Current opinion in insect science最新文献

Seasonal variation in butterfly wing color patterns is a classic model system of adaptive phenotypic plasticity. While decades of studies provided insights on the underlying ecological roles and physiological regulation of this adaptation, recent advances detail how plasticity develops at the transcriptomic level and evolves at the genomic level. Here, we synthesize these recent advances focusing on wing eyespot size plasticity in the subfamily Satyrinae (Lepidoptera, Nymphalidae) and the model species Bicyclus anynana, the most intensively studied system. We also propose future directions in the field.

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.

Pesticide resistance is a growing threat to global food security and crop protection. Beyond chemical overuse, climate change is increasingly recognized as a major driver that can reshape selection and resistance evolution. Here, we synthesize experimental evidence and plausible pathways by which warming and extreme climate events influence insecticide resistance. We first evaluate how resistance mechanisms respond to climatic stressors, including target-site insensitivity, enhanced detoxification, reduced penetration, and behavioural avoidance. We then map climate drivers to changes in resistance-allele frequencies by altering fitness gains and costs of resistance through mostly positive effects on voltinism and population abundance, distribution shifts and migration, and consequent increased insecticide use and selection pressure. Finally, we identify high-risk resistance pests and insecticides under climate change, emphasizing pests with high thermal tolerance and rapid reproduction and insecticides whose efficacy declines with temperature. We conclude that climate change can either facilitate or suppress resistance depending on pest thermal ecology and buffering capacity, the dominant resistance mechanism, MoA-specific temperature-toxicity relationships, and critically the distinction between short-term phenotypic resistance and multi-generation evolutionary trajectories.

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 increased 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 diet substrate, 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 and habitat loss and degradation. Each of these modes of change has been demonstrated to affect the composition of insect microbial communities, with reduction of species diversity within microbial communities (alpha diversity) as the most common result. Results of 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.

In contrast to chemical pest control, biological control (biocontrol) is generally considered evolutionarily stable, with pests rarely evolving resistance to agents such as parasitoid wasps. In 1997, Holt & Hochberg outlined five principles to explain this pattern. Here, we review post-1997 case studies where resistance has contributed to the breakdown of parasitoid-based biocontrol. We evaluate how these examples align with or challenge Holt & Hochberg's framework and propose updates to reflect new findings. While resistance remains rare, reported cases suggest that breakdowns are more likely when pests possess greater standing genetic variation than their parasitoid enemies. We argue that long-term stability depends not just on host constraints but also on the potential for parasitoid virulence to evolve. Finally, we offer practical recommendations for biocontrol practitioners and regulators to minimise the risk of resistance evolution in parasitoid-based systems.

Climate change threatens vital ecosystem services, including biological control mediated by parasitoids. As higher-trophic-level organisms, parasitoids, compared to their hosts, are disproportionately vulnerable to climatic stress because their survival depends on both their own physiology and that of their hosts. This review synthesizes how rising temperatures reconfigure host-parasitoid interactions, with outcomes that are system-dependent. Common disruptions include reduced parasitism success due to narrower parasitoid thermal tolerance, phenological mismatches that desynchronize life cycles, and altered overwintering activity. As these shifts can undermine both natural and artificial biological control, elevating pest outbreak risks and threatening agroecosystem stability, we discuss how mitigating them may require adapting current biocontrol strategies.

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.

Insect polyphenisms are an extreme form of phenotypic plasticity that arise 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, 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.

The evolution of complete metamorphosis, or holometaboly, in insects is thought to have allowed insects to become the most speciose group of eukaryotes. Yet, the evolution of holometaboly is also one of the most elusive mysteries in insect evolution, undiscovered and intriguing ever since Aristotle's time. Recent studies on juvenile hormone and transcription factors, Chronologically inappropriate morphogenesis (Chinmo), Broad and E93, have provided molecular evidence in support of the two major theories for the origin of complete metamorphosis. This review discusses how these recent discoveries offer insights into the origins of the pupal and larval stages and suggests future studies to further probe this mystery. Although there is no consensus on the homologies of life stages, shared views at the molecular and cellular level are emerging.

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.