The stakes are considerable. Agricultural land covers nearly six billion hectares worldwide, roughly forty percent of the planet’s emerged land surface, and in metropolitan France it stretches across twenty-seven million hectares — about half the national territory. This dominance makes farming one of the most impactful human activities on biodiversity. France’s wooded countryside, known as bocage, once formed an intricate patchwork of hedgerows totaling around two million linear kilometers in the early nineteenth century. By 2006, approximately seventy percent of that network had been erased, as mechanized, industrial agriculture redrew parcel boundaries and replaced wooded fields with open ones. The consequences for biodiversity, including species beneficial to crops, have been profound and are still unfolding.

Hedgerows occupy a special ecological position. They create ecotones — transitional zones between distinct ecosystems — that often harbor more biodiversity than the uniform habitats on either side. Previous work has shown that hedgerows can support more ground beetle species than adjacent meadows, and that ant species abundance distributions can display a distinctive ecotonal effect. Yet despite decades of research on hedgerow ecology, no study appears to have focused specifically on how these structures shape ant communities, let alone on the functional traits those ants carry. Ants are ideal candidates for such scrutiny: they are considered keystone species, they are sensitive to soil disturbance and quality, and their species richness correlates with the diversity of numerous other groups, from springtails to beetles to microbes.

To fill this gap, the team deployed three hundred pitfall traps in the Allier department of central France during August 2020. The traps were arranged along transects running from the edge of twenty different hedgerows into the centers of adjacent agricultural plots, at distances of zero, six, twelve, twenty-four, and forty-eight meters. That outermost distance was chosen deliberately: earlier research suggests it approximates the threshold at which hedgerows influence crop yields. The twenty hedgerows were split into two categories — eleven arboreal hedges exceeding five meters in height along most of their length and containing at least five substantial trees, and nine shrubby hedges that fell below those thresholds. Each trap operated for seven days, and every ant collected was identified to species level.

The haul amounted to 2,556 individual ants representing twenty-one species from ten genera and three subfamilies. The most abundant species, Tetramorium grp. caespitum-impurum, accounted for 969 individuals, while two species — Lasius brunneus and Colobopsis truncata — were each represented by a single specimen. When the researchers analyzed species richness using accumulation curves, two patterns emerged: richness tended to increase with proximity to hedgerows, and arboreal hedgerows supported significantly more species than shrubby ones. The latter finding is particularly notable, as the authors know of no previous study that has compared different hedgerow types in terms of insect richness. They suggest that shrubby hedges may be structurally closer to herbaceous infrastructure than to their taller, more complex arboreal counterparts.

Community composition told an equally compelling story. A redundancy analysis revealed that distance from the hedgerow significantly shaped ant communities, explaining nearly twenty-eight percent of the variance, while a factorial correspondence analysis exposed a clear gradient: communities close to hedges differed more sharply from one another than those farther away. Species such as Myrmecina graminicola and Temnothorax nylanderi were largely restricted to within six meters of hedgerows, whereas Tetramorium moravicum and Tapinoma erraticum dominated the forty-eight-meter mark. The researchers interpret this as evidence that agricultural disturbances act as environmental filters, selecting for hardy generalists in the open field while allowing more specialized species to persist in the sheltered hedge margin. Rare species, including the arboreal-nesting C. truncata and the shining black Lasius fuliginosus, appeared almost exclusively at the base of arboreal hedges — consistent with the habitat heterogeneity hypothesis, which holds that more structurally complex vegetation offers more ecological niches.

The functional analysis went a step further, asking not just which ants were present but what traits they carried. Using a database of eighteen functional traits per species, the team computed eight functional diversity indices. Three proved sensitive to hedgerow effects: functional evenness and functional mean nearest neighbor distance declined with distance from hedges, indicating that functions are distributed more evenly and with greater differentiation near the woody corridors, while functional dispersion was higher around arboreal hedges than shrubby ones. Ten of the fourteen response traits correlated with distance. Near hedges, ants tended to be larger, individually foraging, and equipped with more queens and nests; farther out, communities shifted toward smaller, behaviorally dominant, seed-eating species with larger colonies and independent colony foundation — a classic profile of pioneer generalists suited to frequently disturbed environments.

The most agriculturally charged results came from the effect traits, which the researchers linked to presumed ecosystem services and disservices. Soil tilling — the bioturbation ants perform as they excavate nests — decreased with distance from hedgerows, suggesting that hedgerows promote a service known to enhance water infiltration, boost nitrogen and phosphorus availability, and accelerate decomposition. Insect predation, which encompasses the consumption of crop pests, also declined with distance, aligning with earlier findings that natural enemies accumulate near hedgerows. Most strikingly, the aphid breeding and nectar-theft disservice was lowest close to hedgerows and in shrubby hedges. The authors propose that elevated predation near hedges suppresses the ant-aphid mutualism, and they note that their results echo previous reports of reduced aphid abundance in fields adjacent to hedgerows. Seed dispersal showed only a weak, non-significant declining trend.

These findings carry a nuanced message about biodiversity on farmland. The authors caution against framing biodiversity purely in terms of ecosystem services, arguing that such an oversimplified portrayal can backfire when farmers, whose concerns include genuine disservices, feel misled. Soil tilling, for instance, is generally beneficial but can occasionally clash with the needs of particular crops through altered microbial activity or pH. The classification of any biological process as a service or disservice depends on context — a reality the study embraces rather than obscures. Intriguingly, while arboreal hedges hosted greater ant diversity, shrubby hedges appeared to deliver (dis)services more closely aligned with the needs of the adjacent field, hinting that predators spilling out of shrubby corridors are functionally more compatible with farmland conditions.

Ultimately, the study positions hedgerows as strategic infrastructure for the agroecological transition — a more resilient alternative to the intensive practices that have stripped them from the landscape. By supporting taxonomically and functionally distinct ant communities, and by tilting the balance toward beneficial processes like pest predation and soil engineering while suppressing aphid-related problems, hedgerows demonstrate that conservation and productivity need not be adversaries. The authors call for future research extending to other taxa, greater distances, and degraded bocage landscapes, along with standardized pitfall trap designs that prevent vertebrate bycatch. For now, the message is clear: every meter of hedge removed from a French field takes with it an invisible workforce of six-legged laborers whose services agriculture has barely begun to account for.

Subject of Research: The effects of hedgerow type and distance on ant community taxonomy, functional diversity, and agroecosystem services in French farmland

Article Title: The role of hedgerows in shaping ant (Formicidae) communities in agricultural ecosystems: for a better understanding of agroecosystems functioning, including presumed ecosystem services and disservices

Article References: Marty, C., Jamonneau, T., & Johnson, G. (2026). The role of hedgerows in shaping ant (Formicidae) communities in agricultural ecosystems: for a better understanding of agroecosystems functioning, including presumed ecosystem services and disservices. Web Ecology, 26(1), 1-25. https://doi.org/10.5194/we-26-1-2026

Image Credits: AI Generated

DOI: 10.5194/we-26-1-2026

Keywords: hedgerows, ants, Formicidae, agroecology, biodiversity, ecosystem services, functional diversity, bocage, France, agricultural landscapes, soil bioturbation, pest control

The central finding is stark. Across 23 categories of ecosystem services and functions, most of the benefits that nature provides to humanity rose steadily as biodiversity increased, rather than levelling off once a handful of species were present. This pattern directly undermines the concept of functional redundancy, the long-standing assumption that species can readily substitute for one another, so that moderate losses of diversity do little measurable harm. Instead, the data show that ecological benefits keep climbing with every additional unit of diversity, which means, conversely, that they keep declining with every species lost. The comfortable buffer that conservation planning has often relied upon appears, in most cases, to be largely an illusion.

Dr Emma Moffett, the study’s lead author and a lecturer in geography at King’s College London, said the results challenge a deeply embedded assumption. Our findings challenge the comfortable assumption that ecosystems carry plenty of back-up, so losing a species here and there doesn’t change much, she explained. Across most of the ecosystem benefits the team examined, the data simply do not support that view. Because the ecological benefits continue to climb as diversity rises, they are falling as species disappear, and the consequences are likely to accumulate quietly until they become difficult to reverse. The implication for food security and climate protection is considerable, since diverse ecosystems underpin pollination, water purification, carbon storage and natural pest control, all services on which human societies depend daily.

Perhaps the most striking single result concerns the ocean. Ocean carbon sequestration, the process by which carbon dioxide is captured from the atmosphere and stored in marine waters and sediments, showed by far the strongest positive response to biodiversity of any service the researchers measured. This suggests that so-called blue carbon sinks, the ocean and coastal ecosystems such as coral reefs, saltmarshes and mangroves that draw down atmospheric carbon, depend critically on sustaining diverse marine communities, from phytoplankton at the base of the food web to the microbial networks that help pump carbon into deep water. If those communities are simplified by warming, acidification or overfishing, the ocean’s capacity to buffer climate change may weaken in ways that current models do not capture.

The authors are careful to note that the ocean result, while dramatic, rests on a comparatively small number of datasets, and they identify it as an urgent gap in current knowledge. Dr Moffett described the finding as one that stopped the team in its tracks. Carbon capture at sea responded to biodiversity more strongly than anything else measured in the analysis, she said, and yet it remains one of the least studied areas the team encountered. If the world is counting on blue carbon to help address climate change, she argued, marine life cannot be treated as an afterthought. The mismatch between the importance of the service and the paucity of data supporting it is itself a call to action for the research community.

Not every ecosystem service proved equally sensitive to diversity loss, and the exceptions are instructive. Protection against natural hazards such as coastal flooding and erosion was relatively insensitive to biodiversity overall, because this service often depends on one or two foundational species rather than on a broad portfolio of contributors. The shrubs that stabilise sand dunes, for example, deliver most of the protective benefit regardless of how many other species share the habitat. The authors argue that conservation strategy must therefore balance two distinct goals: maintaining overall diversity to preserve the many services that scale with it, and safeguarding irreplaceable foundational species whose loss would remove a single critical function outright.

Dr Will Pearse, an Associate Professor in Evolutionary Ecology in the Department of Life Sciences at Imperial College London, emphasised the practical power of the new synthesis. Biodiversity has long been known to support humanity through food, clean water, clean air and many other ecosystem services, he noted, but the model developed by the team delivers something more precise: a global picture that allows the benefits of biodiversity to be predicted anywhere on Earth. That predictive capability, he argued, makes it easier than ever to recognise those benefits and to take them into account in planning and decision-making. The full database and the model’s forecasts across all 23 categories of ecosystem services and functions have been made publicly available to support policy and planning at every scale.

The team did not stop at describing the present. They linked their database to biodiversity projections under the socioeconomic scenarios used by the Intergovernmental Panel on Climate Change, allowing them to look ahead at how ecosystem services might fare under different development pathways. One projection stands out for its immediate relevance to agriculture: biological pest control on farmland, delivered free of charge by the natural enemies of crop pests, declines under a fossil-fuel-driven development path compared with a scenario involving less fossil fuel use. The sharpest losses are projected for countries experiencing rapid population growth and lower levels of development, precisely the places least equipped to replace a free ecological service with costly chemical alternatives.

The technical achievement underlying these conclusions lies in the scale and consistency of the synthesis. By harmonising data from hundreds of studies across four broad ecosystem types, the researchers were able to test whether the relationship between biodiversity and ecosystem functioning, often demonstrated in small-scale experiments, holds at global scope and across real-world gradients of species loss. The answer, in most service categories, is that it does, and that the relationship is closer to a steady climb than to a plateau. That shape matters enormously for policy: if benefits saturated quickly, moderate biodiversity loss would be tolerable, but a steadily rising curve means every increment of loss carries a measurable cost in pollination, carbon storage, water quality and pest suppression.

For a world negotiating how much habitat it can afford to lose, the study reframes the question. The assumption of plentiful ecological back-up has allowed biodiversity loss to be treated as a secondary concern, something to be addressed once more urgent priorities are met. The new evidence suggests that the margin for error is much narrower than believed, and that the ocean, the planet’s largest carbon reservoir, may be the most biodiversity-dependent and least understood component of the entire system. As the authors make clear, the database and forecasts are now public, giving governments and planners the tools to quantify what is at stake. What remains is the political will to act on a finding that is, in essence, a warning: nature’s resilience has been overestimated, and the services it quietly provides are being spent faster than they can be replaced.

Subject of Research: Global synthesis of biodiversity-ecosystem service relationships across land, freshwater and marine environments

Article Title: Nature’s capacity to ‘bounce-back’ when species are lost vastly overestimated

Article References: Nature’s capacity to ‘bounce-back’ when species are lost vastly overestimated. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: biodiversity, ecosystem services, functional redundancy, blue carbon, ocean carbon sequestration, Nature Ecology & Evolution, King's College London, Imperial College London, climate change, pest control, conservation, IPCC scenarios

The stakes could hardly be higher. Global agriculture must deliver substantial yield gains by 2050 to feed a growing population while sharply reducing its environmental footprint. Today, pests and pathogens destroy between 20 and 40 percent of annual crop production, losses that are overwhelmingly managed with chemical pesticides carrying well-documented ecological and human health costs, from pollinator decline to contaminated waterways and rising greenhouse gas emissions associated with pesticide manufacture and application. RNA interference offers a fundamentally different approach: a mechanism that can be tuned with near-surgical precision to attack a single pest species while leaving beneficial insects, plants, and mammals untouched.

The underlying biology is elegant. RNAi is a natural gene-silencing pathway found across eukaryotes, first characterized by Andrew Fire and Craig Mello in the nematode Caenorhabditis elegans, work that earned the 2006 Nobel Prize in Physiology or Medicine. When a cell encounters double-stranded RNA, or dsRNA, an enzyme called Dicer slices it into small interfering RNAs. These fragments are loaded into the Argonaute-containing RNA-induced silencing complex, which uses one strand as a guide to find and degrade complementary messenger RNAs. If the dsRNA is designed to match a gene that is essential to a pest’s survival, ingesting it can shut down that gene and kill or debilitate the organism. Because the guide sequence can be chosen to match a target found only in the pest, the specificity of the approach far exceeds that of broad-spectrum chemical insecticides.

Two delivery strategies dominate the field. Host-induced gene silencing, or HIGS, builds the silencing construct directly into the crop’s genome, so the plant itself continuously produces dsRNA aimed at its attackers. Spray-induced gene silencing, or SIGS, instead applies dsRNA externally as a foliar spray, much like a conventional pesticide but with a biological active ingredient. HIGS delivered the first commercial success: the trait MON 87411, targeting western corn rootworm, was introduced in 2022 as part of SmartStax PRO maize, followed by additional RNAi-enabled products such as Bayer’s VT4PRO. SIGS reached the market more recently, when Calantha, developed by GreenLight Biosciences, became in 2023 the first foliar-applied RNA-based biopesticide registered by the United States Environmental Protection Agency, targeting the Colorado potato beetle.

Under controlled laboratory conditions, RNAi can achieve efficacy above 90 percent against susceptible target pests, a figure that rivals or exceeds many conventional insecticides. Yet responsiveness varies dramatically across taxa. Coleopteran insects such as beetles tend to be highly sensitive, while lepidopterans, the moths and butterflies that include some of the world’s most destructive caterpillar pests, often show weak or inconsistent responses. Research has traced this variability to several factors: differences in dsRNA uptake mechanisms, the activity of dsRNA-degrading nucleases in the gut and hemolymph, the efficiency of the core silencing machinery itself, and even the pH and enzymatic environment of the digestive tract. Some insects have also evolved outright resistance, as demonstrated in laboratory-selected populations of western corn rootworm and Colorado potato beetle, a reminder that any pest control technology must be deployed within a resistance management framework.

The second major barrier is environmental persistence. Naked dsRNA is fragile. It degrades rapidly in soil, on leaf surfaces, and in water, attacked by ubiquitous ribonucleases, ultraviolet radiation, and microbial activity. Studies of environmental fate have shown that dsRNA applied to soils typically dissipates within days, which is reassuring from an ecological risk perspective but problematic for growers who need a product to remain active long enough to protect the crop. This instability drives up the dose and frequency of application, and with it the cost, since dsRNA remains considerably more expensive to manufacture than conventional agrochemicals.

Formulation science is racing to close that gap. Nanoparticle carriers, including layered double hydroxide clay nanosheets, chitosan particles, lipid nanoparticles, carbon quantum dots, and engineered nanovesicles, can shield dsRNA from degradation and, in some systems, release it gradually over days or weeks. The BioClay platform, for example, has demonstrated prolonged protection against plant viruses and fungal pathogens by anchoring dsRNA on clay nanosheets that slowly desorb the payload. pH-responsive nanoparticles that release dsRNA in the alkaline midgut of target insects, cell-penetrating peptides that ferry RNA across membranes, and chemically modified dsRNAs that resist nuclease attack are all under active development. Meanwhile, microbial delivery systems are emerging as a complementary route: engineered bacteria and fungi can produce dsRNA in situ, and symbiotic microbes have been used to deliver silencing constructs to mosquito larvae and other targets.

Cost, too, is falling. Traditional dsRNA production relied on in vitro transcription, which is expensive at agricultural scale. Bacterial fermentation using strains optimized for dsRNA accumulation, cell-free production systems, and engineered microbes such as Corynebacterium glutamicum equipped with phage expression machinery have all been shown to yield long dsRNAs suitable for pest control at a fraction of the cost. Computational tools for dsRNA design, including multi-target chimeric designers and off-target prediction software, are simultaneously improving the precision and safety of candidate molecules by screening against the genomes of non-target organisms such as pollinators and natural enemies.

The third barrier is regulatory, and it may be the most consequential. Because RNAi products straddle the boundary between biotechnology and crop protection, jurisdictions classify them inconsistently: as biochemical pesticides, as plant-incorporated protectants, or as novel active substances requiring full GMO-style assessment. The United States has moved fastest, registering both transgenic RNAi traits and sprayable dsRNA products, while the European Union and many other regions are still defining their frameworks. This patchwork creates uncertainty for developers, delays market entry, and risks leaving growers in some regions without access to tools approved elsewhere. Review authors and other commentators have called for global regulatory cohesion, arguing that harmonized, science-based risk assessment frameworks are essential if RNAi biopesticides are to contribute meaningfully to sustainable food production and to the United Nations Sustainable Development Goals.

None of these challenges diminishes the underlying promise. RNAi aligns with the central demands of twenty-first-century agriculture: high specificity, low residues, minimal impact on non-target organisms, and compatibility with integrated pest management. The technology extends beyond pest killing, with demonstrated applications in improving shelf life, enhancing abiotic stress tolerance, modifying oil composition, and managing fungal, viral, and nematode pathogens. What the new review makes clear is that the remaining obstacles are engineering and governance problems rather than fundamental biological ones. If nanoparticle formulations, cheap microbial production, and coherent regulation mature together, RNA interference could indeed become a cornerstone of next-generation agriculture, turning a Nobel-winning discovery into the everyday toolkit of the sustainable farm.

Subject of Research: RNA interference as a sustainable crop protection technology and the barriers to its field deployment

Article Title: RNAi: the next wave of green agriculture, challenges, and bridging the translational gap

Article References: Abdullah, Z. K., Kong, L. L., Ariffin, N., & Wong, M. Y. (2026). RNAi: the next wave of green agriculture, challenges, and bridging the translational gap. Plant Cell Reports, 45(9), Article 271. https://doi.org/10.1007/s00299-026-03939-x

Image Credits: AI Generated

DOI: 10.1007/s00299-026-03939-x

Keywords: RNA interference, RNAi biopesticides, double-stranded RNA, spray-induced gene silencing, host-induced gene silencing, crop protection, sustainable agriculture, nanoparticle delivery, dsRNA stability, pest control, regulation, Plant Cell Reports

The logic behind symbiosis-based pest control rests on a fundamental biological reality: insects with nutritionally unbalanced diets often cannot survive without their microbial partners. Sap-feeding insects in the order Hemiptera, which includes some of the world’s most devastating agricultural pests, consume plant phloem that lacks essential amino acids and B vitamins. Their symbiotic bacteria synthesize these indispensable nutrients, allowing the insects to flourish on diets that would otherwise be lethal. Tsetse flies and bed bugs, which feed on B-vitamin-deficient vertebrate blood, harbor symbionts such as Wigglesworthia morsitans and Wolbachia that manufacture these vitamins for them. Storage pests like the cigarette beetle and the drugstore beetle, along with the African cotton stainer, similarly rely on bacterial partners for vitamin production. In leafhoppers, the division of labor is even more elaborate: one symbiont, Sulcia, provides eight essential amino acids, while a second partner, Baumannia, supplies two additional amino acids and a suite of B vitamins. Sever these partnerships, the review suggests, and the pests collapse.

Symbionts do more than feed their hosts. They also serve as chemical bodyguards and environmental shields. The bacterium Pseudomonas living in the rove beetle Paederus fuscipes produces polyketide toxins that deter predators, while the aphid symbiont Regiella helps defend its host against the pathogenic fungus Pandora neoaphidis. Burkholderia gladioli, a symbiont of the false ground beetle, generates antibiotics that protect the host’s eggs from microbial attack. Symbionts can even buffer insects against abiotic stress: strains of Serratia and Rickettsia in the pea aphid improve survival under heat stress, and gut Burkholderia strains help stinkbugs degrade the insecticide fenitrothion, conferring resistance to chemical control. These protective and metabolic services explain why disrupting them, or weaponizing them, holds such tactical appeal for pest managers seeking alternatives to broad-spectrum insecticides.

The most mature application of symbiont-based control involves Wolbachia, a widespread bacterial endosymbiont that has already been deployed at scale against disease vectors. Wolbachia spreads rapidly through insect populations by inducing cytoplasmic incompatibility, a reproductive manipulation that makes infected males unable to produce viable offspring with uninfected females. Beyond suppressing populations, Wolbachia also interferes with pathogen transmission. Field programs have demonstrated that Wolbachia-infected mosquitoes show reduced capacity to transmit dengue virus, and laboratory work has shown that introducing virus-inhibiting Wolbachia strains into planthoppers reduces their ability to transmit plant viruses that damage rice. These successes, the review notes, provide a template for extending symbiont-based strategies from human health into crop protection, where the same principles could blunt the impact of insect-vectored plant pathogens.

Genetic engineering takes the approach a step further through paratransgenesis, the modification of symbiotic bacteria to express anti-pest or anti-pathogen effector molecules. Because symbionts already colonize and persist within their hosts, they can serve as delivery vehicles for molecules that the insects cannot avoid. Researchers have engineered Serratia, a bacterium naturally resident in the mosquito gut, to express antimalarial proteins that interrupt the infection and transmission of mosquito-borne pathogens. In honey bees, the gut bacterium Snodgrassella alvi has been genetically modified to induce RNA interference responses in the host, suppressing bee mite parasitism and altering bee physiology in controllable ways. Against Chagas disease, antitrypanosomal effector genes introduced into the midgut symbiont of the cone nose bug allow the insect to express proteins that inhibit the development of the Trypanosoma parasite within its own gut. These laboratory demonstrations, the review emphasizes, now need validation in open-field environments to confirm their real-world effectiveness.

A second strategy exploits the bioactive compounds that symbionts naturally produce. As the discovery rate of natural products from traditional sources has declined, insect-associated microbes have emerged as a rich and largely untapped chemical reservoir. One striking example comes from the malaria vector Anopheles sinensis, whose gut symbiont Serratia ureilytica Su_YN1 secretes an antimalarial lipase that kills malaria parasites, revealing a molecular mechanism that could be harnessed for disease control. Symbiont chemistry can also manipulate pest behavior rather than killing directly. The gut bacterium Pantoea agglomerans in desert locusts converts the insect’s digestive byproducts into precursors of aggregation pheromones, the chemical signals that drive the formation of devastating locust swarms. Conversely, a microsporidian parasite of locusts suppresses hindgut bacteria, thereby inhibiting pheromone synthesis and preventing swarming. In fruit flies, symbiotic Klebsiella oxytoca and Citrobacter freundii produce volatile compounds such as 3-methyl-1-butanol and 2-phenylethanol that attract female flies, offering bait candidates for trapping programs.

The third strategy is disruption: deliberately breaking the symbiotic partnership on which a pest depends. Agricultural antibiotics, which are microbial secondary metabolites that are environmentally friendly and easily degradable, have shown promise here. Specific fungicides significantly reduce populations of yeast-like symbionts in the brown planthopper, a major rice pest, increasing the insect’s mortality, and the antibiotic zhongshengmycin inhibits three of the planthopper’s symbionts, suggesting that combining antimicrobial agents with chemical pesticides could improve control of this notorious pest. A more surgical variant targets horizontally transferred genes, sequences that insects have acquired from bacteria and that complement functions their symbionts can no longer perform. In whiteflies, horizontally transferred genes provide biotin and cooperate with the symbiont Portiera in lysine synthesis, boosting fecundity. Researchers have used an engineered begomovirus vector to silence these genes in whiteflies, successfully repressing pest performance in both laboratory and greenhouse trials. Symbionts can also be hijacking points for pathogen control: Rice Dwarf Virus binds to the outer membrane of the leafhopper symbiont Sulcia through a specific capsid protein interaction, and antibodies or antibiotics targeting that membrane protein can block viral transmission.

None of this is without obstacles, and the review is candid about the challenges. Engineered symbionts must remain genetically stable and persist within their hosts; modifications intended to enhance pest control can impair a bacterium’s ability to colonize, eroding efficacy over time. Environmental adaptability is another hurdle, since symbionts sensitive to temperature, humidity, or sunlight may fail under field conditions, as illustrated by the heat-sensitive gut symbionts of the green vegetable bug Nezara viridula. Non-target effects loom equally large: generalist microbial agents could harm beneficial insects or destabilize ecosystems, whereas specialist agents, by analogy with selective algicidal bacteria, might spare them. Resistance is a further concern. Just as pests evolve resistance to chemical pesticides, they may mutate the genetic sequences targeted by engineered symbionts, suppress toxic effector molecules, or restructure their microbiomes to exclude engineered strains, potentially spreading resistance rapidly through populations.

The path forward, the authors argue, lies in precision and integration. CRISPR/Cas9-based tools could enable on-demand gene activation or repression within symbionts, allowing microbes to respond dynamically to the presence of pests or pathogens, while synthetic biology may yield adaptive strains that maintain efficacy as pest populations evolve. Multi-strain microbial consortia, each targeting a different pest pathway, could add redundancy and reduce the chance of resistance. Long-term ecological monitoring and field trials will be essential to track the spread and stability of engineered microbes and to detect any cascading effects on biodiversity. Ultimately, the review concludes, symbiosis-based strategies will be most powerful not as standalone replacements for pesticides but as components of integrated pest management, woven together with biological control agents, crop rotation, habitat manipulation, and the judicious use of chemicals. If that integration succeeds, the smallest partners of the insect world may become some of agriculture’s most valuable allies.

Subject of Research: Insect–microbe symbiosis-based strategies for managing insect pests and their transmitted pathogens

Article Title: Insect‒microbe symbiosis-based strategies offer a new avenue for the management of insect pests and their transmitted pathogens

Article References: Lv, C., Huang, Y.-Z., & Luan, J.-B. (2024). Insect‒microbe symbiosis-based strategies offer a new avenue for the management of insect pests and their transmitted pathogens. Crop Health, 2(1), Article 18. https://doi.org/10.1007/s44297-024-00038-9

Image Credits: AI Generated

DOI: 10.1007/s44297-024-00038-9

Keywords: insect symbiosis, symbiotic microorganisms, pest control, Wolbachia, paratransgenesis, brown planthopper, whitefly, horizontal gene transfer, agricultural antibiotics, integrated pest management, sustainable agriculture, CRISPR

To understand why this matters, it helps to start with the chemistry. Since Watson and Crick described the double helix in 1953, DNA has been imagined as a linear molecule in which adenine pairs with thymine and cytosine pairs with guanine. But guanine-rich sequences can do something unusual: four guanine bases can associate in a square, coplanar arrangement called a G-quartet, held together by eight Hoogsteen hydrogen bonds, a bonding pattern first described by biochemist Arthur Hoogsteen in 1963. When two or more of these G-quartets stack on top of one another, they form a G-quadruplex. Monovalent cations such as potassium, sodium and ammonium nestle in the central channel of the stack and stabilize the structure. Depending on the number of stacked quartets, the length of the connecting loops and the polarity of the strands, G-quadruplexes adopt parallel, antiparallel or hybrid conformations, giving them a remarkable structural versatility.

The evidence that these structures exist inside living cells is now strong. Using the G4-specific antibody BG4, researchers visualized G-quadruplex foci in human cell lines, and the signals vanished after DNase treatment and multiplied when cells were exposed to pyridostatin, a small molecule that stabilizes G4s. G4-binding proteins such as the helicase DHX36, the fly protein LARK and the yeast helicase Pif1 provide further indirect proof of their presence in vivo. Genomewide, the picture is striking. Roughly 700,000 potential G4-forming sequences have been predicted in the human genome, and across 37 surveyed species the number and density of these motifs increased with evolutionary complexity. Crucially, the sequences are not scattered randomly: they cluster at replication origins, promoters, telomeres and untranslated regions, exactly the places where a regulatory element would be expected to sit.

That nonrandom distribution underpins the biological roles of G-quadruplexes. In mammalian genomes, 80 to 90 percent of replication origins are GC-rich and capable of forming G4s, and these structures can act both as barriers that helicases must unwind to prevent fork collapse and as recognition sites that recruit initiation factors such as the origin recognition complex and Rif1. In promoters, G4s can either boost or suppress transcription by altering how transcription factors bind. The classic example is the human oncogene c-Myc, whose expression dropped when cells were treated with the G4 ligand TMPyP4 and fell dramatically when the promoter G4 was disrupted by CRISPR-Cas9 editing. Recent work has even shown that promoter G4s serve as common binding hubs for many transcription factors. At telomeres, the single-stranded G-rich overhang folds into G4s that modulate telomerase activity and telomere length, while RNA G-quadruplexes in untranslated regions regulate translation, splicing and mRNA stability.

Plants have their own distinctive G4 landscape. An analysis of 15 sequenced plant genomes, from Arabidopsis thaliana and rice to mosses and lycophytes, revealed that more than 90 percent of plant G4s contain only two G-quartets, a profile quite different from the human genome, where three-quartet structures dominate. The density of predicted G4-forming sequences in monocotyledons was five to ten times higher than in dicotyledons, and G4 motifs were even found in chloroplast and mitochondrial DNA, with mitochondrial DNA showing roughly three times the G4 frequency of nuclear and chloroplast genomes. In Arabidopsis, rice and maize, these motifs concentrate around transcription start sites, 5-prime untranslated regions and other regulatory zones, hinting at cis-regulatory functions in gene expression.

Functional studies in plants have delivered some of the most vivid demonstrations of G4 biology. The first RNA G4 identified in a living plant cell sat in the 5-prime untranslated region of the DNA damage response gene ATR, where it acted as a translational repressor. Another RNA G4 in the untranslated region of SMXL4/5 suppresses translation and restricts phloem differentiation, directly linking a folded RNA structure to vascular development. Perhaps most strikingly, the RNA G4 in the 3-prime untranslated region of the drought-induced dehydrin gene HIRD11 inhibits its translation; when the G4 motif was mutated, Arabidopsis roots grew significantly longer. Even more intriguingly, when researchers compared the nucleotide composition of transcriptomes across 1,000 plant species, they found that plants from cold climates carried G-rich transcriptomes prone to forming RNA G4s, and in Arabidopsis these cold-responsive G4s stabilized mRNAs and helped regulate growth at low temperatures. G4s in maize have also been tied to hypoxia, oxidative stress and energy status, suggesting that these structures are deeply woven into how crops cope with a changing environment.

Insects, meanwhile, offer both the best model systems and the most direct agricultural stakes. In Drosophila, the first predicted G4 was found in the HeT-A retrotransposon at chromosome ends, and subsequent work showed G4 motifs overlapping replication origins, common in all centromeres, and enriched in long intergenic noncoding RNAs, introns and promoters, with an improved G4-seq method detecting 22,511 such sequences genomewide. G4 signals localize to heterochromatin in salivary gland polytene chromosomes and are weaker in germline stem cells, implying a role in cell differentiation. The Drosophila homolog of the helicase DHX36 has been crystallized bound to a G4, revealing at atomic resolution how the enzyme unfolds the structure, and mutations in pif1 cause chromosome segregation defects consistent with unresolved G4s stalling replication forks.

Outside the fruit fly, the silkworm Bombyx mori has become the showcase for insect G4 biology. Its telomeric repeat d[TAGG(TTAGG)3], conserved across many insects, folds into a chair-type intramolecular G4 that is more stable in sodium than in potassium solution. The silkworm genome harbors nearly 24,000 predicted G4s, and the first insect G4 shown to regulate transcription was found in the promoter of BmPOUM2, a gene governing development. The G4-binding protein LARK binds this motif to boost transcription, and CRISPR-Cas9 knockout of LARK causes embryonic lethality with broad changes in cuticle and pigment gene expression. A G4 in the promoter of the acyl-CoA binding protein gene BmACBP regulates lipid metabolism: when fifth-instar larvae were treated with the G4-stabilizing ligand pyridostatin, BmACBP expression and triacylglycerol levels dropped, fat body mass shrank, and larval growth and metamorphosis slowed. A G4 in the promoter of the silk gland factor SGF1 acts as a positive regulator of silk protein production, and its knockout reduced silk output in mutant larvae.

The pest control implications come into sharpest focus in the fall armyworm, Spodoptera frugiperda, a globally destructive crop pest. Genomewide analysis identified 387,875 predicted G4-forming sequences, nearly 67 percent of them upstream of start codons, and the genes carrying promoter G4s were enriched for metabolic pathways, especially xenobiotic metabolism by cytochrome P450 enzymes. Treatment with the G4 ligand N-methyl mesoporphyrin IX suppressed P450 expression and enzyme activity and increased larval mortality. In the corn earworm Helicoverpa zea, a transposon-inserted G4 in the promoter of the detoxification gene CYP321A1 acts as a silencer, and destroying it or stabilizing it with NMM reduced the promoter’s response to plant toxins. Because insects rely on P450s, glutathione-S-transferases and carboxylesterases to survive both plant allelochemicals and pesticides, these findings open a concrete path: G4 ligands could be deployed either as standalone insecticides that disrupt the G4s of development genes, producing abnormal larvae, or as pesticide sensitizers that knock down detoxification genes and restore the potency of existing chemicals.

The review’s authors sketch three strategies for turning this biology into practice. First, cell-permeable G4 ligands could be screened or designed to target the specific structures of pest development genes, exploiting the fact that G4 structural polymorphism offers ligand specificity. Second, G4 ligands could accompany conventional insecticides, either destabilizing the G4s that drive detoxification gene expression or stabilizing them so that transcription factors cannot bind, thereby synergizing with the pesticide. Third, and perhaps most elegant, plants themselves could be engineered to produce higher levels of natural G4-binding compounds, so that feeding pests ingest ligands that disrupt their own gene regulation. Plant-derived molecules such as the flavonoids fisetin and kaempferol and the alkaloids chelerythrine and berberine already bind G4s and are being explored as low-toxicity anticancer leads, and the same chemistry could be redirected toward agriculture. No G4-based pesticide has yet reached the field, and large-scale screening of plant extracts has only just begun, but the underlying logic is compelling: unlike organophosphates or hormone analogs that hit broad physiological processes, a molecule aimed at a single G4 structure in a pest’s DNA or RNA could, in principle, be exquisitely species-specific, sparing beneficial insects and leaving the environment largely untouched. As more G4s are mapped and their regulatory functions confirmed, the humble four-stranded guanine quartet may prove to be one of the most unexpected weapons in the fight to protect the world’s crops.

Subject of Research: G-quadruplex nucleic acid structures and their regulatory roles in plants and insects with applications in pest control

Article Title: G-quadruplex structure in plants and insects and potential applications in pest control

Article References: G-quadruplex structure in plants and insects and potential applications in pest control. (n.d.). https://doi.org/10.1007/s44297-025-00047-2

Image Credits: AI Generated

DOI: 10.1007/s44297-025-00047-2

Keywords: G-quadruplex, DNA structure, RNA G-quadruplex, plants, insects, pest control, silkworm, fall armyworm, cytochrome P450, G4 ligands, gene regulation, crop protection

The review, conducted by Paulo Chiza Athumani and colleagues at the University of Dodoma and published in the journal Discover Conservation, followed rigorous PRISMA guidelines for scoping reviews. The team searched Google Scholar, Scopus, and EBSCOhost using carefully constructed Boolean search strings combining terms for the two species with keywords covering socio-ecological impact, economic damage, crop loss, and pest management. From an initial haul of 643 publications, the researchers screened titles and abstracts, assessed full texts, and ultimately included 59 studies for analysis. Because the two species differ so markedly in how their impacts are measured, the authors could not compare them metric by metric. Instead they used a frequency-of-reporting framework, counting how often each type of impact appeared across the literature.

The headline finding is a stark asymmetry in research attention. The red-billed quelea dominated the literature, appearing in 73 percent of the included studies, most of which concentrated on economic damage and control measures. The Indian house crow attracted fewer papers, but those studies spanned a far wider range of topics, from biodiversity loss and disease transmission to competition with native birds and urban nuisance. Geographically, the picture splits just as cleanly. Quelea research is spread across Western, Eastern, and Southern Africa, reflecting the bird’s vast range and its status as arguably the most economically significant agricultural pest in sub-Saharan Africa. House crow studies cluster along the coasts, particularly in East Africa, where the species first established itself and where its invasion is most pronounced, though the bird is steadily pushing inland.

The quelea’s weapon is sheer numbers. Moving in enormous flocks that track rain fronts and the annual grasses they feed on, queleas descend on farmlands and consume tons of grain daily. The review compiles the staggering arithmetic of this appetite: annual losses of rice and small grains across Africa exceed US$54 million, with reported yield losses reaching 81 percent in maize, 55 percent in wheat, and 55 percent in almonds in southern Africa. Crops such as maize, rice, sorghum, groundnuts, and wheat all fall within the bird’s destructive reach, making it a direct threat to food security in some of the world’s most agriculture-dependent economies. Notably, the quelea’s impact is almost entirely economic; the review found no evidence that it preys on other birds, damages infrastructure, or disrupts tourism, a consequence of its specialized granivorous diet.

The house crow is a different kind of menace, one whose damage radiates outward through ecosystems. Five African studies documented the species preying on, harassing, and destroying the nests of native birds, from small weavers to the much larger black-headed heron, producing measurable biodiversity losses. In Tanzania, house crows have been linked to declining lizard populations. They compete aggressively with the native pied crow, often outcompeting it and surpassing it in numbers across invaded areas. Perhaps most alarmingly for public health, house crows are recognized vectors of an extraordinary catalogue of zoonotic pathogens, including Salmonella, Shigella, Escherichia coli, Campylobacter, influenza A subtype H5N1, chlamydiosis, avian tuberculosis, Newcastle disease virus, and West Nile virus, along with parasites such as Plasmodium, Toxoplasma, and Trypanosoma. In urban areas they snatch food from people, attack tourists, generate relentless noise, and contaminate open water sources with their excreta, while near airports they pose genuine aviation hazards through bird strikes.

The review also catalogued what the two species do not do, and these absences carry their own ecological significance. Neither bird has been documented hybridizing with other species in Africa, a relief given that hybridization occurs in an estimated 10 to 20 percent of bird species and can erode the vigor of native populations or even drive them extinct. Nor has brood parasitism been recorded for either species on the continent, though the authors note an intriguing opportunity: in India, the Asian koel parasitizes house crow nests, a natural mechanism that could theoretically be harnessed for biological control. Equally striking is the absence of predators attacking the house crow in Africa. One study even reported queleas being taken by spotted hyenas in Namibia, yet no organism has been documented preying on house crows, whose carcasses scavengers reportedly ignore. This predator-free status may partly explain the crow’s rapid spread from its coastal strongholds.

Against these threats, humanity’s countermeasures have evolved dramatically over the review’s fifty-year window. Traditional approaches, scarecrows, manual scaring, and nets, have given way to technological solutions including drones, autonomous deterrence systems, solar-powered acoustic repellers, and IoT-based virtual fences. Most recently, researchers have proposed machine learning approaches that promise more targeted and ecologically responsible control. Yet the review’s assessment is blunt: no method has achieved full effectiveness. The house crow’s intelligence makes it a particularly elusive target, as the birds quickly learn to evade new measures. Worse, some of the most effective tools carry heavy collateral costs. Chemical control of queleas, especially aerial spraying of the organophosphate fenthion, kills non-target species, contaminates ecosystems, and raises the specter of poisoned birds entering local food supplies.

These trade-offs push the problem beyond ecology into ethics and governance. The review highlights a tension that is becoming increasingly familiar in conservation technology: the same smart monitoring systems and drone cameras that track pest bird movements around farms and villages can also capture images, locations, and daily routines of nearby residents, raising serious questions about data security and privacy if such information is stored or shared without proper safeguards. The authors argue that effective management of both species demands a framework integrating ethical responsibility, legal compliance, human health protection, and meaningful community involvement. Communities, after all, bear the brunt of crop damage and sanitation problems, and their participation is critical for monitoring outbreaks and implementing interventions on the ground.

Human attitudes toward the two birds add another layer of complexity. Only one study each has examined community awareness and perceptions of the house crow and the quelea in Africa, a gap the authors identify as a critical research priority. What is known suggests both species are widely regarded as pests and even as sources of poverty, yet the quelea occupies a paradoxical position: it is simultaneously a feared agricultural destroyer and a food source harvested and consumed by local communities, a duality that shapes both tolerance and control. This ambivalence matters, because management interventions that ignore social acceptance and compliance are far more likely to fail. The review also flags a broader data problem: most studies lack quantitative monetary estimates of damage, making it impossible to compare the two species’ economic costs on standardized terms or to prioritize interventions on solid evidence.

The study’s ultimate message is that origin matters less than behavior. Whether a species is native, like the quelea, or invasive, like the house crow, if it acts as a pest it inflicts real damage on human livelihoods and ecosystems alike. The quelea primarily attacks the economic sector through its voracious consumption of grain, while the house crow strikes on multiple fronts, ecological, economic, and public health, even if its individual economic toll is comparatively smaller. As climate change reshapes rainfall patterns, human tolerance shifts, and policy frameworks remain unstable, the interactions between people and these two birds are set to intensify. The authors call for advanced, sustainable, and community-supported control strategies, better integration of emerging technologies with environmental safeguards, and a substantial expansion of research into the human dimensions of the conflict. After fifty years of study, the war against Africa’s pest birds is far from over, but for the first time the battlefield has been mapped.

Subject of Research: Comparative socio-ecological and economic impacts and control of the invasive Indian house crow and the native red-billed quelea in Africa

Article Title: Comparison of socio-ecological and economic impact and control techniques of the invasive Indian house crow (Corvus splendens) and the red-billed quelea (Quelea quelea) in Africa: a scoping review

Article References: Comparison of socio-ecological and economic impact and control techniques of the invasive Indian house crow (Corvus splendens) and the red-billed quelea (Quelea quelea) in Africa: a scoping review. (n.d.). https://doi.org/10.1007/s44353-026-00083-1

Image Credits: AI Generated

DOI: 10.1007/s44353-026-00083-1

Keywords: Indian house crow, red-billed quelea, invasive species, pest birds, crop damage, food security, Africa, disease transmission, biodiversity loss, pest control, scoping review, human-wildlife conflict

Wolbachia is famous among biologists for its extraordinary reproductive tricks. Because it is transmitted only from mothers to offspring through the egg cytoplasm, the bacterium has evolved an arsenal of strategies to favor infected females at the expense of males and uninfected individuals. It can kill infected males outright, convert genetically male embryos into females, induce females to reproduce without mating, and, most famously, trigger cytoplasmic incompatibility, or CI. In CI, when a Wolbachia-infected male mates with an uninfected female, or with a female carrying a different Wolbachia strain, the fertilized eggs die during embryonic development. If, however, the female carries the same strain, her eggs can rescue the paternal chromosomes and development proceeds normally. The net effect is that infected females enjoy a reproductive advantage, and the bacterium sweeps through populations on the back of this manipulation.

The review’s central insight is that the three rice planthopper species host strikingly different Wolbachia strains with very different effects. In the brown planthopper, the native strain wLug infects fewer than half of individuals in the field, and rather than inducing CI it appears to boost the fecundity of its host. In the small brown planthopper, by contrast, the strain wStri infects roughly ninety-nine percent of wild populations and induces complete cytoplasmic incompatibility while simultaneously enhancing reproduction. The white-backed planthopper’s strain, wSfur, infects about ninety percent of individuals but shows weak or no CI and only minimal effects on fecundity. These strain-specific differences matter enormously for population dynamics, because the reproductive effects of the bacterium directly alter the base population size of the insects and therefore influence the scale of planthopper infestations in the field.

One of the most intriguing findings concerns what happens when a Wolbachia strain is moved into a new host species. Researchers successfully transfected wStri from the small brown planthopper into the brown planthopper, where the bacterium adopted a tissue distribution similar to that in its native host but reached significantly higher densities than the native wLug strain. Although wStri still induced cytoplasmic incompatibility in its new home, the intensity of the effect was notably reduced. This observation carries an important message: the strength of CI is shaped not only by the symbiont itself but also by the genetic background of the host. The transfection also had a practical payoff, because the introduced wStri inhibited infection and transmission of rice ragged stunt virus in the brown planthopper, hinting at significant pest control potential.

At the molecular level, the mechanism of cytoplasmic incompatibility has only recently come into focus. Because Wolbachia cannot be cultured outside living cells, identifying the bacterial factors behind CI long remained a stubborn challenge. The breakthrough came with the discovery of two adjacent genes, cifA and cifB, encoding proteins that appear to be the key effectors. In transgenic experiments in fruit flies, expressing CifB and CifA in uninfected males was sufficient to reproduce the CI phenotype, with embryos dying after mating with uninfected females. Conversely, expressing CifA alone in uninfected females rescued embryos from Wolbachia-infected males. Mutations in the PD-(D/E)XK nuclease, deubiquitinase, and peptidase domains of CifB impair the function of these factors, and the three-dimensional structures of the two proteins have now been resolved, revealing that their interaction depends on charge attraction across three interfacial regions.

Two competing models attempt to explain how these proteins work. The toxin-antidote model proposes that CifB is delivered to the embryo, where it acts as a toxin, while Wolbachia in the egg synthesizes CifA, which binds CifB and neutralizes it, allowing normal development. The host modification model instead holds that Cif proteins modify targets within the gametes themselves: modifications to sperm induce CI, while modifications to female gametes reverse the damage and rescue embryos. Recent functional studies lend weight to the modification model. CifA has been detected in sperm nuclei during spermatogenesis, where it causes retention of histones and deficiency of protamines in mature sperm, and both CifA and CifB have been shown to act as nucleases that degrade long non-coding RNAs and damage DNA during late sperm formation. Notably, the rules differ across strains: in some systems CifB alone suffices to induce CI, while in others both proteins must be expressed together, underscoring how diverse these mechanisms remain.

The wStri genome adds another layer of complexity. It contains three copies of the cifA-cifB gene pair, and phylogenetic analysis shows that the known CI factor groups have expanded from five to ten, with the wStri factors belonging to newly identified groups VI and VIII whose functions remain unknown. On the host side, proteomic and RNA interference studies in the small brown planthopper have identified candidate host factors. The cytoplasmic aminopeptidase-like protein, or CAL, appears to be associated with CI lethality, while the gene iLvE, involved in branched-chain amino acid biosynthesis, was the most significantly downregulated gene in infected insects, and knocking it down in uninfected males reduced fertility in a way that could be restored by mating with infected females. Another candidate, NDUFA8, which encodes a subunit of a mitochondrial enzyme complex, was upregulated in infected females, and suppressing it reproduced CI-like embryo mortality, suggesting a role in the rescue phenotype.

Beyond incompatibility, Wolbachia acts as a reproductive booster for its planthopper hosts. Removing the bacterium from brown planthoppers significantly shortens oviposition and reduces female fecundity, and wStri similarly promotes egg production in the small brown planthopper. Comparative genomics and metabolomics show that both wStri and wLug carry complete pathways for synthesizing B vitamins, including biotin and riboflavin, nutrients that play crucial roles in host reproduction and that the insects apparently cannot fully supply themselves. At the physiological level, the bacterium upregulates vitellogenin, the yolk precursor protein essential for egg formation, increases mitotic division of germ cells, and accelerates the breakdown of nurse cells during peak oviposition, thereby channeling more nutrients into egg production. Wolbachia also alters microRNA expression in its host, reshaping the expression of fecundity-related genes, and preliminary evidence suggests changes in mitochondrial energy metabolism may contribute as well.

The picture is further complicated by interactions with other symbionts. In the white-backed planthopper, Wolbachia coexists with another intracellular bacterium, Cardinium, and lines carrying both symbionts show distinct microbiomes and metabolite profiles. Remarkably, double-infected lines exhibit lower fecundity than uninfected ones, indicating that combined symbiont effects can be more consequential than either bacterium alone. For pest management, the implications are considerable. The CI principle underlies incompatible insect technique programs already deployed against mosquitoes, in which males carrying specific Wolbachia strains are released to mate with wild females, causing their fertilized eggs to die and suppressing target populations. Whether similar strategies can be scaled up for rice planthoppers remains an open question, and the review’s authors caution that field deployment would require careful risk assessment, including the possibility of resistance evolution, ecological side effects, and horizontal transmission of Wolbachia to non-target species. Still, as planthopper outbreaks intensify and pesticide resistance grows, a bacterium that can both sabotage and supercharge insect reproduction may prove to be one of the most valuable allies rice farmers have.

Subject of Research: Wolbachia-mediated reproductive manipulation, including cytoplasmic incompatibility and fecundity enhancement, in three rice planthopper pest species

Article Title: Wolbachia-mediated reproductive manipulation in rice planthoppers

Article References: Niu, Y.-D., Wang, M.-K., Yan, Z.-C., Bing, X.-L., & Hong, X.-Y. (2025). Wolbachia-mediated reproductive manipulation in rice planthoppers. Crop Health, 3(1), Article 20. https://doi.org/10.1007/s44297-025-00059-y

Image Credits: AI Generated

DOI: 10.1007/s44297-025-00059-y

Keywords: Wolbachia, rice planthoppers, cytoplasmic incompatibility, endosymbiont, Nilaparvata lugens, Laodelphax striatellus, Sogatella furcifera, cif genes, fecundity, pest control, symbiosis, B vitamins

The scale of the undertaking sets this study apart from earlier estimates. In 2024, the evaluation covered 149 locations spread across 144 counties, cities, and districts in 15 provinces, spanning virtually all of the major growing regions for each of the three crops. For wheat, the assessment drew on data from Hebei, Anhui, Shandong, Henan, and Hubei, the five dominant wheat-producing provinces. Rice evaluations ran across ten provinces, from Heilongjiang in the northeast to Guangdong in the south, while maize assessments covered seven provinces including the major corn belt provinces of Jilin and Heilongjiang. Each participating county functioned as an independent experimental unit, chosen to represent the distinct cultivation systems and pest pressures of its region.

The methodological core of the evaluation is elegantly simple: create a gradient of pest damage and measure what happens at each step. In every county, five treatments were established. In the first, pests were controlled under the strict supervision of a plant protection technician, representing the best achievable outcome. In the second, control followed unified rules applied across an area, and in the third, farmers controlled pests using whatever methods they freely adopted, reflecting everyday practice. The final two treatments served as controls: one in which diseases, insect pests, and weeds were all left uncontrolled, and one in which only diseases and insects were left alone while weeds were managed. The unmanaged plots, each covering one-fifteenth of a hectare with a single replicate, were expected to suffer the most severe damage possible.

From these plots, the researchers derived three key quantities. The maximum loss rate compares the yield of strictly protected plots with the yield of completely unprotected plots, revealing the full destructive potential of the local pest complex. The actual loss rate measures the gap between strictly protected plots and each of the other treatments, showing what really happened under a given management regime. The difference between these two figures yields the recovery loss rate, which is precisely the contribution rate of plant protection: the share of potential yield that pest control clawed back. Because crops are distributed unevenly across regions with different damage levels, the team used a weighted averaging scheme, scaling county-level rates up to provinces by the proportion of cultivated area each county represented, and then scaling provinces up to the national level the same way. The overall national figure of 30.56 percent was calculated by weighting each crop’s rate by its share of the pooled cultivation area, which in 2024 stood at 24.41 percent for wheat, 29.91 percent for rice, and 45.68 percent for maize.

The crop-by-crop results reveal striking differences in how much plant protection matters. Rice, consistently the most pest-battered of the three staples, showed a national contribution rate of 35.62 percent, with provincial values ranging from 20.13 to 46.33 percent. Maize followed at 28.63 percent, with provincial rates between 20.08 and 35.61 percent. Wheat, which faces a somewhat narrower spectrum of major pests, registered 27.99 percent. Perhaps more telling than the national averages is what happened when control quality varied. For wheat, contribution rates under strict supervision were 11.73 percentage points higher than under traditional farmer-directed control, and unified control outperformed farmer practice by 5.36 points. For rice, the corresponding advantages were 6.69 and 5.43 percentage points; for maize, strict and unified control reached 30.40 and 29.47 percent respectively, against just 22.54 percent for traditional practice. In every crop, the hierarchy was the same: strict control beat unified control, which beat whatever farmers did on their own.

That consistent pattern carries a clear policy message. The gap between what is achievable and what is routinely practiced represents millions of tons of grain lost not to pests themselves, but to imperfect control of pests. The authors argue that closing this gap requires strengthening technical guidance for farmers and expanding unified control programs, in which professional organizations apply coordinated treatments across contiguous areas rather than leaving each household to improvise. Notably, the evaluation counted control measures implemented across the entire growing season, beginning with seed treatments applied before sowing, rather than restricting the accounting to a few critical growth stages. Preventive measures such as chemical seed treatments deployed against wheat stripe rust and crown rot, and protections applied during rice seedling nursery cultivation, all feed into the final contribution rates, meaning the figures capture a full-season defense rather than a single heroic spray.

One of the most consequential findings concerns a group of pests that often receives less attention than dramatic disease outbreaks: weeds. By comparing the two control treatments, one unprotected against everything and one protected only against weeds, the team isolated the yield toll of weed competition alone. The losses averaged 8.11 percent in wheat, 14.34 percent in rice, and 14.74 percent in maize, but the regional variation was enormous. Wheat fields in Anhui lost up to 13.47 percent of yield to weeds, while rice fields in Heilongjiang suffered losses as high as 33.65 percent, and maize fields in the same province lost up to 32.61 percent. The authors report that weed damage has tended to worsen in recent years, with 2024 losses exceeding those recorded in 2023 for all three crops, although they caution that some of this difference may reflect changes in the locations under evaluation. It was precisely this growing threat that prompted the addition of the weed-specific control treatment starting in 2023.

The geography of weed pressure tells its own story. In both rice and maize, weed infestations are most severe in the northeastern region, where weeds are the primary source of yield loss in local fields. In the Huang-Huai region, by contrast, maize fields lost only 7 to 11 percent to weeds, outside of Heilongjiang and Jilin, a difference the authors attribute partly to the height that maize plants reach later in the season, which shades out competing weeds. In wheat, damage was similar in Shandong and Henan but greater in Anhui, where a rice-wheat rotation system is practiced, a pattern observed in both 2023 and 2024. Neighboring provinces tended to show similar weed pressure, as seen in Jiangsu and Zhejiang, and in Jiangxi and Hunan, both double-cropping rice regions where staggered planting seasons create continuous windows for weed establishment.

The 2024 results also fit into a three-year arc of increasingly refined national accounting. The first evaluation in 2022, which excluded weeds and rodents, estimated an overall contribution rate of just 20.31 percent, with 24.20 percent for wheat, 19.46 percent for rice, and 18.84 percent for maize. In 2023, the addition of a blank control treatment produced a more realistic figure of 30.59 percent. The 2024 wheat rate of 27.99 percent proved remarkably stable compared with 2023’s 27.58 percent, but the rice rate fell from 40.58 to 35.62 percent, a shift the authors attribute primarily to changes in which provinces were included. Anhui, for instance, suffered severe rice stem borer and weed damage in 2024 and posted a contribution rate of 65.72 percent, but its data were not used in the national rice calculation because neighboring Jiangsu and Zhejiang were included instead. In regions where single- and double-cropping rice coexist, such as Jiangxi and Hunan, interyear fluctuations were pronounced, reflecting the spatiotemporal complexity of pest occurrence across overlapping cultivation systems.

The authors are candid about the limits of their method. Some blank control plots were small, and because control plots were sometimes located close to treated plots, pests occasionally spilled over from protected areas into unprotected ones, potentially blunting the measured damage and slightly understating the true contribution of plant protection. Reducing these edge effects will be a priority in future evaluations. Even so, the headline numbers stand as a landmark quantification. China’s Grain Security Guarantee Law now explicitly enshrines pest prevention and control, and the promotion of green and unified control strategies, as legal pillars of national food production. This study provides the empirical backbone for that policy: nearly a third of the country’s wheat, rice, and maize harvest exists only because someone fought for it, and the fight, done strictly and in a coordinated fashion, is demonstrably worth millions of tons more than the fight done casually. As weed pressure climbs and pest complexes shift with changing cultivation patterns, the annual accounting that NATESC has pioneered is likely to become an indispensable instrument for measuring, and improving, the return on one of agriculture’s oldest investments.

Subject of Research: Quantifying the contribution of pest control to wheat, rice, and maize production in China

Article Title: Evaluation of pest control contributions to the production of three major grain crops in China

Article References: Evaluation of pest control contributions to the production of three major grain crops in China. (n.d.). https://doi.org/10.1007/s44297-025-00060-5

Image Credits: AI Generated

DOI: 10.1007/s44297-025-00060-5

Keywords: China, grain crops, wheat, rice, maize, pest control, plant protection, yield loss, weed damage, food security, unified control, NATESC

The research team, led by Yucheng Wang and Fei Yang of the University of Minnesota together with David L. Kerns of Texas A&M University, Graham P. Head of Bayer Crop Science, Dawson Kerns of Louisiana State University, and Bruce E. Tabashnik of the University of Arizona, set out to answer two questions with direct consequences for resistance management. First, does selection for resistance to Vip3Aa cause cross-resistance to Cry proteins, which would undermine the pyramided crops that produce both toxin classes? Second, do Cry proteins and Vip3Aa interact synergistically against insects that are already resistant, a property that could extend the useful life of multi-toxin Bt crops?

To address these questions, the researchers generated five strains of H. zea carrying more than 100-fold resistance to Vip3Aa in a susceptible genetic background. The strains originated from F2 screens of field populations collected in Louisiana, Mississippi, and Texas between 2019 and 2020, a technique that exposes hidden recessive resistance alleles carried by mating pairs of field-collected insects. Each strain was then crossed repeatedly with a laboratory-susceptible strain, BZ-SS, obtained from a commercial supplier, and reselected with Vip3Aa in the laboratory. After five to six rounds of backcrossing and selection, the resulting strains, designated LT70-Vip, AC4-Vip, M1-Vip, R2-Vip, and R15-Vip, showed such profound resistance that even the highest concentration of Vip3Aa tested, 100 micrograms per square centimeter of diet, killed no more than 15 percent of larvae, implying resistance ratios exceeding 500-fold.

The team then tested these Vip3Aa-resistant strains against five Cry proteins used in commercial Bt crops: Cry1Ab, Cry1Ac, Cry1A.105, Cry1Fa, and Cry2Ab. The verdict was strikingly inconsistent. Across 23 bioassay comparisons, seven LC50 values were significantly higher than those of the susceptible strain, seven were significantly lower, and nine did not differ significantly, a seven-to-seven split that matches exactly what would be expected if no consistent cross-resistance existed. The overall mean cross-resistance ratio was 1.2, statistically indistinguishable from the value of 1.0 expected if selection with Vip3Aa had no effect on susceptibility to Cry proteins. Only Cry1Ac showed a statistically significant mean positive cross-resistance, and only one strain, AC4-Vip, displayed significant overall positive cross-resistance across the Cry proteins tested.

What astonished the researchers was not the absence of a trend but the sheer magnitude of the variation around it. The 23 cross-resistance ratios spanned an extraordinary 1100-fold range, from 0.06, indicating 17-fold negative cross-resistance to Cry1Fa in strain LT70-Vip, to 65-fold positive cross-resistance to Cry1A.105 in strain AC4-Vip. That range is roughly 49 to 70 times wider than those reported in previous reviews of cross-resistance between Vip3 and Cry proteins in other lepidopteran species. The authors suggest that the genetic diversity of the field-derived resistance alleles, which complementation tests place at three distinct loci among the five strains, likely contributes to this variability, as does the unknown mechanism of resistance in most of the strains. Only LT70-Vip has a biochemically characterized mechanism, reduced binding of Vip3Aa to midgut brush border membrane vesicles, and as expected under the receptor model of Bt toxicity, that strain showed no significant cross-resistance to any Cry protein.

The second half of the study tackled synergy, an interaction in which two toxins combined kill more insects than would be predicted from the independent action of each toxin alone. Previous surveys suggested synergy between Cry and Vip proteins is relatively rare, appearing in only about 19 percent of bioassay evaluations reviewed in 2020, though more recent studies on fall armyworm and peach fruit moth reported far higher frequencies. Critically, nearly all prior synergy work used susceptible insects. To test synergy against resistant insects, the team created a triple-resistant strain, TRE-RR, by crossing the Vip3Aa-resistant LT70-Vip strain with a Cry-resistant strain derived from Texas field corn, then selecting successive generations with all three toxins. The resulting strain exhibited resistance ratios of 265 for Cry1Ac, 495 for Cry2Ab, and greater than 96 for Vip3Aa.

Against this formidable laboratory adversary, synergy emerged clearly. In diet bioassays conducted at two concentrations, combinations of Vip3Aa with Cry1Ac produced significantly lower observed survival than expected under independent action at both concentrations tested, and Cry2Ab combined with Vip3Aa was synergistic at the higher concentration. Most remarkably, the three-toxin combination of Cry1Ac, Cry2Ab, and Vip3Aa was synergistic at both concentrations, meaning that even larvae equipped with resistance to every toxin individually died more often when the toxins were delivered together than their separate toxicities would predict. The finding is consistent with the authors’ earlier analysis of field data from Bt corn showing synergy between Cry1Ab and Vip3Aa against susceptible H. zea, but it is, to the authors’ knowledge, the first demonstration of Cry-Vip synergy against a strain resistant to both toxin classes.

The practical implications are substantial. If synergy between Cry proteins and Vip3Aa operates in the field against resistant H. zea, as it appears to against susceptible populations, it would kill some insects that survive either toxin alone, reducing the intensity of selection for Vip3Aa resistance and potentially slowing its evolution. That would be welcome news for an industry and a grower community watching early warning signs of Vip3Aa resistance accumulate in the United States, where practical resistance to Vip3Aa has already been documented in Brazil. The synergy finding also carries a cautionary note for resistance monitoring. Current surveillance relies partly on sentinel plots of corn producing Cry1Ab plus Vip3Aa, from which a phenotypic frequency of resistance is calculated by comparing larval abundance in Bt ears with that in non-Bt ears. If synergy kills some larvae that are resistant to either toxin alone, this approach could underestimate the true frequency of Vip3Aa resistance, a discrepancy the authors recommend resolving by comparing estimates from F2 screens with those from sentinel plots.

The study also refines the scientific understanding of how Bt resistance evolves and spreads. Because Vip3Aa and Cry proteins bind to different midgut receptors, strong cross-resistance between them was not expected, and the new results largely vindicate that expectation while revealing how messy the underlying biology can be. Mechanisms other than altered receptor binding, such as changes in toxin processing within the midgut, can confer broad cross-resistance, and the authors note that determining the resistance mechanisms in the remaining strains could explain the puzzling differences between R2-Vip and R15-Vip, which share a resistance locus yet differed 13-fold in their mean cross-resistance to Cry proteins. For now, the message for resistance management is cautiously optimistic: pyramiding Vip3Aa with Cry proteins remains a sound strategy, the lack of consistent cross-resistance means Cry resistance alleles should not compromise Vip3Aa efficacy, and synergy may quietly buy precious time for one of agriculture’s most valuable pest control technologies as its chief adversary continues to adapt.

Subject of Research: Cross-resistance and synergy between the Bt toxins Vip3Aa and Cry proteins in Vip3Aa-resistant strains of the corn earworm Helicoverpa zea

Article Title: Evaluating cross-resistance and synergy between Vip3Aa and Cry proteins from Bt in six strains of Helicoverpa zea derived via F2 screens

Article References: Evaluating cross-resistance and synergy between Vip3Aa and Cry proteins from Bt in six strains of Helicoverpa zea derived via F2 screens. (n.d.). https://doi.org/10.1007/s44297-026-00073-8

Image Credits: AI Generated

DOI: 10.1007/s44297-026-00073-8

Keywords: Helicoverpa zea, corn earworm, Bt crops, Vip3Aa, Cry proteins, cross-resistance, synergy, insect resistance, transgenic crops, resistance management, Bacillus thuringiensis, pest control