A new study published in Nota Lepidopterologica by entomologist Enrique García-Barros of the Universidad Autónoma de Madrid tackles this mismatch head-on, and the results overturn a long-standing assumption. The best single predictors of dry body weight in adult male moths and butterflies turn out to be thorax length, total body length and head width — none of which is among the popular descriptors of size in this insect order. Forewing length, the metric most often published, is well correlated with body weight but is not the best linear predictor. The finding matters because researchers who want to estimate body mass from published descriptions have been working with suboptimal tools.

The scale of the new dataset is what gives the study its statistical muscle. García-Barros weighed and photographed 5,341 adult male specimens representing 2,645 species, a seven-fold increase in species sampling compared with his own earlier attempt published in 2015. Each insect was dried to constant weight at 70 degrees Celsius for 24 to 72 hours to obtain dry body weight in milligrams, then re-moistened, spread and digitized together with a metric scale. Thirteen linear measurements were taken from the digitized images using ImageJ, covering the head, thorax, abdomen, forewing, hindwing and two alternative estimates of wingspan. The largest part of the sample was deposited in the collections of the Madrid Natural History Museum, with vouchers of the Tortricidae held in Valencia.

The range of body masses covered is extraordinary. The lightest species, some Nepticulidae and Heliozelidae, weighed between 0.04 and 0.05 milligrams, and the study suggests that the tiniest known leaf-mining moths with forewings of just 1.2 to 1.3 millimeters would come in at roughly 0.017 to 0.020 milligrams. At the other extreme, some tropical Cossidae such as Xyleutes persona exceeded three grams — 3,000 milligrams — of dry weight. That means male dry body weight in known Lepidoptera spans five orders of magnitude, while forewing length spans only three. The allometric exponents recovered from the bivariate regressions fell between 1.92 and 2.96, exactly what length-to-volume scaling predicts, and every linear measurement correlated with dry body weight at R above 0.97 on logarithmically transformed values.

Eight multivariate regression models were fitted to the log-transformed species means, reflecting different combinations of measurements a researcher might realistically have available. The most complex models, based on five to seven body measurements, predicted dry body weight most accurately, with adjusted R-squared values of 0.980 and the lowest cross-validation errors. Models combining wingspan with body length performed reasonably but suboptimally, and simple models based on forewing length alone or wingspan alone were acceptable but clearly inferior. The author recommends two models in particular: one combining head width, thorax length and width, abdomen length and width, forewing length and forewing width, and another built on forewing length as the primary predictor with the residuals of the remaining variables added as supplementary terms — the latter having the advantage of near-complete linear independence among its predictors.

One of the study’s most technically interesting results concerns collinearity. Whenever more than one variable entered a regression model, the variance inflation factor climbed well above the threshold of 4 to 10 generally identified as excessive — with a single exception, the residual-based model 8, which kept minimum VIF at 1.00. High collinearity carries the risk of overprediction: species with unusual body plans not covered by the dataset could receive wildly inaccurate weight estimates. Variance partitioning of the regression residuals showed that most of the unexplained variation was attributable to morphology rather than phylogeny — the pure phylogenetic effect was virtually negligible, roughly a ten-fold smaller contribution than the shared morphology-phylogeny effect. This suggests the best models may be stable and reliable for prediction, provided the species being predicted falls within the morphological range the dataset covers.

The study also tested taxon-by-taxon approaches, fitting separate regressions for families and superfamilies, and ANCOVA-based methods that assign family-level coefficients to intercepts and slopes. The results were sobering. In the butterflies, an instructive example, three families — Lycaenidae, Riodinidae and Nymphalidae — proved homogeneous for slope and intercept, but all six families differed significantly from each other in intercept, slope, or both. That means a single family-level equation risks systematically overestimating the weight of some species and underestimating others. Because the phylogenetic structure in the residuals was so weak, García-Barros argues that clustering species on morphological grounds rather than taxonomic ones would be far preferable — a conclusion with implications for anyone building order-wide reference equations.

Two practical extensions round out the work. A limited sample of females from 362 species revealed a nearly isometric relationship between male and female dry body weight, described by the equation female DBw = 0.1574 + 0.9770(male DBw) with an adjusted R-squared of 0.953 — a clear-cut result, though the author cautions that evidence from other studies shows this relationship is not uniform across all moth and butterfly families. A subset of field-caught Spanish males, frozen shortly after capture and weighed within 24 hours, established that fresh body weight scales to dry weight with a slope close to isometry and that dry weight accounts for about 38 percent of live weight — a water content squarely within the typical range for adult insects. These conversions let field researchers translate predicted dry masses into approximate live weights, at some cost in accuracy.

The optimistic and pessimistic readings of the study are both on offer, and García-Barros presents them honestly. The pessimistic view notes that the sample represents barely more than 2 percent of described Lepidoptera species, most species contributed only one to three individuals, and female data are scarce. Yet the optimistic view is compelling: the seven-fold increase in species sampling raised the fit of the best model by merely 1 percent, suggesting that the broad morphological variation across the order is redundant enough for multivariate prediction to work well. The full dataset has been made openly available through the Dryad Data Repository, and the author argues that in the face of global change and documented insect biomass declines, publishing more standardized body size data on moths and butterflies should be actively encouraged. For a hyper-diverse group whose masses span five orders of magnitude, a ruler and the right equation may now be all that stands between a museum specimen and a usable number.

Subject of Research: A multivariate regression study of 2,645 Lepidoptera species refines estimates of adult dry body weight from thirteen linear measurements, showing that combinations of body and wing metrics outperform traditional size descriptors.

Article Title: Refining estimates of dry body weight from linear measurements in adult moths and butterflies ( Lepidoptera )

Article References: García-Barros, E. (2025). Refining estimates of dry body weight from linear measurements in adult moths and butterflies (Lepidoptera). Nota Lepidopterologica, 48, 165-184. https://doi.org/10.3897/nl.48.144747

Image Credits: AI Generated

DOI: 10.3897/nl.48.144747

Keywords: Lepidoptera, body size, allometry, dry body weight, insect ecology, moths, butterflies, morphometrics, Refining, estimates, body, weight

The research team, led by Jingwei Hou and Yong Geng, applied dynamic material flow analysis (dMFA), a mass-conservation accounting framework that tracks every tonne of a substance through extraction, refining, manufacturing, use, and disposal. Their system boundary covered mainland China and divided the boron industry chain into seven stages: mining and beneficiation, refining and separation, smelting, fabrication, manufacture, use, and waste management and recycling. Thirty-eight boron-containing commodities were tracked, with trade data drawn from China Customs Yearbooks and the UN Comtrade database, production statistics from the U.S. Geological Survey and the CBC Metal database, and process parameters validated through field visits to major producers and ten face-to-face interviews with industry executives and technical personnel.

The methodological machinery is considerable. Process flows were calculated by multiplying production quantities by boron concentrations, losses were applied at each stage using documented loss rates, and the accumulation and retirement of boron in products was modeled with a Weibull probability distribution, the standard statistical tool for describing how products fail and exit service over time. To test robustness, the team ran a Monte Carlo simulation with 10,000 iterations, assigning coefficients of variation of 5 percent to reliable official statistics and 10 percent to literature-derived parameters. The results showed uncertainty below 5 percent for imports, exports, and consumption, and 13 to 19 percent for end-of-life flows, narrow enough that the study’s central conclusions hold firm.

The headline numbers are sobering. Over the twenty-year period, net imported boron at the mining and refining stages reached 2,784 kilotonnes, while domestic extraction contributed only 1,026.7 kilotonnes. China’s reserves, ranked fifth globally at 9.1 million tonnes of boron trioxide equivalent, are concentrated in Qinghai and Liaoning provinces but suffer from low ore grades that make domestic mining economically punishing. Turkey, which holds 950 million tonnes of reserves, dominates the global market and supplied roughly half of China’s total boron imports, with borax, boron ores, boric acid, and boron oxides making up 99.5 percent of that bilateral trade. Such concentration in a single supplier exposes China to geopolitical, trade-policy, and natural-disaster risks.

Consumption tells its own story of transformation. Annual boron use climbed from 41.3 kilotonnes in 2004 to a peak of 161.8 kilotonnes in 2021, before easing to 94.6 kilotonnes in 2023 as upstream mining constraints bit. Glass, ceramics, and enamel products consistently absorbed more than 40 percent of total consumption, with the chemical industry, spanning disinfectants, flame retardants, and catalysts, taking another 24 percent. But the fastest growth came from emerging technologies: by 2020, new energy vehicles and batteries accounted for over 4 percent and 8 percent of consumption respectively, a share that seemed set to expand before supply bottlenecks curtailed it.

The losses along the chain are enormous. Refining borax generates roughly four tonnes of boron mud for every tonne of product, and China discharges about two million tonnes of this waste annually, with boron content of only 0.76 percent. Across the full period, total boron losses reached 1,757.1 kilotonnes, while just 24 kilotonnes were recycled, an overall recycling rate of approximately 1.37 percent. Chemical extraction from boron mud requires acid leaching with high reagent and energy costs and risks secondary pollution, so most recovery involves low-value physical processes such as sintering the mud into construction materials. By contrast, Turkey recovers more than 90 percent of boron from industrial wastes, a benchmark the authors argue China should urgently study.

Meanwhile, an invisible reservoir is quietly building. In-use boron stocks, the element embedded in products currently serving society, nearly doubled during the second decade of the study, rising from 502.5 kilotonnes in 2014 to 966.8 kilotonnes in 2023. Glass, ceramics, and enamel dominate this urban mine at 664.2 kilotonnes, followed by batteries, which grew from 25.7 to 68.7 kilotonnes over the decade, earthmoving machinery, glazed tiles, and aircraft. End-of-life flows, delayed by the roughly 16.5-year average lifespan of boron-containing products, entered rapid growth in the 2010s and reached 31 kilotonnes in 2023, signaling a secondary resource stream that current infrastructure is not equipped to capture.

The trade structure reveals a low-value trap. China imported 2,955.2 kilotonnes of boron over the period, dominated by raw and intermediate materials, then exported 1,257.4 kilotonnes of finished products, chiefly glass and ceramics, glazes, and boron steel, to 225 countries and regions, with Indonesia the largest buyer. Fabrication losses ran at roughly 20 percent, and the authors conclude that the whole boron industry chain remains low-value oriented, generating thin profits while imposing heavy environmental pressure. High-end products such as boron carbide, boron nitride, and rare earth borides are still largely manufactured in developed countries, and Chinese enterprises struggle to achieve large-scale production of these materials essential for energy, defense, and nuclear applications.

The policy prescriptions are concrete. The authors call for increased research and development investment and university-industry cooperation to crack the technological bottlenecks in high-end boron products and boron mud valorization, including promising but unconfirmed routes such as converting the waste into nuclear radiation shielding materials or fertilizers. They recommend a national boron information platform, national standards requiring retired boron-containing products to reach designated disassembly stations, and financial support for recycling enterprises. On supply security, they point to diversification through Chile, Russia, Peru, Argentina, Bolivia, and Kazakhstan, countries aligned with China’s Belt and Road frameworks and recent green minerals cooperation agreements. Economic instruments, including differentiated resource taxes tied to ore recovery rates, carbon taxes on energy-intensive operations, emission fees, and green labeling, round out the governance agenda.

What makes this study resonate beyond China is the method itself. dMFA has previously illuminated the metabolism of steel, aluminum, copper, rare earths, and dozens of critical metals, but boron, a nonmetallic critical material with extreme import dependence, had never received this treatment at national scale. As the world’s clean energy transition accelerates demand for every element that hardens steel, toughens glass, and steadies neutrons, the study warns that a country can dominate manufacturing yet remain dangerously exposed at the raw material frontier, and that the urban mines accumulating in its cities, currently leaking 790.7 kilotonnes of boron into the environment as waste, represent both an untapped opportunity and an unaddressed environmental burden.

Subject of Research: Dynamic material flow analysis of boron flows, stocks, trade, and recycling in China from 2004 to 2023

Article Title: Uncovering the features of boron flows and stocks in China

Article References: Hou, J., Geng, Y., Zhong, C., Gao, Z., & Liu, S. (2026). Uncovering the features of boron flows and stocks in China. Environmental Challenges, 25, Article 101675. https://doi.org/10.1016/j.envc.2026.101675

Image Credits: AI Generated

DOI: 10.1016/j.envc.2026.101675

Keywords: boron, material flow analysis, China, critical materials, recycling, supply chain, boron mud, in-use stocks, Turkey, import dependence, urban mining, resource policy

The letter, written by Nashmia Faraz, Haider Imran and Abdul Basit of the Department of Medicine at Foundation University Medical College in Islamabad, Pakistan, takes aim at the gap between objective and subjective measures of adherence in oral appliance therapy. Published in September 2026, the correspondence responds to emerging longitudinal evidence on how adults with obstructive sleep apnea actually use their appliances over a full year, and it argues that the field must refine how adherence is defined, measured and interpreted before the therapy’s real-world effectiveness can be judged fairly.

The concern is not academic hair-splitting. An oral appliance that sits in a drawer delivers no therapeutic benefit, no matter how well it was designed or how effectively it advanced the jaw in a laboratory titration study. Adherence is the hinge on which the entire treatment turns. For CPAP, this lesson was learned early and painfully: studies famously showed that early patterns of use in the first days and weeks strongly predicted long-term adherence, prompting sleep medicine to invest heavily in objective compliance monitoring, telehealth coaching and early intervention programs. Modern CPAP machines log every hour of use, and those data streams are now woven into routine care. Oral appliance therapy, by contrast, has largely depended on what patients report at follow-up visits.

Self-report is a notoriously fragile foundation for clinical decisions. Patients may genuinely believe they wear their devices more than they do, because nights of fragmented sleep blur memory and because social desirability nudges people toward the answers they think their clinicians want to hear. The literature cited in the letter makes the scale of the discrepancy unmistakable. A landmark 2013 study published in Chest by Dieltjens and colleagues compared objectively measured compliance, captured by embedded microsensors, with self-reported compliance among patients using mandibular advancement devices for sleep-disordered breathing. The objective data revealed substantially lower usage than patients reported, exposing a gap large enough to distort outcome studies, cost-effectiveness analyses and clinical audit alike.

Embedded microsensors have since become the technical benchmark for objective adherence measurement in oral appliance therapy. These tiny temperature-sensitive chips sit inside the appliance and register when the device is actually in the mouth, distinguishing genuine use from mere possession. When the appliance is inserted, oral temperature triggers the sensor; when it rests on a bedside table, no temperature change is recorded. The approach mirrors the objective compliance chips that transformed CPAP monitoring, and it offers sleep medicine something it has long lacked for dental devices: a truthful, time-stamped record of real-world use patterns, including how many nights per week the appliance is worn and for how many hours per night.

The new longitudinal pilot data that prompted the letter tracked both objective and subjective adherence in adults with obstructive sleep apnea over one year, providing a rare window into how usage evolves well beyond the initial adaptation period. The corresponding letter argues that such data should push the field toward a more nuanced adherence framework, one that distinguishes between objective device use, patient-perceived use and clinical response, rather than collapsing them into a single self-reported figure. The authors, who conceptualized and drafted the correspondence with no external funding and no competing interests, position their contribution as a call to tighten the methodological standards of oral appliance research.

Why does this refinement matter now? Oral appliance therapy is expanding rapidly. Clinical guidelines recommend it for patients with mild to moderate obstructive sleep apnea and for those with severe disease who cannot tolerate or decline CPAP. Dental sleep medicine has grown into a distinct subspecialty, and the global market for mandibular advancement devices continues to climb as obesity rates and disease prevalence rise. Every prescription implicitly assumes that the device will be worn consistently. If adherence measurement lags behind prescription volume, the field risks both overtreatment, with devices dispensed to patients who will never use them, and undertreatment, with genuine adherence problems overlooked until symptoms return or cardiovascular risk quietly accumulates.

The letter also draws an instructive parallel with the CPAP literature, including the 2007 study by Budhiraja and colleagues in the journal Sleep demonstrating that early CPAP use identified subsequent long-term adherence. That finding reshaped clinical practice, motivating early follow-up and, eventually, remote monitoring programs that flag struggling patients within days. For oral appliances, the analogous evidence base is younger and thinner, but studies such as the 2022 investigation by Kwon and colleagues in the Journal of Sleep Research show that remote monitoring and structured feedback can measurably improve objective compliance with mandibular advancement devices. Together, these strands of evidence suggest that objective adherence measurement is not merely a research nicety; it is the enabling technology for the same kind of proactive, data-driven care that rescued CPAP adherence a generation ago.

The technical challenges, however, are real. Microsensor data must be validated against true wear events, sensors can fail or be damaged during cleaning, and different sensor generations may not produce comparable metrics. The field lacks universally accepted adherence thresholds for oral appliances, whereas CPAP benefited from widely used conventions such as the Medicare definition of four hours per night on seventy percent of nights, itself a contested standard. Without consensus definitions, meta-analyses of appliance effectiveness will continue to mix studies whose adherence figures mean different things, blurring genuine differences in therapeutic efficacy with differences in measurement practice. The authors of the letter imply that resolving this definitional tangle is a prerequisite for the next generation of oral appliance research.

What would refined adherence assessment look like in practice? The ingredients are already on the table: objective sensor-derived metrics reporting nights and hours of use, patient-reported measures captured with validated questionnaires, and clinical outcomes such as the apnea-hypopnea index on follow-up polysomnography or home testing. Longitudinal designs, like the one-year pilot study that sparked the correspondence, add the crucial temporal dimension, revealing whether adherence decays over months and which patients are at greatest risk of abandoning therapy. Integrating these data streams into electronic health records and telemedicine platforms could finally give dental sleep medicine the feedback loops that clinicians need, allowing early, targeted interventions before non-adherence becomes entrenched. As oral appliance therapy takes its place alongside CPAP in mainstream sleep medicine, the message from Islamabad is clear: the therapy can only be as good as the evidence that patients are actually using it, and measuring that use honestly is the field’s next essential task.

Subject of Research: Objective versus subjective adherence assessment in oral appliance therapy for obstructive sleep apnea

Article Title: Refining adherence assessment in oral appliance therapy for obstructive sleep apnea

Article References: Faraz, N., Imran, H., & Basit, A. (2026). Refining adherence assessment in oral appliance therapy for obstructive sleep apnea. Journal of Clinical Sleep Medicine, 22(1), Article 158. https://doi.org/10.1007/s44470-026-00176-7

Image Credits: AI Generated

DOI: 10.1007/s44470-026-00176-7

Keywords: obstructive sleep apnea, oral appliance therapy, mandibular advancement device, adherence measurement, microsensors, CPAP, sleep medicine, self-reported compliance, remote monitoring, dental sleep medicine, Journal of Clinical Sleep Medicine, Refining