The evolutionary success of insects may be partly attributed to their profound ability to adjust metabolism in response to environmental stress or resource variability at a range of timescales. Metabolic flexibility encompasses the ability of an organism to adapt or respond to conditional changes in metabolic demand and tune fuel oxidation to match fuel availability. Here, we evaluate the mechanisms of metabolic flexibility in insects that are considered short-term, medium-term, and long-term responses. We describe mechanisms that enhance metabolic flexibility by intermediary metabolites, transcription, tissue resculpting, the nervous system and hormone response, and more permanent genetic adaptations. We consider how metabolic flexibility may provide fitness advantages in diverse environmental conditions, and how this might be related to population dynamics, fundamental niches, and shifting geographic ranges. We conclude by discussing how mechanisms of metabolic flexibility might have broad implications for the management of pests and disease vectors and for the conservation of rare species in an era of rapid change.

Climate adaptation in insects can proceed via responses in life-history traits and their thermal plasticity and through phenological shifts mediated by responses to photoperiodic cues (photoperiodism). While experimental studies demonstrate evolutionary potential for both modes of adaptation, it remains unclear how evolution will unfold in natural populations, limiting our ability to predict how insects will respond to climate change. Here, we review the literature and analyze published studies revealing that photoperiodism for diapause induction evolves predictably along latitude, with high-latitude populations entering diapause earlier. In contrast, although a few species showed clinal variation in life history and thermal plasticity, the direction of these clines was not consistent across taxa. These findings suggest that while insect life history and physiological adaptation to temperature can evolve, phenological shifts via evolution of photoperiodism are likely to be more common and predictable responses to future climate change.

Bumble bees (Bombus) are prominent keystone pollinators globally and thus serve as model taxa for numerous facets of biology from social evolution to foraging economics. Many of the ∼265 species are in decline, motivating research that aims to better understand which traits make them susceptible. Despite a long history of taxonomic and natural history research, much of their biology is understood from just a few commercially available species. This review compiles the breadth of biotic trait diversity of bumble bees to provide a comparative perspective on their biology, evolution, and conservation. It features ecological traits most pertinent to their conservation, as well as traits of these primitively eusocial bees that inform our understanding of their social evolution. Many of these traits are interdependent, making a broadly comparative analysis valuable for interpreting evolution and declines. These data are organized in a phylogenetic context to show patterns of trait correlation and knowledge gaps, highlighting the depauperate natural history data in Asian and South American species. Limitations in comparative interpretation due to data standardization are emphasized.

The genus Liriomyza Mik (Diptera: Agromyzidae) comprises a diverse group of leaf-mining flies that feed internally on plant tissues, with species ranging from host plant specialists to highly polyphagous pests. In this genus, Liriomyza trifolii, Liriomyza sativae, and Liriomyza huidobrensis have emerged as the dominant invasive species in China over the past three decades, causing extensive damage and complicating pest management efforts. Owing to having overlapping host ranges, these species frequently co-occur, resulting in intense interspecific competition and, in many cases, competitive displacement. This review synthesizes recent advances in understanding the invasion dynamics, species displacement processes, and ecological interactions of these three species. We highlight how interspecific competition, driven by variation in host preference, insecticide resistance, and climatic adaptability, has shaped species distributions and displacement outcomes. We also examine cryptic diversity within species, the importance of accurate diagnostics, and the limitations of current quarantine and management strategies. Finally, we discuss promising directions for integrated pest management, including the development of host plant resistance, the deployment of novel insecticides, and the application of molecular tools. By positioning Liriomyza as a model system, this review contributes to a broader understanding of invasive species ecology and offers guidance for the sustainable management of leafminers and other invasive agricultural pests.

Fabre's nineteenth-century observation that smell is central to insect communication spurred entomologists and, later, chemical ecologists, neurobiologists, geneticists, structural biologists, and evolutionary biologists to investigate how insects detect survival-related compounds. Structural biologists resolved the three-dimensional structures of pheromone-binding proteins and odorant receptors (ORs), revealing features that enable specific interactions with semiochemicals. Researchers proposed that ORs evolved from gustatory receptors as insects adapted to terrestrial life and then specialized to detect species-specific sex pheromones. Most insects use both broadly and finely tuned receptors, but migratory locusts rely mainly on finely tuned ones. To test hypotheses, genes were silenced, expressed in empty neurons, or resurrected, leading to receptor de-orphanization and discovery of new semiochemicals through reverse chemical ecology. These receptors and coreceptors are expressed in olfactory receptor neurons (ORNs) within sensilla of the antennae and maxillary palps. Recent evidence suggests ORNs may express multiple receptor types, including odorant, ionotropic, and gustatory receptors.

The insect cuticle is a complex extracellular matrix that provides physical support and protection against infection, dehydration, mechanical injury, and stress. Chitin with different degrees of deacetylation and various kinds of cuticle proteins, lipids, and other organic molecules are crucial structural components of the insect cuticle. To meet the demands of development, insects periodically molt to shed their old cuticles and form new ones. Increasing research attention has been focused on the molecular mechanism of cuticle biosynthesis and the intracellular transport and assembly of the structural components. Although the whole picture of how insect cuticle is precisely formed remains elusive, breakthroughs in the last decade have revealed a number of enzymes and protein factors that are involved in the cuticle formation. This review summarizes recent advances in molecular aspects of insect cuticles, with particular emphasis on the roles of proteins, which are also promising targets for pest control and management.

Historically, contact insecticides have played a major role in managing pests in postharvest stored commodities. Despite the availability of significant literature published over the past three decades, the current status and potential future use of contact insecticides are not known. In this review we synthesize the literature to identify reasons for the ongoing decline in the use of contact insecticides in postharvest commodity protection, and outline the challenges and opportunities for their future use by the grain industry. Development of resistance in major stored-product insect pests to conventional pesticides and the stricter regulatory requirements driven by consumer sensitivity to pesticide residues on food are discussed in detail to explain the limitations to their current use. We also highlight the strategic integration of currently available contact insecticides into a fumigation-dominated pest management program. We conclude by proposing several research aspects that may prompt their continued use by the grain industry in the near future.

Bees are generally agreed to be the most important pollinators. Their pollination functions and services not only closely link to crop production and food security, but also underlie ecosystem health and stability. Unfortunately, bees face a combination of stressors such as land-use intensification and pesticide overuse, leading to declines and potential risks to human welfare. These facts underscore the urgent need for global research and action to protect bees and their pollination services. In this review, we examine the current understanding of pollinator bee diversity, function, and conservation in China. We discuss existing knowledge gaps, summarize the stressors affecting bees in China, and highlight their uniqueness when compared to advances in better-studied regions. We also provide insights into promising areas for future research, while advocating for more investments in the conservation of bees and their pollination services in China and Asia more broadly.

Bacillus thuringiensis (Bt) is an important bacterium used worldwide to manage pest insects. A full understanding of how Bt establishes infection and how hosts elicit defense is crucial to develop Bt-derived pesticidal formulations. In this review, we propose that Caenorhabditis elegans is a promising model host for investigating the pathogenic process of Bt. Studies on Bt-C. elegans interactions substantially guide and exhibit the potential to accelerate the research on Bt infection biology in insect hosts, helping to improve Bt-based pest management. In this article, we synthesize these advances, highlight the application and promise of the C. elegans model in defining Bt-insect interplays, and discuss limitations of this model.