Evolution; International Journal Of Organic Evolution[JOURNAL]
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200 papers
Superorganismal Anisogamy: A Comparative Test of an Extended Theory.
Downing PA, Lehtonen J, Bell-Roberts L … +1 more , Helanterä H
Evolution · 2026 Jul · PMID 42392197 · Publisher ↗
Multicellular organisms and superorganisms (e.g., ant colonies) are both products of major evolutionary transitions in individuality, and they share many analogous traits. Theory developed to explain the evolution of one...
Multicellular organisms and superorganisms (e.g., ant colonies) are both products of major evolutionary transitions in individuality, and they share many analogous traits. Theory developed to explain the evolution of one such trait, anisogamy, has recently been adapted to explain its superorganismal analogue: large egg-like queens and small sperm-like males. To test this theory with comparative data, we first extended it to determine if changing how multi-queen colonies arise affects the model's predictions. We then used data from 732 ant species to investigate the effects of colony size, worker caste number, and queen number on queen size (thorax volume) and queen-male dimorphism. Queen size and queen-male size dimorphism both increased with colony size and number of worker castes, consistent with predictions. Contrary to predictions, queen size and queen-male size dimorphism were not associated with queen number. To further understand the commonalities and idiosyncrasies of evolution at different hierarchical levels, future work should consider the adaptive and non-adaptive causes for correlated evolution between queen and male, and egg and sperm sizes.
The role of microbial resource mutualists in plant adaptation to abiotic environments.
Suwa T, Lau JA
Evolution · 2026 Jun · PMID 42370652 · Publisher ↗
Despite more than eighty years of study, the selective agents driving local adaptation largely remain unknown, in part because populations exist in complex environments where they experience both abiotic and biotic condi...
Despite more than eighty years of study, the selective agents driving local adaptation largely remain unknown, in part because populations exist in complex environments where they experience both abiotic and biotic conditions that can exert strong selection. We used a replicated reciprocal transplant experiment combined with a greenhouse inoculation experiment to investigate plant adaptation to soil moisture and the role of nitrogen-fixing rhizobium mutualists in plant local adaptation. We find that the annual legume hog peanut (Amphicarpaea bracteata) is locally adapted to soil moisture conditions and that interactions with nitrogen-fixing rhizobia likely contribute to the observed local adaptation. Specifically, plant populations from wet sites transplanted into wet habitats were more likely than those from dry sites to associate with rhizobium mutualists and formed more nodules and had higher nitrogen fixation rates when inoculated with rhizobium strains isolated from wet compared to dry habitats. As a result, local adaptation to wet environments was most apparent when plants successfully associated with rhizobia in the field. In sum, our results suggest that: 1) soil moisture is a strong cause of local adaptation in this system and 2) divergence in how plant populations interact with rhizobia likely contributes to plant local adaptation to soil moisture. These findings illustrate how biotic interactions can influence plant adaptation to a strong abiotic gradient and highlight the need to consider microbial mutualists in studies of plant local adaptation.
Museum genomics links MC1R alleles to adaptive winter coat color polymorphism in the long-tailed weasel.
Pimenta J, Miranda I, Farelo L … +3 more , Alvarenga M, Mills LS, Melo-Ferreira J
Evolution · 2026 Jun · PMID 42335941 · Publisher ↗
Understanding the architecture of biological adaptations is a major endeavor of evolutionary biology. Using Natural History collections, we study the genetic basis and evolution of white/brown winter coat color variation...
Understanding the architecture of biological adaptations is a major endeavor of evolutionary biology. Using Natural History collections, we study the genetic basis and evolution of white/brown winter coat color variation in the long-tailed weasel (Neogale frenata), a crucial phenological adaptation for camouflage in habitats with seasonal snow. We produced whole-genome sequencing data for museum specimens, along two winter color morph transition areas in North America, at the West and East coasts. Genome-wide association scans identified a single genomic region linked to color variation polymorphism with approximately 300 kb and 200 kb in the West and East regions, respectively, which included the pigmentation gene MC1R. We identified three MC1R alleles, two of which with deletions of nine or eight amino acids, alternatively associated with the winter brown morphs in the West and East, respectively. These deletions affect the second transmembrane domain, and in one case also the first extracellular loop, which in silico analyses predicted to impact the protein's function. Our findings show alternative intraspecific evolutionary solutions for environmental adaptation in long-tailed weasels, building on the evidence that major genes of the melanin production pathway are hotspots for recurrent and independent evolution of winter camouflage adaptation. This adaptive variation may be crucial to anchor adaptive responses facing future environmental change.
Repeated evolution of iridescence and hindwing tails is associated with morphometric flight proxies in skipper butterflies.
Linke D, Debat V, Matos-Maraví P
Evolution · 2026 Jun · PMID 42329784 · Publisher ↗
Phenotypic evolution is shaped by phylogenetic history, ecology and biomechanical constraints. Butterfly wings offer an ideal system to explore these forces, as the relationships between wing morphology and flight charac...
Phenotypic evolution is shaped by phylogenetic history, ecology and biomechanical constraints. Butterfly wings offer an ideal system to explore these forces, as the relationships between wing morphology and flight characteristics have been intensively studied. Here, we focus on Eudamina skipper butterflies, which display repeated phenotypic convergences of dorsal iridescence and hindwing tails; traits linked to escape ability whose convergence may be driven by predator selection. Using a comprehensive morphometric dataset of 176 species, we assess the evolution of these convergent traits in a phylogenetic framework. We show that hindwing tails and dorsal iridescence have repeatedly evolved in tropical species. Hindwing tails are associated with intermediate body size and forewing shapes that can increase flight manoeuvrability; iridescence is more common in large species with high wing loading and aspect ratio, indicating greater flight speed and manoeuvrability. The evolution of these traits is best described by Ornstein-Uhlenbeck models, consistent with attraction towards trait optima. Further, we reveal co-evolutionary dynamics between fore- and hindwing shapes. Hindwing tails significantly affect forewing shapes in independent lineages, suggesting trade-offs between flight and defence. Together, our results suggest that convergent morphologies in Eudamina likely arose through ecological selection and biomechanical constraints, rather than neutral evolution.
Temperature-dependent competition predicts contrasting outcomes of adjacent secondary contact zones in darters (Percidae:Etheostoma).
Johnson BE, Adkins C, Black-Bergrud TN … +3 more , Dye M, Mendoza I, Moran RL
Evolution · 2026 Jun · PMID 42315488 · Publisher ↗
Understanding how abiotic conditions interact with species interactions to shape outcomes of secondary contact remains a central challenge in evolutionary biology. Environmental stress may limit persistence through physi...
Understanding how abiotic conditions interact with species interactions to shape outcomes of secondary contact remains a central challenge in evolutionary biology. Environmental stress may limit persistence through physiological constraints, but it can also alter competitive dynamics, determining whether closely related species can coexist. We investigated these mechanisms in two long-studied secondary contact zones between the darter species Etheostoma pulchellum and E. radiosum spp. in southeastern Oklahoma that have experienced different fates: long-term coexistence in the spring-fed Blue River versus the disappearance of E. pulchellum from Little Glasses Creek in the warmer, more variable Washita River drainage. Using critical thermal maximum (CTmax) assays, field temperature records, and standardized feeding trials in parental species, we tested whether contrasting outcomes in these systems are better explained by differences in physiological tolerance or by temperature-mediated shifts in competitive interactions. Although CTmax varied among rivers, we found no consistent species-level differences in thermal tolerance across drainages. In contrast, exploitative competition was strongly temperature dependent, with E. pulchellum dominating under cooler conditions characteristic of the Blue River, whereas E. radiosum spp. outcompeted E. pulchellum under elevated temperatures matching summer conditions in Little Glasses Creek. These results show that warming can flip competitive hierarchies, providing a mechanistic explanation for contrasting secondary contact zone trajectories and underscoring how environmental variability shapes species persistence following secondary contact.
Sex allocation of hermaphrodites in metapopulations with frequent population extinction and recolonization.
Mullon C, Sudbrack V, Roux C … +1 more , Pannell JR
Evolution · 2026 Jun · PMID 42303241 · Publisher ↗
Competition among related males, male gametes, or pollen grains to fertilize a limited number of females, eggs, or ovules (local mate competition) is expected to favor female-biased progeny sex ratios in dioecious specie...
Competition among related males, male gametes, or pollen grains to fertilize a limited number of females, eggs, or ovules (local mate competition) is expected to favor female-biased progeny sex ratios in dioecious species. In hermaphrodites, local mate competition should similarly promote female-biased sex allocation, with reduced investment in sperm or pollen relative to eggs, ovules, or seeds. Because inbreeding, especially self-fertilization, tends to generate local mate competition, female-biased sex allocation should be associated with positive inbreeding, for example as measured by FIS. Although inbreeding may result from mating among relatives within local populations, it can also be generated by population turnover in metapopulations subject to frequent local extinction and recolonization. This effect of population turnover has previously been considered for species with separate sexes. Here, we use formal analysis and individual-based simulations to show that population turnover can select for strongly female-biased sex allocation in hermaphroditic metapopulations, particularly when among-deme dispersal is low. When mating within established populations is random, so that FIS is zero, female-biased sex allocation is instead associated with positive FST, a measure of inbreeding at the metapopulation level caused by population structure. Our results thus extend local mate competition theory to hermaphroditic metapopulations and identify FST as a key predictor of sex allocation when inbreeding is generated by population turnover rather than by non-random mating within demes.
The phylogenetic signal of extinction through the rise and fall of early vertebrates: field of bullets or clustered strike?
Flannery-Sutherland JT, Tims AR, Clarke J … +2 more , Friedman M, Giles S
Evolution · 2026 Jun · PMID 42303238 · Publisher ↗
We investigate patterns of phylogenetic selectivity of extinction in early aquatic vertebrates from the Silurian to the Carboniferous, an interval punctuated by one of the "Big Five" mass extinctions and marked by many c...
We investigate patterns of phylogenetic selectivity of extinction in early aquatic vertebrates from the Silurian to the Carboniferous, an interval punctuated by one of the "Big Five" mass extinctions and marked by many critical anatomical (e.g., jaws, limbs) and ecological (e.g., macrophagy, terrestrialization) vertebrate evolutionary innovations. Using a new > 1300 taxon, formally inferred supertree, we show that phylogenetic extinction clustering in early vertebrates varied through time and between major ecomorphological divisions of the tree. At the end of the Silurian and into the Early Devonian, jawless fishes became marginalized components of vertebrate faunas and show more strongly clustered extinction than jawed fishes, which became ecologically dominant during this interval. Clustered extinction (contemporaneous extinction of close relatives) is typical of most stages of the Devonian, particularly during the Late Devonian extinctions. By contrast, the subsequent early Carboniferous interval of putative recovery is characterized by overdispersed extinction (contemporaneous extinction of distant relatives), consistent with widespread persistence of phylogenetically distinct lineages. This work shows how varying patterns of extinction selectivity pruned the vertebrate tree at the time when the first-order patterns of diversity apparent in modern aquatic vertebrate faunas were first established.
Reproductive value and primary sex ratios under facultative asexual reproduction by both sexes in age-structured populations.
Rautiala P, Lehtonen J
Evolution · 2026 Jun · PMID 42297015 · Publisher ↗
Reproductive value (RV) and evolutionarily stable primary sex ratios are fundamentally linked, centrally important topics in evolutionary biology. Recent theoretical studies have advanced our understanding of (i) the rel...
Reproductive value (RV) and evolutionarily stable primary sex ratios are fundamentally linked, centrally important topics in evolutionary biology. Recent theoretical studies have advanced our understanding of (i) the relationship between the RV of juveniles of the two sexes under arbitrary transmission genetics, age structures, and fecundity schedules, and (ii) sex ratio evolution under facultative asexual reproduction. Here, we unite and build upon these two strands of work. We derive the relative RVs of daughters and sons in an age-structured population with arbitrary transmission genetics when both sexes can reproduce asexually and can produce offspring of either sex. We then apply this result to sex ratio evolution and derive a general expression for the primary sex ratio of the sexual pathway. A key finding is that the primary sex ratio of the sexual pathway is unaffected by asexual reproduction by either sex when asexually produced offspring are of the same sex as their parents. If asexual reproduction produces offspring of the opposite sex, the sex ratio of the sexual pathway is altered. The post-hatching population sex ratio results derived in earlier studies are recovered as special cases.
Digest: Form-function relationships across scales in lacertid lizards.
Parra V, Liao Y, Skipwith P
Evolution · 2026 Jun · PMID 42285549 · Publisher ↗
Are form and function always correlated, and if so, is this relationship predictable across taxonomic levels? Vicent-Castelló et al. (2026) show that in lizards from the family Lacertidae there is a significant correlati...
Are form and function always correlated, and if so, is this relationship predictable across taxonomic levels? Vicent-Castelló et al. (2026) show that in lizards from the family Lacertidae there is a significant correlation between form and function, but this correlation differs in magnitude and direction across evolutionary scales. The direction of this relationship is not conserved across taxonomic levels, suggesting that similar functional outcomes can arise from different morphological configurations.
Correction to: Ecological, behavioral, and phylogenetic influences on the evolution of dorsal color pattern in geckos.
Evolution · 2026 Jun · PMID 42283532 · Publisher ↗
Abstract loading — click title to view on PubMed.
Generalization as the great leap in evolvability: insights from machine learning.
Frank SA
Evolution · 2026 Jun · PMID 42276576 · Publisher ↗
Natural selection encodes learned information in the genome. Learned solutions may be tuned specifically to past challenges, failing in altered environments. Or solutions can be general, capturing the essential structure...
Natural selection encodes learned information in the genome. Learned solutions may be tuned specifically to past challenges, failing in altered environments. Or solutions can be general, capturing the essential structure of the challenge and performing well across variations within the abstract class. For example, a neural system might recognize the exact outlines of a rattlesnake but not other snakes, or it might recognize the essence of snakeness. The problem of how a system generalizes is a fundamental aspect of evolvability, the ability of a system to learn broad solutions to novel challenges. In recent years, machine learning has significantly advanced our understanding of when systems generalize their learned solutions and how they accomplish such generalization. One surprising discovery overturned conventional wisdom about learning. Large systems, with more adjustable parameters than the dimensions of the incoming data, do not merely memorize the data patterns in the way suggested by traditional theory. Instead, systems with more parameters generalize better than smaller systems. Because natural selection is a learning algorithm, the new theory of generalization applies to biological evolution. Specifically, increasing regulatory complexity and parameterization associates with increasing evolvability for the discovery of general solutions. This link between genomic complexity and generalization may have been a primary driving force in evolutionary history.
Autopolyploid establishment under gametophytic self-incompatibility: the impact of self-fertilization and pollen limitation.
Douet D, Vekemans X, Clo J
Evolution · 2026 Jun · PMID 42264455 · Publisher ↗
Polyploidy is widespread in plants, yet the establishment of neo-polyploids is limited by minority cytotype exclusion (MCE). As polyploidy has been associated with higher selfing rates in empirical studies, a shift from...
Polyploidy is widespread in plants, yet the establishment of neo-polyploids is limited by minority cytotype exclusion (MCE). As polyploidy has been associated with higher selfing rates in empirical studies, a shift from self-incompatibility (SI) to self-compatibility (SC) may help overcome MCE, particularly under gametophytic SI (GSI) with non-self-recognition where an automatic shift to SC is associated with polyploidy. We investigated theoretically the joint evolution of polyploidy and self-compatibility and its impact on tetraploid establishment in initially diploid populations with GSI under different pollen limitation scenarios, and with fixed or variable selfing rates for polyploids. It is shown that, for high pollen limitation scenarios, autotetraploids can invade an initially diploid population only when the selfing rates are high. Under low pollen limitation, the conditions for tetraploid invasion are less restrictive (selfing rates above 0.3). These results apply to scenarios with either fixed or variable selfing rates in polyploids, but in the latter, high mutation rates of the selfing rate are needed for polyploidy to invade. These results suggest that tetraploid establishment is possible through the evolution of selfing, without introducing a non-functional S-allele. However, the conditions strongly depend on the degree of pollen limitation.
Adaptive Benefits of Hybridization in Saccharomyces Yeast are Constrained by Genomic Background and Depend on Temperature.
Haberkorn C, Gettle N, Elsen J … +7 more , Medina Chavez NO, Sivigny J, Baselga-Cervera B, Greig D, Travisano M, Saxer G, Stelkens R
Evolution · 2026 Jun · PMID 42247603 · Publisher ↗
Climate change urges us to better understand and predict evolutionary responses to temperature shifts. Hybridization, by increasing genetic variation, can widen the range of adaptive responses and genetic mechanisms avai...
Climate change urges us to better understand and predict evolutionary responses to temperature shifts. Hybridization, by increasing genetic variation, can widen the range of adaptive responses and genetic mechanisms available to survive temperature changes. However, genomic data on the long-term effect of hybridization on adaptation is rare, and the molecular mechanisms usually remain unclear. Here, we hybridized two divergent species of Saccharomyces yeast. We experimentally evolved both hybrid and parental populations for 200 generations under hot (30°C), cold (16°C), and fluctuating (16-30°C) temperature regimes. Most hybrids showed intermediate growth but the large variance produced by hybridization also led to thermally transgressive hybrids with high performance. Across regimes, response to selection scaled negatively with ancestral growth, consistent with diminishing-returns epistasis. Analysis of genes with identified mutations revealed enrichment in multiple shared annotation terms between populations evolved in cold and fluctuating environments, such as cell wall functions. Evolved hybrid populations, across all evolution regimes, accumulated significantly more de novo copy number variants (CNVs) than both parental species, indicating extensive genome restructuring in hybrids. This increased structural variation may provide a substrate for selection and adaptive divergence among hybrid lineages. Our results suggest that hybridization can lead to increased growth, especially in hot and thermally unstable environments, by capitalizing on the genomic content inherited from one or the other parental species.
Behavior evolves as a correlated response to selection on cuticle color in Drosophila melanogaster and D. simulans.
Ruckman SN, Duffy AG, Mendez PM … +8 more , McCaffery KD, Miller S, Crews A, Tan N, Campbell LA, March A, Brown EB, Houle D
Evolution · 2026 Jun · PMID 42247595 · Publisher ↗
To predict adaptive evolution, we need to understand the degree to which selection on one trait can constrain or redirect evolutionary responses in other traits. We used artificial selection on cuticle color in Drosophil...
To predict adaptive evolution, we need to understand the degree to which selection on one trait can constrain or redirect evolutionary responses in other traits. We used artificial selection on cuticle color in Drosophila melanogaster and D. simulans to investigate whether color and behavior evolve in tandem. We selected for light and dark thoracic colors for 16 generations in two populations per species and measured correlated responses in aggression, basal activity, total activity, sleep, and geotaxis. Dark selected individuals consistently showed higher aggression and basal activity than light selected or control flies across both species and sexes, pointing to a modest but repeatable correlated response. In contrast, patterns for geotaxis, sleep, and total activity evolved unpredictably, often varying across species and populations, and showed no clear association with color. Within-population phenotypic correlations between color and aggression were significant but weak (rho = -0.035, rho² = 0.001), suggesting that color is a poor predictor of individual aggressive behavior. Populations evolving higher aggression also tended to evolve higher basal activity (rho = 0.52, p = 0.004), suggesting activity may have evolved as a correlated response rather than through a direct color-activity link. The persistence of correlated responses in aggression and basal activity in response to selection on color is consistent with a conserved genetic basis, such as pleiotropy or linkage disequilibrium, although our data do not distinguish between these mechanisms. Identifying the loci underlying variation in both color and behavior, and testing their effects experimentally, will clarify how multivariate genetic covariance shapes the direction and pace of adaptive evolution.
Parent-offspring conflict over sex determination in non-Mendelian systems.
Hitchcock TJ, Baird RB
Evolution · 2026 Jun · PMID 42246567 · Publisher ↗
Across the tree of life, many organisms exhibit asymmetric inheritance systems in which males and females contribute differently to the long-term genetic future of the population. Although, in such groups, the sexes ulti...
Across the tree of life, many organisms exhibit asymmetric inheritance systems in which males and females contribute differently to the long-term genetic future of the population. Although, in such groups, the sexes ultimately differ in their contributions, the zygotes that become males and females often start out genetically identical, with sex determined by maternal factors deposited into the embryo. However, there has been little work considering what the optimal sex ratio is from the perspective of the offspring in such scenarios, how this may differ from their parents, and how such conflicts may be modulated by other ecological factors. To investigate this, we develop analytical models to calculate the optimal sex allocation under a range of asymmetric genetic systems, and under the control of different parties. We then investigate the effects of various population structures and mating systems to consider their effects in shaping such conflicts. We find that asymmetric genetic systems may be prone to perpetual ongoing conflict between mothers and offspring over sex determination, even in panmictic populations. This may be one factor explaining the diverse and unusual sets of sex determining systems seen in these groups.
Effects of deleterious mutations on the fixation of chromosomal inversions on autosomes and sex chromosomes.
Roze D, Lenormand T
Evolution · 2026 Jun · PMID 42241728 · Publisher ↗
Deleterious mutations have multiple effects on the fate of chromosomal inversions. In this article, we use individual-based simulations to estimate the fixation probabilities of neutral inversions under a constant input...
Deleterious mutations have multiple effects on the fate of chromosomal inversions. In this article, we use individual-based simulations to estimate the fixation probabilities of neutral inversions under a constant input of deleterious mutations. As shown previously, we find that 'lucky' inversions carrying a lower-than-average mutation load are initially favored and tend to selectively spread. Our results also outline the importance of Muller's ratchet caused by the absence of recombination in Y-linked and in rare autosomal inversions, reducing their fixation probabilities. Despite the fact that Y-linked inversions are more susceptible to Muller's ratchet, they can more easily fix than autosomal inversions despite initially carrying mutations when these mutations have sufficiently low selection or dominance coefficients (sheltering effect). Similarly, the sheltering of deleterious alleles can increase the fixation probability of inversions capturing a mating-type locus, particularly under intermediate rates of self-fertilization. Overall, our results confirm that when mating is random and for realistic parameter values, the presence of deleterious alleles reduces the average fixation probability of autosomal, sex-linked or mating type-linked inversions below that of a neutral mutation. Nevertheless, the occasional fixation of a lucky inversion may have important macroevolutionary consequences, potentially contributing to the evolution of recombination arrest on sex chromosomes.
Feeding ecology and allometry underlie distinct axes of mandible and leg evolution in tropical termites.
Cerezer FO, de Azevedo RA, de Morais JW … +1 more , Dambros CS
Evolution · 2026 Jun · PMID 42240517 · Publisher ↗
Understanding how ecological pressures and allometry contribute to morphological evolution remains a central goal in evolutionary biology. We examined mandible and leg shape in nearly 100 Amazonian termite species using...
Understanding how ecological pressures and allometry contribute to morphological evolution remains a central goal in evolutionary biology. We examined mandible and leg shape in nearly 100 Amazonian termite species using geometric morphometrics and phylogenetic comparative methods. This approach allowed us to assess how feeding ecology and centroid size of body parts contribute to shape variation while accounting for shared evolutionary history across species. We show that mandible shape varies with feeding ecology along a wood-to-soil (humification) gradient, with wood-feeding species exhibiting shorter, more robust mandibles and soil-feeding species showing more elongated forms with a prominent apical tooth. In contrast, leg shape is best explained by leg centroid size and shows limited differentiation across feeding groups. Evolutionary model comparisons indicate that mandible shape is consistent with models suggesting multiple evolutionary optima associated with feeding habit, whereas leg shape is better described by a single optimum. Together, our results indicate that mandible and leg morphology vary along complementary axes: mandibles reflect dietary variation, while legs predominantly scale with size. This illustrates how different processes govern morphological variation in a dominant tropical termite radiation.
Clade-specific drivers of rapid vertebral evolution in squamate reptiles.
Stepanova N, Crowell HL, Rabosky DL … +1 more , Rabosky ARD
Evolution · 2026 Jun · PMID 42240514 · Publisher ↗
In vertebrates, larger body length can evolve through two mechanisms: the addition of vertebrae (pleomerism) versus the enlargement of vertebrae (proportional change). These two processes have significant but distinct fu...
In vertebrates, larger body length can evolve through two mechanisms: the addition of vertebrae (pleomerism) versus the enlargement of vertebrae (proportional change). These two processes have significant but distinct functional consequences for locomotion and stem from different developmental mechanisms. Squamate reptiles (lizards and snakes) show tremendous variation in precloacal vertebral number, ranging from 14 to nearly 400 vertebrae. By compiling vertebral counts for 2,357 squamate species from radiographs of museum specimens and supplementing with data from primary literature records, we tested how body size and habitat may influence variation in vertebral number across clades. We found that much of the variation in vertebral number reflects phylogenetic relatedness, likely due to other conserved causal variables or "macroevolutionary drift". Size and habitat also explained a small proportion of variance in elongate clades. Vertebral number in amphisbaenians and blind snakes differed significantly from patterns observed in other elongate clades, showing little influence of body size or phylogenetic history. Their extreme fossoriality may explain the decoupling between vertebrae and body size in these groups. Taken together, our results indicate a surprising complexity to vertebral evolution and we find little evidence that any single factor affects vertebral variation consistently across all squamates.
Correction to: Quantitative genetics of microbiome-mediated traits.
Evolution · 2026 Jun · PMID 42237944 · Publisher ↗
Abstract loading — click title to view on PubMed.
Parasitic infection and resource acquisition shape senescence through oxidative stress and energy depletion.
Hamley JID, Sanchez-Taltavull D, Koella JC … +1 more , Stroka D
Evolution · 2026 Jun · PMID 42233895 · Publisher ↗
There is currently no theory which mechanistically links parasite virulence and host senescence. One driver of senescence is energy metabolism. We expect parasites to contribute to senescence because infection increases...
There is currently no theory which mechanistically links parasite virulence and host senescence. One driver of senescence is energy metabolism. We expect parasites to contribute to senescence because infection increases energy allocation to the immune system, which elevates oxidative stress and damages macromolecules. Additionally, parasites deplete their host's energy, which can increase the host's rate of mortality. While these within-host processes can contribute to mortality, they also determine the risk of parasite infection through epidemiological dynamics. To understand quantitatively the impact of these interactions on infection dynamics and on the evolution of within-host parasite growth (virulence), we developed a multiscale model that describes within-host and among-host dynamics. We found that infection prevalence is maximised at intermediate levels of resource acquisition only when energy depletion contributes to senescence. Furthermore, for a single resource level, there are two evolutionary equilibria for the parasites' growth rate. This is the first time the molecular mechanisms determining senescence have been considered in the context of parasite infection, allowing us to link virulence and senescence. Our mechanistic framework provides an alternative to the virulence-transmission trade-off and reconciles conflicting empirical findings on the impact of resources on epidemiological dynamics and virulence.
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