Genetic divergence and one-way gene flow influence contemporary evolution and ecology of a partially migratory fish.

Recent work has revealed the importance of contemporary evolution in shaping ecological outcomes. In particular, rapid evolutionary divergence between populations has been shown to impact the ecology of populations, communities, and ecosystems. While studies have focused largely on the role of adaptive divergence in generating ecologically important variation among populations, much less is known about the role of gene flow in shaping ecological outcomes.

Intraspecific variation in a predator changes intertidal community through effects on a foundation species.

Intraspecific variation is an important form of biodiversity that can alter community and ecosystem properties. Recent work demonstrates the community effects of intraspecific variation in predators via altering prey communities and in foundation species via shaping habitat attributes. However, tests of the community effects of intraspecific trait variation in predators acting on foundation species are lacking despite the fact that consumption of foundation species can have strong community effects by shaping habitat structure.

The effect of pregnancy on metabolic scaling and population energy demand in the viviparous fish Gambusia affinis.

Metabolism is a fundamental attribute of all organisms that influences how species affect and are affected by their natural environment. Differences between sexes in ectothermic species may substantially alter metabolic scaling patterns, particularly in viviparous or live-bearing species where females must support their basal metabolic costs and that of their embryos. Indeed, if pregnancy is associated with marked increases in metabolic demand and alters scaling patterns between sexes, this could in turn interact with natural sex ratio variation in nature to affect population-level energy demand.

Drivers and Cascading Ecological Consequences of Trait Variation.

AbstractPhenotypic trait differences among populations can shape ecological outcomes for communities and ecosystems. However, few studies have mechanistically linked heritable and plastic components of trait variation to generalizable processes of ecology, such as trophic cascades. Here, we assess morphological and behavioral trait variation in nine populations of common garden-reared western mosquitofish () from three distinct ancestral predator environments (three populations per environment), each reared in the presence and absence of predator cues.

Inconsistent evolution and growth-survival tradeoffs in .

Growth-survival tradeoffs may be a generalizable mechanism influencing trajectories of prey evolution. Here, we investigate evolutionary contributions to growth and survival in western mosquitofish () from 10 populations from high- and low-predation ancestral environments. We assess (i) the degree to which evolutionary components of growth and survival are consistent or inconsistent across populations within ancestral predation environments, and (ii) whether growth and survival trade off at the population level.

Consumer trait responses track change in resource supply along replicated thermal gradients.

Rising temperatures may alter consumer diets through increased metabolic demand and altered resource availability. However, current theories assessing dietary shifts with warming do not account for a change in resource availability. It is unknown whether consumers will increase consumption rates or consume different resources to meet increased energy requirements and whether the dietary change will lead to associated variation in morphology and nutrient utilization.

The legacy of predator threat shapes prey foraging behaviour.

Predators exert strong selection on prey foraging behaviour such that prey responses may reflect a combination of ancestral effects of predators (genetic and nongenetic transgenerational effects), past individual experience with predators (phenotypic plasticity), and current exposure to predators (behavioural response). However, the importance of these factors in shaping prey foraging behaviour is not well understood. To test the relative effects of ancestry, prior experience, and current exposure, we measured foraging rates and food size preference of different ancestry and exposure groups of Western mosquitofish in the presence and absence of immediate threat from predatory largemouth bass.

Shade affects magnitude and tactics of juvenile Chinook salmon antipredator behavior in the migration corridor.

Environmental conditions strongly affect antipredator behaviors; however, it is less known how migrating prey adjust antipredator behavior in migration corridors, in part, because active migrants are difficult to observe and study. Migrants are vulnerable and encounter many predators in the corridor, and their propensity to travel towards their destination ties antipredator behavior with movement. We evaluated how environmental risk cues in the migration corridor including in-water habitat structure (present, absent) and overhead shade (sun, shade), and salmon origin (hatchery, wild) affected how juvenile Chinook salmon (Oncorhynchus tshawytscha) reacted to a live predator.

Predation landscapes influence migratory prey ecology and evolution.

Migratory prey experience spatially variable predation across their life cycle. They face unique challenges in navigating this predation landscape, which affects their perception of risk, antipredator responses, and resulting mortality. Variable and unfamiliar predator cues during migration can limit accurate perception of risk and migrants often rely on social information and learning to compensate.

Using seasonal genomic changes to understand historical adaptation to new environments: Parallel selection on stickleback in highly-variable estuaries.

Parallel evolution is considered strong evidence for natural selection. However, few studies have investigated the process of parallel selection as it plays out in real time. The common approach is to study historical signatures of selection in populations already well adapted to different environments.

Conserving intraspecific variation for nature's contributions to people.

The rapid loss of intraspecific variation is a hidden biodiversity crisis. Intraspecific variation, which includes the genomic and phenotypic diversity found within and among populations, is threatened by local extinctions, abundance declines, and anthropogenic selection. However, biodiversity assessments often fail to highlight this loss of diversity within species.

Socio-eco-evolutionary dynamics in cities.

Cities are uniquely complex systems regulated by interactions and feedbacks between nature and human society. Characteristics of human society-including culture, economics, technology and politics-underlie social patterns and activity, creating a heterogeneous environment that can influence and be influenced by both ecological and evolutionary processes. Increasing research on urban ecology and evolutionary biology has coincided with growing interest in eco-evolutionary dynamics, which encompasses the interactions and reciprocal feedbacks between evolution and ecology.

A century of intermittent eco-evolutionary feedbacks resulted in novel trait combinations in invasive Great Lakes alewives ().

Species introductions provide opportunities to quantify rates and patterns of evolutionary change in response to novel environments. Alewives () are native to the East Coast of North America where they ascend coastal rivers to spawn in lakes and then return to the ocean. Some populations have become landlocked within the last 350 years and diverged phenotypically from their ancestral marine population.

Recent declines in salmon body size impact ecosystems and fisheries.

Declines in animal body sizes are widely reported and likely impact ecological interactions and ecosystem services. For harvested species subject to multiple stressors, limited understanding of the causes and consequences of size declines impedes prediction, prevention, and mitigation. We highlight widespread declines in Pacific salmon size based on 60 years of measurements from 12.

Evolutionary origins for ecological patterns in space.

Historically, many biologists assumed that evolution and ecology acted independently because evolution occurred over distances too great to influence most ecological patterns. Today, evidence indicates that evolution can operate over a range of spatial scales, including fine spatial scales. Thus, evolutionary divergence across space might frequently interact with the mechanisms that also determine spatial ecological patterns.

Recent warming reduces the reproductive advantage of large size and contributes to evolutionary downsizing in nature.

Body size is a key functional trait that is predicted to decline under warming. Warming is known to cause size declines via phenotypic plasticity, but evolutionary responses of body size to warming are poorly understood. To test for warming-induced evolutionary responses of body size and growth rates, we used populations of mosquitofish () recently established (less than 100 years) from a common source across a strong thermal gradient (19-33°C) created by geothermal springs.

An escape theory model for directionally moving prey and an experimental test in juvenile Chinook salmon.

Prey evaluate risk and make decisions based on the balance between the costs of predation and those of engaging in antipredator behaviour. Economic escape theory has been valuable in understanding the responses of stationary prey under predation risk; however, current models are not applicable for directionally moving prey. Here we present an extension of existing escape theory that predicts how much predation risk is perceived by directionally moving prey.

Restoration-mediated secondary contact leads to introgression of alewife ecotypes separated by a colonial-era dam.

Secondary contact may have important implications for ecological and evolutionary processes; however, few studies have tracked the outcomes of secondary contact from its onset in natural ecosystems. We evaluated an anadromous alewife ( reintroduction project in Rogers Lake (Connecticut, USA), which contains a landlocked alewife population that was isolated as a result of colonial-era damming. After access to the ocean was restored, adult anadromous alewife were stocked into the lake.

Prey adaptation along a competition-defense tradeoff cryptically shifts trophic cascades from density- to trait-mediated.

Trophic cascades have become a dominant paradigm in ecology, yet considerable debate remains about the relative strength of density- (consumptive) and trait-mediated (non-consumptive) effects in trophic cascades. This debate may, in part, be resolved by considering prey experience, which shapes prey traits (through genetic and plastic change) and influences prey survival (and therefore density). Here, we investigate the cascading role of prey experience through the addition of mosquitofish (Gambusia affinis) from predator-experienced or predator-naïve sources to mesocosms containing piscivorous largemouth bass (Micropterus salmoides), zooplankton, and phytoplankton.

Climate shapes population variation in dogwhelk predation on foundational mussels.

Trait variation among populations is important for shaping ecological dynamics. In marine intertidal systems, seawater temperature, low tide emersion temperature, and pH can drive variation in traits and affect species interactions. In western North America, Nucella dogwhelks are intertidal drilling predators of the habitat-forming mussel Mytilus californianus.

Climate-driven habitat change causes evolution in Threespine Stickleback.

Climate change can shape evolution directly by altering abiotic conditions or indirectly by modifying habitats, yet few studies have investigated the effects of climate-driven habitat change on contemporary evolution. We resampled populations of Threespine Stickleback (Gasterosteus aculeatus) along a latitudinal gradient in California bar-built estuaries to examine their evolution in response to changing climate and habitat. We took advantage of the strong association between stickleback lateral plate phenotypes and Ectodysplasin A (Eda) genotypes to infer changes in allele frequencies over time.

Eco-evolutionary feedbacks link prey adaptation to predator performance.

Eco-evolutionary feedbacks may determine the outcome of predator-prey interactions in nature, but little work has been done to quantify the feedback effect of short-term prey adaptation on predator performance. We tested the effects of prey availability and recent (less than 100 years) prey adaptation on the feeding and growth rate of largemouth bass (), foraging on western mosquitofish (). Field surveys showed higher densities and larger average body sizes of mosquitofish in recently introduced populations without bass.

Eco-Evolutionary Dynamics of Sexual Dimorphism.

Sexual dimorphism is widespread, but we have a limited understanding of its significance for communities and ecosystems. Several new experiments demonstrate that sexual dimorphism can have far-reaching ecological effects. These results suggest that sexual dimorphism and sexual selection are potent, but largely overlooked components of eco-evolutionary dynamics.