搜索结果：Biological reviews of the Cambridge Philosophical Society

The Anthropocene is characterised by a continuous human-mediated reshuffling of the distributions of species globally. Both intentional and unintentional introductions have resulted in numerous species being translocated beyond their native ranges, often leading to their establishment and subsequent spread - a process referred to as biological invasion. Biological invasions are associated with profound changes in the composition, structure, and functioning of recipient ecosystems, plus substantial financial losses and disruptions to society, culture, and human well-being. These ecological, economic, and socio-cultural impacts are interrelated, ubiquitous, and detrimental, yet they are often subjectively perceived or inaccurately quantified. Persistent knowledge gaps remain, however, which limit our understanding of the complex and multifaceted causes and mechanisms of invasion impacts. To overcome these gaps and comprehensively capture all related facets pertaining to the nature and diversity of invasion impact, this scoping review of academic studies, grey literature, and expert reports provides a conceptual model for interpreting invasion impacts, structured around three interrelated pillars: impact domains, challenges in the study of impacts, and available risk- and impact assessments. We initially explore the various mechanisms and consequences of ecological, economic, and socio-cultural invasion impacts and their temporal dynamics, substantiating these with relevant empirical examples. We then review common challenges and fallacies in studying invasion impacts, including context specificity and inter-comparability of impact magnitudes, challenges associated with quantifying non-ecological impacts, and research biases, before synthesising how risks are analysed and impacts assessed, and how these assessments ultimately inform management decisions. Our review underscores the multifaceted and complex nature of invasion impacts, and that effectively addressing biological invasions requires more than isolated, reactive interventions; it calls for globally coordinated, proactive action underpinned by reliable scientific knowledge, sincere political commitment, and broad public engagement. Drawing on nearly a century of literature and global expert contributions, this work offers a comprehensive, nuanced, and timely overview of the potential consequences of biological invasions, providing a valuable foundation for informing future research directions, management interventions, and policy development.

The waggle dance of bees has given rise to some of the most striking and detailed studies of animal communication. But because of its gradient character, the waggle dance has widely been taken to have properties that are wholly distinct from those of human language. We argue that this is mistaken, and that the waggle dance represents the oldest instantiation of an iconic system also found in human language, notably in sign language. The waggle dance helps bees locate a food source through four properties: (1) food distance is conveyed through the duration of the waggling phase; and (2) food direction is conveyed through the orientation of the waggle run. In addition, (3) while in bees that dance horizontally, the waggle run points towards the food source, in bees that dance vertically the information involves transposition: the angle of the dance relative to 'upwards' is interpreted as the angle of the food direction relative to the sun. Finally, (4) the number of waggle runs increases with food quality. We show that properties 1 and 2 are instantiated in sign language classifier predicates, highly iconic constructions that produce visual animations of the orientation and movement of an entity. Furthermore, classifier movement (property 3) can be interpreted either directly or with 'viewpoint shift', a more flexible version of transposition. Property 4 seems to be instantiated more generally in the pragmatics of human and animal communication, as repetition can convey intensification and/or excitement (e.g. Go, go, go!). We further show experimentally that properties 1-3 are instantiated in some gestures understood by non-signers. Thus the waggle dance is a primitive form of a semantic system also found (through convergent evolution) in human language. It is remarkably ancient, at least 20 million years old according to phylogenetic reconstructions. While the horizontal dance (without transposition) is usually thought to be ancestral, a closer look at extant phylogenies suggests that the vertical dance (with transposition) might be more primitive, and furthermore that pre-adaptations guarantee that transposition might have been available from the start.

The alarm call sequences of titi monkeys (genera Plecturocebus, Callicebus and Cheracebus) have sparked important debates over whether they exhibit parallels with human language. Some researchers consider these sequences to involve both semantics and syntax, while others argue that the sequences convey semantic information without syntax. In this review, we revisit this issue by applying fine-grained linguistic analyses to the most comprehensive data set of titi monkey alarm sequences available to date. Specifically, we evaluate three competing hypotheses: one rich hypothesis suggesting that titi alarm sequences are compositional, and two deflationary alternatives. The first deflationary hypothesis holds that an alarm sequence is a single vocalisation that only superficially resembles a combination of discrete calls. The second deflationary hypothesis posits that an alarm sequence consists of a series of independent calls emitted in rapid succession, governed by no syntactic rule. The data set allows us to reject the first deflationary hypothesis but not the second, preventing us from concluding that titi monkey sequences are compositional. This leads us to another important question: if the sequences are not compositional, what information do they convey, and how? We examine the information encoded in the alarm calls and find that alarm calls likely reflect the caller's arousal level at the time of emission of the call: A-calls encode high arousal, B-calls lower arousal, and sequences appear to track dynamic changes in arousal over time. However, strikingly, receivers still manage to extract relevant information about the event eliciting alarm sequences, likely through inferences relying on contextual cues and prior knowledge. This pragmatic enrichment suggests that emotion-based communication can give rise to complex cognitive processes, particularly on the receiver's side. Titi monkeys thus offer a valuable model for investigating the evolutionary roots of pragmatics. More broadly, our review challenges the misconception that emotional communication is cognitively simple, and invites renewed attention to the role of affective communication in the emergence of linguistic-like abilities.

Gain curves have been a staple of sex allocation theory for decades. They represent patterns in which fitness is obtained from resource investments in reproductive functions. The monotonic forms that have been used for gain curves can represent fitness accrual by individuals, but only on the assumption that sufficient mates are always available to allow the stipulated monotonic pattern of reproductive success to occur. However, sexual populations do not have external banks of mating opportunities that lie outside the dynamics of the population (such opportunities would, by definition, be part of the population). Thus, the reproductive behaviour of whole populations cannot be simple scaled-up versions of individual gain curves. As sex allocation evolves within a breeding population, frequency-dependent selection creates a shifting advantage for the rarer sex. Individual gain curves cannot then remain stable possibilities at the population level. Evolutionary models based on fixed gain curves can predict evolutionary outcomes with unequal total fitness for male and for female function, an outcome that the biology of syngamy does not allow. Such biologically impossible outcomes are easily demonstrated. Gain curves have also been widely used as a framework for interpretation of interspecific empirical patterns, such as low male allocation in monogamously mating hermaphroditic animals or self-pollinating plants, and higher male allocation in wind-pollinated than in animal-pollinated plants. However, if gain curves incorrectly characterize whole populations or species, interspecific differences in gain curves cannot explain these patterns. Even if they superficially appear to predict the empirical pattern, other processes must be operating. The selective effects of local mating competition and sex-specific dispersal patterns have long been known. They are likely replacements for gain curves as explanations of many broad interspecific patterns, but the predominance of gain-curve explanations has distracted attention from these alternatives. A revision of our understanding of gain curves seems needed.

The ecology of forests, their losses, and terrestrial wood decomposition dynamics have been intensively studied and reviewed. In the aquatic realm, reviews have concentrated on large wood (LW) in rivers and the transition from freshwater to marine environments in the Pacific Northwest of North America. However, a comprehensive global synthesis of LW dynamics, including decomposition processes and human influences across the freshwater-marine continuum, is lacking. Here, we review the role of LW and its fate across the entire freshwater-to-marine gradient and synthesise our findings in an integrative conceptual overview. LW has been exported by rivers to sea for hundreds of millions of years. During this journey, LW acts as an ecosystem engineer by modifying its environment and the landscape. In rivers, LW alters hydrodynamics, resulting in sediment retention and changes to riverbed and shoreline morphology. Along coastlines, driftwood initiates dunes, prevents erosion, retains moisture, and provides lignocellulose-based nutrients. Important habitats provided by floating rafts and sunken 'islands' of wood are found across estuarine, shelf and open/deep seas. Wood degradation gradually transitions from mechanical to biomechanical and chemotrophic. In rivers, degradation is primarily mechanical due to abrasion and impacts. In estuaries, salinity increases, allowing marine wood borers to begin biomechanical degradation; their activity remains the main degradation cause across marine environments. On the seafloor, chemotrophic micro-organisms finalise decomposition of small fragments. LW accumulations act as biodiversity hotspots across the freshwater-to-marine gradient. River communities rely on induced abiotic changes such as meanders, pools, and riffles, while log jams and dams serve as velocity and predation shelters, and create pools with cooler, deeper water. The wood itself acts as attachment substrate for eggs and larvae. From estuaries seaward, the focus fully shifts to LW itself: driftwood provides lignocellulose for wood-boring organisms and stable substrate for sessile animals and macroalgae. In shelf seas and open oceans, floating LW rafts provide shade, shelter, and attachment substrate. Humans have greatly decreased export of LW from river to sea by clearing forests for agriculture and urbanisation, damming rivers, and removing LW 'debris' that is often deemed a hazard or nuisance in developed areas. Indeed, the annual export of LW >3 m long to marine environments has decreased by 5,000,000 m3 compared to the pre-landscape-domestication period. Any wood that reaches the sea washes up on shore or sinks, where it is often removed by bottom trawling. Restoring historic levels of LW is implausible, but reintroductions can restore ecosystem functions along the freshwater-to-marine gradient. Thus far, restoration research has focused on freshwater systems, while such work is in its infancy in coastal and marine environments. We argue that managers should consider incorporating LW reintroductions at scale, as a natural and cost-effective restoration measure across freshwater and marine environments.

Among the vertebrates, mammals are notable for the dominance of live birth and placental nutrition. The structural diversity of the mammalian placenta is remarkable, despite sharing a single common ancestor and conserved physiological functions. Historically, investigations into the evolution of the mammalian placenta have been grounded in 'the efficiency paradigm', i.e. the assumption that certain placental configurations permit easier nutrient exchange, but this paradigm has struggled to explain the diversity of mammalian placentation strategies. Here, we propose a new paradigm to understand mammalian placental evolution. Using multidimensional plotting of recorded placental structures, quantitative metrics for mammalian maternal investment, and illustrative computational modelling of physiological processes, we argue that the ancestral mammalian placenta is not a streamlined 'highly efficient' design, but rather a product of low maternal investment, with fitness costs that manifest as gestational demand increases. Expansion of small mammals into larger-bodied, longer-lived niches induces a 'placental crisis' characterised by maternal under-investment and chronic gestational dysfunction, triggering an arms race through the interaction of disruptive selection and materno-fetal conflict. We propose the acute severity of the placental crisis is the foundation of placental evolution. We go on to argue that some primates are currently in a state of placental crisis and that maternal under-investment and inappropriate placentation are the evolutionary foundations of human gestational dysfunctions such as pre-eclampsia. We conclude that the ancestral mammalian placenta was not an efficiently optimised design that allowed placentation to dominate the clade, but rather an idiosyncrasy of mammal-specific biology, which likely hindered mammalian expansion into larger-bodied niches.

Three categories of explanations exist for why we age: mechanistic theories, which omit reference to evolutionary forces; weakening force of selection theories, which posit that barriers exist that prevent evolutionary forces from optimising fitness in ageing; and optimisation theories, which posit that evolutionary forces actually select for ageing under the constraints that exist due to limited energy and other resources. We now have a broad data set of observed features of ageing against which these categories of theories can be tested, including results of interventions like caloric restriction, features of long-lived organisms, the existence of mortality rate plateaus, longevity of eusocial insect queens, and the malleability of lifespan. Optimisation theories are the only ones that fit all the observed data. Moreover, this category of theory makes a very ordinary claim, consistent with significant other data: evolution by natural selection is operating in ageing. It is actually quite extraordinary, either implicitly or explicitly, to claim that natural selection fails to operate, as the other categories of theories do. A key prediction of optimisation theories that differs from other theories is that mutations that extend lifespan should generally reduce fitness under natural conditions. Contrary to some suggestions in the literature, to date the available evidence supports this prediction. Optimisation theories have several implications, including that lifespan should be relatively easy to manipulate by tapping into existing biological mechanisms, and that the geroscience hypothesis, which states that intervention on the rate of ageing should also modulate the incidence of age-related diseases, is likely to be correct.

Taxon cycle models describe eco-evolutionary patterns of lineage colonization, diversification, and decline across archipelagos, inferring an important role for competition amongst ecologically similar taxa in driving concurrent niche changes. Hitherto described in detail only for animal taxa (notably ants and land birds), we extend the application of taxon cycle analysis to the flora of the Canary Islands, in the process describing several variants on the classic model. Our analysis is based on the premise that taxon cycle dynamics are driven by interactions within closely related species, represented here by congenerics. We compiled distributional and phylogenetic data for 556 species (59% of the native vascular flora), enabling us to allocate the members of each colonist lineage to one of five taxon cycle distributional stages (colonization and range expansion, diversification, range contraction and further diversification, becoming threatened, and extinction). We then grouped the genera into six models: classic taxon cycle (23% of flora), intra-lineage taxon cycle (39%), spontaneous taxon cycle (22%), incomplete taxon cycle (4%), evolutionary stasis (5%), and no taxon cycle (6%). We discuss the drivers that may be shaping these distributions and evaluate how well they conform to the taxon cycle paradigm. We also highlight the use and limitations of stem and crown ages as a tool to test or refine taxon cycle attributions. Our analyses demonstrate that the taxon cycle provides a plausible framework for the analysis of the flora of an oceanic archipelago, while highlighting that both its general applicability and the mechanisms responsible for it will require further independent verification.

Endemism, a hallmark of island biodiversity, reaches its lowest levels among bryophytes compared with other land plants. Whether this pattern reflects low diversification rates, and why, or whether it is a result of loss of endemicity due to extinctions or subsequent continental (back-)colonization, is examined here through a review of available evidence in the Macaronesian flora. Significant genetic differentiation (GST, based on allele frequencies) was consistently found between Macaronesian and continental populations, ruling out the hypothesis that intense migrations necessarily hamper differentiation. A significant phylogeographical signal in the data (NST > GST; where NST is a GST analog incorporating phylogenetic relationships among alleles), involving higher mutation rates than dispersal rates and evidencing incipient speciation, was further found in more than 1/3 of the species investigated. The significantly higher average NST between extra-European regions and Macaronesia compared to Europe and Macaronesia suggests, however, that incipient speciation is more likely to occur between distant (Macaronesian versus extra-European) than closer (Macaronesian versus European) populations. In line with this, ancestral area estimations in Macaronesian endemic bryophyte species revealed that at least 50% of them have an extra-European origin, in contrast with the almost exclusively (>90%) European/Mediterranean origin of Macaronesian endemic spermatophytes. Allopatric speciation via long-distance dispersal and subsequent divergence of a single endemic species prevails in island bryophytes, wherein sympatric radiations virtually never occur. Such a speciation mode does not trigger high rates of endemism, in contrast to radiations in Macaronesian spermatophytes, which contribute to 56% of the total number of endemics. Several mechanisms may explain the failure of island bryophytes to diversify in situ, including the fact that oceanic islands are too small or insufficiently isolated from each other or from continents to promote sympatric speciation, the lack of key innovations, and phylogenetic niche conservatism for stable habitats not prone to trigger radiations. In comparison with spermatophytes, continental (back-)colonization further largely prevails in bryophytes and, unlike in many instances in angiosperms, is not followed by in situ speciation on the mainland. The consequent loss of the endemic status of species that did speciate on islands but subsequently enlarged their range further accounts for the low rates of endemism among island bryophyte floras and invalidates the use of endemism rates as a proxy of speciation rates in this group.

Endothelial cells (ECs) and endothelial progenitor cells (EPCs) are key cells in the formation of nascent vascular units. These cells, in collaboration with other cell types, support the formation of blood vessels and supply essential components to target ischemic sites. EPCs can exit the bone medullary cavity and enter the circulation to reach the injured tissues, where they commit to becoming functionally mature ECs. Like other cell lineages, several signalling factors can dictate specific behaviour in EPCs after exposure to different biological conditions. Among these signalling pathways, the autophagy machinery is a focus of attention because of its diverse biological effects in different cell lineages. Autophagy, an early-stage cell mechanism, is activated in response to diverse external stimuli. Upon its activation, several signalling molecules are produced with the ability to influence cell functions and behaviour, especially in terms of angiogenesis. Herein, we collect recent data related to the stimulatory/inhibitory role of autophagy in the vascularization properties of EPCs. We hope that this review will help in the development of de novo therapeutic strategies for the alleviation of ischemic injuries and/or inhibition of blood support to the tumour niche.

One of the major subfields of chemical ecology is the study of toxins and how they mediate interactions between organisms. Toxins produced by harmful algae (phycotoxins) impact a wide variety of organisms connected to the marine food web. Significant research efforts have thus aimed to identify the ecological and evolutionary drivers behind harmful algal blooms (HABs) to facilitate their forecasting, mitigation, and management. Nutrient availability is a key factor controlling growth and toxin production. Additionally, recent evidence has shown that harmful algae can sense the presence of zooplankton grazers, primarily copepods, and respond by dramatically increasing toxin production. Phycotoxin production is consequently controlled by a combination of bottom-up and top-down drivers, but the relative importance of the two is not understood. We therefore conducted a meta-analysis of 113 control-treatment contrasts from 37 peer-reviewed experimental studies, comparing the effects of relative nitrogen enrichment (defined here as an increased nitrogen: phosphorus ratio relative to control) and elevated grazing risk (exposure to zooplankton grazers or their chemical cues) on phycotoxin induction. We focused on the two most studied marine HAB-forming genera, Alexandrium dinoflagellates and Pseudo-nitzschia diatoms. We show that phycotoxins are induced in response to both relative nitrogen enrichment and elevated grazing risk. Although both genera responded similarly to relative nitrogen enrichment, Pseudo-nitzschia toxins increased 10 times more than Alexandrium toxins in response to grazers. Grazing risk thus appears to rival, perhaps even supersede, the well-established phycotoxin-inducing effect of relative nitrogen enrichment in marine harmful algae. Although this analysis is limited to the two most-studied marine HAB genera, we conclude that future attempts to understand the evolution and variable production of phycotoxins require integration of bottom-up nutrient availability and top-down selective pressures to elucidate phycotoxin dynamics in marine HAB-forming species.

Oropharyngeal food processing exhibits a remarkable diversity among vertebrates, reflecting the evolution of specialised 'processing centres' associated with the mandibular, hyoid, and branchial arches. Although studies have detailed various food-processing strategies and mechanisms across vertebrates, a coherent and comprehensive terminology is lacking. Here, we provide a synthesis, including a unified terminology for the intricate complexity of vertebrate oropharyngeal processing. Among gnathostomes, mandibular food processing predominates, ranging from discrete bites to rhythmic, cyclic chewing facilitated by precise tongue mechanics in aquatic and terrestrial environments alike. By contrast, some taxa have abandoned oropharyngeal processing entirely, relying instead on post-oesophageal strategies such as gastric milling and chemical digestion. Interestingly, teleost (bony) fishes illustrate the evolutionary trade-off between increased jaw protrusion for prey capture and reduced mandibular processing capacity. They compensated for this trade-off by developing derived processing behaviours early in their evolutionary development. Through the re-evolution of mandibular chewing, they succeeded in utilising all three known processing centres. Mastication is a specialised, dimensionally complex form of unignathic mandibular chewing (i.e. chewing restricted to the lower jaw) exclusive to mammals. However, our findings demonstrate that dimensionally complex forms of mandibular chewing have arisen independently multiple times and are widespread among gnathostomes. Notably, diverse taxa, including elasmobranch stingrays, Australian lungfish, sirenid salamanders, various songbirds, herbivorous turtles, and the tuatara, exhibit complex jaw movements combining arcuate, longitudinal, and sometimes transverse components enabled by specialised jaw joints, suspensions, and intracranial motions ('cranial kinesis'). From a comparative, functional-morphological perspective, mammalian mastication may best be characterised as dimensionally complex chewing mediated by the secondary or temporomandibular joint. By contrast, analogous dimensionally complex non-mammalian chewing involving motions confined to the primary or quadrate-articular jaw joint qualifies as pseudomastication. Both mastication and pseudomastication resemble functional masticatory behaviours, while those incorporating intracranial motions and movements of the jaw suspension belong to distinct categories. Our anatomical analysis highlights the convergent evolution of dimensionally complex chewing among gnathostomes and emphasises the importance of comprehensive studies on jaw development and function to deepen our understanding of the evolution of oropharyngeal processing.

Biological invasions have intensified in recent decades, mostly driven by international trade and travel, raising significant concerns, particularly regarding insect pests. Once non-native species establish, they can disrupt natural ecosystem stability, undermine agroecosystem sustainability and cause substantial economic losses. The urgency to anticipate these socio-economic impacts has accelerated research into the traits and processes that predispose certain species to invasion success. Our review examines the factors contributing to invasion success, using the well-documented case of Drosophilidae as a model taxon given the extensive literature on this family. The invasion of Drosophila suzukii is the most well studied, yet it represents just one example among several Drosophilidae successful invasions, including those from the genera Drosophila, Scaptomyza and Zaprionus. Their traits and adaptive capacities have enabled them to overcome environmental barriers, facilitating their global spread and establishment. We first explore the selective forces acting on pioneer individuals and their ability to establish reproducing populations. We then analyse the roles of abiotic factors (through phenotypic plasticity, tolerance to thermal and water stress, synergies between multiple stressors) and biotic factors (through the exploitation of novel trophic niches, resistance to competition and predation, symbiont-mediated assistance) in shaping invasion success. A nuanced understanding of how these constraints interact is essential for predicting and managing the proliferation of invasive Drosophilidae and other non-native species. We propose that successful invasive species do not necessarily excel in one single trait but rather perform adequately across multiple traits and processes. In this review, we found support in the literature for 14 key traits and processes of Drosophilidae biology that facilitate a species' ability to become invasive and provide future perspectives to address critical knowledge gaps, paving the way towards a comprehensive understanding of invasion success.

A global standard for the identification of Key Biodiversity Areas (KBAs) was published 10 years ago to provide a unified set of criteria for identifying 'sites of significance for the global persistence of biodiversity'. We review the initiative's origins, the KBA identification process, characteristics of the current network, threats, policy uptake, private sector applications and future priorities. KBAs are identified using criteria with quantitative thresholds relating to threatened or geographically restricted species or ecosystems, ecological integrity, biological processes, or irreplaceability. These criteria can be applied in terrestrial, inland water, marine and subterranean environments, and to all taxonomic groups. A total of 16,596 KBAs covering 22.1 million km2 has been identified, with 29% of these sites in marine and 26% in freshwater ecosystems. KBAs range from 0.001 km2 to 712,457 km2 in extent, with a median size of 141 km2 and a mean of 1,364 km2. Most (63%) qualify due to the globally threatened species they support, with 48% being important for biological processes and 39% for geographically restricted species. KBAs have been identified for 18,365 qualifying species in total, of which 37% are plants and 32% are birds. The most prevalent threats are biological resource use (hunting, logging, fishing, etc., impacting 40.8% of sites with available data), unsustainable agriculture (40.7%), human intrusions and disturbance (38.4%) and natural systems modifications (water management and fire; 33.4%). KBAs are important for delivering ecosystem services to people, both locally and globally. KBAs have had widespread impact in informing protected area designation in all regions. In total, 10,054 sites (62%) are covered completely or partially by protected areas. Hence, KBAs are highly relevant to Target 3 (and other targets) in the Kunming-Montreal Global Biodiversity Framework, and to Sustainable Development Goals 14.5, 15.1, and 15.4. Indicators based on KBA data are therefore being used by the Convention on Biological Diversity and United Nations to track progress towards these targets. Many companies and financial institutions use KBAs to assess their exposure to nature-related risks and to identify opportunities for site-level, nature-positive actions. Future priorities include expanding and updating KBA assessments, and strengthening efforts to protect, conserve and safeguard these sites effectively.

Troodontidae is a clade of small-to medium-sized maniraptoran theropods that mainly lived in Laurasia (modern Asia, North America and Europe) during the Jurassic and Cretaceous periods and are believed to have had a variety of diets. The uniqueness of troodontid teeth suggests that they diverged from the typical flesh-based diet of non-avian theropods. Some Asian troodontids even lack tooth serrations completely, which has been linked to herbivory or omnivory. However, troodontids still possessed multiple traits suited for predation. These include a large curved second pedal digit; laterally compressed, curved, and serrated teeth; and 'puncture-and-pull' microwear on their teeth. Extrinsic evidence, such as stomach contents and gastric pellets, supports a diverse dietary intake among troodontids with evidence that they ingested both plant and animal material. Environmental, morphological, and biogeochemical analyses suggest that the iconic North American troodontid, Troodon, was likely to have been omnivorous, potentially preying on both plants and small animals, such as mammals and baby dinosaurs (hatched or unhatched). Our understanding of different diets among troodontids remains limited due to the sparsity of both relevant fossil material and palaeodiet research. Nevertheless, what information we have on troodontid diet informs ancestral deinonychosaurian and paravian diets, which we suggest were omnivorous. We encourage research into troodontids outside the Late Cretaceous of North America and further study of troodontid biogeochemistry and postcranial anatomy to improve our understanding of troodontid diet and the larger story of theropod ecological diversity.

Urbanisation is a key driver of global environmental change and presents animals with novel stressors and challenges. It can fundamentally influence social behaviour and has the potential to reshape within- and between-species social interactions. Given the role of social behaviour in reproductive fitness and survival, understanding how social interactions change in response to urban conditions is crucial in addressing individual-, population-, and species-level responses to urbanisation, as well as the consequential ecological impacts. Here, we conducted the first systematic review addressing the impact of urbanisation on social systems and interspecific interactions. We synthesise the outcomes of the 227 studies from our literature search, organised across three key topics: (i) effects of urban stressors on social behaviour (N = 170), (ii) social system responses to urban environments (N = 75), and (iii) the impact of urbanisation on interspecific interactions (N = 12). Our review revealed that urbanisation is having a substantial impact on multiple facets of social behaviour, with 92% of studies finding a significant impact. We also identified several biases and gaps in the current literature. For example, 62% of all studies were conducted on birds, and 85% of studies testing urban stressors focused on anthropogenic noise. Given the diversity of animal social systems, there is obvious variation in social responses to urban conditions. However, we offer predictions for how social systems might change as urban environments continue to expand rapidly and suggest guidelines for future research to enhance generalisations across taxa. Our review brings together multiple areas of research, provides timely insights and outlines a framework for a unified and proactive approach to addressing social responses to urbanisation. This represents an essential foundation for anticipating species' responses to urban expansion and guiding effective conservation efforts.

The global redistribution of species through human agency is one of the defining ecological signatures of the Anthropocene, with biological invasions reshaping biodiversity patterns, ecosystem processes and services, and species interactions globally. Here, we review the facets underlying the spread of non-native species - the key process by which introductions translate into large-scale invasions. In particular, we synthesise the ecological, evolutionary, and anthropogenic mechanisms underpinning the spread of non-native species, highlighting how dispersal, recruitment, and establishment interact across spatial and temporal scales. We examine the dynamics of non-native species spread in animals, plants, fungi, and pathogens, as well as across terrestrial, freshwater, and marine realms, with particular attention to the dynamics and processes modulating spread. We further evaluate essential phenomena of non-native species spread, such as the role of invasion fronts, Allee effects, propagule pressure, interactions with environmental change, landscape properties, and biotic interactions. We then outline how spread can be measured, modelled, and predicted using tools ranging from classical diffusion models to cutting-edge Artificial Intelligence and individual-based simulations. By offering a cross-system and cross-scale synthesis, this review advances the theoretical and practical understanding of non-native species spread for supporting policy and management.

Historically, a vertebrate-centric paradigm has framed our interpretation of molluscan endocrinology, with considerable research focusing on vertebrate-type steroid hormones (e.g. oestrogens, testosterone). However, contradictory evidence on the occurrence of vertebrate-type steroid hormones in molluscan tissues, and a lack of the specific steroidogenesis enzymes involved in producing these steroids has fuelled an ongoing debate about the ability of molluscs to biosynthesise vertebrate-type steroids de novo. Consequently, the exploration of other hormonal pathways that may exist in the phylum remains a significant knowledge gap. This study systematically identified, combined and evaluated evidence from 147 eligible studies (published between 2012 and 2021) on the occurrence of hormones, hormone receptors and hormone-metabolising enzymes in Mollusca according to the 2015 PRISMA-P systematic review guidelines and the 2020 COSTER guidelines. The data collected are holistically summarised and visualised in a fully searchable, interactive and openly accessible online database using Tableau Public 2023.1 software. A critical appraisal assessment (Risk-of-Bias tool) accompanied by tailor-made guidelines as well as a narrative synthesis using comparative endocrinology is presented. Strikingly, 95% of studies measuring hormones in molluscs did not investigate the hormones' ability to bind to their respective receptors. Moreover, many studies either used methods now considered unreliable (e.g. lack specificity) to identify relevant biomolecules (i.e. hormones, receptors, enzymes) or did not employ robust internal validation steps, with 83% of all studies not independently repeating their experiments. This highlights an urgent need for greater experimental rigour in the field. Most studies were also found to be heavily skewed towards vertebrate-type sex steroidogenesis, with 66% measuring 17β-oestradiol in mollusc tissues, despite unconvincing evidence that molluscs can biosynthesise vertebrate-type steroids. By contrast, the retinoic acid signalling pathway, known to be more evolutionarily conserved (and a target of environmental pollution), has received far less attention. However, a limited number of studies are now looking beyond vertebrate-type sex steroids, notably those looking at thyroid hormones, phytosterols (plant sterols) and ecdysteroids (insect steroids) in molluscs. These studies should act as a catalyst to spark interest in further exploration of understudied or unexplored hormonal pathways in Mollusca to elucidate fully the endocrinology of this important phylum.

Extra-pair behaviours - reproductive behaviours, including those related to copulation and paternity of offspring, amongst animals outside of a social pair bond - have long intrigued behavioural ecologists, particularly from the female animal's perspective. Female extra-pair paternity is not supported by classic models of sexual selection yet is common across birds. Researchers recognise that variation in extra-pair paternity, both within and between species, is in part driven by the costs to the individual; however, empirical studies tend to focus on benefits. This is because benefits are often measured through direct fitness measurements, whereas costs have more complex, indirect pathways to fitness. However, both the prevalence and magnitude of a cost are experienced in the context of an individual's environment and may affect fitness, either directly (by affecting reproduction or survival) or indirectly (through the fitness of offspring). Here, we review our current understanding of costs associated with extra-pair paternity and extra-pair copulation. For example, we review both the costs of producing extra-pair offspring and the behaviour associated with extra-pair paternity. We conclude that the costs of extra-pair paternity and extra-pair copulation are understudied, but are likely a key factor shaping this behaviour. More research, particularly empirical and experimental studies in taxa other than birds, is needed to understand the intricate cost-benefit equation underlying extra-pair paternity.