Biological Reviews

Exotic species can reshape native communities, in the extreme, to local extirpation. Before that, natives may adjust where and when they use the landscape, in ways that allow coexistence and may be the earliest sign of trouble. Distinguishing coexistence built on such adjustment from one built on pre-existing niche differences requires comparing a native where the invader is absent with the same native where it is present, across sites at different invasion stages. Using eight years (2018-2026) of camera-trap data from 103 stations across Uruguay (154,590 camera-nights), we asked how the invasive axis deer (Axis axis) affects the space and time use of two native cervids: the forest-dwelling brown brocket (Subulo gouazoubira) and the grassland-restricted pampas deer (Ozotoceros bezoarticus). Activity-overlap, directional-avoidance, hierarchical activity, and two-species occupancy analyses showed sharply divergent dyads. A. axis and S. gouazoubira shared forest yet segregated in space and along the understory stratum the brocket requires and the invader avoids, and shifted their diel activity by context; understory cover fell with A. axis abundance, consistent with habitat modification. For A. axis and O. bezoarticus, segregation was intrinsic, opposite diel niches and habitats, with no support for a detectable shift in pampas deer behavior. The only behavioral signal was asymmetric: the invader, rather than the native, appeared to adjust, though few shared sites warrant caution. The same invader thus drives different mechanisms, but coexistence is provisional: A. axis is still expanding, far from equilibrium, so these shifts read best as early warning signals.

Multifunctional anatomical structures must accommodate potentially competing performance demands, leading to functional tradeoffs. The mammal rostrum (snout) is involved in multiple functions, including feeding, respiratory conditioning, olfaction, and, in most bats, echolocation. Therefore, it serves as an ideal system to investigate whether and how functional tradeoffs promote or constrain morphological diversification. While the external morphology of the rostrum has been linked with mechanical demands of feeding in bats, the factors and processes influencing its internal morphology, including the turbinals in the nasal cavity, remain comparatively unexplored. Here we investigate how internal rostral morphology reflects specialization and tradeoffs among respiratory air conditioning, echolocation, and olfaction by quantifying turbinal morphological diversity in a phylogenetically and ecologically diverse sample of bat species. We find that echolocation mode predominantly influences both the ethmoturbinal complex (ETc) and maxilloturbinal (MT) systems, with nasal-emitting bats having reduced and less complex turbinals compared to oral and non-laryngeally echolocating bat species. MT complexity and surface area are not associated with bioclimatic variables representing thermal variability and aridity. However, the ETc exhibits higher complexity in plantivorous bats than faunivorous bats, suggesting higher olfactory reliance. While MT morphological disparity was predominantly explained by echolocation mode, ETc morphological disparity was associated with both echolocation mode and diet, suggesting potentially opposing demands favoring turbinal reduction for sound transmission and elaboration for olfaction. Among nasal emitters, which must accommodate both demands within the nasal cavity, ETc complexity exhibited higher relative disparity compared to MT complexity. These patterns suggest that competing functional demands may promote or maintain morphological diversity, possibly through ecological specialization and/or many-to-one mapping between morphology and performance.

Urbanization is an accelerating evolutionary force, yet the patterns and drivers of urban gene flow remain largely obscured. This leaves a critical gap in testing the interplay between demographic and genetic models of urban connectivity. Specifically: the urban fragmentation model, where structural barriers restrict gene flow and drive genetic drift; the urban facilitation model, where permeable matrices enhance functional connectivity; and the urban sink hypothesis, a demographic model where high mortality creates unsustainable population sinks. We used high-resolution RAD-capture data to conduct landscape genomics and gene flow analyses to resolve these models and investigate contemporary evolution in urban coyotes (Canis latrans) across the greater Los Angeles, CA, USA metropolitan area. By incorporating fine-scale environmental, social-ecological, and historical variables of the built environment, we rigorously assessed how urban heterogeneity shapes intra-city evolutionary dynamics. We found weak population structure, heavily influenced by family groups. There was extensive landscape permeability and gene flow across the study area including across four major highways. We also identified heavily asymmetric gene flow from exurban source populations into the urban core, supporting the urban sink paradigm. However, rather than acting as a genetic dead-end, the urban matrix showed striking functional heterogeneity: one urban core functioned as a 'genetic sponge,' absorbing unique transient alleles from multiple surrounding sources, and both urban cores operated as permeable 'leaky sinks,' exporting critical gene flow to other populations. Consequently, urban demographic sinks can simultaneously act as vital genetic bridges. Our findings reject a pure urban fragmentation model while demonstrating that demographic sink dynamics and genetic facilitation are not mutually exclusive. This demonstrates that high-turnover urban sinks can buffer regional biodiversity against genetic erosion, highlighting the need to prioritize matrix permeability and inter-patch connectivity in urban conservation strategies.

The palaeogeographic history of the Neotropics has inspired multiple diversification models, emphasizing either the Andes or Amazonia as primary drivers of biodiversity. However, the extensive Pebas wetland system that covered western Amazonia during the Miocene has gained attention as a potential barrier to dispersal and diversification. This system may have contributed to the modern diversity imbalance between the Andes and Amazonia, known as the Gentry pattern. Most evidence for this hypothesis comes from isolated case studies and fossils. Here, we conduct a meta-analysis including 1,361 species of Neotropical butterflies to evaluate the role of the Pebas wetland on the dynamics of dispersal and diversification. We found that Andean- and Amazonian-centred clades show complementary but temporarily distinct biogeographic patterns. High Andean diversity reflects an Andean origin, with early occupancy and diversification occurring within the Andes, followed by post-Pebas dispersal into Amazonia. By contrast, Amazonian-centred clades, reflect an Amazonian origin, with an early diversification in Amazonia and subsequent post-Pebas colonization of the Andes. While several clades show little evidence of Pebas influence, our study suggests that the Pebas wetland did not uniformly restrict diversification, but rather selectively constrained dispersal between the Andes and Amazonia, preventing simultaneous diversification in both regions and thereby creating a diversity imbalance that characterizes the modern Neotropic.

Global biodiversity recovery demands restoration at landscape scales, where ecological outcomes are shaped not only by habitat amount but also spatial arrangement. Alternative landscape restoration strategies can increase habitat amount, improve quality, and alter configuration in fundamentally different ways and may therefore vary in their efficiency. Here, we conceptualise five landscape restoration strategies and use a spatially explicit metapopulation framework to compare their ability to increase predicted species persistence across heterogeneous landscapes and trait space defined by dispersal ability and specialisation. We find that restoration outcomes are strongly trait-dependent, with restoration of existing degraded habitats yielding the highest benefits - particularly for specialists. Improvement of the landscape matrix to create low-quality habitat primarily benefits generalists, while strategies creating new habitat patches or enlarging patches provide more consistent but modest gains. These results reveal fundamental trade-offs among restoration strategies and highlight the utility of trait-explicit approaches to inform their implementation and evaluation.

Geographic isolation is a major driver of lineage divergence. However, strong ecological selection can promote reproductive isolation despite opportunities for gene flow in geographically continuous landscapes such as mountains. Here, we test whether ecological divergence across elevational gradients can promote speciation within a single mountain range. Integrating phylogenomic (ddRAD), morphological, and bioacoustic data, we test predictions of elevation-mediated parapatric speciation in Platymantis (Lahatnanguri) ground-dwelling frogs on Mindanao Island, Philippines. Phylogenomic analyses recovered an endemic radiation across neighboring mountain ranges and revealed a hierarchical pattern of diversification among three monophyletic lineages, with deeper divergence separating the mountain lineages Highland 1 and Highland 2 and more recent divergence occurring within a single mountain range. This topology identified a morphologically and acoustically distinct low-elevation lineage (<1,400 m a.s.l.) as closely related to the high-elevation Highland 1 lineage (>1,400 m a.s.l.), providing a natural test of divergence along an elevational gradient. The parapatric Lowland and Highland 1 lineages appear to have diverged relatively recently, as reflected in their shallow genome-wide differentiation, yet exhibit pronounced morphological and acoustic divergence. Population genomic analyses further recover discrete genomic clusters and no evidence of contemporary hybridization between the parapatric lineages, indicating independent evolutionary trajectories despite geographic continuity. Together, these findings are consistent with parapatric speciation along an elevational gradient and demonstrate how substantial phenotypic and reproductive-isolation divergence can accumulate despite limited genome-wide differentiation. More broadly, our results indicate that the exceptional biodiversity of oceanic archipelagos may arise not only from diversification among islands (and among mountains within islands) but also from lineage divergence along elevational gradients within mountains themselves. These empirical results support the biological plausibility of parapatric speciation within single mountain systems and highlight an underrecognized mechanism contributing to biodiversity in topographically complex oceanic archipelagos.

Social relationships are strongly linked to health and biological fitness in humans and other animals. For example, social support may buffer individuals against harsh ecological conditions. Reciprocally, better health may allow for greater investment in social relationships. We examined links between health and social behaviour in an endangered population of northern bottlenose whales (Hyperoodon ampullatus). Using photo-identifications spanning 37 years, we visually classified whether individuals had poor body condition on each day they were observed (N = 3,086 whale-days). We then used generalized linear mixed models to explore how body condition varied with sex, age, and within-individual deviations in group size or other social metrics derived from Bayesian social networks. Approximately 11% of individuals were classified as being in poor condition at any time, though the prevalence of poor condition varied across raters and years. Visually assessed condition was successfully validated with morphometric measures, though there was only weak evidence that poor condition predicted apparent survival. Contrary to expectations, whales in poor condition were found in larger groups and had more social partners than their average across the study period. These findings run counter to the expectation that health and social connectedness are positively correlated in social mammals.

1. Group foraging reduces the risks associated with foraging: larger groups dilute individual predation risk, allow group members to share the costs of vigilance, and provide a social structure for exchanging information about predators. The benefits of shared social information over simple safety in numbers should depend on the relationships among group members. Consequently, group composition should affect the selection of risky and safe habitats in social species. 2. We asked whether relationships among elk (Cervus canadensis) group members moving together influence their selection of risky habitats more than grouping alone. We tested three hypotheses. The familiarity hypothesis predicts that elk with close social ties are most likely to select risky habitats together. The inclusive fitness hypothesis predicts that the closest genetic relatives are most likely to select risky habitats together. The dilution hypothesis predicts that familiarity and genetic relationships do not influence habitat selection, with all group foraging benefits derived from proximity to others. 3. We used integrated Step Selection Analysis to test whether the identity of the closest group members influenced habitat selection. We tested whether the relationship of the nearest elk--either genetic or social--incentivized selection of risky habitat more than proximity to the nearest elk. 4. Group foraging clearly reduced risk, with elk more likely to select risky habitat when near others. Elk were also more likely to select risky habitats when near closer relatives, albeit with considerable variation among individuals. However, familiarity had a large and consistent effect: elk were far more likely to select risky habitats when near socially familiar group members. 5. Our results suggest that information shared within foraging groups, especially between socially familiar individuals, may lower the risks associated with habitat selection. Similarly, the benefits of reliable social information for reducing risk likely incentivizes the formation of stronger social ties within foraging groups. This positive feedback between social familiarity and habitat selection could thereby increase access to profitable habitats that are otherwise too risky, cementing what we term the social information landscape as a key driver of movement and habitat selection.

Understanding the transmission and persistence of zoonoses in wild reservoirs is crucial for outbreak prevention, demographic assessment, and conservation planning. Host demography, ecology, behaviour and within-host viral kinetics together underpin transmission dynamics but are rarely united within epidemiological models. Here we characterised the transmission dynamics of European bat lyssavirus 2 (EBLV-2) infection dynamics by uniting a long-term study (2010-2018) of the ecology of five greater mouse-eared bat (Myotis myotis) colonies in France (~2700 marked individuals) with diagnostic evidence of virus circulation. Although no lyssavirus was detected in any of the 442 saliva samples tested, seropositivity showed synchronised peaks across colonies (0-100% annually), with the highest seroprevalence in 2015-2017, but remaining low otherwise. Fitting Bayesian compartmental epidemiological models, we found evidence that shifts in EBLV-2 prevalence were primarily driven by the gregarious behaviour of populations during the mating season and age-dependent variation in transmission. The duration of maternal immunity emerged as a key, and still empirically unknown factor, which shaped whether EBLV-2 maintenance was enzootic or required an external force of infection. Lyssavirus outbreaks in M. myotis were associated with few deaths overall and had a negligible impact on population dynamics. These findings underscore the value of integrating ecological and individual-level data with mechanistic modelling to enhance our understanding and management of zoonotic pathogens in wildlife.

Disturbances alter ecosystem resilience by killing organisms and leaving behind material legacies. We tested how material legacies from marine heat waves and cyclones govern transitions between coral- and seaweed-rich states on tropical reefs. Heat waves kill coral tissue but leave their skeletons to erode gradually, whereas cyclones scour away emergent biota. Field experiments revealed that dead skeletons protect seaweeds from herbivory, catalyzing a transition to a seaweed-rich state that becomes self-sustaining after skeletons disappear. After four years, 73% of skeleton-added (heat wave) plots transitioned to seaweeds compared to 0% of scoured (cyclone) plots that lacked skeletons, while 87% of seaweed-rich plots scoured to simulate a cyclone stayed seaweed-free. Reef trajectories after natural disturbances were similar: four years after heat wave-induced coral mortality, 63% of time-series plots had transitioned to seaweeds with none recovering to coral; four years after a cyclone removed skeletons from a prior disturbance, none had transitioned to seaweeds and 60% had returned to coral. A disturbance not only can displace an ecosystem state, it can rapidly reshape the resilience landscape through the material legacies it creates or removes. Our findings also show that successive disturbances need not have cumulative negative effects: after a reef is driven into a seaweed-rich state, a cyclone can act as a rescue disturbance by removing established seaweeds and, when structural refugia are also removed, shrinking the seaweed stability domain. By reshaping resilience through contrasting material legacies, disturbance type and sequence can be as important as frequency and severity in determining ecosystem trajectories.

Eusociality, characterized by overlapping generations, cooperative brood care, and reproductive division of labour, has arisen independently across diverse, phylogenetically distant insect orders, including Hymenoptera (ants, bees, and wasps), Blattodea (termites), and Coleoptera (weevils). While multiple studies have investigated the molecular evolution of sociality from solitary ancestors in Hymenoptera and Blattodea, so far little is known about the evolutionary signatures of social evolution in Coleoptera. Weevils (Curculionidae) provide an ideal system for addressing this question, as they cover the full spectrum of social complexity from parental care, through several origins of facultative eusociality to the only obligately eusocial beetle, Austroplatypus incompertus. We generated genome assemblies for A. incompertus and two facultatively eusocial weevil species, Xylosandrus germanus and Xyleborinus saxesenii, which together with 18 publicly available weevil genomes span two independent evolutionary origins of sociality. Our analyses reveal a genome-wide relaxation of purifying selection with increasing social complexity, which is most pronounced in A. incompertus. We find a significant excess of convergent gene family contractions in lineages where sociality evolved, and no evidence of elevated positive selection. These findings indicate that the molecular mechanisms of social evolution in weevils are primarily characterised by relaxed selection and gene loss, rather than adaptive innovation and gene family expansions. These observations are consistent with sheltering and reduced effective population size playing an important role, a pattern not previously observed in other clades.

Beta diversity is a fundamental component of regional biodiversity that accumulates from compositional differences between local species assemblages. Although beta diversity is increasingly applied across spatial scales, its scale dependence remains incompletely synthesized, particularly concerning variation in spatial scale used to define alpha diversity (grain size). Using tree community data from Barro Colorado Island, we find that both additive and multiplicative beta diversity are consistently higher for unequal than equal grain divisions across different spatial extents and numbers of grains. These results can be explained by Jensen's inequality based on the concave-down relationship of alpha diversity with area that in turn increases beta diversity through the scaling relationship between alpha and gamma diversity. Combined with our additional analysis showing that this prediction is robust to more general models of species richness, including species--area and species--sampling-effort curves, these results reveal a previously unrecognized, predictable range of beta diversity variation.

Primates maintain cooperative relationships largely through grooming reciprocity, yet studies disagree on the timescales over which grooming is returned. Part of this disagreement stems from statistical issues: inconsistent definitions of a reciprocation window, combined with the exclusion of unreciprocated grooming, leave the debate unresolved. We still do not know if primates exchange grooming within the short windows predicted by biological market theory or over much longer timescales. Whilst survival analysis can identify reciprocation windows objectively by retaining unreciprocated grooming as censored data, previous studies have applied it inconsistently. This inconsistency leaves the true time frames over which primates reciprocate grooming somewhat blurred. Here, we use a statistical approach that addresses these problems to examine grooming reciprocity in crested macaques (Macaca nigra), a socially tolerant macaque species. We applied survival analysis to identify each group's short-term reciprocation window without imposing arbitrary cut offs, and Bayesian survival models to test whether social bond strength and eigenvector centrality predicted reciprocation latency. Short-term reciprocation occurred rarely (29% of events in one group and 5% in the other); most reciprocation occurred over longer timescales than previous research commonly assumes. Stronger bonds predicted faster reciprocation; this finding suggests that crested macaques express social investment in valued partners through how promptly they return grooming, meaning that the timing of exchange carries information about relationship value. Eigenvector centrality showed no credible effect, though our small sample size and dense groups prevent us from interpreting this outcome more robustly. Substantial variation between dyads remained unexplained, pointing to partnerspecific properties we have yet to identify. These findings caution against assuming that reciprocity operates over short windows. They show that social predictors, such as bond strength, remain essential to understanding when primates return grooming. This work provides a baseline for testing whether grooming is exchanged for other social commodities, and for comparing reciprocation timescales across macaque species that differ in social tolerance.

Disentangling whether gut microbiome diversification reflects host evolutionary history or spatial processes remains challenging because these factors are often confounded. The Macaronesian chaffinch (Fringilla) radiation provides a replicated natural experiment to separate these effects. Using long-read 16S sequencing, diet metabarcoding, and whole-genome data, we evaluated competing models of community assembly, testing host-mediated dispersal versus neutral assembly, and environmental filtering versus host control. We show that microbiome alpha diversity across host species was largely shaped by island size and isolation, aligning with Island Biogeography Theory, rather than host colonisation history. This indicates that microbial dispersal occurs independently of their hosts. Moreover, spatial and host factors influenced different aspects of the microbiome: geography and diet primarily predicted which taxa were present, whereas host genetic relatedness and heterozygosity were associated with the abundance of established residents. Notably, we show that inbreeding compromises a host's ability to regulate microbial abundance, leading to highly variable microbiomes. While we detected phylosymbiosis (closely related hosts harboring similar microbiomes), we found no evidence of co-diversification between birds and microbes. Instead, associations likely arise from convergent ecological filtering, where shared host traits filter similar bacteria from the local environment. Together, our results show that avian microbiomes are shaped by distinct spatial and host-mediated processes, and that separating microbial presence from abundance is important for understanding the mechanisms driving microbiome assembly.

Any mechanistic biodiversity-ecosystem functioning theory must explain how biodiversity in natural communities arises, which requires an evolutionary metacommunity perspective. Using a model of adaptive evolution of competitive metacommunities in landscapes with spatially heterogeneous supply of two resources, we studied the evolution of resource-uptake specialization as a function of resource type (substitutable/essential) and trade-off shape between resource-uptake affinities (generalist-/specialist-favouring). We identified "critical essentiality" as a key phenomenon separating parameter regions with fundamentally different biodiversity--ecosystem function relationships. Specifically, while greater spatial heterogeneity in resource supply increases biodiversity, this comes at the cost of reduced productivity when resources are essential. Moreover, when resources are essential, both generalist- and specialist-favoring trade-offs select for phenotypes that prevent efficient resource partitioning, leading to low resource use efficiency and consumer biomass - despite often high species richness. In contrast, when resources are substitutable, a specialist-favoring affinity trade-off selects for phenotypes that partition resources efficiently, promoting a metacommunity of only two species characterized by high functional diversity, resource use efficiency, and biomass. Overall, our analyses thus suggest that conditions promoting the evolution of diverse consumer communities often do not engender higher functional richness, consumer biomass, or resource use efficiency.

Lineages that have undergone little apparent evolutionary change over long geological intervals are often described as "living fossils", with iconic examples including the coelacanth, tuatara, and Ginkgo. However, studies of morphological and molecular data have produced mixed evidence regarding whether living fossils have evolved more slowly than their relatives. We tested for reduced evolutionary rates using a sister-pairs approach, analysing a comprehensive set of morphological and molecular data for 45 living-fossil lineages and their close relatives across the Tree of Life. Living-fossil lineages showed substantially reduced rates of morphological evolution, whereas evidence for reduced molecular rates was weaker. To test whether this pattern could be explained by species poverty, we also analysed other depauperate lineages (species-poor clades contrasted with species-rich sister clades) and found a weak tendency towards reduced molecular rates but without a corresponding slowdown in morphological evolution. Our study reveals that the living-fossil concept captures a quantifiable pattern of prolonged morphological conservatism, but also suggests that living fossils lack other shared biological or life-history characteristics that might unite them as a group.

Understanding the evolution of cognition is fundamental to understanding the origins and nature of our own cognitive abilities, with cross-species comparisons providing a cornerstone of this endeavor. Yet, comparative cognition so far has largely focused on endothermic vertebrates, particularly mammals and birds, while ectotherms--representing a substantial proportion of vertebrate diversity--remain relatively understudied. Moreover, variation in experimental methods makes existing data difficult to compare across species. Big-team science offers a way to overcome these limitations by enabling standardized cognitive testing across broad taxonomic scales. Here, we apply this approach to fishes, using inhibitory control as a proof of concept for standardized comparative testing in 444 individuals across 22 teleost species spanning 19 genera. We demonstrate that standardized cognitive testing across such diversity is feasible, while also revealing substantial heterogeneity in the sample. Performance varied markedly among species, but, strikingly, showed only a weak phylogenetic signal, contrasting with patterns previously reported in mammals and birds. In addition, we detected great within-species variation, including differences across research groups, suggesting that performance may reflect not only species-level evolutionary history but also ontogenetic experience and the capacity to adjust decision rules to local conditions. Together, our findings highlight the importance of both evolutionary and environmental sources of cognitive variation and demonstrate that extending standardized comparative approaches beyond traditionally studied endotherms can reveal a more dynamic and complex picture of cognitive evolution across the vertebrate lineage.

Extreme climatic events (ECEs) could potentially induce episodes of rapid adaptive evolution, altering the evolutionary trajectories and viability of wild populations experiencing increasingly stochastic environments. Adaptive potential stems substantially from additive genetic variance (V) in survival. However, the degree to which ECEs impact this variance, and the resulting evolutionary implications, have not been fully conceptualised or quantified in nature. These aims are highly challenging because underlying genetic and environmental variances have fundamentally non-linear effects on the dichotomous phenotypic outcome of survival versus death, while substantial data are required for estimation. We present a conceptual and analytical framework that formalises biological hypotheses for how V depends on environmental severity, how such dependences are reshaped by non-linear genotype-environment-phenotype relationships and demographic structure, and the implications for evolutionary responses. We then use 25 years of survival and pedigree data from European shags (Gulosus aristotelis) to decompose variance in adult survival across diverse environmental conditions including ECEs. Using a capture-recapture animal model, we demonstrate non-negligible V underlying adult survival across all years combined, implying notable adaptive potential. Yet, partitioning by environmental severity revealed substantial V in good years with high survival but negligible V in bad years with ECE-induced low survival, implying a genotype-by-environment interaction that constrains adaptive potential under severe conditions. However, scale transformations showed how the non-linear genotype-environment-phenotype relationship can distort or even reverse such patterns, by reducing the extent to which V is phenotypically expressed in good conditions with high mean survival and amplifying it in more severe conditions with lower mean survival. Evolutionary responses to severe conditions could consequently be non-negligible even given small underlying V. We thereby demonstrate how ECEs can reshape adaptive potential, highlighting the need to integrate impacts of environmental severity on genetic variation in fitness components into predictions of population resilience under climate change.

Understanding when species diversification and phenotypic evolution are coupled remains a central challenge in macroevolution. Such coupling may depend on the traits considered, phenotypic integration, or the geographic context in which diversification occurs. Here, we investigate these relationships in Ithomiini, a diverse Neotropical butterfly tribe whose diversification is strongly associated with the Andes-Amazonia system. We quantified forewing and hindwing size and shape for 1,618 individuals representing 291 species using geometric morphometrics, and combined these data with phylogenetic comparative methods, diversification-rate estimates, and spatial analyses of species distributions. Evolutionary rate shifts were largely trait- and wing-specific, indicating limited coupling between forewing and hindwing evolution. Across the phylogeny, wing size evolution and extant wing size were not associated with species diversification, nor was hindwing shape evolution. By contrast, forewing shape evolutionary rates showed a positive association with diversification. Spatial analyses revealed that this coupling was geographically concentrated in the Andes, where high diversification rates coincided with elevated forewing size and shape diversity and increased forewing evolutionary rates. Hindwing diversity, by contrast, more closely tracked phylogenetic diversity and showed weaker or opposing relationships with diversification. Our results show that diversification and phenotypic evolution in Ithomiini are neither generally coupled nor fully independent, but linked in trait-specific and geographically structured ways. More broadly, they highlight the need to decompose complex phenotypes and integrate spatial context when testing macroevolutionary coupling.

Artificial intelligence (AI) assistants can improve individual performance but may weaken unaided performance and limit interest diversity, raising questions about their long-term effects on collective intelligence (CI). Here, we consider an evolutionary model in which individuals predict, consult AI, and imitate better-performing peers. Classic reward structures that promote CI without AI can fail under Chatbot AI, whose predictions depend on users' interests, by reducing interest diversity or propagating bias. Directly rewarding or penalizing AI use does not reliably mitigate these effects. Instead, a balanced incentive that preserves minority expertise and rewards collective contributions can promote CI, but an additional incentive is needed to restore unaided collective accuracy. Our framework offers an explanation for emerging evidence of AI's societal impact and clarifies its long-term implications.