category: Biology Authors: Lehmann L, Rousset F Tags: Am Nat Source Type: research

Ecological and Evolutionary Stochasticity Shape Natural Selection.
Abstract The distribution of biodiversity depends on the combined and interactive effects of ecological and evolutionary processes. The joint contribution of these processes has focused almost exclusively on deterministic effects, even though mechanisms that increase the importance of random ecological processes are expected to also increase the importance of random evolutionary processes. Here we manipulate the sizes of old field fragments to generate correlated sampling effects for a focal population (a gall maker) and its enemy community. Traits and communities were more variable in smaller patches. However, be...
Source: The American Naturalist - March 30, 2020 Category: Biology Authors: Start D, Weis AE, Gilbert B Tags: Am Nat Source Type: research

Flies Exploit Predictable Perspectives and Backgrounds to Enhance Iridescent Signal Salience and Mating Success.
Abstract Communication requires both the encoding of information and its effective transmission, but little is known about display traits that primarily serve to enhance efficacy. Here we examined the visual courtships of Lispe cana, a cursorial fly that lives and mates in heterogeneous foreshores, and tested the prediction that males should seek to enhance signal salience and consequent fitness through the flexible choice of display locations. We show that courting males access the field of view of females by straddling them and holding their wings closed before moving ahead to present their structurally colored ...
Source: The American Naturalist - March 30, 2020 Category: Biology Authors: White TE, Vogel-Ghibely N, Butterworth NJ Tags: Am Nat Source Type: research

Pathogens and Mutualists as Joint Drivers of Host Species Coexistence and Turnover: Implications for Plant Competition and Succession.
Abstract The potential for either pathogens or mutualists to alter the outcome of interactions between host species has been clearly demonstrated experimentally, but our understanding of their joint influence remains limited. Individually, pathogens and mutualists can each stabilize (via negative feedback) or destabilize (via positive feedback) host-host interactions. When pathogens and mutualists are both present, the potential for simultaneous positive and negative feedbacks can generate a wide range of possible effects on host species coexistence and turnover. Extending existing theoretical frameworks, we explo...
Source: The American Naturalist - March 30, 2020 Category: Biology Authors: Jiang J, Abbott KC, Baudena M, Eppinga MB, Umbanhowar JA, Bever JD Tags: Am Nat Source Type: research

Belowground Competition Can Influence the Evolution of Root Traits.
Abstract Although root traits play a critical role in mediating plant-plant interactions and resource acquisition from the soil environment, research examining whether and how belowground competition can influence the evolution of root traits remains largely unexplored. Here we examine the possibility that root traits may evolve as a target of selection from interspecific competition using Ipomoea purpurea and I. hederacea, two closely related morning glory species that commonly co-occur in the United States, as a model system. We show that belowground competitive interactions between the two species can alter the...
Source: The American Naturalist - March 30, 2020 Category: Biology Authors: Colom SM, Baucom RS Tags: Am Nat Source Type: research

Thermal Variability and Plasticity Drive the Outcome of a Host-Pathogen Interaction.
Abstract Variable, changing climates may affect each participant in a biotic interaction differently. We explored the effects of temperature and plasticity on the outcome of a host-pathogen interaction to try to predict the outcomes of infection under fluctuating temperatures. We infected Gryllus veletis crickets with the entomopathogenic fungus Metarhizium brunneum under constant (6°, 12°, 18°, or 25°C) or fluctuating (from 6° to 18°C or from 6° to 25°C) temperatures. We also acclimated crickets and fungi to constant or fluctuating conditions. Crickets acclimated to fluctuating con...
Source: The American Naturalist - March 30, 2020 Category: Biology Authors: Ferguson LV, Sinclair BJ Tags: Am Nat Source Type: research

An Empirical Test of the Role of Small-Scale Transmission in Large-Scale Disease Dynamics.
Abstract A key assumption of epidemiological models is that population-scale disease spread is driven by close contact between hosts and pathogens. At larger scales, however, mechanisms such as spatial structure in host and pathogen populations and environmental heterogeneity could alter disease spread. The assumption that small-scale transmission mechanisms are sufficient to explain large-scale infection rates, however, is rarely tested. Here, we provide a rigorous test using an insect-baculovirus system. We fit a mathematical model to data from forest-wide epizootics while constraining the model parameters with ...
Source: The American Naturalist - March 30, 2020 Category: Biology Authors: Mihaljevic JR, Polivka CM, Mehmel CJ, Li C, Dukic V, Dwyer G Tags: Am Nat Source Type: research

Safety Cues Can Give Prey More Valuable Information Than Danger Cues.
Abstract The ability of prey to assess predation risk is fundamental to their success. It is routinely assumed that predator cues do not vary in reliability across levels of predation risk. We propose that cues can differ in how precisely they indicate different levels of predation risk. What we call danger cues precisely indicate high risk levels, while safety cues precisely indicate low risk levels. Using optimality modeling, we find that prey fitness is increased when prey pay more attention to safety cues than to danger cues. This fitness advantage is greater when prey need to protect assets, predators are mor...
Source: The American Naturalist - March 30, 2020 Category: Biology Authors: Luttbeg B, Ferrari MCO, Blumstein DT, Chivers DP Tags: Am Nat Source Type: research

Competitive Exclusion and Evolution: Convergence Almost Never Produces Ecologically Equivalent Species: (A Comment on McPeek, "Limiting Similarity? The Ecological Dynamics of Natural Selection among Resources and Consumers Caused by Both Apparent and Resource Competition").
Competitive Exclusion and Evolution: Convergence Almost Never Produces Ecologically Equivalent Species: (A Comment on McPeek, "Limiting Similarity? The Ecological Dynamics of Natural Selection among Resources and Consumers Caused by Both Apparent and Resource Competition"). Am Nat. 2020 Apr;195(4):E112-E117 Authors: Pásztor L, Barabás G, Meszéna G Abstract In a recent modeling study ("Limiting Similarity? The Ecological Dynamics of Natural Selection among Resources and Consumers Caused by Both Apparent and Resource Competition") that appeared in the April 2019 ...
Source: The American Naturalist - March 30, 2020 Category: Biology Authors: Pásztor L, Barabás G, Meszéna G Tags: Am Nat Source Type: research

Adaptive Maternal Investment in the Wild? Links between Maternal Growth Trajectory and Offspring Size, Growth, and Survival in Contrasting Environments.
Abstract Life-history theory predicts that investment per offspring should correlate negatively with the quality of the environment that offspring are anticipated to encounter; parents may use their own experience as juveniles to predict this environment and may modulate offspring traits, such as growth capacity and initial size. We manipulated nutrient levels in the juvenile habitat of wild Atlantic salmon (Salmo salar) to investigate the hypothesis that the egg size that maximizes juvenile growth and survival depends on environmental quality. We also tested whether offspring traits were related to parental growt...
Source: The American Naturalist - March 30, 2020 Category: Biology Authors: Burton T, Rollinson N, McKelvey S, Stewart DC, Armstrong JD, Metcalfe NB Tags: Am Nat Source Type: research

Reinforcement Learning Theory Reveals the Cognitive Requirements for Solving the Cleaner Fish Market Task.
ary R Abstract Learning is an adaptation that allows individuals to respond to environmental stimuli in ways that improve their reproductive outcomes. The degree of sophistication in learning mechanisms potentially explains variation in behavioral responses. Here, we present a model of learning that is inspired by documented intra- and interspecific variation in the performance of a simultaneous two-choice task, the biological market task. The task presents a problem that cleaner fish often face in nature: choosing between two client types, one that is willing to wait for inspection and one that may leave if ignor...
Source: The American Naturalist - March 30, 2020 Category: Biology Authors: Quiñones AE, Leimar O, Lotem A, Bshary R Tags: Am Nat Source Type: research

How Long Does It Take to Fix a Favorable Mutation, and Why Should We Care?
The American Naturalist, Ahead of Print. (Source: The American Naturalist)
Source: The American Naturalist - March 30, 2020 Category: Zoology Authors: Brian Charlesworth Source Type: research

Front and Back Matter
The American Naturalist,Volume 195, Issue 4, April 2020. (Source: The American Naturalist)
Source: The American Naturalist - March 27, 2020 Category: Zoology Source Type: research

Parental Age Effects and the Evolution of Senescence
The American Naturalist, Ahead of Print. (Source: The American Naturalist)
Source: The American Naturalist - March 24, 2020 Category: Zoology Authors: Patrick M. Barks Robert A. Laird Source Type: research

Selection for Rhythm as a Trigger for Recursive Evolution in the Elaborate Display System of Woodpeckers
The American Naturalist, Ahead of Print. (Source: The American Naturalist)
Source: The American Naturalist - March 24, 2020 Category: Zoology Authors: Meredith C. Miles Eric R. Schuppe Matthew J. Fuxjager Source Type: research

Ecological Transitions in Grouping Benefits Explain the Paradox of Environmental Quality and Sociality
The American Naturalist, Ahead of Print. (Source: The American Naturalist)
Source: The American Naturalist - March 20, 2020 Category: Zoology Authors: Mark Liu ( 劉彥廷) Shih-Fan Chan ( 詹仕凡) Dustin R. Rubenstein Syuan-Jyun Sun ( 孫烜駿) Bo-Fei Chen ( 陳伯飛) Sheng-Feng Shen ( 沈聖峰) Source Type: research

Ecology and Evolution of Blood Oxygen-Carrying Capacity in Birds
The American Naturalist, Ahead of Print. (Source: The American Naturalist)
Source: The American Naturalist - March 20, 2020 Category: Zoology Authors: Piotr Minias Source Type: research

Ecological Limits as the Driver of Bird Species Richness Patterns along the East Himalayan Elevational Gradient
The American Naturalist, Ahead of Print. (Source: The American Naturalist)
Source: The American Naturalist - March 19, 2020 Category: Zoology Authors: Matthew Schumm Alexander E. White K. Supriya Trevor D. Price Source Type: research

Frequency of Occurrence and Population-Dynamic Consequences of Different Forms of Density-Dependent Emigration
The American Naturalist, Ahead of Print. (Source: The American Naturalist)
Source: The American Naturalist - March 18, 2020 Category: Zoology Authors: Rachel R. Harman Jerome Goddard Ratnasingham Shivaji James T. Cronin Source Type: research

Increased Levels of Perceived Competition Decrease Juvenile Kin-Shoaling Preferences in a Cichlid Fish
The American Naturalist, Ahead of Print. (Source: The American Naturalist)
Source: The American Naturalist - March 18, 2020 Category: Zoology Authors: Timo Th ünken Saskia Hesse Denis Meuthen Source Type: research

Revisiting a Landmark Study System: No Evidence for a Punctuated Mode of Evolution in Metrarabdotos
The American Naturalist, Ahead of Print. (Source: The American Naturalist)
Source: The American Naturalist - March 17, 2020 Category: Zoology Authors: Kjetil Lysne Voje Emanuela Di Martino Arthur Porto Source Type: research

Age-Related Brood Parasitism and Egg Rejection in Magpie Hosts
The American Naturalist, Ahead of Print. (Source: The American Naturalist)
Source: The American Naturalist - March 17, 2020 Category: Zoology Authors: Juan Gabriel Mart ínez Mercedes Molina-Morales Marta Precioso Jes ús Miguel Avilés Source Type: research

Prey Exploits the Auditory Illusions of Eavesdropping Predators
The American Naturalist, Ahead of Print. (Source: The American Naturalist)
Source: The American Naturalist - March 12, 2020 Category: Zoology Authors: Henry D. Legett Claire T. Hemingway Ximena E. Bernal Source Type: research

Maintenance of Fertility in the Face of Meiotic Drive
The American Naturalist, Ahead of Print. (Source: The American Naturalist)
Source: The American Naturalist - March 9, 2020 Category: Zoology Authors: Lara Meade Sam Ronan Finnegan Ridhima Kad Kevin Fowler Andrew Pomiankowski Source Type: research

Life-History Plasticity and Water-Use Trade-Offs Associated with Drought Resistance in a Clade of California Jewelflowers
The American Naturalist, Ahead of Print. (Source: The American Naturalist)
Source: The American Naturalist - March 9, 2020 Category: Zoology Authors: Ian S. Pearse Jessica M. Aguilar Sharon Y. Strauss Source Type: research

Belowground Competition Can Influence the Evolution of Root Traits
The American Naturalist, Ahead of Print. (Source: The American Naturalist)
Source: The American Naturalist - March 4, 2020 Category: Zoology Authors: Sara M. Colom Regina S. Baucom Source Type: research

When Do Individuals Maximize Their Inclusive Fitness?
The American Naturalist, Ahead of Print. (Source: The American Naturalist)
Source: The American Naturalist - March 4, 2020 Category: Zoology Authors: Laurent Lehmann Fran çois Rousset Source Type: research

Thermal Variability and Plasticity Drive the Outcome of a Host-Pathogen Interaction
The American Naturalist, Ahead of Print. (Source: The American Naturalist)
Source: The American Naturalist - March 3, 2020 Category: Zoology Authors: Laura V. Ferguson Brent J. Sinclair Source Type: research

Adaptive Maternal Investment in the Wild? Links between Maternal Growth Trajectory and Offspring Size, Growth, and Survival in Contrasting Environments
The American Naturalist, Ahead of Print. (Source: The American Naturalist)
Source: The American Naturalist - March 3, 2020 Category: Zoology Authors: Tim Burton Njal Rollinson Simon McKelvey David C. Stewart John D. Armstrong Neil B. Metcalfe Source Type: research

An Empirical Test of the Role of Small-Scale Transmission in Large-Scale Disease Dynamics
The American Naturalist, Ahead of Print. (Source: The American Naturalist)
Source: The American Naturalist - March 3, 2020 Category: Zoology Authors: Joseph R. Mihaljevic Carlos M. Polivka Constance J. Mehmel Chentong Li Vanja Dukic Greg Dwyer Source Type: research

Reinforcement Learning Theory Reveals the Cognitive Requirements for Solving the Cleaner Fish Market Task
The American Naturalist, Ahead of Print. (Source: The American Naturalist)
Source: The American Naturalist - March 2, 2020 Category: Zoology Authors: Andr és E. Quiñones Olof Leimar Arnon Lotem Redouan Bshary Source Type: research

Competitive Exclusion and Evolution: Convergence Almost Never Produces Ecologically Equivalent Species
The American Naturalist, Ahead of Print. (Source: The American Naturalist)
Source: The American Naturalist - February 28, 2020 Category: Zoology Authors: Liz P ásztor Gy örgy Barabás G éza Meszéna Source Type: research

Flies Exploit Predictable Perspectives and Backgrounds to Enhance Iridescent Signal Salience and Mating Success
The American Naturalist, Ahead of Print. (Source: The American Naturalist)
Source: The American Naturalist - February 28, 2020 Category: Zoology Authors: Thomas E. White Nina Vogel-Ghibely Nathan J. Butterworth Source Type: research

Factors That Can Affect the Spatial Positioning of Large and Small Individuals in Clusters of Sit-and-Wait Predators
The American Naturalist, Ahead of Print. (Source: The American Naturalist)
Source: The American Naturalist - February 28, 2020 Category: Zoology Authors: Inon Scharf Source Type: research

Developmental Constraints Do Not Influence Long-Term Phenotypic Evolution of Marsupial Forelimbs as Revealed by Interspecific Disparity and Integration Patterns.
n RBJ Abstract Marsupials show a smaller range of forelimb ecomorphologies than placental mammals, and it is hypothesized that this results from macroevolutionary constraints imposed by the specialized reproductive biology of marsupials. Specifically, the accelerated development of the marsupial forelimb allows neonates to crawl to the mother's pouch but may constrain adult morphology. This hypothesis makes three main predictions: (i) that marsupial forelimbs should show less interspecific disparity than their hindlimbs, (ii) that morphological integration within the marsupial forelimb is stronger than integration...
Source: The American Naturalist - February 26, 2020 Category: Biology Authors: Martín-Serra A, Benson RBJ Tags: Am Nat Source Type: research

A General Model for Seed and Seedling Respiratory Metabolism.
Abstract The ontogeny of seed plants usually involves a dormant dehydrated state and the breaking of dormancy and germination, which distinguishes it from that of most organisms. Seed germination and seedling establishment are critical ontogenetic stages in the plant life cycle, and both are fueled by respiratory metabolism. However, the scaling of metabolic rate with respect to individual traits remains poorly understood. Here, we tested metabolic scaling theory during seed germination and early establishment growth using a recently developed model and empirical data collected from 41 species. The results show th...
Source: The American Naturalist - February 26, 2020 Category: Biology Authors: Huang H, Ran J, Li X, Wang Z, Chen R, Wu F, Ye M, Jia F, Niklas KJ, Deng J Tags: Am Nat Source Type: research

Tolerance of Novel Toxins through Generalized Mechanisms: Simulating Gradual Host Shifts of Butterflies.
Abstract Organisms encounter a wide range of toxic compounds in their environments, from chemicals that serve anticonsumption or anticompetition functions to pollutants and pesticides. Although we understand many detoxification mechanisms that allow organisms to consume toxins typical of their diet, we know little about why organisms vary in their ability to tolerate entirely novel toxins. We tested whether variation in generalized stress responses, such as antioxidant pathways, may underlie variation in reactions to novel toxins and, if so, their associated costs. We used an artificial diet to present cabbage whi...
Source: The American Naturalist - February 26, 2020 Category: Biology Authors: Sikkink KL, Hostager R, Kobiela ME, Fremling N, Johnston K, Zambre A, Snell-Rood EC Tags: Am Nat Source Type: research

Local Adaptation to Biotic Interactions: A Meta-analysis across Latitudes.
Abstract Adaptation to local conditions can increase species' geographic distributions and rates of diversification, but which components of the environment commonly drive local adaptation-particularly the importance of biotic interactions-is unclear. Biotic interactions should drive local adaptation when they impose consistent divergent selection; if this is common, we expect transplant experiments to detect more frequent and stronger local adaptation when biotic interactions are left intact. We tested this hypothesis using a meta-analysis of transplant experiments from>125 studies (mostly of plants). Overall,...
Source: The American Naturalist - February 26, 2020 Category: Biology Authors: Hargreaves AL, Germain RM, Bontrager M, Persi J, Angert AL Tags: Am Nat Source Type: research

Context Dependence of Local Adaptation to Abiotic and Biotic Environments: A Quantitative and Qualitative Synthesis.
Abstract Understanding how spatially variable selection shapes adaptation is an area of long-standing interest in evolutionary ecology. Recent meta-analyses have quantified the extent of local adaptation, but the relative importance of abiotic and biotic factors in driving population divergence remains poorly understood. To address this gap, we combined a quantitative meta-analysis and a qualitative metasynthesis to (1) quantify the magnitude of local adaptation to abiotic and biotic factors and (2) characterize major themes that influence the motivation and design of experiments that seek to test for local adapta...
Source: The American Naturalist - February 26, 2020 Category: Biology Authors: Briscoe Runquist RD, Gorton AJ, Yoder JB, Deacon NJ, Grossman JJ, Kothari S, Lyons MP, Sheth SN, Tiffin P, Moeller DA Tags: Am Nat Source Type: research

Stochasticity and Infectious Disease Dynamics: Density and Weather Effects on a Fungal Insect Pathogen.
Abstract In deterministic models of epidemics, there is a host abundance threshold above which the introduction of a few infected individuals leads to a severe epidemic. Studies of weather-driven animal pathogens often assume that abundance thresholds will be overwhelmed by weather-driven stochasticity, but tests of this assumption are lacking. We collected observational and experimental data for a fungal pathogen, Entomophaga maimaiga, that infects the gypsy moth, Lymantria dispar. We used an advanced statistical-computing algorithm to fit mechanistic models to our data, such that different models made different ...
Source: The American Naturalist - February 26, 2020 Category: Biology Authors: Kyle CH, Liu J, Gallagher ME, Dukic V, Dwyer G Tags: Am Nat Source Type: research

Stochastic Dynamics of Three Competing Clones: Conditions and Times for Invasion, Coexistence, and Fixation.
Abstract In large clonal populations, several clones generally compete, resulting in complex evolutionary and ecological dynamics: experiments show successive selective sweeps of favorable mutations as well as long-term coexistence of multiple clonal strains. The mechanisms underlying either coexistence or fixation of several competing strains have rarely been studied altogether. Conditions for coexistence have mostly been studied by population and community ecology, while rates of invasion and fixation have mostly been studied by population genetics. To provide a global understanding of the complexity of the dyna...
Source: The American Naturalist - February 26, 2020 Category: Biology Authors: Billiard S, Smadi C Tags: Am Nat Source Type: research

Evolution Transforms Pushed Waves into Pulled Waves.
Abstract Understanding the dynamics of biological invasions is crucial for managing numerous phenomena, from invasive species to tumors. While the Allee effect (where individuals in low-density populations suffer lowered fitness) is known to influence both the ecological and the evolutionary dynamics of an invasion, the possibility that an invader's susceptibility to the Allee effect might itself evolve has received little attention. Since invasion fronts are regions of perpetually low population density, selection should be expected to favor vanguard invaders that are resistant to Allee effects. This may not only...
Source: The American Naturalist - February 26, 2020 Category: Biology Authors: Erm P, Phillips BL Tags: Am Nat Source Type: research

The Evolution of Egg Trading in Simultaneous Hermaphrodites.
Puebla O Abstract Egg trading-whereby simultaneous hermaphrodites exchange each other's eggs for fertilization-constitutes one of the few rigorously documented and most widely cited examples of direct reciprocity among unrelated individuals. Yet how egg trading may initially invade a population of nontrading simultaneous hermaphrodites is still unresolved. Here, we address this question with an analytical model that considers mate encounter rates and costs of egg production in a population that may include traders (who provide eggs for fertilization only if their partners also have eggs to reciprocate), providers...
Source: The American Naturalist - February 26, 2020 Category: Biology Authors: Peña J, Nöldeke G, Puebla O Tags: Am Nat Source Type: research

Disturbances Can Promote and Hinder Coexistence of Competitors in Ongoing Partner Choice Mutualisms.
Abstract Ecosystems are under threat from anthropogenic and natural disturbances, yet little is known about how these disturbances alter mutualistic interactions. Many mutualistic interactions are highly context dependent and dynamic due to "ongoing" partner choice, impeding our understanding of how disturbances might influence mutualistic systems. Previously we showed that in the absence of additional known mechanisms of competitive coexistence, mutualistic fungi can coexist in a system where the plant community associates dynamically with two empirically defined arbuscular mycorrhizal fungal types: a c...
Source: The American Naturalist - February 26, 2020 Category: Biology Authors: Bachelot B, Lee CT Tags: Am Nat Source Type: research