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1. Heritable intraspecific variation among prey in size and movement interact to shape predation risk and potential natural selection

   https://doi.org/10.1111/1365-2435.14644  

   Coblentz, Kyle E; Yang, Liuqingqing; Dalal, Arpita; Incarnato, Miyauna_M N; Thilakarathne, Dinelka D; Shaw, Cameron; Wilson, Ryan; Biagioli, Francis; Montooth, Kristi L; DeLong, John P (November 2024, Functional Ecology)

   Abstract Predator and prey traits are important determinants of the outcomes of trophic interactions. In turn, the outcomes of trophic interactions shape predator and prey trait evolution. How species' traits respond to selection from trophic interactions depends crucially on whether and how heritable species' traits are and their genetic correlations. Of the many traits influencing the outcomes of trophic interactions, body size and movement traits have emerged as key traits. Yet, how these traits shape and are shaped by trophic interactions is unclear, as few studies have simultaneously measured the impacts of these traits on the outcomes of trophic interactions, their heritability, and their correlations within the same system.We used outcrossed lines of the ciliate protistParamecium caudatumfrom natural populations to examine variation in morphology and movement behaviour, the heritability of that variation, and its effects onParameciumsusceptibility to predation by the copepodMacrocyclops albidus.We found that theParameciumlines exhibited heritable variation in body size and movement traits. In contrast to expectations from allometric relationships, body size and movement speed showed little covariance among clonal lines. The proportion ofParameciumconsumed by copepods was positively associated withParameciumbody size and velocity but with an interaction such that greater velocities led to greater predation risk for large body‐sized paramecia but did not alter predation risk for smaller paramecia. The proportion of paramecia consumed was not related to copepod body size. These patterns of predation risk and heritable trait variation in paramecia suggest that copepod predation may act as a selective force operating independently on movement and body size and generating the strongest selection against large, high‐velocity paramecia.Our results illustrate how ecology and genetics can shape potential natural selection on prey traits through the outcomes of trophic interactions. Further simultaneous measures of predation outcomes, traits, and their quantitative genetics will provide insights into the evolutionary ecology of species interactions and their eco‐evolutionary consequences. Read the freePlain Language Summaryfor this article on the Journal blog. 

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2. Like mother, like daughter? Phenotypic plasticity, environmental covariation, and heritability of size in a parthenogenetic wasp

   https://doi.org/10.1093/jeb/voaf027  

   Tovar, Alicia; Monahan, Scott; Mugoya, Trevor; Kristan, Adrian; Welch, Walker; Dettmers, Ryan; Arce, Camila; Buck, Theresa; Ruben, Michele; Rothenberg, Alexander; et al (March 2025, Journal of Evolutionary Biology)

   Abstract Parthenogenetic wasps provide an ideal natural experiment to study the heritability, plasticity, and microevolutionary dynamics of body size. Dinocampus coccinellae (Hymenoptera:Braconidae, Euphorinae) is a solitary, generalist braconid parasitoid wasp that reproduces through thelytokous parthenogenesis, and parasitizes over fifty diverse species of coccinellid ladybeetles worldwide as hosts. Here we designed an experiment with parthenogenetic lines of D. coccinellae presented with three different host ladybeetle species of varying sizes, across multiple generations to investigate heritability, and plasticity of body size measured via a combination of morphometric variables such as thorax width, abdominal width, and wing length in D. coccinellae. We expected positively correlated parent-offspring parasitoid regressions, indicative of heritable size variation, from unilineal (parent and offspring reared on same host species) lines, since these restrict environmental variation in phenotypes. In contrast, because multilineal (parent and offspring reared on different host species) lines would induce phenotypic plasticity of clones reared in varying environments, we expected negatively correlated parent-offspring parasitoid regressions. Our results indicate (1) little heritable variation in body size, (2) strong independence of offspring size on the host environment, (3) small mothers produce larger offspring, and vice versa, independent of host. We then model the evolution of size and host-shifting under a constrained fecundity advantage model of Cope’s Law using a Hidden Markov Model, showing that D. coccinellae likely has fitness advantages to maintain plasticity in body size despite parthenogenetic reproduction. 

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3. Partitioning the Impacts of Spatial-Temporal Variation in Demography and Dispersal on Metapopulation Growth Rates

   https://doi.org/10.1086/733434  

   Schreiber, Sebastian J (February 2025, The American Naturalist)

   Spatial-temporal variation in environmental conditions is ubiquitous in nature. This variation simultaneously impacts survival, reproduction, and movement of individuals and thereby the rate at which metapopulations grow. Using the tools of stochastic demography, the metapopulation growth rate is decomposed into five components corresponding to temporal, spatial, and spatial-temporal variation in fitness and spatial and spatial-temporal covariation in dispersal and fitness. While temporal variation in fitness always reduces the metapopulation growth rate, all other sources of variation can either increase or reduce the metapopulation growth rate. Increases occur either by reducing the impacts of temporal variation or by generating a positive fitness-density covariance where individuals tend to concentrate in higher-quality patches. For example, positive autocorrelations in spatial-temporal variability in fitness generate this positive fitness-density covariance for less dispersive populations but decrease it for highly dispersive populations (e.g., migratory species). Negative autocorrelations in spatial-temporal variability have the opposite effects. Positive covariances between movement and future fitness, on short or long timescales, increase growth rates. These positive covariances can arise in unexpected ways. For example, the win-stay, lose-shift dispersal strategy in negatively autocorrelated environments can generate positive spatial covariances that exceed negative spatial-temporal covariances. This decomposition of the metapopulation growth rate provides a way to quantify the relative importance of fundamental sources of variation for metapopulation persistence. 

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4. Dissociation of Reliability, Heritability, and Predictivity in Coarse- and Fine-Scale Functional Connectomes during Development

   https://doi.org/10.1523/JNEUROSCI.0735-23.2023  

   Busch, Erica L.; Rapuano, Kristina M.; Anderson, Kevin M.; Rosenberg, Monica D.; Watts, Richard; Casey, B. J.; Haxby, James V.; Feilong, Ma (December 2023, The Journal of Neuroscience)

   The functional connectome supports information transmission through the brain at various spatial scales, from exchange between broad cortical regions to finer-scale, vertex-wise connections that underlie specific information processing mechanisms. In adults, while both the coarse- and fine-scale functional connectomes predict cognition, the fine scale can predict up to twice the variance as the coarse-scale functional connectome. Yet, past brain-wide association studies, particularly using large developmental samples, focus on the coarse connectome to understand the neural underpinnings of individual differences in cognition. Using a large cohort of children (age 9–10 years;n = 1,115 individuals; both sexes; 50% female, including 170 monozygotic and 219 dizygotic twin pairs and 337 unrelated individuals), we examine the reliability, heritability, and behavioral relevance of resting-state functional connectivity computed at different spatial scales. We use connectivity hyperalignment to improve access to reliable fine-scale (vertex-wise) connectivity information and compare the fine-scale connectome with the traditional parcel-wise (coarse scale) functional connectomes. Though individual differences in the fine-scale connectome are more reliable than those in the coarse-scale, they are less heritable. Further, the alignment and scale of connectomes influence their ability to predict behavior, whereby some cognitive traits are equally well predicted by both connectome scales, but other, less heritable cognitive traits are better predicted by the fine-scale connectome. Together, our findings suggest there are dissociable individual differences in information processing represented at different scales of the functional connectome which, in turn, have distinct implications for heritability and cognition. 

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5. Mosaic of Somatic Mutations in Earth’s Oldest Living Organism, Pando

   https://doi.org/10.1101/2024.10.19.619233  

   Pineau, Rozenn M; Mock, Karen E; Morris, Jesse; Kraklow, Vachel; Brunelle, Andrea; Pageot, Aurore; Ratcliff, William C; Gompert, Zachariah (October 2024, bioRxiv)

   Understanding how mutations arise and spread through individuals and populations is fundamental to evolutionary biology. Most organisms have a life cycle with unicellular bottlenecks during reproduction. However, some organisms like plants, fungi, or colonial animals can grow indefinitely, changing the manner in which mutations spread throughout both the individual and the population. Furthermore, clonally reproducing organisms may also achieve exceedingly long lifespans, making somatic mutation an important mechanism of creating heritable variation for Darwinian evolution by natural selection. Yet, little is known about intra-organism mutation rates and evolutionary trajectories in long-lived species. Here, we study the Pando aspen clone, the largest known quaking aspen (Populus tremuloides) clone founded by a single seedling and thought to be one of the oldest studied organisms. Aspen reproduce vegetatively via new root-borne stems forming clonal patches, sometimes spanning several hectares. To study the evolutionary history of the Pando clone, we collected and sequenced over 500 samples from Pando and neighboring clones, as well as from various tissue types within Pando, including leaves, roots, and bark. We applied a series of filters to distinguish somatic mutations from the pool of both somatic and germline mutations, incorporating a technical replicate sequencing approach to account for uncertainty in somatic mutation detection. Despite root spreading being spatially constrained, we observed only a modest positive correlation between genetic and spatial distance, suggesting the presence of a mechanism preventing the accumulation and spread of mutations across units. Phylogenetic models estimate the age of the clone to between ~16,000-80,000 years. This age is generally corroborated by the near-continuous presence of aspen pollen in a lake sediment record collected from Fish Lake near Pando. Overall, this work enhances understanding of mutation accumulation and dispersal within and between ramets of long-lived, clonally-reproducing organisms. Significance StatementThis study enhances our understanding of evolutionary processes in long-lived clonal organisms by investigating somatic mutation accumulation and dispersal patterns within the iconic Pando aspen clone. The authors estimated the clone to be between 10,000 and 80,000 years old and uncovered a modest spatial genetic structure in the 42.6-hectare clone, suggesting localized mutation build-up rather than dispersal along tissue lineages. This work sheds light on an ancient organism and how plants may evolve to preserve genetic integrity in meristems fueling indefinite growth, with implications for our comprehension of adaptive strategies in long-lived perennials. 

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