3,732 results match your criteria American Naturalist[Journal]


Predicting Habitat Choice after Rapid Environmental Change.

Am Nat 2019 May 13;193(5):619-632. Epub 2019 Mar 13.

Decisions made while searching for settlement sites (e.g., nesting, oviposition) often have major fitness implications. Read More

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http://dx.doi.org/10.1086/702590DOI Listing

Effects of Predator Avoidance Behavior on the Coexistence of Competing Prey.

Am Nat 2019 May 7;193(5):E132-E148. Epub 2019 Mar 7.

Predator avoidance behavior, in which prey limit foraging activities in the presence of predation threats, affects the dynamics of many ecological communities. Despite the growing theoretical appreciation of the role predation plays in coexistence, predator avoidance behavior has yet to be incorporated into the theory in a general way. We introduce adaptive avoidance behavior to a consumer-resource model with three trophic levels to ask whether the ability of prey-the middle trophic level-to avoid predators alters their ability to coexist. Read More

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http://dx.doi.org/10.1086/701780DOI Listing

Evolution of the Two Sexes under Internal Fertilization and Alternative Evolutionary Pathways.

Am Nat 2019 May 18;193(5):702-716. Epub 2019 Mar 18.

Transition from isogamy to anisogamy, hence males and females, leads to sexual selection, sexual conflict, sexual dimorphism, and sex roles. Gamete dynamics theory links biophysics of gamete limitation, gamete competition, and resource requirements for zygote survival and assumes broadcast spawning. It makes testable predictions, but most comparative tests use volvocine algae, which feature internal fertilization. Read More

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http://dx.doi.org/10.1086/702588DOI Listing

Heterogeneous Matrix Habitat Drives Species Occurrences in Complex, Fragmented Landscapes.

Am Nat 2019 May 12;193(5):748-754. Epub 2019 Mar 12.

A fundamental tenet of modern ecology and conservation science is the fact that species occurrence in habitat patches can be determined by patch area and isolation. But such island biogeographic models often poorly predict actual species occurrences in structurally complex landscapes that typify most ecosystems. Recent advances in circuit theory have enhanced estimates of species dispersal and can provide powerful ways to predict landscape-scale distribution of species assemblages through integration with island biogeography. Read More

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https://www.journals.uchicago.edu/doi/10.1086/702589
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May 2019
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Higher Nest Predation Favors Rapid Fledging at the Cost of Plumage Quality in Nestling Birds.

Am Nat 2019 May 27;193(5):717-724. Epub 2019 Mar 27.

High predation risk can favor rapid offspring development at the expense of offspring quality. Impacts of rapid development on phenotypic quality should be most readily expressed in traits that minimize fitness costs. We hypothesize that ephemeral traits that are replaced or repaired after a short period of life might express trade-offs in quality as a result of rapid development more strongly than traits used throughout life. Read More

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http://dx.doi.org/10.1086/702856DOI Listing

Predicting the Thermal and Allometric Dependencies of Disease Transmission via the Metabolic Theory of Ecology.

Am Nat 2019 May 4;193(5):661-676. Epub 2019 Apr 4.

The metabolic theory of ecology (MTE) provides a general framework of allometric and thermal dependence that may be useful for predicting how climate change will affect disease spread. Using and a microsporidian gut parasite, we conducted two experiments across a wide thermal range and fitted transmission models that utilize MTE submodels for transmission parameters. We decomposed transmission into contact rate and probability of infection and further decomposed probability of infection into a product of gut residence time (GRT) and per-parasite infection rate of gut cells. Read More

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https://www.journals.uchicago.edu/doi/10.1086/702846
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May 2019
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The Evolutionary Ecology of Metamorphosis.

Am Nat 2019 May 8;193(5):E116-E131. Epub 2019 Mar 8.

Almost all animal species undergo metamorphosis, even though empirical data show that this life-history strategy evolved only a few times. Why is metamorphosis so widespread, and why has it evolved? Here we study the evolution of metamorphosis by using a fully size-structured population model in conjunction with the adaptive-dynamics approach. We assume that individuals compete for two food sources; one of these, the primary food source, is available to individuals of all sizes. Read More

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https://www.journals.uchicago.edu/doi/10.1086/701779
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http://dx.doi.org/10.1086/701779DOI Listing
May 2019
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Sexually Antagonistic Variation and the Evolution of Dimorphic Sexual Systems.

Am Nat 2019 May 4;193(5):688-701. Epub 2019 Apr 4.

Multicellular Eukaryotes use a broad spectrum of sexual reproduction strategies, ranging from simultaneous hermaphroditism to complete dioecy (separate sexes). The evolutionary pathway from hermaphroditism to dioecy involves the spread of sterility alleles that eliminate female or male reproductive functions, producing unisexual individuals. Classical theory predicts that evolutionary transitions to dioecy are feasible when female and male sex functions genetically trade off with one another (allocation to sex functions is sexually antagonistic) and rates of self-fertilization and inbreeding depression are high within the ancestral hermaphrodite population. Read More

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http://dx.doi.org/10.1086/702847DOI Listing

Resolving the Measurement Uncertainty Paradox in Ecological Management.

Am Nat 2019 May 5;193(5):645-660. Epub 2019 Apr 5.

Ecological management and decision-making typically focus on uncertainty about the future, but surprisingly little is known about how to account for uncertainty of the present: that is, the realities of having only partial or imperfect measurements. Our primary paradigms for handling decisions under uncertainty-the precautionary principle and optimal control-have so far given contradictory results. This paradox is best illustrated in the example of fisheries management, where many ideas that guide thinking about ecological decision-making were first developed. Read More

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http://dx.doi.org/10.1086/702704DOI Listing

Larger Area Facilitates Richness-Function Effects in Experimental Microcosms.

Am Nat 2019 May 18;193(5):738-747. Epub 2019 Mar 18.

Species-area relationships (SAR) and biodiversity-ecosystem function (BEF) relationships are central patterns in community ecology. Although research on both patterns often invokes mechanisms of community assembly, both SARs and BEFs are generally treated as separate phenomena. Here we link the two by creating an experimental SAR in microcosm communities and show that greater species richness in larger areas is accompanied by greater ecosystem function. Read More

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https://www.journals.uchicago.edu/doi/10.1086/702705
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May 2019
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Condition-Dependent Begging Elicits Increased Parental Investment in a Wild Bird Population.

Am Nat 2019 May 14;193(5):725-737. Epub 2019 Mar 14.

The coevolution of parental supply and offspring demand has long been thought to involve offspring need driving begging and parental care, leaving other hypotheses underexplored. In a population of wild birds, we experimentally tested whether begging serves as a negatively condition-dependent signal of need or a positively condition-dependent signal of quality. Across multiple years, we supplemented nestling house wrens with food shortly after hatching and simultaneously manipulated corticosterone levels to simulate the hunger-induced increase in glucocorticoids thought to mediate begging. Read More

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https://www.journals.uchicago.edu/doi/10.1086/702848
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May 2019
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Upscaling Microclimatic Conditions into Body Temperature Distributions of Ectotherms.

Am Nat 2019 May 20;193(5):677-687. Epub 2019 Mar 20.

Realistic projections of the biological impacts of climate change require predicting fitness responses to variations in environmental conditions. For ectotherms, this challenge requires methods to scale-up microclimatic information into actual body temperatures, , while dealing with uncertainty regarding individual behaviors and physiological constraints. Here, we propose an information-theoretical model to derive microhabitat selection and distributions of ectotherm populations from microclimatic data. Read More

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https://www.journals.uchicago.edu/doi/10.1086/702717
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May 2019
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When Do Shifts in Trait Dynamics Precede Population Declines?

Am Nat 2019 May 27;193(5):633-644. Epub 2019 Mar 27.

Predicting population responses to environmental change is an ongoing challenge in ecology. Studies investigating the links between fitness-related phenotypic traits and demography have shown that trait dynamic responses to environmental change can sometimes precede population dynamic responses and thus can be used as an early warning signal. However, it is still unknown under which ecological and evolutionary circumstances shifts in fitness-related traits can precede population responses to environmental perturbation. Read More

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http://dx.doi.org/10.1086/702849DOI Listing

Nighttime Ecology: The "Nocturnal Problem" Revisited.

Authors:
Kevin J Gaston

Am Nat 2019 Apr 7;193(4):481-502. Epub 2019 Mar 7.

The existence of a synthetic program of research on what was then termed the "nocturnal problem" and that we might now call "nighttime ecology" was declared more than 70 years ago. In reality, this failed to materialize, arguably as a consequence of practical challenges in studying organisms at night and instead concentrating on the existence of circadian rhythms, the mechanisms that give rise to them, and their consequences. This legacy is evident to this day, with consideration of the ecology of the nighttime markedly underrepresented in ecological research and literature. Read More

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https://www.journals.uchicago.edu/doi/10.1086/702250
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April 2019
15 Reads

Morphological Polymorphism Associated with Alternative Reproductive Tactics in a Plethodontid Salamander.

Am Nat 2019 Apr 1;193(4):608-618. Epub 2019 Mar 1.

Understanding polymorphism is a central problem in evolution and ecology, and alternative reproductive tactics (ARTs) provide compelling examples for studying the origin and maintenance of behavioral and morphological variation. Much attention has been given to examples where "parasitic" individuals exploit the reproductive investment of "bourgeois" individuals, but some ARTs are instead maintained by environmental heterogeneity, with alternative tactics exhibiting differential fitness in discontinuous reproductive niches. We use genomic, behavioral, karyological, and field observational data to demonstrate one such example in plethodontid salamanders. Read More

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http://dx.doi.org/10.1086/702251DOI Listing
April 2019
3 Reads

Prey Responses to Exotic Predators: Effects of Old Risks and New Cues.

Am Nat 2019 Apr 27;193(4):575-587. Epub 2019 Feb 27.

Exotic predators can have major negative impacts on prey. Importantly, prey vary considerably in their behavioral responses to exotic predators. Factors proposed to explain variation in prey response to exotic predators include the similarity of new predators to familiar, native predators, the prevalence and diversity of predators in a prey's past, and variation in a prey's innate ability to discriminate between predators and safety. Read More

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https://www.journals.uchicago.edu/doi/10.1086/702252
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April 2019
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Time Explains Regional Richness Patterns within Clades More Often than Diversification Rates or Area.

Am Nat 2019 Apr 20;193(4):514-529. Epub 2019 Feb 20.

Most groups of organisms occur in multiple regions and have different numbers of species in different regions. These richness patterns are directly explained by speciation, extinction, and dispersal. Thus, regional richness patterns may be explained by differences in when regions were colonized (more time for speciation in regions colonized earlier), differences in how often they were colonized, or differences in diversification rates (speciation minus extinction) among regions (with diversification rates potentially influenced by area, climate, and/or many other variables). Read More

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http://dx.doi.org/10.1086/702253DOI Listing

Speciation Rate Is Independent of the Rate of Evolution of Morphological Size, Shape, and Absolute Morphological Specialization in a Large Clade of Birds.

Am Nat 2019 Apr 6;193(4):E78-E91. Epub 2019 Feb 6.

Whether ecological differences between species evolve in parallel with lineage diversification is a fundamental issue in evolutionary biology. These processes might be connected if conditions that favor the proliferation of species, such as release from competitors, facilitate the evolution of novel ecological relationships. Despite this, phylogenetic studies do not consistently identify such a connection. Read More

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http://dx.doi.org/10.1086/701630DOI Listing
April 2019
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Mate Choice versus Mate Preference: Inferences about Color-Assortative Mating Differ between Field and Lab Assays of Poison Frog Behavior.

Am Nat 2019 Apr 15;193(4):598-607. Epub 2019 Feb 15.

Codivergence of mating traits and mate preferences can lead to behavioral isolation among lineages in early stages of speciation. However, mate preferences limit gene flow only when expressed as mate choice, and numerous factors might be more important than preferences in nature. In the extremely color polytypic strawberry poison frog (Oophaga pumilio), female mate preferences have codiverged with color in most allopatric populations tested. Read More

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http://dx.doi.org/10.1086/702249DOI Listing

Age-Specific Offspring Mortality Economically Tracks Food Abundance in a Piscivorous Seabird.

Am Nat 2019 Apr 20;193(4):588-597. Epub 2019 Feb 20.

Earlier offspring mortality before independence saves resources for kin, which should be more beneficial when food is short. Using 24 years of data on age-specific common tern (Sterna hirundo) chick mortality, best described by the Gompertz function, and estimates of energy consumption per age of mortality, we investigated how energy wasted on nonfledged chicks depends on brood size, hatching order, and annual abundance of herring (Clupea harengus), the main food source. We found mortality directly after hatching (Gompertz baseline mortality) to be high and to increase with decreasing herring abundance. Read More

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https://www.journals.uchicago.edu/doi/10.1086/702304
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http://dx.doi.org/10.1086/702304DOI Listing
April 2019
3 Reads

The Relationship between Spatial Structure and the Maintenance of Diversity in Microbial Populations.

Am Nat 2019 Apr 12;193(4):503-513. Epub 2019 Feb 12.

Spatial structure is pervasive in the microbial world, yet we know little about how it influences the evolution of microbial populations. It is thought that spatial structure limits the scale of competitive interactions and protracts selective sweeps. This may allow microbial populations to simultaneously explore multiple evolutionary paths. Read More

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http://dx.doi.org/10.1086/701799DOI Listing

Stage-Structured Evolutionary Demography: Linking Life Histories, Population Genetics, and Ecological Dynamics.

Am Nat 2019 Apr 11;193(4):545-559. Epub 2019 Mar 11.

Demographic processes and ecological interactions are central to understanding evolution and vice versa. We present a novel framework that combines basic Mendelian genetics with the powerful demographic approach of matrix population models. The ecological components of the model may be stage classified or age classified, linear or nonlinear, time invariant or time varying, and deterministic or stochastic. Read More

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http://dx.doi.org/10.1086/701857DOI Listing

Two-Year Bee, or Not Two-Year Bee? How Voltinism Is Affected by Temperature and Season Length in a High-Elevation Solitary Bee.

Am Nat 2019 Apr 18;193(4):560-574. Epub 2019 Feb 18.

Organisms must often make developmental decisions without complete information about future conditions. This uncertainty-for example, about the duration of conditions favorable for growth-can favor bet-hedging strategies. Here, we investigated the causes of life cycle variation in Osmia iridis, a bee exhibiting a possible bet-hedging strategy with co-occurring 1- and 2-year life cycles. Read More

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https://www.journals.uchicago.edu/doi/10.1086/701826
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http://dx.doi.org/10.1086/701826DOI Listing
April 2019
2 Reads

Grow Where You Thrive, or Where Only You Can Survive? An Analysis of Performance Curve Evolution in a Clade with Diverse Habitat Affinities.

Am Nat 2019 Apr 18;193(4):530-544. Epub 2019 Feb 18.

Performance curves are valuable tools for quantifying the fundamental niches of organisms and testing hypotheses about evolution, life-history trade-offs, and the drivers of variation in species' distribution patterns. Here, we present a novel Bayesian method for characterizing performance curves that facilitates comparisons among species. We then use this model to quantify and compare the hydrological performance curves of 14 different taxa in the genus Lasthenia, an ecologically diverse clade of plants that collectively occupy a variety of habitats with unique hydrological features, including seasonally flooded wetlands called vernal pools. Read More

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http://dx.doi.org/10.1086/701827DOI Listing

Limiting Similarity? The Ecological Dynamics of Natural Selection among Resources and Consumers Caused by Both Apparent and Resource Competition.

Authors:
Mark A McPeek

Am Nat 2019 Apr 17;193(4):E92-E115. Epub 2019 Jan 17.

Much of ecological theory presumes that natural selection should foster species coexistence by phenotypically differentiating competitors so that the stability of the community is increased, but whether this will actually occur is a question of the ecological dynamics of natural selection. I develop an evolutionary model of consumer-resource interactions based on MacArthur's and Tilman's classic works, including both resource and apparent competition, to explore what fosters or retards the differentiation of resources and their consumers. Analyses of this model predict that consumers will differentiate only on specific ranges of environmental gradients (e. Read More

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http://dx.doi.org/10.1086/701629DOI Listing

Predator-Prey Games in Multiple Habitats Reveal Mixed Strategies in Diel Vertical Migration.

Am Nat 2019 Mar 20;193(3):E65-E77. Epub 2018 Dec 20.

Prey and predators continuously react to each other and to their environment, adjusting their behavior to maximize their fitness. In a pelagic environment, organisms can optimize their fitness by performing diel vertical migrations. We applied a game-theoretic approach to investigate the emergent patterns of optimal habitat selection strategies in a multiple-habitat arena. Read More

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http://dx.doi.org/10.1086/701041DOI Listing

Catastrophic Mortality, Allee Effects, and Marine Protected Areas.

Am Nat 2019 Mar 1;193(3):391-408. Epub 2019 Feb 1.

For many species, reproductive failure may occur if abundance drops below critical Allee thresholds for successful breeding, in some cases impeding recovery. At the same time, extreme environmental events can cause catastrophic collapse in otherwise healthy populations. Understanding what natural processes and management strategies may allow for persistence and recovery of natural populations is critical in the face of expected climate change scenarios of increased environmental variability. Read More

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http://dx.doi.org/10.1086/701781DOI Listing

Predator-Prey Models with Competition: The Emergence of Territoriality.

Am Nat 2019 Mar 14;193(3):436-446. Epub 2019 Jan 14.

We introduce a model aimed at shedding light on the emergence of territorial behaviors in predators and on the formation of packs. We consider the situation of predators competing for the same prey (or spatially distributed resource). We observe that strong competition between groups of predators leads to the formation of territories. Read More

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http://dx.doi.org/10.1086/701670DOI Listing

Shifting Vital Rate Correlations Alter Predicted Population Responses to Increasingly Variable Environments.

Am Nat 2019 Mar 7;193(3):E57-E64. Epub 2019 Jan 7.

Time series of vital rates are often used to construct "environment-blind" stochastic population projections and calculate the elasticity of population growth to increased temporal variance in vital rates. Here, we show that the utility of this widely used demographic tool is greatly limited by shifts in vital rate correlations that occur as environmental drivers become increasingly variable. The direction and magnitude of these shifts are unpredictable without environmentally explicit models. Read More

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http://dx.doi.org/10.1086/701043DOI Listing

Brood Size Affects Future Reproduction in a Long-Lived Bird with Precocial Young.

Am Nat 2019 Mar 1;193(3):458-471. Epub 2019 Feb 1.

Estimation of trade-offs between current reproduction and future survival and fecundity of long-lived vertebrates is essential to understanding factors that shape optimal reproductive investment. Black brant geese (Branta bernicla nigricans) fledge more goslings, on average, when their broods are experimentally enlarged to be greater than the most common clutch size of four eggs. Thus, we hypothesized that the lesser frequency of brant clutches exceeding four eggs results, at least partially, from a future reduction in survival, breeding probability, or clutch size for females tending larger broods. Read More

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http://dx.doi.org/10.1086/701783DOI Listing

The Effect of Pollen Limitation on the Evolution of Mating System and Seed Size in Hermaphroditic Plants.

Am Nat 2019 Mar 18;193(3):447-457. Epub 2019 Jan 18.

Pollen limitation, when inadequate pollen receipt results in a plant setting fewer seeds and fruits, can reduce plant reproductive success and promote the evolution of self-fertilization as a mechanism of reproductive assurance. However, the effect of pollen limitation on the joint evolution of mating system and seed size is not known. Using an evolutionarily stable strategy resource allocation model, we show that where moderate pollen limitation and strong inbreeding depression select for complete outcrossing, pollen limitation should also increase the optimal seed size. Read More

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http://dx.doi.org/10.1086/701782DOI Listing

Meeting Yield and Conservation Objectives by Harvesting Both Juveniles and Adults.

Am Nat 2019 Mar 25;193(3):373-390. Epub 2019 Jan 25.

Sustainable yields that are at least 80% of the maximum sustainable yield are sometimes referred to as "pretty good yields" (PGY). The range of PGY harvesting strategies is generally broad and thus leaves room to account for additional objectives besides high yield. Here, we analyze stage-dependent harvesting strategies that realize PGY with conservation as a second objective. Read More

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http://dx.doi.org/10.1086/701631DOI Listing

Indirect Interactions Shape Selection in a Multispecies Food Web.

Am Nat 2019 Mar 17;193(3):321-330. Epub 2019 Jan 17.

Species do not live, interact, or evolve in isolation but are instead members of complex ecological communities. In ecological terms, complex multispecies interactions can be understood by considering indirect effects that are mediated by changes in traits and abundances of intermediate species. Interestingly, traits and abundances are also central to our understanding of phenotypic selection, suggesting that indirect effects may be extended to understand evolution in complex communities. Read More

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http://dx.doi.org/10.1086/701785DOI Listing
March 2019
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Rapid Divergence of Predator Functional Traits Affects Prey Composition in Aquatic Communities.

Am Nat 2019 Mar 23;193(3):331-345. Epub 2019 Jan 23.

Identifying traits that underlie variation in individual performance of consumers (i.e., trait utility) can help reveal the ecological causes of population divergence and the subsequent consequences for species interactions and community structure. Read More

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http://dx.doi.org/10.1086/701784DOI Listing

Shortsighted Evolution Constrains the Efficacy of Long-Term Bet Hedging.

Am Nat 2019 Mar 24;193(3):409-423. Epub 2019 Jan 24.

To survive unpredictable environmental change, many organisms adopt bet-hedging strategies that are initially costly but provide a long-term fitness benefit. The temporal extent of these deferred fitness benefits determines whether bet-hedging organisms can survive long enough to realize them. In this article, we examine a model of microbial bet hedging in which there are two paths to extinction: unpredictable environmental change and demographic stochasticity. Read More

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http://dx.doi.org/10.1086/701786DOI Listing
March 2019
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Conspicuous Plumage Does Not Increase Predation Risk: A Continent-Wide Test Using Model Songbirds.

Am Nat 2019 Mar 23;193(3):359-372. Epub 2019 Jan 23.

The forces shaping female plumage color have long been debated but remain unresolved. Females may benefit from conspicuous colors but are also expected to suffer costs. Predation is one potential cost, but few studies have explicitly investigated the relationship between predation risk and coloration. Read More

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http://dx.doi.org/10.1086/701632DOI Listing

Ecological and Evolutionary Consequences of Viral Plasticity.

Am Nat 2019 Mar 12;193(3):346-358. Epub 2019 Feb 12.

Viruses use the host machinery to replicate, and their performance thus depends on the host's physiological state. For bacteriophages, this link between host and viral performance has been characterized empirically and with intracellular theories. Such theories are too detailed to be included in models that study host-phage interactions in the long term, which hinders our understanding of systems that range from pathogens infecting gut bacteria to marine phage shaping the oceans. Read More

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http://dx.doi.org/10.1086/701668DOI Listing

The Evolution of Marine Larval Dispersal Kernels in Spatially Structured Habitats: Analytical Models, Individual-Based Simulations, and Comparisons with Empirical Estimates.

Am Nat 2019 Mar 17;193(3):424-435. Epub 2019 Jan 17.

Understanding the causes of larval dispersal is a major goal of marine ecology, yet most research focuses on proximate causes. Here we ask how ultimate, evolutionary causes affect dispersal. Building on Hamilton and May's classic 1977 article "Dispersal in Stable Habitats," we develop analytic and simulation models for the evolution of dispersal kernels in spatially structured habitats. Read More

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http://dx.doi.org/10.1086/701667DOI Listing

Grazing Away the Resilience of Patterned Ecosystems.

Am Nat 2019 Mar 18;193(3):472-480. Epub 2019 Jan 18.

Ecosystems' responses to changing environmental conditions can be modulated by spatial self-organization. A prominent example of this can be found in drylands, where formation of vegetation patterns attenuates the magnitude of degradation events in response to decreasing rainfall. In model studies, the pattern wavelength responds to changing conditions, which is reflected by a rather gradual decline in biomass in response to decreasing rainfall. Read More

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http://dx.doi.org/10.1086/701669DOI Listing

Queen Longevity and Fecundity Affect Conflict with Workers over Resource Inheritance in a Social Insect.

Am Nat 2019 Feb 26;193(2):256-266. Epub 2018 Dec 26.

Resource inheritance is a major source of conflict in animal societies. However, the assumptions and predictions of models of conflict over resource inheritance have not been systematically tested within a single system. We developed an inclusive fitness model for annual eusocial Hymenoptera that predicts a zone of conflict in which future reproductive workers are selected to enforce nest inheritance before the queen is selected to cede the nest. Read More

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http://dx.doi.org/10.1086/701299DOI Listing
February 2019
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Pheromone-Induced Accuracy of Nestmate Recognition in Carpenter Ants: Simultaneous Decrease in Type I and Type II Errors.

Am Nat 2019 Feb 13;193(2):267-278. Epub 2018 Dec 13.

The ecological and evolutionary success of social insects relies on their ability to efficiently discriminate between group members and aliens. Nestmate recognition occurs by phenotype matching, the comparison of the referent (colony) phenotype to the one of an encountered individual. Based on the level of dissimilarity between the two, the discriminator accepts or rejects the target. Read More

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https://www.journals.uchicago.edu/doi/10.1086/701123
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http://dx.doi.org/10.1086/701123DOI Listing
February 2019
2 Reads

Mutualists Stabilize the Coexistence of Congeneric Legumes.

Am Nat 2019 Feb 26;193(2):200-212. Epub 2018 Dec 26.

Coexistence requires that stabilizing niche differences, which cause species to limit themselves more than others, outweigh relative fitness differences, which cause competitive exclusion. Interactions with shared mutualists, which can differentially affect host fitness and change in magnitude with host frequency, can satisfy these conditions for coexistence, yet empirical tests of mutualist effects on relative fitness and stabilizing niche differences are largely lacking within the framework of coexistence theory. Here, we show that N-fixing rhizobial mutualists mediate coexistence in four naturally co-occurring congeneric legume (Trifolium) species. Read More

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http://dx.doi.org/10.1086/701056DOI Listing
February 2019

Evolution of Personal and Social Immunity in the Context of Parental Care.

Am Nat 2019 Feb 20;193(2):296-308. Epub 2018 Dec 20.

Social immunity moderates the spread of pathogens in social groups and is especially likely in groups structured by genetic relatedness. The extent to which specific immune pathways are used is unknown. Here, we investigate the expression and social role of three functionally separate immune genes (pgrp-sc2, thaumatin, and defensin) during parental care in the beetle Nicrophorus vespilloides. Read More

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http://dx.doi.org/10.1086/701122DOI Listing
February 2019
1 Read

The Snail's Charm.

Authors:
Kathleen Donohue

Am Nat 2019 Feb 7;193(2):149-163. Epub 2018 Dec 7.

In 2017, The American Naturalist celebrated its 150th anniversary. It was founded as a journal of natural history, yet it developed into an important vehicle of the evolutionary synthesis. During the early years of the journal and through much of the twentieth century, evolutionary theory was developed to explain the history of nature before humankind existed to alter it-when time was expansive and uncommon events, though rare, were frequent enough to effect evolutionary change. Read More

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http://dx.doi.org/10.1086/700960DOI Listing
February 2019

Testing Darwin's Hypothesis about the Wonderful Venus Flytrap: Marginal Spikes Form a "Horrid Prison" for Moderate-Sized Insect Prey.

Am Nat 2019 Feb 28;193(2):309-317. Epub 2018 Dec 28.

Botanical carnivory is a novel feeding strategy associated with numerous physiological and morphological adaptations. However, the benefits of these novel carnivorous traits are rarely tested. We used field observations, lab experiments, and a seminatural experiment to test prey capture function of the marginal spikes on snap traps of the Venus flytrap (Dionaea muscipula). Read More

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http://dx.doi.org/10.1086/701433DOI Listing
February 2019
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Reconstructing the Geography of Speciation from Contemporary Biodiversity Data.

Am Nat 2019 Feb 14;193(2):240-255. Epub 2018 Dec 14.

Inferring the geographic mode of speciation could help reveal the evolutionary and ecological mechanisms that underlie the generation of biodiversity. Comparative methods have sought to reconstruct the geographic speciation history of clades, using data on phylogeny and species geographic ranges. However, inference from comparative methods has been limited by uncertainty over whether contemporary biodiversity data retain the historic signal of speciation. Read More

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http://dx.doi.org/10.1086/701125DOI Listing
February 2019

Drivers of Phylogenetic Assemblage Structure of the Furnariides, a Widespread Clade of Lowland Neotropical Birds.

Am Nat 2019 Feb 29;193(2):E41-E56. Epub 2018 Nov 29.

Species co-occurrence in local assemblages is shaped by distinct processes at different spatial and temporal scales. Here we focus on historical explanations and examine the phylogenetic structure of local assemblages of the Furnariides clade (Aves: Passeriformes), assessing the influence of diversification rates on the assembly and species co-occurrence within those assemblages. Using 120 local assemblages across Bolivia and Argentina and a nearly complete phylogeny for the clade, we analyzed assemblage phylogenetic structure, applying a recently developed model (DAMOCLES, or dynamic assembly model of colonization, local extinction, and speciation) accounting for the historical processes of speciation, colonization, and local extinction. Read More

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http://dx.doi.org/10.1086/700696DOI Listing
February 2019

Increased Temperature Disrupts the Biodiversity-Ecosystem Functioning Relationship.

Am Nat 2019 Feb 26;193(2):227-239. Epub 2018 Dec 26.

Gaining knowledge of how ecosystems provide essential services to humans is of primary importance, especially with the current threat of climate change. Yet little is known about how increased temperature will impact the biodiversity-ecosystem functioning (BEF) relationship. We tackled this subject theoretically and experimentally. Read More

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http://dx.doi.org/10.1086/701432DOI Listing
February 2019

Animal Coloration Patterns: Linking Spatial Vision to Quantitative Analysis.

Am Nat 2019 Feb 16;193(2):164-186. Epub 2019 Jan 16.

Animal coloration patterns, from zebra stripes to bird egg speckles, are remarkably varied. With research on the perception, function, and evolution of animal patterns growing rapidly, we require a convenient framework for quantifying their diversity, particularly in the contexts of camouflage, mimicry, mate choice, and individual recognition. Ideally, patterns should be defined by their locations in a low-dimensional pattern space that represents their appearance to their natural receivers, much as color is represented by color spaces. Read More

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http://dx.doi.org/10.1086/701300DOI Listing
February 2019
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Rarity of Size-Assortative Mating in Animals: Assessing the Evidence with Anuran Amphibians.

Authors:
David M Green

Am Nat 2019 Feb 13;193(2):279-295. Epub 2018 Dec 13.

Assortative mating in animals can have substantial evolutionary impact. Numerous reports also make it appear to be pervasive in occurrence. In assortative mating, defined here in behavioral terms, animals select their mates according to a particular shared trait such that mated individuals phenotypically resemble each other more than expected by chance. Read More

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http://dx.doi.org/10.1086/701124DOI Listing
February 2019