Recent studies have brought the alarming decline of insect populations into the global spotlight, highlighting challenges that extend far beyond mere numbers. Notably, a comprehensive special issue published in Nature synthesized data from 106 distinct studies or continuous biomonitoring programs, collectively assessing trends in insect abundance over periods ranging from 16 to 27 years. While these abundance metrics provide essential information, they fall short of fully describing the health of species. This gap is especially evident in agricultural systems and livestock management, where large population sizes might mask underlying issues related to long-term sustainability and resilience.
A critical obstacle in understanding insect population dynamics is the scarcity of longitudinal datasets obtained through rigorous, repeatable sampling methods. Without these precisely controlled data collections, the current status and trajectory of insect biodiversity remain shrouded in uncertainty. Here, natural history museum collections emerge as invaluable repositories. These collections harbor preserved genetic material from specimens collected over centuries, serving as time capsules of historical biodiversity. Their extensive assemblages, particularly rich in insect specimens, offer unprecedented opportunities to investigate how anthropogenic factors have influenced species’ genetic architectures through time.
Building on this conceptual foundation, an international consortium of researchers, including teams from the Institute of Zoology at the Chinese Academy of Sciences, China Agricultural University, and the University of Copenhagen, embarked on an ambitious project. This collaboration aimed to unlock hidden genetic insights enshrined within museum specimens, focusing specifically on the Asian honeybee (Apis cerana). Their innovative approach harnesses the power of museomics—integrating whole-genome sequencing with historical samples—to reconstruct shifts in genetic diversity and evolutionary pressures over the last century.
The researchers procured 46 Apis cerana specimens dating back approximately 120 years, a rare feat given that institutional records, such as those from the Chinese National Animal Collection Resource Center, report only one specimen from this era. Alongside these historical samples, they included 352 contemporary specimens spanning primary geographical populations. Whole-genome comparisons between these cohorts revealed that although the principal lineages of A. cerana persisted throughout the century, the genetic diversity within core populations suffered a major decline. This decline in genetic variability signals a worrying erosion of the species’ adaptive potential, potentially compromising resilience to environmental fluctuations, diseases, and climatic stress.
Delving deeper into the genomic data, the team identified single nucleotide polymorphism (SNP) loci exhibiting significant temporal allele frequency shifts. Intriguingly, these SNPs were predominantly localized within genomic regions related to nervous system function, including components such as synaptic membranes, ion channels, and notably, nicotinic acetylcholine receptors (nAChRs). The latter serve as primary molecular targets for many commercial pesticides, suggesting a compelling link between pesticide exposure and genomic evolution. This relationship presents a striking example of human-driven rapid evolution, wherein A. cerana populations appear to be engaged in a genetic arms race against neurotoxic agrochemicals.
One of the most remarkable findings arises from analyses of the modern Malaysian honeybee subpopulation. This group retains more “ancestral” genetic features within these rapidly evolving nervous system gene regions, positioning them as a living analogue of historical A. cerana populations. The Malaysian bees’ heightened sensitivity to pesticides was experimentally validated through clothianidin exposure assays. Compared to populations from Central China, Malaysian bees endured significantly higher mortality at pesticide concentrations that Central Chinese bees survived robustly. Transcriptome profiling further revealed a downregulation of the X3 transcript variant of the nAChR α gene in Central China populations, implicating this gene expression change in enhanced pesticide tolerance.
This comprehensive investigation delivers a new paradigm for quantifying population health beyond mere abundance, incorporating genetic architecture and functional genomics. The data empower conservation biologists and policymakers to design more nuanced and effective biodiversity monitoring and management programs. Equally important, the study highlights the unparalleled utility of museum specimens in reconstructing historical baselines, allowing scientists to discern subtle genetic erosion invisible in present-day surveys alone.
Beyond technical achievements, the research sets a precedent for addressing biodiversity knowledge gaps exacerbated by geopolitical fragmentation. Through international collaboration and specimen sharing, scientists can overcome regional limitations, ensuring that global biodiversity assessments accurately reflect diverse evolutionary histories and pressures. Moreover, insights gained from Apis cerana have broader implications for non-model insects and other taxa facing accelerated environmental change.
Ultimately, this investigation underscores the precarious position of insect species navigating rapid anthropogenic disturbances. The genetic adaptations observed in A. cerana illustrate a species under intense selective pressure, continually evolving to withstand chemical onslaughts while grappling with reduced genetic variation. Preservation of such genetic resources—both in the wild and within museum archives—is critical for maintaining ecological balance and food security, given the pivotal role of pollinators.
As the global community confronts escalating environmental challenges, the intersection of museomics, evolutionary biology, and conservation science emerges as a powerful toolkit. Harnessing the deep historical insights embedded within natural history collections not only refines our understanding of past and present biodiversity but also equips humanity with the knowledge to formulate informed strategies for safeguarding the future of vital species and ecosystems.
Subject of Research: Genetic diversity and evolutionary responses to pesticides in Asian honeybee (Apis cerana) populations over the last century, leveraging historical museum specimens and whole-genome sequencing.
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Web References: http://dx.doi.org/10.1093/nsr/nwaf438
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Image Credits: ©Science China Press
Keywords: Asian honeybee, Apis cerana, genetic diversity, museum specimens, whole-genome sequencing, nicotinic acetylcholine receptors, pesticides, rapid evolution, museomics, biodiversity conservation, insect population decline, environmental adaptation
