Biological Reviews最新文献

Social inequality among individuals is a common cause of conflict in the animal kingdom. In eusocial insects, such as ants, bees, wasps, and termites, for example, the large differences in reproductive potential between castes result in conflicts over caste fate during development. Here, we present the first comprehensive review on caste fate conflict, drawing on data from diverse taxa and recent theoretical advances. In many eusocial species, caste fate is determined by differential feeding, which results in caste fate being socially controlled, thereby aligning larval development with the collective needs of the colony. However, in some taxa, mechanisms of individual self-determination disrupt this balance, leading to overproduction of reproductive individuals at the expense of workers, with significant costs to colony fitness. Such conflicts are particularly pronounced in some stingless bees and lower termites, where larvae can bypass social control to determine their own caste fate. Indications of caste conflict can also be found in other groups, such as in some parasitic ants and in ant hybrid zones. Overall, the observed dynamics illustrate how conflicts in biological systems can be resolved in favour of either individual or collective interests, and how this affects the functioning of higher levels of organisation.

Ants and phloem-feeding hemipterans have established one of the most widespread and best-known mutualisms on Earth. In this mutualism, known as trophobiosis, ants feed on honeydew excreted by phloem-feeding hemipterans and, in exchange, protect hemipterans from their antagonists. Parasitoid wasps are among the main groups of antagonists of phloem-feeding hemipterans. Like trophobiosis, the interaction between trophobiotic ants and parasitoids of phloem-feeding hemipterans has evolved over millions of years and is widely distributed both geographically and phylogenetically. Ants protect phloem-feeding hemipterans from their parasitoids in many different ways, with outcomes for parasitoids that vary from altered reproduction or development to death. Consequently, parasitoids have evolved a series of behavioural, chemical, and morphological adaptations that reduce or limit the impact of trophobiotic ants. Our review shows that research on these interactions is asymmetric and strongly biased towards certain taxa and ecosystems, mostly aphids that feed on temperate crops. It will be necessary to broaden the range of taxa and ecosystems studied to evaluate how these interactions have shaped the evolution of phloem-feeding hemipterans, their parasitoids, and trophobiotic ants. While, in general, the presence of trophobiotic ants reduces the top-down regulation of phloem-feeding hemipterans by parasitoids, recent findings suggest that the mechanisms that explain this reduction are more complex than expected. By reviewing these interactions, the limitations of past research, and the advantages of current techniques, we provide perspectives to understand: (i) the mechanisms that ants use to protect hemipterans from parasitoids; (ii) the strategies evolved by parasitoids to counteract these ants; and (iii) the multiple factors that modulate the effects of trophobiotic ants on parasitoids of hemipterans. We suggest that a better understanding of these interactions will improve the management of phloem-feeding hemipterans, which constitute one of the most damaging groups of pests to global agriculture.

Microplastics (MPs) and nanoplastics (NPs) have emerged as pervasive vectors of antimicrobial resistance (AMR), with the plastisphere being a microbial niche on plastic surfaces acting as a nexus for pathogen colonization, gene transfer, and global health risks. These particles adsorb antibiotics, transport pathogens, and serve as reservoirs for antibiotic resistance genes (ARGs), fostering pathogen-ARG coevolution and horizontal gene transfer (HGT) through biofilm-mediated mechanisms. Despite their recognized role in AMR dissemination, critical gaps persist in understanding how environmental stressors (e.g. salinity, pH) modulate plastisphere dynamics and socioeconomic disparities in exposure. This review synthesizes evidence positioning MPs/NPs as triple threats: microbial habitats, ARG reservoirs, and HGT conduits. We also discuss synergistic interactions of plastisphere biofilms with antibiotics to amplify selective pressures, enabling resistance dissemination across ecosystems and food chains, thereby escalating global health risks. Current research lacks mechanistic insights into real-world plastisphere interactions and longitudinal data linking MPs/NPs to clinical AMR outcomes. We propose actionable One Health strategies including artificial intelligence (AI)-enhanced surveillance, circular economy frameworks, and pathogen-resistant biodegradable polymers to disrupt the plastisphere-driven AMR nexus. Our synthesis underscores the urgency of integrating environmental science, epidemiology, and policy to mitigate risks to ecological and human resilience.

Marine foundation species play a critical role in shaping seascapes and supporting biodiversity through their physical structure and biological activity. However, global changes can alter foundation species and subsequently induce profound changes in ecosystem functions and integrity. To understand better how foundation species influence biodiversity, we first conducted a systematic review of 311 articles that either compared biodiversity metrics associated with foundation species or examined relationships between biodiversity and foundation species traits (at the individual or habitat scale). A subsequent meta-analysis on a subset of suitable articles showed that foundation species generally enhance species richness by an average of 72%, although the strength and nature of this effect vary across scales and taxa. To understand these variations better, we synthesised the range of traits associated with foundation species and how these relate to various diversity metrics. While many traits are measured at both individual and habitat scales, inconsistencies across studies and foundation species groups prevent a formal assessment of functional trade-offs across marine foundation species. Despite high variability in trait-richness relationships, both common (e.g. density) and more specific (e.g. interstitial space) traits can serve as reliable proxies for species richness when capturing facilitative processes at the relevant scale for the response community. To reconcile this diversity of traits, we classify foundation species traits into 26 standardised categories, which constitutes a valuable framework to consolidate the interoperability of future research on the effects of foundation species on biodiversity. This classification and the associated database on foundation species-biodiversity relationships set a baseline for a comprehensive assessment of how multiple foundation species shape heterogeneous seascapes, which is essential for predicting the effects of habitat alteration or restoration on coastal biodiversity.

Chemical communication is the oldest and most widespread form of signalling among and within organisms. Among the many compounds involved in such communication, pyrazines - nitrogen-containing heterocyclic molecules - are especially intriguing due to their widespread occurrence across the tree of life, from bacteria and fungi to insects and mammals. In this review, we focus on the role of pyrazines in insects, where they mediate both intra- and interspecific communication. Social insects, particularly within the order Hymenoptera, exhibit a greater diversity and frequency of pyrazine use compared to solitary species and other insect orders. This diversity may be associated with the complexity of communication systems required by eusociality. Pheromonal pyrazines predominantly feature alkyl and alkenyl group substituents, whereas allomonal pyrazines more often feature methoxy groups. Pyrazines have been identified in seven insect orders. Hemimetabolous insects, such as Phasmatodea, Orthoptera, and Hemiptera typically produce alkyl-substituted pyrazines, with some Hemiptera also producing methoxy variants. Methoxy-substituted pyrazines are absent in Hymenoptera but present in Coleoptera and Lepidoptera, where they serve as both pheromones and allomones. In Diptera, pyrazines are only known from a few species, and have alkyl or alkenyl substituents. Pyrazines are mainly associated with adult stages, suggesting a predominant role in later-life communication but more research is needed on early life stages. Current evidence suggests that pyrazine biosynthesis may be carried out by microbial symbionts. To understand fully the evolutionary origins and ecological functions of pyrazines in insects, comprehensive surveys across taxa and life stages alongside functional studies are essential.

Ultraviolet (UV) radiation (comprising UVA, UVB, and UVC wavelengths) lies in the non-ionizing region of the electromagnetic spectrum and is a key environmental factor affecting living organisms. While excessive UV exposure is well known for its harmful effects - such as DNA damage, oxidative stress, and cellular dysfunction - mounting evidence indicates that low-dose UV can induce beneficial adaptive responses (hormesis) in biological systems. This review offers a comprehensive synthesis of UV-induced hormetic effects across diverse organisms, with particular emphasis on plants and animals. We highlight examples of beneficial outcomes under mild UV exposure, including enhanced growth, strengthened pathogen resistance, and elevated secondary metabolite production in plants, as well as improved stress tolerance and reproductive performance in animals. These benefits are underpinned by molecular mechanisms such as upregulation of antioxidant defences, activation of DNA repair pathways, and accumulation of protective biomolecules. The review also explores practical applications of UV hormesis in agriculture - for instance, using controlled UV treatments to boost crop resilience - while cautioning against the risks of excessive exposure. By illuminating the balance between the beneficial and detrimental effects of UV radiation, this synthesis provides a broad perspective to guide the safe application of low-level UV in biological systems and identifies promising directions for future research.

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.

Prolonged mechanical unloading leads to significant musculoskeletal degradation, posing serious health risks for bedridden patients and astronauts. By contrast, hibernating animals such as Spermophilus dauricus have evolved natural resistance to muscle atrophy and bone loss during extended periods of inactivity. These animals deploy coordinated protective mechanisms, including calpain inhibition, Wingless-related integration site (Wnt)/β-catenin signalling modulation, mitochondrial dynamics regulation, and enhanced antioxidant defences, to maintain musculoskeletal homeostasis. In this study, we systematically compare the molecular adaptations to disuse in both hibernation and unloading models. Our findings reveal both overlapping and distinct regulatory strategies that govern skeletal muscle and bone preservation under mechanical unloading. These insights offer a unique perspective for developing mechanism-based countermeasures against spaceflight-induced musculoskeletal deterioration, and may further inform strategies to combat age-related or disease-associated muscle and bone loss in terrestrial settings. This work underscores the translational potential of hibernation biology for advancing space medicine and human health.

The gut tissue is at the frontline of early onset of ageing. It exhibits high cell turnover rates and rapid telomere shortening, which can have systemic effects on the developing or senescing organism. We conducted a literature review of studies on the crosstalk between telomere length dynamics, telomerase activity, oxidative stress, and gut microbiota composition and activity in animals. Studies mainly on humans and animal models include correlations between telomere dynamics and gut microbiome components, particularly under pathogenic conditions, but also manipulations of either the gut microbiome through faecal microbiota transplantations or of telomere dynamics using telomerase knockout models. This synthesis reveals that components of the gut microbiome including microbial metabolites and pathogenic bacteria can affect telomere dynamics through oxidative-stress-inducing processes, and that telomere maintenance is critical in maintaining gut barrier and tissue integrity, which link inflammation and gut dysbiosis. Some of the interactions between the gut microbiome and host telomere dynamics are bidirectional and important in maintaining intestinal homeostasis. However, many of the causal molecular or cellular mechanisms - and how they translate into organismal senescence - remain to be identified. Furthermore, we highlight how recent advances in whole genome sequencing capacities and bioinformatic tools represent an often-unexploited resource for measuring telomere lengths and may be particularly valuable tools within the hologenomic framework outlined here. Investigating the role of telomere dynamics in mediating gut microbiota-host interactions in different species will improve our understanding of how crosstalk between these hallmarks of ageing shape holobiont physiology in general and the ageing phenotype in particular.

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.