The review followed PRISMA 2020 guidelines, searching Scopus and Web of Science for peer-reviewed studies published within the last 20 years. After screening titles, abstracts, and full texts against strict inclusion criteria, the researchers identified 52 primary studies examining neonicotinoid effects on bumblebees under field-realistic or controlled conditions. The resulting dataset reveals a research field that has expanded rapidly since 2012, with roughly half of all studies published in just the last six years and a peak of six papers in 2021, a surge the authors link to the European Union’s partial ban in 2013, the complete outdoor ban of three compounds in 2018, and the controversial resurgence of virus yellows in UK sugar beet in 2020 that reignited the debate.

Technically, neonicotinoids are systemic insecticides developed in the 1980s to replace older organophosphates and combat rising pesticide resistance. Their small molecular size and high water solubility allow them to be absorbed by plants and transported primarily through the xylem, accumulating in leaves, flowers, and pollen. Once inside the insect nervous system, they bind to nicotinic acetylcholine receptors, or nAChRs, overstimulating neural pathways and effectively paralyzing herbivorous pests such as aphids, whiteflies, and leafhoppers. The compounds fall into three chemical groups: the N-nitroguanidines including imidacloprid, thiamethoxam, clothianidin, and dinotefuran; the nitromethylenes such as nitenpyram; and the N-cyanoamidines including acetamiprid and thiacloprid. Their versatility as foliar sprays, seed treatments, and soil drenches made them suitable for maize, sugarbeet, oilseed rape, fruits, and vegetables, and within two decades they accounted for a third of the global insecticide market.

But the review’s most striking finding is not what the science says, but where it comes from. Of the 52 studies, 81 percent were conducted in just two countries: the United Kingdom, which produced 54 percent of the research, and the United States, which produced 27 percent. Only single studies emerged from the Netherlands, Belgium, Finland, Israel, Mexico, China, and Canada. This geographic concentration matters enormously because neonicotinoids remain widely used in the roughly 35 percent of countries that lack pesticide legislation, with clothianidin, imidacloprid, and thiamethoxam still dominating the global market. In the United States alone, over 1,000 neonicotinoid-containing products remain registered with the EPA. Meanwhile, East Asia hosts the richest bumblebee diversity on Earth, with more than 50 percent of known species concentrated in China, Mongolia, Japan, and parts of Russia and India, yet virtually no neonicotinoid research has been conducted there.

The taxonomic bias is equally pronounced. Bombus terrestris, its subspecies B. terrestris audax, and the North American commercial staple B. impatiens dominate the literature, while the Mesoamerican B. ephippiatus appears in only a single study. With over 260 known bumblebee species worldwide, native to every biogeographic region except Australia, New Zealand, and sub-Saharan Africa, the review argues that risk assessments relying on commercially convenient species may systematically underestimate the vulnerability of wild populations. Species with smaller colonies, such as B. pseudobaicalensis and B. schrencki, could be far more sensitive to the loss of even a few foragers, while larger-bodied species that travel further when foraging may suffer greater navigation and endurance impairments. Differences in metabolic detoxification rates, floral specialization, and colony activity timing could all shape which species are hit hardest.

On the compound side, imidacloprid was the most studied, appearing in 54 percent of the identified papers, followed by thiamethoxam at 23 percent and clothianidin at 19 percent. Together, these three nitroguanidine compounds were represented in 88 percent of the studies. The authors attribute this skew partly to commercial sales, citing earlier work showing a positive correlation between research volume and global sales, and partly to the strong binding affinity of these compounds for nAChRs, which drives their toxicological risk. In contrast, acetamiprid and thiacloprid, classified as lower-risk cyanoamidines, received far less attention, and dinotefuran and nitenpyram were entirely absent from the bumblebee literature, despite dinotefuran having been implicated in bee mortality events and nitenpyram showing adverse effects on non-target organisms in other contexts.

The behavioral toll documented across these studies is staggering in its scope. Exposed bumblebees exhibit reduced flower visitation rates, altered flower preferences, and decreased foraging motivation. Chronic exposure impairs flight endurance, increases exhaustion rates, and disrupts homing ability, meaning bees literally cannot find their way back to the nest. Learning and memory deficits compound the damage, with impaired associative learning, olfactory conditioning, and spatial memory documented across multiple species. Since bumblebees rely on learned foraging routes to locate and return to high-quality floral resources, these cognitive impairments cascade through the colony, reducing resource intake and impairing colony growth. Exposed bees also show reduced responsiveness to food rewards, decreased sucrose and nectar consumption, and diminished food storage within the colony, while disruptions in essential social behaviors such as nest thermoregulation and brood care further weaken colony cohesion.

Reproductive effects were the second most commonly reported outcome, documented in 40 percent of studies. Exposed colonies produce fewer new queens, limiting their ability to establish future generations. Brood production and overall colony growth are often impaired, with fewer workers and reproductive individuals emerging, and delayed colony development including slower nest initiation and egg laying further compromises population stability. Male reproduction is also affected, with reduced drone weight, disrupted production timing, and impaired sperm viability limiting mating success. Physiologically, neonicotinoids disrupt neurophysiology by interfering with nAChRs, impairing neural development, and altering brain ion transport-related gene expression. Increased acetylcholinesterase expression suggests impaired neurotransmission, while metabolic effects include elevated oxygen consumption and metabolic activity in flight muscles and the brain, potentially leading to hyperactivity and exhaustion. Exposure also upregulates antimicrobial peptide gene expression, which could lead to immune overactivation and long-term susceptibility to pathogens.

Perhaps most concerning is what the review did not find enough of. Direct measures of pollination efficiency and ecosystem impacts were the least observed outcomes, reported in only 11 percent of studies, largely because only five of the 52 studies were performed in the field relative to laboratory conditions. Yet the behavioral and reproductive impairments documented so extensively are inherently linked to pollination performance. Compromised buzz pollination efficiency, with shorter buzzing duration, results in lower pollen deposition and reduced crop yield. Smaller or poorly structured colonies result in fewer foragers, limiting floral visitation and pollen transfer. At a broader scale, exposure disrupts plant-pollinator networks, with altered interactions between bumblebees and wild plants potentially affecting plant reproductive success and overall ecosystem stability. The authors argue that subtle, chronic impairments in behavior and reproduction could undermine colony health long before direct mortality is observed, meaning the true ecological cost of neonicotinoid exposure may be far greater than current regulatory thresholds suggest.

The review also grapples with the agricultural benefits that keep these chemicals in widespread use. As systemic insecticides, neonicotinoids offer high efficacy, targeted action, and ease of application, and their use as seed treatments reduces the need for repeated foliar spraying, lowering labor costs and farmworker exposure. They effectively combat pests resistant to older insecticides, and long-term crop protection benefits crops like sugar beet, which is often harvested before flowering, reducing direct pollinator exposure. However, their persistence in soil, sometimes exceeding 1,000 days, leads to accumulation and prolonged contamination, and they have been detected in non-crop plants like wildflowers at field margins, exposing pollinators even in untreated areas. The phenomenon of delayed toxicity, where lethal effects only appear after prolonged exposure, further complicates environmental risk assessments. The authors call for expanded research into alternative pest management strategies, field-realistic exposures, long-term monitoring, species-specific responses, and broader geographic coverage, arguing that addressing these critical knowledge gaps will be vital to developing ecologically sustainable agricultural systems that protect pollinators like bumblebees while ensuring adequate crop protection for a growing global population.

Subject of Research: Neonicotinoids quietly scramble bumblebee brains, landmark systematic review reveals

Article Title: The effect of neonicotinoids on bumblebees (Bombus spp.): a systematic review

Article References: Dennis, D. J., & Gibbs, A. J. (2025). The effect of neonicotinoids on bumblebees (Bombus spp.): a systematic review. Frontiers in Bee Science, 3, Article 1657493. https://doi.org/10.3389/frbee.2025.1657493

Image Credits: AI Generated

DOI: 10.3389/frbee.2025.1657493

Keywords: neonicotinoids, bumblebees, pollinators, pesticides, systematic review, bee health, colony collapse, agriculture, ecotoxicology, Frontiers in Bee Science, effect, Bombus

The research team, led by Ramadan D. El Shoukary of New Valley University in Egypt, exposed 320 Japanese quail chicks to oral doses of imidacloprid equivalent to one-tenth of the compound’s lethal dose for fifty percent of a population, administered twice weekly from hatch through twelve weeks of age. The birds were then tracked through their entire sexual development, from the onset of puberty through peak reproductive condition, with behavioral observations, hormone profiling, organ measurements, and genetic testing conducted at weekly intervals.

The results were striking. Treated birds of both sexes reached sexual maturity significantly later than controls, with males maturing at 44.22 days compared to 41.9 days in untreated birds, and females at 47.44 days versus 45.3 days. Exposed birds also weighed more at maturity, a paradoxical finding that the researchers attribute to disrupted metabolic and endocrine regulation rather than improved health. More concerning were the persistent reductions in the brain-somatic index and gonado-somatic index, measures of relative brain and gonad mass, which fell dramatically in treated animals and never recovered throughout the observation period.

Endocrine profiling revealed a systemic collapse of the hypothalamic-pituitary-gonadal axis, the hormonal cascade that governs reproduction. Circulating testosterone crashed in treated males, showing profound suppression at weeks ten and eleven, while total estrogens, progesterone, follicle-stimulating hormone, and luteinizing hormone were all significantly depleted in exposed birds. Notably, 17β-estradiol displayed a biphasic response, initially rising at week seven before collapsing sharply from week nine onward, a pattern the researchers suggest may reflect an early compensatory upregulation of ovarian aromatase that is ultimately overwhelmed by cumulative follicular damage and precursor exhaustion.

Behaviorally, the effects were equally dramatic. Male quails exposed to the pesticide showed severe deficits in both appetitive courtship behaviors, including chasing, waltzing, and wing flapping, and consummatory copulatory actions such as mounting and cloacal contact movements. The cloacal gland, an androgen-dependent structure essential for sperm transfer, shrank significantly, and foam production fell from 58.5 to 50.06 milligrams. In testing arenas, exposed males took longer to initiate sexual interactions, showed depressed libido scores, and completed successful matings far less frequently than controls. Crucially, the frequency of unsuccessful mating attempts did not increase, indicating that the pesticide does not merely make males clumsy but fundamentally impairs the neurological competence required to achieve copulation at all.

Female quails fared no better. Treated hens showed a profound reduction in proceptive squatting and holding-still compliance during mounting encounters, while running escape frequency remained unchanged, suggesting the pesticide selectively abolishes the neuroendocrine mechanisms driving receptive immobility rather than inducing active avoidance. Egg production collapsed across all measured parameters, with total weekly egg numbers falling from 36.8 to 31.7, egg weight dropping from 14.7 to 11.3 grams, and hen-day egg production declining from 72.7 to 62.4 percent. The researchers attribute this reproductive failure to a convergence of gonadotropin withdrawal, follicular atresia, impaired vitellogenesis, and the energetic toll of chronic sickness behavior.

Perhaps the most alarming findings came from the alkaline comet assay, a sensitive technique for detecting DNA strand breaks at the single-cell level. Liver tissue from exposed birds showed marked elevations in the percentage of DNA damage, tail length, and tail moment, reflecting the organ’s role as the primary site of xenobiotic biotransformation where imidacloprid metabolism generates reactive oxygen species. Brain tissue exhibited similarly significant genomic damage, confirming that the pesticide’s genotoxic effects cross the blood-brain barrier and directly injure the central nervous system. The researchers propose that this cerebral DNA fragmentation provides the molecular foundation for the broader behavioral and neuroendocrine collapse observed throughout the study, as oxidative injury to hypothalamic and preoptic neurons compromises the transcription of gonadotropin-releasing hormone and the neural circuitry governing sexual motivation and motor execution.

The behavioral changes also functioned as sensitive early indicators of toxicity. Exposed birds exhibited pronounced hypodipsia, drinking significantly less than controls at every evaluated week, alongside progressive increases in stationary crouching and sickness behaviors that emerged from week nine onward. Because behavioral traits are flexible, rapid responses that often manifest at lower exposure levels than structural or genetic endpoints, the authors argue that monitoring courtship and maintenance behaviors in wild birds could provide a non-invasive, cost-effective proxy for detecting neuroendocrine-disrupting contamination before populations begin to decline.

The study’s findings carry significant implications beyond the laboratory. Imidacloprid is frequently detected in agricultural soils, surface waters, and wildlife habitats worldwide, and humans are exposed through contaminated food, water, household dust, and contact with treated companion animals. Previous research has linked neonicotinoid exposure to delayed migration in songbirds and compromised energy homeostasis in game birds, and the new work extends this evidence by demonstrating that reproductive behavior itself is among the most sensitive endpoints for detecting sublethal toxicity. The researchers caution that their study was conducted under controlled laboratory conditions and did not assess hatchability or transgenerational effects, leaving open questions about whether the observed damage persists after exposure ends or is passed to offspring.

Ultimately, the authors call for integrating behavioral ecotoxicology into regulatory risk assessments, arguing that a pesticide capable of dismantling the hormonal, neurological, and genetic machinery of reproduction at one-tenth of its lethal dose poses a threat that conventional toxicological testing may systematically underestimate. As wild bird populations continue to decline across agricultural landscapes, the silent courtship of contaminated quails may be sounding an alarm that regulators can no longer afford to ignore.

Subject of Research: Neuroendocrine, behavioral, and genotoxic effects of chronic imidacloprid exposure in Japanese quails

Article Title: Sexual behavior dysfunction and sickness behavior as an early warning indicators of imidacloprid exposure, associated with pituitary–adrenal axis dysregulation and DNA damage in Japanese quails

Article References: El Shoukary, R. D., Abd El-Maguid, D. S., Abd El Kareem, A. H., Abd El-Maguid, A. S., Seddik, G. N., Khafaga, A. F., & Abdelbaeth, N. (2026). Sexual behavior dysfunction and sickness behavior as an early warning indicators of imidacloprid exposure, associated with pituitary–adrenal axis dysregulation and DNA damage in Japanese quails. Frontiers in Veterinary Science, 13, Article 1914494. https://doi.org/10.3389/fvets.2026.1914494

Image Credits: AI Generated

DOI: 10.3389/fvets.2026.1914494

Keywords: imidacloprid, neonicotinoids, Japanese quail, endocrine disruption, reproductive toxicity, DNA damage, comet assay, sickness behavior, courtship behavior, ecotoxicology, HPG axis, pesticides

The demographic statistics cited in the editorial deserve closer attention because they reveal a structural pattern often described as a leaky pipeline. Women earning roughly half of entomology doctoral degrees in North America while remaining underrepresented in permanent academic and government positions indicates that attrition occurs after training, not before it. The Brazilian case is especially instructive: when women receive the majority of bachelor’s and master’s degrees in a discipline yet occupy fewer permanent research posts, the bottleneck lies in hiring, promotion, and retention rather than in interest or preparation. Similar patterns have been documented across many scientific fields, and the consistency of the finding across countries with different academic systems suggests that the causes are systemic rather than local. Career-stage timing compounds the problem, since the years in which researchers typically establish independent laboratories often coincide with peak caregiving responsibilities, and institutions that fail to accommodate this reality lose trained scientists at precisely the moment their investment matures.

The scientific content assembled in the Research Topic also illustrates how methodological diversity strengthens inference in pollination science. Species distribution modeling, as applied by the authors studying Neotropical crops and Amazonian bumblebees, relies on occurrence records, environmental layers, and climate projections to estimate where species can persist under future conditions. Such models carry inherent uncertainties, including assumptions about dispersal ability, biotic interactions, and physiological tolerance, which is why the finding that one bumblebee species may lose more than forty percent of suitable climate area while a close relative faces milder projected losses is best interpreted as a call for species-specific field validation rather than a definitive forecast. The contrast between the two Bombus species underscores a recurring lesson in conservation biology: closely related taxa sharing a region can respond very differently to the same climatic pressures, so conservation planning must be grounded in the ecology of individual species rather than in group-level assumptions.

The treatment of neonicotinoid pesticides across the Research Topic similarly demonstrates the value of complementary approaches. A field-focused study of stingless bees in Brazilian coffee cultivation can capture real-world exposure scenarios in a tropical agroecosystem, while a systematic review of bumblebee studies across Europe and North America can synthesize patterns that no single experiment could reveal. The observation that behavioral and reproductive effects are better characterized than effects on pollination efficiency itself identifies a genuine gap: a bee may survive exposure yet deliver fewer or lower-quality pollination services, with consequences for crop yields that current risk assessments may not fully capture. Stingless bees add another dimension to this question because they are dominant pollinators in many Neotropical systems, manage colonies differently from honey bees, and may experience distinct exposure routes through their nesting materials and food storage practices.

The honey bee contributions in the collection connect laboratory-scale mechanisms to practical beekeeping decisions. Hygienic behavior, the removal of diseased or mite-infested brood from cells, has long been recognized as a heritable colony-level defense, and tools that allow breeders to identify resistant colonies without waiting for natural disease outbreaks can accelerate selection programs. Synthetic semiochemical-based assays are valuable precisely because they standardize a stimulus that varies unpredictably in nature, letting beekeepers compare colonies on equal footing. Resistance to the parasitic mite Varroa destructor matters not only for mite control itself but also for the viral complexes that mites vector, which is why a single behavioral trait can correlate with resilience against RNA viruses, microsporidian parasites, and fungal pathogens. At the same time, the study of competition between managed honey bees and cavity-nesting native bees at the urban-bushland interface in Australia addresses a different side of the same species: the same bee that supports crop pollination can, at high densities, compete with native assemblages for floral resources. Practical recommendations for colony placement and for planting pollen sources used by native bees represent the kind of actionable output that emerges when ecological research is designed with management questions in mind.

The waggle dance research highlights how new instrumentation revitalizes classical questions. Karl von Frisch’s decoding of the dance in the mid-twentieth century established that foragers communicate direction and distance, but modern video capture and network analysis allow researchers to follow individual dancers and followers over time, quantifying how recruitment actually propagates through a colony’s forager workforce. Viewing the dance as one node in a social network rather than as an isolated signal opens questions about which bees attend dances, how information spreads unevenly among colony members, and how collective foraging decisions emerge from many individual interactions. This shift from signal description to network dynamics exemplifies a broader trend in animal behavior research, enabled by affordable high-resolution recording and computational tools that were unavailable to earlier generations.

The historical figures invoked by the editors also merit reflection. Eva Crane’s founding of the International Bee Research Association in 1949 created an institutional home for apicultural science at a time when the field was scattered across national traditions, and her prolific career demonstrated that rigorous synthesis could itself be a scientific contribution. Anna Maurizio’s role in establishing the forerunner of the International Commission for Plant-Pollinator Relationships helped build the pollination biology community that now underpins much of the research described in this collection. These women worked in eras when formal recognition of female scientists was rarer, and their legacies illustrate how infrastructure-building, not only experimental discovery, shapes a discipline’s trajectory. Tracing such lineages matters for contemporary equity efforts because it corrects the perception that women are newcomers to bee science rather than long-standing contributors whose visibility in historical accounts has lagged behind their actual influence.

The international composition of the Research Topic carries its own significance. Bee science conducted in Brazil, Australia, North America, and Europe addresses ecosystems, pollinator faunas, and agricultural systems that differ profoundly, from stingless bee coffee pollination in the Neotropics to honey bee and native bee interactions in Australian bushland. Research agendas shaped primarily in a few wealthy countries risk overlooking questions critical to biodiversity hotspots where pollinator dependence of crops and wild plants is high and monitoring capacity is limited. Editorial platforms that deliberately gather work from multiple regions help distribute scientific attention more evenly and expose readers to study systems and bee taxa they might otherwise never encounter. They also create collaboration opportunities, since global challenges such as climate-driven range shifts and pesticide regulation cannot be resolved within any single country’s data.

Ultimately, the editorial frames a dual commitment that characterizes much of contemporary bee science: addressing urgent applied problems, including pollinator decline, crop pollination security, and sustainable pest management, while pursuing fundamental questions about behavior, genetics, and ecology. The two commitments are mutually reinforcing, because applied urgency attracts funding and public interest that sustain basic research, and mechanistic understanding provides the foundation on which practical tools are built. Whether the demographic gap in research positions narrows in the coming decades will depend on institutional choices in hiring, mentoring, and workload allocation, but initiatives that make contributions visible, document persistent inequities with transparent data, and connect researchers across regions and career stages represent concrete steps toward a community in which the full breadth of talent devoted to understanding and protecting bees can flourish.

Subject of Research: Editorial: Women in bee science

Article Title: Editorial: Women in bee science

Article References: Fahrbach, S. E., Imperatriz-Fonseca, V. L., Nunes-Silva, P., & Wallace, H. M. (2026). Editorial: Women in bee science. Frontiers in Bee Science, 4, Article 1781526. https://doi.org/10.3389/frbee.2026.1781526

Image Credits: AI Generated

DOI: 10.3389/frbee.2026.1781526

Keywords: bee science, women in science, pollination, climate change, neonicotinoids, stingless bees, honey bees, bumblebees, Editorial, Women, science, scientific research

The yield numbers are striking. In the study, conducted between 2022 and 2023, ripe berries were manually harvested from 360 branches across six farms supplemented with stingless bee colonies. Branches close to the colonies averaged 0.50 kilograms of coffee each, while branches far from the colonies averaged 0.30 kilograms. The researchers analysed these data with linear mixed-effects models that accounted for the spatial non-independence of sampling sites, nesting plots within farms and treating farm identity as a random effect. The 67 percent gain survived all statistical scrutiny, confirming that supplemental pollination by a native bee can transform productivity in a crop once thought immune to pollinator deficits.

Why would a self-pollinating plant respond so dramatically to bee visits? The answer lies in the subtle biology of arabica coffee. Although the species does not require pollen transfer between different plants to set fruit, decades of research worldwide have shown that flowers isolated from visiting insects form about 28 percent fewer fruits than flowers open to natural pollinators. Bees appear to enhance fruit set even in self-compatible flowers, likely through more efficient pollen deposition on stigmas. Scaptotrigona depilis brings a suite of traits that make it unusually effective at this job: a small body of roughly 5.5 millimeters, short foraging trips of about 4.2 minutes, constant activity from morning to early afternoon, mass-recruitment foraging using scent trails to rapidly mobilize nestmates, and colonies of around 10,000 workers.

There is also a mechanical quirk that may give stingless bees an edge over honeybees. Like Apis mellifera, S. depilis foragers moisten collected coffee pollen with nectar and pack it into their metatibial pollen baskets. But apparently they carry more free pollen grains incidentally attached to their bodies, and those loose grains are the ones most likely to be available for pollination as bees move from flower to flower. Add the fact that stingless bees lack a functional sting, posing less hazard to farm workers, and their well-developed colony management protocols, and the case for renting them out to coffee growers becomes compelling. Bee rental is already routine for apples and melons in Brazil, and the authors expect arabica coffee to follow the same trajectory.

But the study was designed to answer a second, more contentious question: does thiamethoxam, a neonicotinoid insecticide widely used against the coffee leaf miner and coffee leaf rust, harm stingless bee colonies under real farming conditions? Neonicotinoids are systemic, meaning they are absorbed by the treated plant and translocated to all organs, including nectar and pollen in flowers. Laboratory studies have documented lethal and sublethal effects on social bees, including impaired foraging, learning and memory, colony development and disease resistance. Yet field-realistic colony-level studies on stingless bees have been scarce, and most regulatory ecotoxicology relies on honeybees as the model species.

The researchers installed thiamethoxam-based products, Verdadero 600 WG and Actara 250 WG, by soil drenching during the berry expansion stage of the 2021 season, following label recommendations at field rates of 1 kilogram per hectare. Colonies were introduced the following season, roughly 10 to 18 days before coffee blooming in September and October 2022, so that residues from the previous application could be assessed. Three colony strength parameters were tracked according to international standardized protocols: brood production, counted in pre-provisioning and oviposition stages; brood mortality, calculated as the percentage of empty pupal cells; and foraging activity, counted as foragers leaving the colony during 3-minute observation windows. Measurements were taken before and after blooming and again at 45, 75 and 105 days post-exposure, spanning approximately three complete generations of stingless bees.

The residue analysis told a nuanced story. Using liquid chromatography tandem mass spectrometry, the team detected thiamethoxam and its metabolite clothianidin in all coffee leaves sampled at conventional farms, with leaf concentrations ranging from 0.0093 to 0.1071 milligrams per kilogram. Low but detectable residues also appeared in nectar and pollen stored within the stingless bee nests, generally below 0.02 milligrams per kilogram. At the two organic control farms, residues were below the limit of quantification. Critically, these levels sat well beneath thresholds known to affect honeybee colonies: continuous feeding with 100 parts per billion thiamethoxam for six weeks impaired colony development in prior research, with no adverse effects at 50 parts per billion and a no-observed-effect concentration of 37.5 parts per billion, roughly 1.8 to 2-fold higher than the residues found in the stingless bee food stores.

The colony health data matched the residue picture. Brood production and brood mortality were statistically indistinguishable between colonies on conventional and organic farms, with no significant interaction between farming system and sampling period. Foraging activity did differ between farm types, but the lower baseline activity at conventional farms was observed before coffee flowering began, before foragers had any exposure to coffee nectar or pollen, pointing instead to pre-existing differences in floral resource availability in the surrounding landscape. Both systems showed similar proportional increases in foraging activity once blooming started, and the temporary difference normalized in subsequent assessments. The authors argue that thiamethoxam exposure should not be considered the primary cause of the foraging difference, and that transient effects on foraging do not threaten colony viability when they recover without translating into brood impacts.

Why do laboratory findings of neonicotinoid harm so often fail to materialize in the field? The study explores several explanations. Coffee flowers remain open for only 3 to 4 days and open synchronously in brief but intense flowering periods driven by rainfall, which concentrates foraging into narrow windows and limits exposure duration. Stingless bees visit a wide array of flowering plants, mixing pollen and nectar from treated crops with resources from untreated plants and diluting residue levels. Applications made an average of 8 months before blooming, as the label requires, leave systemic residues on flowers very low, a pattern also seen in apple orchards where fall foliar sprays produced no detectable spring residues. Social bee colonies also possess recovery mechanisms and nutritional buffers that can compensate for some sublethal costs of losing foragers.

The implications ripple outward from the farm gate. Introducing stingless bee colonies gives farmers a direct method to increase coffee yield and generate sustainable profit, which the authors suggest can be invested in native forest restoration, creating a synergistic loop between agriculture and conservation. Brazil produces a record forecast of 178.7 million bags of coffee for 2025/26 across 2.25 million hectares, 82 percent of it arabica, so even modest pollination gains scale into enormous volumes. The study is among the first to combine a pollinator abundance manipulation with a higher-tier colony strength assessment for a non-Apis bee under field-realistic pesticide exposure, and the authors caution that different application timings or rates could yield different results. Still, the message is clear: with responsible label-compliant pesticide use, native stingless bees can markedly boost coffee production while remaining healthy themselves, offering a practical template for sustainable intensification in the tropics.

Subject of Research: Crop pollination and pesticide risk assessment in Brazilian arabica coffee

Article Title: Stingless bees in coffee: yield gains and assessing neonicotinoid impact

Article References: Ramos, J. D., Santos, G. S., dos Santos, C. F., De Oliveira Kaminski, T. S., Cione, A. P., Alves, D. A., Quenzer, F. C. L., Campbell, A. J., Pereira, A. M., Thompson, H., Martins de Queiroz, A. C., Bento, J. M. S., & Menezes, C. (2026). Stingless bees in coffee: yield gains and assessing neonicotinoid impact. Frontiers in Bee Science, 3, Article 1644205. https://doi.org/10.3389/frbee.2025.1644205

Image Credits: AI Generated

DOI: 10.3389/frbee.2025.1644205

Keywords: stingless bees, Scaptotrigona depilis, coffee pollination, Coffea arabica, thiamethoxam, neonicotinoids, clothianidin, colony strength, Brazil, sustainable agriculture, crop yield, pesticide residues

Between 2022 and 2023, researchers collected 35 field populations of B. tabaci from 18 major agricultural regions spanning the country, from the tropical vegetable fields of Sanya on Hainan Island to the northern plains of Inner Mongolia. The sampling covered crops as varied as eggplant, tomato, cucumber, chili pepper, sweet potato, and winter melon. Each population was subjected to laboratory bioassays against nine widely used insecticides representing six chemical classes: the biological pesticide abamectin, the neonicotinoids thiamethoxam and imidacloprid, the chloronicotinyl compound thiacloprid, the pyrethroids bifenthrin and deltamethrin, the ketoenol spirotetramat, the diamide cyantraniliprole, and the insect growth regulator pyriproxyfen. Crucially, the team tested adults, eggs, and nymphs separately, recognizing that susceptibility can differ dramatically across the whitefly’s life stages.

The methodology was rigorous and standardized. For adult bioassays, treated cotton leaf discs were placed on agar in small tubes, each receiving 40 to 50 field-collected adults, with mortality scored after 48 hours. Egg assays involved dipping leaves bearing freshly laid eggs into serial insecticide dilutions and counting unhatched embryos seven days later, while nymph assays used root-dipped cotton seedlings infested with synchronized second-instar nymphs, evaluated after two weeks. All results were compared against a laboratory-susceptible reference strain, originally collected in 2008 and never exposed to pesticides, allowing the calculation of resistance factors, the ratio of the field population’s lethal concentration to that of the susceptible baseline. Resistance was classified on a five-tier scale ranging from susceptible to very high, with resistance factors above 100 marking the most alarming category.

The good news first: abamectin remains a rare bright spot. Across 27 tested populations, adults were either fully susceptible or showed only low resistance, and several regions, including Sanya, Jinan, Hangzhou, Beijing, and Yuncheng, actually became more sensitive to the compound in 2023 than in 2022. This suggests that, when used appropriately, abamectin continues to deliver effective field control in China, a finding consistent with earlier nationwide monitoring from 2015 to 2021. In an era when many once-reliable insecticides are failing, the durability of this biological pesticide stands out.

The neonicotinoids tell a very different story. Resistance to imidacloprid ranged from a modest 1.79-fold to a staggering 255-fold in a Sanya population, with very high resistance also recorded in Yuncheng. Thiamethoxam resistance reached high levels in three populations, peaking at 71-fold, and thiacloprid resistance climbed to 140-fold in Sanya. Year-over-year comparisons revealed troubling upward trends in several regions, particularly in central and southern China, where median resistance factors for neonicotinoids exceeded 50. The authors attribute this escalation to prolonged and intensive use of these compounds, and note that cross-resistance mediated by metabolic detoxification enzymes, particularly cytochrome P450s and esterases, likely accelerates the problem. Continued reliance on neonicotinoids, they warn, risks eroding their long-term efficacy entirely.

Pyrethroid resistance presented a more mixed picture. Bifenthrin resistance remained low to moderate nationwide, peaking at around 16-fold, but deltamethrin resistance spanned an extraordinary range, from 2-fold to nearly 105-fold, with the highest value recorded in Yunnan’s Yuanmou region. Southwest China emerged as a pyrethroid hotspot, with median resistance factors exceeding 40. The researchers also compared molecular genotyping data with the bioassay phenotypes and found a crucial nuance: resistance-associated mutations alone do not fully determine phenotypic resistance. Some mutations appeared even in susceptible reference insects, indicating that genetic background, mutation frequency, and metabolic mechanisms all interact to shape real-world resistance. Molecular diagnostics, the authors conclude, must always be interpreted alongside bioassay data.

The newer chemistries, often promoted as solutions to resistance problems, showed their own warning signs. Egg-stage bioassays revealed consistently high resistance to spirotetramat, with resistance factors exceeding 300 in multiple populations and peaking at 357-fold in Suzhou, Anhui. Cyantraniliprole resistance was generally moderate, but a few populations displayed extreme values, with Hangzhou eggs showing a resistance factor above 4,000, and Tianjin above 2,000. Among nymphs, spirotetramat resistance reached 204-fold in Yueyang, while cyantraniliprole resistance peaked at 721-fold in Beijing in 2022, though it declined sharply the following year. Pyriproxyfen, an insect growth regulator used against whitefly nymphs since 1989, showed consistently high resistance across most monitored regions, with values up to 195-fold. The authors suggest that in some areas pyriproxyfen may no longer be suitable for whitefly control at all, a striking verdict for a compound with decades of market history.

Beneath the chemical story lies an evolutionary one. Genotyping of the ace1 acetylcholinesterase gene and the voltage-gated sodium channel gene revealed that resistance-associated alleles are already widespread. At the F331W locus, 15 of 18 populations were homozygous resistant, a legacy of more than 60 years of organophosphate exposure. The pyrethroid-linked mutations L925I and T929V were also common, often appearing as heterozygotes or mixed genotypes that signal ongoing selection and gene flow among populations. Equally significant was the species composition: of the 35 populations sampled, 31 were exclusively the Mediterranean (MED) cryptic species, with only four mixed MEAM1-MED populations, all from Sanya. MED, known for its superior insecticide tolerance and more efficient virus transmission, has essentially completed its displacement of MEAM1 across China, likely because it survives better under intensive neonicotinoid and pyriproxyfen spraying.

The virus dimension amplifies the concern. TYLCV, transmitted exclusively by B. tabaci, was detected in 10 of 11 tomato-derived populations, with infection rates exceeding 95 percent in nearly all of them. The virus also appeared in chili, cucumber, watermelon, and hami melon samples, though at more variable rates. Previous research has shown that TYLCV infection actually enhances MED survival and reproduction while shortening development time, creating a feedback loop in which the most insecticide-resistant vector is also the most efficient virus spreader. This dual threat, resistant insects and rampant virus, is precisely the scenario that integrated pest management programs are designed to prevent, and the study’s authors argue it demands coordinated action.

The path forward, the researchers emphasize, is resistance-informed and region-specific management. Because resistance profiles differ sharply across China’s cropping systems and climates, a one-size-fits-all spraying schedule is doomed to fail. Instead, they recommend rotating insecticides with distinct modes of action, selecting compounds according to the susceptibility of specific life stages, using molecular monitoring as an early-warning system for emerging resistance alleles, and pairing chemical control with virus suppression tactics such as removing infected plants, managing weed hosts, and reducing vector populations early in the crop cycle. Although the survey focused on China, the patterns it documents, rapid susceptibility shifts, strong regional selection pressures, immature-stage resistance, MED dominance, and widespread virus transmission, mirror challenges reported from Spain and Israel to Australia and Pakistan. Continuous surveillance, cross-regional data sharing, and adaptive management, the authors conclude, will be essential to curb further resistance escalation and protect agricultural productivity far beyond China’s borders.

Subject of Research: Nationwide monitoring of insecticide resistance, cryptic species composition, and TYLCV prevalence in Bemisia tabaci across China

Article Title: Nationwide spatiotemporal monitoring of insecticide resistance in Bemisia tabaci in China (2022–2023)

Article References: Yang, J., Li, Q., Zhang, Y., Ji, Y., Du, H., Guo, Z., Xie, W., Wang, S., Wu, Q., Zhang, Y., & Yang, X. (2026). Nationwide spatiotemporal monitoring of insecticide resistance in Bemisia tabaci in China (2022–2023). Journal of Agriculture and Food Research, 31, Article 103339. https://doi.org/10.1016/j.jafr.2026.103339

Image Credits: AI Generated

DOI: 10.1016/j.jafr.2026.103339

Keywords: Bemisia tabaci, insecticide resistance, whitefly, neonicotinoids, TYLCV, MED cryptic species, pyriproxyfen, spirotetramat, cyantraniliprole, resistance monitoring, integrated pest management, China

Neonicotinoids are systemic insecticides applied as coatings on crop seeds before planting. As the seed germinates and grows, the chemical is taken up into plant tissues, protecting the young seedling from chewing and sucking insects. But only a fraction of the active ingredient ends up inside the plant. The rest can persist in the soil, where it encounters an enormous community of microorganisms that drive nutrient cycling, decompose organic matter, and form partnerships with plant roots. While the impacts of neonicotinoids on insects and aquatic invertebrates have been studied extensively, their effects on soil fungal communities have remained surprisingly underexplored, a gap the new research set out to fill.

The team designed a controlled microcosm experiment in which soil was treated with three commonly applied neonicotinoids: imidacloprid, thiamethoxam, and clothianidin. These compounds represent the backbone of modern seed-treatment agriculture, coating millions of tonnes of seed annually across the world’s major cropping systems. By working in microcosms, the researchers could isolate the effect of each compound on the fungal community without the confounding noise of weather, cropping history, or management variation that complicates field studies. Soil samples were then collected at multiple time points after exposure, allowing the team to track not just whether the fungi responded, but when.

To profile the fungal communities, the researchers turned to amplicon sequencing of the internal transcribed spacer, or ITS, region of fungal DNA. The ITS region is the standard molecular barcode for fungi, allowing scientists to identify which fungal taxa are present in a soil sample even when those organisms cannot be cultured in the laboratory. This technique revealed hundreds of fungal taxa across the samples, spanning dominant phyla such as Ascomycota and Basidiomycota as well as rarer, more enigmatic lineages. Sequencing-based approaches like this have transformed microbial ecology in recent years, making it possible to detect subtle community shifts that would be invisible under a microscope.

One of the study’s most striking findings concerns timing. Overall diversity indices remained largely stable across the treatments when averaged over the whole experiment, which might initially suggest the fungicide exposure had little effect. But post-hoc comparisons told a different story: on day 10, fungal diversity dropped significantly under both imidacloprid and thiamethoxam exposure. This kind of delayed, transient response is exactly the sort of signal that single end-point sampling would miss. The lesson, the authors suggest, is that the ecological footprint of a pesticide cannot be judged from a single snapshot in time.

Beta diversity analysis, which measures how community composition differs between samples, reinforced this temporal picture. The researchers found significant effects of sampling day and, critically, a treatment-by-time interaction, meaning the fungal communities under different insecticide treatments did not simply follow the same trajectory. Instead, each compound appeared to push the community along its own path as the experiment unfolded. Such temporally variable responses complicate risk assessment, because a pesticide that looks benign in one week of a field season may produce measurable disruption in another.

Not all fungi responded equally. The dominant phyla, Ascomycota and Basidiomycota, which include many decomposers and plant-associated species, remained relatively stable throughout the experiment. But several less abundant phyla declined over time, including Mortierellomycota, Rozellomycota, and Olpidiomycota. These obscure-sounding groups are far from ecologically trivial. Mortierellomycota species are important decomposers and plant growth promoters, Rozellomycota comprises widespread intracellular parasites of other microorganisms, and Olpidiomycota includes fungi that can vector plant viruses. A decline in these rarer lineages may signal subtle erosion of functions that only become apparent when soil health degrades.

Perhaps the most consequential result came from functional guild analysis, which classifies fungi by their ecological roles rather than their taxonomy. Here the researchers found that clothianidin exposure drove an increase in saprotroph abundance, the fungi that break down dead organic matter, alongside a decrease in symbiotroph abundance, the fungi that live in mutually beneficial partnerships with plants. The most important symbiotrophs in agricultural soil are the arbuscular mycorrhizal fungi, which colonize crop roots and exchange soil nutrients for plant sugars. A shift away from symbiotrophs and toward saprotrophs could alter how nutrients flow through the soil food web, potentially affecting crop nutrition in ways that standard pesticide evaluations never measure.

Differential abundance analysis, a statistical technique for identifying which taxa increase or decrease under specific conditions, revealed that each compound left its own fingerprint on the community. Imidacloprid was associated exclusively with suppressed fungal biomarkers, meaning every taxon linked to this compound was depleted rather than enriched. Thiamethoxam induced both enriched and depleted taxa, suggesting a more mixed restructuring of the community. Clothianidin stood out as the most disruptive of the three, associated with the greatest number of discriminatory fungal biomarkers and accompanied by the increase in saprotrophs and reduction in symbiotrophs. The compound-specific nature of these responses suggests that treating all neonicotinoids as a single ecological hazard may obscure important differences among them.

The study, which was funded by the Australian National University and conducted with colleagues Julia F. Jasonsmith, Nilantha R. Hulugalle, and Craig L. Strong, carries implications well beyond the laboratory. As regulators and farmers weigh the costs and benefits of neonicotinoid seed treatments, fungal communities have rarely featured in the calculus, even though these organisms underpin soil fertility, carbon storage, and crop resilience. The authors argue that fungal community responses deserve a place in evaluations of the broader ecological effects of neonicotinoids, and they call for long-term, functionally oriented studies in real agroecosystem contexts. A ten-day microcosm can reveal the shape of a disturbance, but only sustained field research can determine whether these shifts persist, compound across seasons, or ultimately translate into measurable consequences for the crops that depend on the hidden life below ground.

Subject of Research: Effects of neonicotinoid seed treatments on soil fungal community diversity, composition, and function over time

Article Title: Fungal Responses to Neonicotinoid Seed Treatments in Soil: Temporal Shifts in Community Diversity and Composition

Article References: Akter, S., Jasonsmith, J. F., Hulugalle, N. R., & Strong, C. L. (2026). Fungal Responses to Neonicotinoid Seed Treatments in Soil: Temporal Shifts in Community Diversity and Composition. Microbial Ecology. https://doi.org/10.1007/s00248-026-02892-2

Image Credits: AI Generated

DOI: 10.1007/s00248-026-02892-2

Keywords: neonicotinoids, soil fungi, fungal diversity, imidacloprid, thiamethoxam, clothianidin, ITS amplicon sequencing, soil microbiome, temporal dynamics, saprotrophs, symbiotrophs, agroecosystems

The research team, led by scientists at the University of São Paulo and the University of Campinas in Brazil, set out to answer a question that has lingered in ecotoxicology for years. Plastic debris floating in rivers and lakes is not a static pollutant. Sunlight, heat, and oxygen steadily break polymer chains apart, and this weathering alters everything about the particle, from its surface chemistry to its roughness and its appetite for other contaminants. Yet most laboratory toxicity studies still rely on pristine, factory-fresh plastic, potentially painting a misleading picture of what actually drifts through natural waters.

To simulate years of environmental exposure in the laboratory, the researchers bombarded commercial polyethylene microparticles with UV-C radiation for 94 days in an accelerated aging chamber, a dose they calculated to be equivalent to roughly 643 days of natural sunlight. The transformation was striking. Scanning electron microscopy showed that smooth, homogeneous particles emerged covered in cracks, cavities, and pitted surfaces, evidence of a progressively weakening polymer matrix. Fourier-transform infrared spectroscopy confirmed the chemical counterpart of this physical decay: new absorption bands at 1710 and 1181 inverse centimeters revealed the formation of carbonyl and carbon-oxygen groups, the classic fingerprints of polyethylene photo-oxidation.

These chemical changes matter far beyond materials science. Oxygenated functional groups make the plastic surface more polar and more reactive, increasing its capacity to adsorb organic pollutants such as pesticides. The aging process also nudged the particle size distribution upward slightly, with degraded particles averaging 30 micrometers compared with 27 for pristine ones, and produced a more porous structure that could offer additional binding sites for dissolved chemicals. In other words, every day a plastic particle spends in the sun converts it into a more chemically active platform for carrying other contaminants into the food web.

The ecotoxicological centerpiece of the study was the water flea Daphnia similis, a tiny filter-feeding crustacean and a standard sentinel of freshwater health. In 21-day chronic exposure tests conducted under OECD guidelines, control animals thrived, with 90 percent survival and healthy production of around 66 offspring per female. But exposure to pristine polyethylene microplastics proved unexpectedly lethal. At 80 milligrams per liter, mortality reached 90 percent, and at 140 milligrams per liter it reached 70 percent, concentrations the authors note correspond to just a few times the highest levels of microplastics reported in natural freshwaters.

Curiously, the dose-response was not neatly linear, with the strongest lethal effect appearing at the intermediate concentration rather than the highest one. The researchers attribute the mortality to physical mechanisms: daphnids readily ingest particles in this size range, and accumulated microplastics can create a false sense of satiety, starve the animals of real nutrition, abrade the gut lining, and even impair oxygen diffusion through the filtering apparatus. The observed particles were also smaller on average than the manufacturer’s specification, and prior work suggests finer particles are substantially more harmful to daphnids than larger ones.

Photodegraded particles told a different and arguably more insidious story. While they killed fewer animals outright, they delivered sharper sublethal blows, particularly to reproduction. At 140 milligrams per liter, aged microplastics cut neonate production by nearly 70 percent. Reproduction is the demographic engine of any population, and a generation of daphnids that fails to replace itself cannot sustain the base of freshwater food webs that fish and other predators depend upon. The study demonstrates that the toxicity profile of a microplastic particle is not fixed; it is rewritten by every hour of sunlight it absorbs.

The most provocative results emerged when imidacloprid entered the picture. This neonicotinoid insecticide, which acts on the nervous systems of insects by overstimulating nicotinic acetylcholine receptors, is highly water soluble, persistent to hydrolysis, and routinely detected in surface waters worldwide at concentrations ranging from nanograms to hundreds of micrograms per liter. Because polyethylene is known to adsorb imidacloprid efficiently, the researchers expected the plastic to act as a vector, concentrating the pesticide and amplifying its harm.

Instead, the mixture data revealed an antagonistic interaction. In combination with 1.5 milligrams per liter of imidacloprid, pristine microplastics caused no lethal effects at any concentration, and a model deviation ratio analysis confirmed that the observed toxicity at 80 and 140 milligrams per liter fell significantly below what additive behavior would predict. The likely explanation lies in feeding behavior: daphnid feeding depends on the rhythmic beating of filtering appendages under nervous control, and imidacloprid’s neurotoxic action disrupts this neuromotor coordination. Animals exposed to the insecticide simply ingest fewer plastic particles, indirectly shielding them from the plastic’s physical harms, even as reproduction still dropped by up to 75.7 percent in some mixture treatments.

The authors caution that this apparent mercy is temporary. Previous research shows that prolonged imidacloprid exposure starves daphnids by suppressing feeding until energy reserves are exhausted, and the long-term ecological cost of a contaminated, underfed zooplankton community could be severe. Meanwhile, mixtures involving photodegraded particles followed a largely additive pattern, with progressive, dose-dependent reproductive losses up to fourfold below controls, likely reflecting hydrogen bonding between the polymer’s new oxygenated groups and the insecticide’s amine moieties. Taken together, the study delivers a clear message for regulators and risk assessors: the ecological risk of microplastics cannot be evaluated in isolation from their weathering state or their chemical traveling companions, and realistic assessments must embrace chronic exposures, aged materials, and contaminant mixtures if they are to protect the integrity of freshwater ecosystems.

Subject of Research: Photodegradation of polyethylene microplastics and its combined chronic toxicity with the insecticide imidacloprid to the freshwater cladoceran Daphnia similis

Article Title: Integrated Study of Polyethylene Microplastic Degradation and Its Interaction with the Insecticide Imidacloprid: Chronic Toxicity to Daphnia similis

Article References: Kiihl, M. E., da Silva Pinto, T. J., Dias, M. A., Montagner, C. C., Espíndola, E. L. G., & Alexandre, D. S. (2026). Integrated Study of Polyethylene Microplastic Degradation and Its Interaction with the Insecticide Imidacloprid: Chronic Toxicity to Daphnia similis. Archives of Environmental Contamination and Toxicology, 91(2), Article 16. https://doi.org/10.1007/s00244-026-01213-5

Image Credits: AI Generated

DOI: 10.1007/s00244-026-01213-5

Keywords: microplastics, polyethylene, photodegradation, imidacloprid, Daphnia similis, freshwater ecotoxicology, chronic toxicity, contaminant mixtures, UV aging, reproduction, neonicotinoids, water pollution