Fine-scale thermal heterogeneity within intertidal and subtidal microhabitats could drive divergence in organismal heat tolerance. Reef corals from the extreme intertidal may hold optimism for the future of coral reefs and give insights into the mechanisms by which coral may persist under future conditions. Here, we compared the thermal sensitivities of intertidal and subtidal Acropora digitifera and evaluated their bleaching phenotypes, transcriptomes, host genetic differentiation and bacterial communities. Results showed that only heat-exposed subtidal corals displayed significantly reduced photochemical efficiency, symbiont densities, pigment and host protein concentrations, suggesting bleaching and host starvation. Despite being genetically similar, heat-exposed subtidal corals mounted stronger immune activation and amino acid degradation but downregulated monocarboxylate transport and calcification compared to intertidal corals. In contrast to the prevalence of Cladocopium in subtidal corals, intertidal corals were dominated by Durusdinium, whose transcriptional signature was characterised by lineage-specific and constitutively high transcript abundance of orthologs involved in stress response, metabolism, photosynthesis, cell cycle and symbiotic interactions. Furthermore, 16S rRNA sequencing demonstrated an origin-dependent bacterial composition, with Endozoicomonas being more abundant and important in co-occurrence networks of intertidal corals. Our findings suggest that distinction in Symbiodiniaceae and bacterial communities and Symbiodiniaceae lineage-specific transcriptional footprint largely underpin the exceptional thermotolerance of intertidal Acropora. Although these corals provide promising avenues for restoration, such a mechanism may bring attention to the risk of using them in selective breeding, particularly given the horizontal transmission of algal symbionts in Acropora.

Understanding factors influencing the dynamics and distribution of parasites is essential to decipher the mechanism behind their spread and the identification of populations with elevated risks of infection. Bats-together with the diverse parasites they host and the influence of their social behaviour on parasitism-offer a suitable system. We investigated the extent to which differences in life history traits between parasite species found on the same host influence their dispersal dynamics across bat metapopulations. To do so, we compared the population genetic structure of two obligate ectoparasites of the same bat, the Daubenton's bat (Myotis daubentonii): the specialist wing mite Spinturnix andegavinus and the more generalist bat fly Nycteribia kolenatii, and we expected the bat fly to exhibit a higher connectivity than the wing mites. Using double-digest restriction site-associated DNA sequencing (ddRADseq), we genotyped 426 bat flies and 171 wing mites across 13 maternity colonies and foraging sites and 1 putative swarming site in Switzerland. We found high genetic homogeneity across the metapopulations for both species, highlighting the dispersal capacity of N. kolenatii and S. andegavinus, probably driven by the high mobility of their bat hosts. The positive population-specific FIS and the excess of low-frequency alleles in both species suggest within-site expansion and provide insights into the life cycle of these ectoparasites. Altogether, these findings enhance our understanding of the interplay between nycteribiid flies and spinturnicid mites and their host movement in shaping population structure in Europe, offering broader insights into their potential role in pathogen transmission across bat populations.

Extreme climatic events and gradual climate change are increasingly anticipated to interact and reshape ecological communities. However, the combined effects of ocean warming, acidification and marine heatwaves on host-associated microbial communities and their potential role in host adaptation remain poorly understood. Here, we assessed shifts in gut microbiome communities and their associations with physiological performance in one tropical (Abudefduf vaigiensis) and one subtropical (Microcanthus strigatus) reef fish species, across three temperate reefs representing natural analogues of climate change: a present-day baseline ('cool reef'), a chronically warmed reef ('warm reef') and a reef experiencing combined warming and extreme acidification ('extreme reef'). We also examined gut microbiome changes in A. vaigiensis before and during a severe marine heatwave. A. vaigiensis had lower gut microbiome evenness and diversity at the warm (43% and 44% decrease, respectively) and extreme (38% and 31% decrease) reefs compared to the cool reef, and its gut microbiome community shifted at the extreme reef with a 122% increase in abundance of opportunistic bacteria Vibrio. A. vaigiensis also had lower gut microbiome richness at the warm (42% decrease) and extreme (52% decrease) reefs during the heatwave compared to pre-heatwave individuals. In contrast, M. strigatus showed higher microbiome evenness (99% increase) and diversity (98% increase) at the warm reef compared to the cool reef; however, these gains were lost at the extreme reef, with microbiome diversity and evenness returning to cool reef levels. Microbiome changes in both species were generally not associated with their physiological performance (protein content, oxidative stress, antioxidant capacity or body condition). Our findings suggest that marine heatwaves, ocean warming and acidification can reshape reef fish gut microbiomes, driving simplification in Abudefduf vaigiensis but distinct restructuring in Microcanthus strigatus. We conclude that climate-driven microbiome reshuffling may alter host-microbiome relationships and functions in fishes in a future ocean.

Most herbivores are specialised on particular host plants but some are generalists that can exploit distinct hosts. Generalists may have evolved adaptive transcriptional plasticity to cope with the defences of the different hosts. However, the fundamental differences in plant-induced transcriptional plasticity between generalists and specialists remain poorly understood. Here, we investigated transcriptional plasticity of the generalist aphid Myzus persicae and two specialist aphids, Brevicoryne brassicae and Rhopalosiphum padi, by transferring them between Brassica napus (a host for B. brassicae but not for R. padi) and Zea mays (a host for R. padi but not for B. brassicae), both suitable hosts for M. persicae. Generalist and specialist aphids exhibited transcriptional plasticity coordinately in response to different plant species, but their gene expression patterns often diverged. Generalist aphids attenuate the activation or even suppress salicylic acid (SA) signalling in host plants, whereas specialist aphids provoke it in nonhost plants. SA signalling had limited effects on gene expression in the generalist aphids, but significantly shaped transcriptional responses of the specialists. These findings underscore the fundamental differences in plant-induced transcriptional plasticity between generalists and specialists and highlight the critical role of plasticity directionality in insect adaptation.

Malaria, a febrile disease caused by the Plasmodium parasites and transmitted by mosquitoes, is a leading cause of mortality in children under 5 in endemic countries. The widespread deployment of insecticide-treated bed nets (ITNs) has significantly reduced malaria transmission, but rising levels of insecticide resistance threaten to halt the progress. Monitoring insecticide resistance is vital for effective vector control, particularly when deploying new tools. Understanding mosquito population responses to these interventions is crucial for guiding control programmes in making informed decisions about the selection, timing and geographic deployment of tools. This genomic study investigates the demographic and evolutionary consequences on the malaria vector Anopheles gambiae of deploying standard ITNs (containing only pyrethroids) and pyrethroid-PBO nets (containing pyrethroids plus the synergist piperonyl butoxide) during a clinical trial in Uganda. Despite substantial reductions in indoor mosquito densities in the clinical trial, estimates of nucleotide diversity (π) and linkage disequilibrium revealed no significant decline in effective population size, reflecting continued large population size even after effective control. Marked allele frequency shifts at resistance-associated loci indicated strong selection pressures driven by the interventions, with distinct selective dynamics between the two net types, highlighting alternative pyrethroid detoxification pathways in the presence of PBO. A duplication in the Cyp9k1 gene significantly increased in frequency in populations exposed to pyrethroid-only nets but decreased in populations exposed to PBO-treated nets, suggesting that selection for over-expression of this gene is removed when this resistance mechanism is impacted by PBO. An alternative potential detoxification mechanism was selected within a region of the 2La chromosomal inversion on chromosome 2 L, which encompasses the UDP-glucose 6-dehydrogenase gene. This variant consistently increased in frequency when exposed to PBO-treated nets. Additionally, pyrethroid-only nets selected for a novel locus on the X chromosome containing the diacylglycerol kinase gene, which is potentially linked to behavioural adaptations through its role in neurotransmission modulation. Our findings underscore the importance of genomic surveillance in vector control, revealing distinct evolutionary dynamics of insecticide resistance mechanisms in the presence of PBO. While ITNs remain effective, the persistence and evolution of resistance-associated alleles highlight the need for adaptive and dynamic resistance management strategies. By integrating high-resolution genomic data with epidemiological and entomological monitoring, this study offers actionable insights to sustain malaria control efforts amid the ongoing challenge of insecticide resistance.

Parasites are a ubiquitous force in nature threatening wildlife populations and ecosystems. Interactions between hosts and their parasites are impacted by host-associated microbiomes, which are essential for host development, physiology and immunity. We synthesise current understanding of the ecological interactions between host microbiomes and parasites, ranging from competitive to facilitative, and explore their potential evolutionary consequences for parasite virulence and transmission in the wild. We highlight recent mechanistic insights that support integrating a microbiome perspective into wildlife parasitology, with examples across diverse animal taxa including amphibians, bats, insects and corals, particularly within the context of climate change. Adopting such a holistic approach can open new avenues whereby host microbial shifts can be used to predict and mitigate infectious diseases in wild populations. Finally, we propose a conceptual framework to guide future research on microbiome-parasite-host interactions, aiming to better reflect natural ecological complexities and advance both fundamental understanding and conservation applications.

Invasive species that undergo a founder event may experience a decline in genetic diversity yet still establish successful populations. A possible example is a population of the common wall lizard (Podarcis muralis) in Cincinnati, Ohio, USA, which was founded following an introduction in the 1950s of a small number of individuals from Europe. We used whole genome sequences of individuals from source and introduced populations to assess the origin, demographic history, population structure, and possible signatures of adaptation in this successful lizard introduction. We first confirmed that the introduced lizards in Ohio are Podarcis muralis using phylogenetic analysis. Patterns of genetic diversity indicate introduced lizards in Cincinnati went through a short-term bottleneck with increased inbreeding but then rapidly increased in population size, thus minimising losses in genetic diversity. Comparisons of genomic variation between source and introduced populations demonstrate that populations in Cincinnati represent a subset of source genetic variation and show minimal losses of overall genetic diversity. Comparisons of mutation load between source and introduced populations reveal only small increases in load in introduced populations. Finally, tests for selection on the basis of outlier analyses detect targets for potential positive selection in multiple regions of the genome of introduced individuals, suggesting possible adaptation to a novel environment. Overall, we suggest that rapid population growth and possible adaptation have allowed the founding population of introduced lizards to evade the potential negative genetic impacts of small population size and successfully colonise a novel environment.

Many species have become threatened during the Anthropocene, requiring conservation strategies based on biological evidence. Wood-inhabiting fungi face multiple threats due to a complex interplay of a short lifespan, removal of dead wood as a resource and climate change. Furthermore, rare fruiting events might restrict dispersal via spores, leading to a significant population genetic structure. Yet, little is known about the genetic structure of both rare and common wood-inhabiting fungal species across Europe. Here, we investigate the rare polypore fungus Antrodiella citrinella, which co-occurs with the common wood-decay fungus Fomitopsis pinicola. We analysed a total of 149 individuals of both species across 13 countries, sequenced their genomes and analysed single-nucleotide polymorphisms. Based on a broad set of analyses, we found a very weak population structure in A. citrinella, suggesting historically wide dispersal and effective gene flow across Europe. In contrast, we found support for two moderately differentiated populations following a southwest-northeast separation in F. pinicola, possibly due to dispersal limitation through its relatively larger spores, a more intense forest use history in southern Europe and a post-glacial history of co-immigration with the main host tree species, Norway spruce. While the weak to moderate genetic structure of wood-inhabiting fungi suggests historically sufficient habitat connectivity, conservation measures should consider strategies providing deadwood as an important habitat to restore and maintain connectivity throughout Europe.

High-elevation systems support species adapted to extreme conditions, and their rugged terrain and variable microclimates strongly shape evolution and persistence. Yet few studies have evaluated how geography and climate jointly shape genetic diversity, local adaptation and vulnerability to environmental change. Here, we investigate these processes in the Tibetan Partridge (Perdix hodgsoniae), a high-altitude endemic distributed across arid western and humid northeastern regions of the Sino-Himalayan landscape. This region's complex topography and contrasting climatic conditions provide a natural setting for examining population divergence, climate-associated adaptation and future resilience. We integrated whole-genome sequencing, ecological, climatic, landscape and morphological data to examine current patterns of local adaptation and forecast climate-induced risks. Our findings show that both biogeographic barriers and climatic gradients drive rapid population divergence in P. hodgsoniae, reflected in distinct morphological traits and population genetic structure. Populations in dry, fragmented western landscapes show adaptation to temperature, whereas those in humid northeastern regions exhibit adaptation primarily to precipitation. These contrasting adaptive trajectories lead to varying levels of vulnerability, with arid, isolated landscapes limiting gene flow and genetic diversity, thereby heightening sensitivity to future climate change. In contrast, humid regions maintain stronger connectivity and larger effective population sizes, supporting higher genetic diversity and facilitating precipitation-linked adaptation. Together, we demonstrate that mountain landscapes function as a 'double-edged sword' by simultaneously generating and limiting biodiversity through isolation, and by constraining persistence within microclimatic refugia. This study underscores the value of integrating genomic, ecological, climate and landscape data to uncover mechanisms of divergence and inform conservation planning under rapid environmental change.