搜索结果：Current opinion in insect science

Insulin signaling connects nutrient availability to the energy-consuming processes of growth and development throughout the animal kingdom. Insulin was discovered for its role in mammalian glucose homeostasis over one hundred years ago. Since then, research in diverse animals, and especially in insects, has vastly expanded our understanding of the myriad processes that insulin signaling regulates. Here, we focus on the developmental roles of the insulin signaling pathway in diverse insect species. Most insect genomes encode multiple insulin-like peptides (ILPs) and multiple insulin receptors. ILPs act in temporally specific ways to regulate tissue-specific processes, and in some cases, ILPs act with extreme specificity to control development. Our goal in this review is to highlight work in insects ranging from the fruit fly Drosophila melanogaster to mosquitoes, beetles, ants, and termites that illustrates these principles. Among these insects, insulin signaling regulates cell growth and proliferation, developmental timing, polyphenism, caste differentiation, and the very earliest stages of development via the production of healthy oocytes by adult female insects.

In holometabolous insects, the larval, pupal, and adult stages are determined by three metamorphic genes: chinmo, broad, and E93, respectively. A temporal endocrine landscape, involving ecdysteroids, juvenile hormone (JH), and myoglianin, acts on these genes to move insects through their life history. Chinmo is anti-metamorphic and suppresses the expression of broad and E93. The JH target gene Krüppel-homolog 1 (Kr-h1) also suppresses metamorphosis, but the need for JH in maintaining the larva varies. Early larval molts are JH-independent, but later ones use JH (via Kr-h1) to maintain larval molting and suppress E93 expression until larvae cross a size threshold for metamorphosis. Myoglianin and/or ecdysteroids cause broad expression, and the decline in JH can stimulate E93. Based on whether JH is needed to maintain the larva, either E93 (Tribolium) or broad (Drosophila) serves as the entry to metamorphosis. Inhibitory interactions between broad and E93, and a return of JH in the prepupa, ensure that Broad and pupa formation occur before E93 and adult differentiation. In hemimetabolous insects, Chinmo and JH, via Kr-h1, maintain the nymphal stage and suppress E93 and adult differentiation. Broad is co-expressed with chinmo, and they collaborate to direct nymphal growth, especially of the wing pads. Chinmo supports isomorphic growth, while Broad supports positive allometric growth. The evolution of mutual inhibition between these two high-level transcription factors was a key innovation in the transition to holometaboly. It allowed imaginal primordia to rapidly expand through self-renewing growth in the larva before transitioning to morphogenetic growth to form the pupa.

Widespread insect declines have raised concerns about ecosystem stability, yet emerging evidence shows that population trends are heterogeneous and shaped by interacting drivers rather than single stressors. The challenge is therefore to move beyond documenting patterns toward understanding the mechanisms that generate them and predicting how insects will respond to future environmental change. Environmental pressures operate across spatial and temporal scales to shape insect populations. Mechanisms determine the physiological, behavioural and ecological processes underlying population shifts, while species traits constrain sensitivity. Detection processes generate observable signals, and causal inference reveals how multiple drivers propagate through ecological networks. Here, we synthesise these domains to outline predictive entomology - an integrative framework linking drivers, mechanisms, detection and forecasting through explicit causal inference. Drawing on long-term datasets, mechanistic experiments and emerging sensing technologies, we illustrate how multiple drivers interact across scales and how causal tools can help separate confounding processes and detection artefacts from causal effects. Embedding mechanistic and causal understanding into monitoring and analytical pipelines provides the foundation for predicting ecological change, identifying emerging risks and guiding proactive conservation under global change.

Humans have greatly altered the Earth and its environments through activities such as agriculture, industry, and urbanization. In recent years, the impact of anthropogenic global change on insect populations has become a topic of increasing interest, with much written for both scientists and the public on how insect populations are in decline due to climate change, land-use change, and exposure to chemical pollution. Additionally, many insects host microbial symbionts, which some insect species rely on for a wide range of physiological needs, such as nutrient acquisition, detoxifying dietary substrates, or reproduction. This review summarizes recent experimental and observational studies on the effects of anthropogenic global change on insect microbial symbioses from multiple ecosystems and continents, with a focus on the impacts of climate change, habitat loss, and degradation. Each of these modes of change has been demonstrated to affect the composition of insect microbial communities, with a reduction in species diversity within microbial communities (alpha diversity) as the most common result. Results of an experimental study on heat-stress response in bacterial symbionts suggest that warming temperatures often associated with climate change may have direct impacts on symbiont mortality, as symbionts tend to be more sensitive to thermal stress than free-living bacteria. Habitat loss and degradation impact insect microbial symbionts via the changed microbiomes of host food and environmental substrate. Chemical pollution associated with habitat degradation has altered the microbiomes of insects, though some insects may be able to detoxify chemical pollutants with symbiotic microbial taxa. While early research has shown that human-induced climate change can have negative impacts on insect symbionts, there is still much to learn about how the changing world will impact insect microbiomes and how this, in turn, will impact entire ecosystems at a global scale.

Insect polyphenisms are an extreme form of phenotypic plasticity that arises when environmental cues are transduced into endocrine signals that redirect development, producing discrete morphs from a single genome. Aphid wing polyphenisms have been important to establishing this framework. In asexual females, stress-inducing conditions result in winged daughters, whereas benign environments yield wingless offspring. Classic work emphasized juvenile hormone, but recent evidence points to a causal role for ecdysone. Upstream neurotransmitter pathways, including glutamate and possibly dopamine, translate tactile crowding into endocrine responses, while downstream processes such as autophagy, Transforming growth factor (TGF-β) signaling, and insulin signaling shape wing development. Epigenetic mechanisms, including microRNAs and chromatin modifiers, stabilize morph-specific transcriptional states. Collectively, these studies outline a multi-step process, from environmental sensing to neuroendocrine integration, hormonal signaling, and epigenetic maintenance, that governs aphid wing plasticity. Emerging genomic and chromatin profiling tools now position aphids as a powerful model for dissecting environmentally induced developmental plasticity.

Understanding the causes, consequences, and solutions to global pollinator decline will require more extensive and intensive monitoring programs. However, species-level identification remains a major challenge because of the difficulty of scaling manual identification workflows. Participatory science (PS) programs generate millions of pollinator sightings with associated images, but spatial and taxonomic biases along with expert capacity limit their full potential for conservation science. In this paper, I explore how artificial intelligence (AI), particularly computer vision-based detection and classification models, can be integrated with PS to enable scalable, reliable pollinator monitoring, with a focus on bees. Recent advances demonstrate that AI image classifiers can achieve high accuracy across hundreds to thousands of taxa and can be deployed on web, mobile, and edge device platforms. AI has the potential to substantially reduce expert workloads while maintaining reliability when carefully integrated into expert verification pipelines. Such pipelines can include confidence-based filtering based on quality or priority and improved models using contextual Bayesian priors, model calibration, and ensemble approaches. However, uneven training data, observational biases, and limited image availability for rare species constrain model completeness. Addressing these gaps will require targeted image collection, integration of museum and field datasets, and standardized protocols linking AI development with monitoring objectives. Rather than replacing taxonomic expertise, AI should function as a force multiplier that accelerates feedback between data collection, model improvement, and conservation.

Insects undergo precisely coordinated developmental transitions regulated by ecdysteroids and juvenile hormone (JH). Recent studies in the hemimetabolous cricket, Gryllus bimaculatus, have revealed that transforming growth factor-β signaling directly regulates JH biosynthesis. In this system, Decapentaplegic (Dpp) promotes juvenile hormone acid methyltransferase (jhamt) expression and JH production, whereas Myoglianin (Myo) represses jhamt transcription. Functional analyses using RNA interference and CRISPR/Cas9-mediated gene knockout demonstrate that loss of myo leads to sustained JH overproduction, supernumerary molts, and failure of metamorphosis, establishing Myo as a key regulator of developmental timing during nymphal development. This review integrates findings from diverse insect lineages to place Myo-dependent regulation of JH biosynthesis within an evolutionary framework, highlighting its conserved endocrine roles in hemimetabolous insects and its lineage-specific diversification in holometabolous species. Together, these studies provide new insights into how Myo signaling links growth status to endocrine control of developmental progression and metamorphosis.

Insects frequently harbor intracellular bacterial symbionts whose genomes have undergone varying degrees of extreme reduction. This process eliminates many microbial genes required for a free-living lifestyle, including canonical transcription factors, sigma factors, and other regulatory proteins typically responsible for dynamic transcriptional and translational control. Despite this erosion of regulatory machinery, some obligate symbionts may still adjust metabolic output to meet host developmental, nutritional, and environmental demands. How gene expression is modulated in these streamlined genomes remains an open question. One proposed mechanism is post-transcriptional regulation mediated by bacterial small RNAs (sRNAs). Although some symbionts with moderately reduced genomes retain limited transcriptional responsiveness, symbionts with extremely reduced genomes often exhibit minimal variation in mRNA abundance across host conditions. In several systems, however, sRNAs are expressed, conserved across evolutionary timescales, and in some cases experimentally validated as functional regulators. These observations suggest that RNA-based mechanisms may compensate, at least in part, for the loss of canonical transcriptional control. Here, we synthesize current evidence for sRNA-mediated regulation in insect-associated bacteria, examine how genome reduction reshapes regulatory architectures, and outline conceptual and methodological challenges that remain for disentangling transcriptional and post-transcriptional control in obligate symbionts. We argue that integrative approaches including multi-omics methods and in vitro genetic methods will be essential to resolve how highly reduced symbiont genomes achieve regulatory flexibility despite severe constraints on conventional gene regulatory networks.

Insect metamorphosis depends on the precise coordination of developmental timing, growth, and morphogenesis. Hemimetabolous insects, which undergo gradual postembryonic development culminating in a single terminal molt, provide a critical framework for understanding how these processes are integrated and how holometabolous metamorphosis evolved. Here, we synthesize recent advances in the regulation of hemimetabolous metamorphosis, focusing on how stage-specific transcription factors - E93, Kr-h1, Chinmo, and Broad - constituting the Metamorphic Gene Network, control temporal identity and determine the irreversible transition to adulthood ("the when problem"). We then highlight a parallel regulatory layer governing the growth and morphogenesis of metamorphic traits ("the how much problem"), involving Myoglianin-dependent endocrine gating, local growth-control pathways, and transcriptional modulation of growth mode. Together, these findings reveal a modular yet integrated regulatory architecture and highlight key unresolved questions regarding how hormonal, transcriptional, and tissue-intrinsic growth pathways are mechanistically coupled to coordinate developmental timing, trait growth, and metamorphic commitment.

Gene body DNA methylation is an evolutionarily conserved, stable yet reversible modification of DNA, where cytosines in CpG contexts are covalently methylated (5-methyl-cytosine) by DNA methyltransferase (DNMT) enzymes. The discovery of a functional gene body DNA methylation system in honey bees (Apis mellifera L.) with high homology to the human machinery has positioned social insects, including wasps, ants, and bees, as tractable models for epigenetic research. Their advanced societies consist of multiple phenotypes with distinct morphologies, physiologies, and behaviors, all developed from the same genome. Here we examine seminal studies on DNA methylation in social Hymenoptera, focusing on three recent advances: (i) gene body DNA methylation has minimal, if any, effect on transcription; (ii) methylomes are faithfully inherited across generations and somatic tissues; and (iii) DNMT1 is essential for the germline but dispensable for somatic development. As a mechanistic complement to Hamilton's inclusive fitness theory, we propose that colony-specific gene body DNA methylation patterns may facilitate (but not determine) the multiple independent transitions to eusociality in Hymenoptera. With the framework of a 'DNA methylation-mediated Genetic Recombination Hypothesis', we suggest that DNMT1-maintained gene body DNA methylation accelerates genome evolution toward social complexity in eusocial species. On the other hand, DNMT3, likely operating downstream of the sex-determination pathways, promotes altruism in sterile workers in the presence of the queen, possibly through DNA methylation-independent mechanisms.

Symbiotic interactions, which run the gamut from microbial assemblages to synergistic or antagonistic interactions with macro-organisms, can shape ecological communities across levels of biological organization, from solitary hosts to large social groups. Web-building spiders have given rise to two types of social systems: outbred colonial orb weavers, which form web complexes with a modular structure and no cooperation, and inbred social species with tightly knit societies displaying cooperation within shared communal webs. We synthesize recent findings on the macro- or micro-organisms that colonize individual spiders or their living quarters in social and colonial species, highlighting their potential contributions to population stability and vulnerability as a function of the hosts' social and breeding system. The tightly knit societies of social spiders facilitate microbial homogenization and prolonged associations with potential macro-symbionts, whereas colonial spiders likely maintain more transient relationships with heterospecific inquilines. Individual spiders and colonies must navigate relationships with diverse inquilines, ranging from mutualistic fungi that attract prey to their webs to behavior-manipulating parasitoid wasps. Macro-symbionts exploit colony resources, including nest materials for living quarters, spider-caught prey for food, or feed on spiders or their eggs. Micro-symbionts seem to colonize all tissues or materials, except eggs, with some having a greater affinity for specific host substrates. These systems offer insights into broader ecological and evolutionary questions, including the role of symbiosis for host population stability, adaptation, and ecosystem function. Understanding how host-symbiont dynamics scale from individuals to communities provides critical perspectives on the mechanisms that structure cooperative and antagonistic interactions in nature.

Ants are among the most ubiquitous animals in cities, yet only a small subset of the world's ant fauna consistently thrives in urban environments. Despite the prominence of ants in urban ecosystems, we lack a cohesive framework for understanding why certain species succeed while others decline. Here, we synthesize emerging research to describe an 'urban ant syndrome,' or a modular set of behavioral and ecological pathways that enable ants to overcome the characteristic challenges of human-built environments. We first develop a functional definition of 'urban ants,' distinguishing true urban exploiters from species that merely occur within city boundaries. We then describe three domains in which successful urban ants repeatedly exhibit convergent strategies: (1) life history, including supercoloniality, polydomy, and budding dispersal; (2) thermal biology, particularly the use of urban heat for foraging, survival, and brood development; and (3) nutritional ecology, characterized by reliance on high-carbohydrate anthropogenic foods or mutualisms with honeydew-producing insects. While no species expresses all pathways, consistent combinations emerge across continents, including in native species that evolve urban-specialist traits. Understanding these shared strategies provides a predictive foundation for identifying future urban dominants and for managing ecological outcomes in increasingly urbanized landscapes.

Bacteriocytes are specialized eukaryotic cells that house bacterial symbionts. In insects, they are essential for host nutrition, development, and reproduction. Over the past two decades, bulk transcriptomics and genomics have built a strong molecular framework for how hosts support and control intracellular symbionts, highlighting nutrient exchange, immune modulation, and cellular homeostasis within bacteriocytes. However, these approaches provide limited insight into where these processes occur. Organs made of bacteriocytes (bacteriomes) vary widely in architecture and origin across insects, may contain multiple symbiont-bearing cell types and non-bacteriocyte support cells, and likely implement distinct host support programs for different symbionts. Inspired by recent single-cell and spatial studies in non-insect bacteriocyte systems, we argue that spatially resolved approaches are the natural next step for insect symbiosis research. We organize these recurring functions as 'host-control modules', including compensation for symbiont gene loss, regulation of host-symbiont exchange, and control of symbiont abundance or localization. We show how single-cell, spatial, and volumetric imaging approaches can localize these modules to specific cell states, tissue zones, membranes, and organelle contact sites. Finally, we outline a practical hypothesis-driven roadmap for adopting spatial omics and 3D microscopy in insect bacteriomes.

Developmental plasticity, the ability of organisms to produce distinct phenotypes in response to environmental factors, can play a critical role in adaptation and diversification. Onthophagine horned beetles have emerged as a powerful model system for investigating the molecular mechanisms underlying plasticity and their evolution. Here, we synthesize our current understanding of the role of key insect hormones (juvenile hormone, ecdysone, and the insulin/insulin-like growth factor signaling pathway) and their interactions with major genetic regulators of horn development, doublesex and Hedgehog signaling. We contrast the mechanisms of plasticity in horned beetles with those in other insect species, highlighting critical gaps in our understanding of the interactions linking hormones, nutrition-sensitive signaling pathways, and developmental genetic regulators. Finally, we discuss how novel genomic and functional genetic tools, combined with integrative approaches, offer promising opportunities to unravel these complex mechanisms.

The house fly (Musca domestica) is a globally important pest that affects human and livestock health and contributes to significant economic losses in animal-production systems. Intensive and prolonged insecticide use has led to rapid, recurrent resistance across nearly all major chemical classes. This review synthesizes recent advances in understanding the molecular basis of metabolic resistance in M. domestica, emphasizing four detoxification enzyme families: cytochrome P450s, carboxylesterases, glutathione S-transferases, and Uridine diphosphate (UDP)-glucuronosyltransferases. Key genes, including CYP6A1, CYP6D1, CYP6G4, and MdαE7, illustrate the polygenic and interconnected nature of detoxification pathways. Chromosomal mapping highlights both cis- and trans-regulatory mechanisms, with autosome 2 emerging as a central regulatory hub. Recent studies further identify G protein-coupled receptor (GPCR) signaling as an upstream modulator of resistance, where rhodopsin-like GPCR overexpression elevates resistance levels and P450 expression. Additionally, a CYP6G4 allele containing a CncC/Maf binding-site insertion connects GPCR signaling to oxidative-stress pathways, contributing to multi-insecticide resistance.

Global warming is exposing insect populations to environmental conditions that may change faster than they can adapt. Therefore, understanding whether rapid evolution can enable insects to persist in the face of ongoing warming has therefore become a central challenge in evolutionary ecology. Here, we examined recent advances in assessing the potential for and constraints on rapid thermal adaptation, focusing us on quantitative genetics, experimental evolution and environmental gradients as complementary approaches. Quantitative genetic approaches have revealed that thermal traits have sufficient genetic variation to respond to natural selection; however, these responses may be constrained by their underlying genetic architecture. Experimental evolution has demonstrated that rapid adaptive responses are possible; however, laboratory conditions may oversimplify the environmental complexity experienced by natural populations. Environmental gradients can impose differential selection on populations, leading to phenotypic differentiation that can be evaluated through common-garden experiments. Recent evidence further suggests that thermal adaptation under climate warming cannot be fully understood from a single-stressor perspective because interacting selective pressures can reshape both the direction and magnitude of evolutionary responses. To improve predictions of insect persistence under future warming scenarios, it is essential to integrate evolutionary, ecological, and genomic approaches.

While correlative studies show worrying insect declines in recent times, the nature of insect population dynamics and the paucity of long-term data makes the assessment of the status and trends of insect populations challenging and disconnected from conservation actions. The assessment of life-history dynamics, the joint responses of reproduction, survival, and other vital rates across the life cycle to environmental change, is increasingly seen as an important bridge joining underlying mechanisms to population outcomes under global change, which can substantially improve predictions of declines. However, life-history dynamics under global change have been assessed for a very biased sample of animals in the tree of life, namely mammals, birds, and, among invertebrates, species of economic or cultural significance. This hinders us from developing sound predictions and actionable conservation actions to mitigate declines for a wide range of species. Here, we review methods for assessing life-history dynamics effectively given heterogeneous data. We also argue that insects, and invertebrates more generally, have unique ecological and evolutionary niches and thus show unique life-history dynamics that are strongly linked to environmental cues. Hence, while we can learn a lot from life-history population dynamics developed for vertebrate species, this uniqueness calls for its own model development. We emphasize that such model development can advance the theory and conservation applications of life-history research more broadly.

Insects, the most species-rich group of organisms on Earth, provide crucial ecosystem processes such as crop pollination, nutrient cycling, or pest control. Recent evidence indicates declines in insect biodiversity and altered community composition across habitat types. Declines are driven by land-use change, loss of suitable habitats, climatic changes, establishment of non-native species, and pollutants such as pesticides and fertilisers. Arriving at a more solid data basis requires improved insect monitoring through indicator taxa, essential biodiversity variables, and significant technological advancements allowing for real-time monitoring. Halting insect declines will require societal transformation, reduced land-use intensity, and adherence to climate change mitigation strategies. Addressing these challenges requires coordinated efforts and immediate action to preserve insect biodiversity for the benefit of human well-being and planetary health.

As insect pollinators continue to decline across much of the world, understanding the factors that support them in the wild has become increasingly critical. Leafcutter bees, which are widespread and represent the first successfully managed solitary bees, require detailed knowledge of their nutrient sources, nesting materials, and nesting opportunities for effective conservation. While 'bee hotels' have been developed to provide nesting sites and nutrient resources are relatively well understood, our knowledge of the leaf sources that underpin nesting remains limited. Recent studies - though largely concentrated in North America and India - offer valuable insights into the plant species used by leafcutter bees and the ecological and biological factors influencing leaf selection. These emerging findings may prove transformative, illuminating the chemical, molecular, microbial, and biochemical mechanisms that shape leaf-foraging decisions. Such knowledge could also inform agricultural practices, enabling farmers to enhance habitats by provisioning suitable leaf sources. In this review, we examine the drivers of nesting and leaf-foraging behavior, the diversity of leaf resources, and patterns of brood mortality. We highlight research priorities that should be pursued in an integrative manner to advance the management and conservation of leafcutter bees, with particular emphasis on deepening our understanding of their sensory ecology.