{"title":"From individual thresholds to collective hysteresis: a mechanistic model of the dawn chorus.","authors":"Alexander R Kaye","doi":"10.1098/rsif.2026.0267","DOIUrl":"10.1098/rsif.2026.0267","url":null,"abstract":"<p><p>At dawn, many bird communities exhibit a rapid and highly synchronous transition from silence to vocal activity. Although light levels increase gradually, the onset of this dawn chorus can appear abrupt, suggesting the possibility of tipping behaviour. While such dynamics are frequently described using catastrophe theory, direct mechanistic links between individual behavioural rules and macroscopic bifurcation structure remain limited. We develop a stochastic threshold model for this phenomenon in which each individual sings when a combination of light and social stimulation exceeds its activation threshold. Under mean-field scaling, the population dynamics converge to a deterministic equation for the proportion of singing individuals, with nonlinearity determined entirely by the cumulative distribution of thresholds. We show that for a broad class of threshold distributions, this system exhibits cusp bifurcations and hysteresis. Thus, the abrupt onset of singing can emerge directly from heterogeneity and social feedback, without imposing nonlinearities at the population level. Extending the model to spatially structured populations yields travelling waves, providing an explanation for the spatial variation of song across a landscape. Our results demonstrate how heterogeneity in behavioural thresholds can generate hysteresis in socially coupled populations, offering a general framework for linking individual decision rules to emergent ecological transitions.</p>","PeriodicalId":17488,"journal":{"name":"Journal of The Royal Society Interface","volume":"23 240","pages":""},"PeriodicalIF":3.4,"publicationDate":"2026-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148604368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Kalman-filter force inference: an estimation framework for cellular forces from temporal evolution of epithelial morphogenesis.","authors":"Goshi Ogita, Takemasa Miyoshi, Tatsuo Shibata","doi":"10.1098/rsif.2026.0017","DOIUrl":"10.1098/rsif.2026.0017","url":null,"abstract":"<p><p>Epithelial morphogenesis is orchestrated by cellular forces, including cell junctional tension and cellular pressure. Elucidating their spatio-temporal dynamics is paramount for understanding morphogenesis during development. While various methods have been proposed to infer cellular forces from the shape and geometry of cells within epithelial tissues, most rely on the assumption of static force balance, which neglects cell deformation, thereby limiting their applicability to tissues undergoing dynamic deformation. To address this, we develop a novel method to accurately infer cellular forces from time-lapse imaging data by explicitly accounting for tissue dynamics. Our method rests on two fundamental assumptions. First, cellular forces balance dissipative forces (viscous and frictional forces) arising from cell deformation, termed the dynamic force balance. Second, cellular forces evolve smoothly. A Bayesian formalization of these assumptions yields a new force inference approach: Kalman-filter force inference. We evaluated our method using synthetic data from cell vertex model simulations. The results demonstrated accurate estimation of cellular force dynamics across diverse cell mechanical parameters. Furthermore, the method proved robust to observation noise. Our method will broaden the applicability of force inference and provide new insights into the mechanical principles underlying epithelial morphogenesis.</p>","PeriodicalId":17488,"journal":{"name":"Journal of The Royal Society Interface","volume":"23 240","pages":""},"PeriodicalIF":3.4,"publicationDate":"2026-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148604495","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A mathematical model for inflammation and demyelination in multiple sclerosis.","authors":"Adrianne Jenner, Georgia Weatherley, Federico Frascoli","doi":"10.1098/rsif.2026.0364","DOIUrl":"10.1098/rsif.2026.0364","url":null,"abstract":"<p><p>Multiple sclerosis (MS) is an incurable, life-long disease caused by the demyelination of neurons in the brain and spine. MS is often characterized by relapses in inflammation and demyelination, followed by periods of remission. Symptoms can be highly debilitating, and there are still many open questions about the origin and progression of the disease. Mathematical modelling is well placed to capture the dynamics of MS and provide insight into disease aetiology. In this work, we present a minimal model for MS disease onset and progression driven by inflammation and demyelination. The model dynamics are capable of describing a typical evolution of the illness, with changes from a healthy state to a diseased scenario captured by certain ranges of parameter values. Our model also describes the non-uniform oscillatory nature of the disease, born from a Hopf bifurcation owing to the strength of the inflammatory response. In particular, using experimental data for contrast-enhancing lesions obtained from MS patients, we can reproduce some of the typical relapsing-remitting behaviours of this disease. We hope that the model presented here can serve as a baseline for more complex approaches and as a tool for predicting possible evolutions of the disease.</p>","PeriodicalId":17488,"journal":{"name":"Journal of The Royal Society Interface","volume":"23 240","pages":""},"PeriodicalIF":3.4,"publicationDate":"2026-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148549400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kirill Kavokin, Julia Bojarinova, Dmitriy Sannikov, Roman Cherbunin, Alexander Pakhomov, Alexandra Fedorishcheva, Nikita Chernetsov
{"title":"Disruption of magnetic orientation in migratory songbirds by radiofrequency magnetic fields is mediated by a specialized sensory system.","authors":"Kirill Kavokin, Julia Bojarinova, Dmitriy Sannikov, Roman Cherbunin, Alexander Pakhomov, Alexandra Fedorishcheva, Nikita Chernetsov","doi":"10.1098/rsif.2026.0129","DOIUrl":"10.1098/rsif.2026.0129","url":null,"abstract":"<p><p>Direction finding in migratory birds is known to be affected by oscillating magnetic fields (OMFs) in the radiofrequency range. This experimental fact was earlier interpreted in terms of the direct influence of OMFs on electron spins in the molecule of cryptochrome that, according to the photochemical model of magnetoreception, serves as the primary sensor of the geomagnetic field. In our experiments, birds (pied flycatchers) were subjected to OMFs with carrier frequencies of 1.41 and 1.5 MHz with the square wave amplitude modulation at 500 Hz. The modulated OMF, having twice less mean power than that without modulation, nevertheless caused disorientation at a lower amplitude of the carrier wave than the unmodulated OMF. Since the prediction of the photochemical theory is exactly the opposite, we conclude that the effect of OMFs on the magnetic orientation of birds is not related to the decoherence of electron spins in cryptochrome. Instead, we suggest that OMFs are perceived by a separate sensory system, most likely based on electromagnetic induction. This hypothetic sensory system, specialized at the detection of magnetic perturbations caused by solar flares or thunderstorms, might react to shape rather than to the mean power of the detected signal, which would explain its higher sensitivity to modulated OMFs.</p>","PeriodicalId":17488,"journal":{"name":"Journal of The Royal Society Interface","volume":"23 240","pages":""},"PeriodicalIF":3.4,"publicationDate":"2026-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148549402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tetsuhiro S Hatakeyama, Kunihiko Kaneko, Kunihiro Ohta, Arisa H Oda
{"title":"Evolvability of the toxin-adaptation system in yeast.","authors":"Tetsuhiro S Hatakeyama, Kunihiko Kaneko, Kunihiro Ohta, Arisa H Oda","doi":"10.1098/rsif.2026.0345","DOIUrl":"10.1098/rsif.2026.0345","url":null,"abstract":"<p><p>Crises such as starvation pose a serious threat to microbial populations, prompting cells to adopt survival strategies, such as cooperation or competition. Although cooperation among clones is common, recent studies have shown that yeast cells can kill clonal cells under glucose depletion by secreting autotoxins. Adapted cells survive, whereas non-adapted latecomers are eliminated. Remarkably, this toxin-adaptation (TA) system, which uses the same set of autotoxins, is conserved across distantly related yeast species. This is puzzling because conventional toxin-immunity (TI) systems are prone to exploitation by 'cheaters', cells that benefit from immunity without producing toxins, and typically diverge in an evolutionary arms race. To investigate how this system is maintained, we analysed its evolutionary stability using population dynamics modelling. The system does not evolve in constant environments: cheaters outcompete adaptive cells during continuous starvation, while sensitive cells that produce neither toxin nor immunity dominate in continuous nutrient-rich conditions. However, when the environment switches stochastically between starvation and nutrient-rich phases, with short starvation periods and long nutrient-rich periods, the TA system becomes evolutionarily stable. These findings suggest that fluctuating environments can promote the emergence and long-term maintenance of the TA system, highlighting the critical role of environmental switching in shaping microbial survival strategies.</p>","PeriodicalId":17488,"journal":{"name":"Journal of The Royal Society Interface","volume":"23 240","pages":""},"PeriodicalIF":3.4,"publicationDate":"2026-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148549426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Olga V Konevtsova, Dmitrii V Chalin, Aleksey S Roshal, Sergei B Rochal
{"title":"Non-viral protein shells with octahedral and tetrahedral symmetries and a theory of critical density waves.","authors":"Olga V Konevtsova, Dmitrii V Chalin, Aleksey S Roshal, Sergei B Rochal","doi":"10.1098/rsif.2025.1202","DOIUrl":"10.1098/rsif.2025.1202","url":null,"abstract":"<p><p>Unlike viral capsids, which protect and transport genetic material, non-viral protein shells perform diverse biological functions, including enzymatic catalysis, iron storage and protein chaperone activity. These shells often exhibit tetrahedral (T) and octahedral (O) point group symmetries, and their structures can include four- and even eightfold capsomers that are absent in viral capsids. Here, to rationalize the design of such nanocages, we develop a phenomenological theory based on the approach of critical density waves (DWs). We consider these spherical proteinaceous structures to be the result of condensation of one or two irreducible spherical DWs with close wavenumbers and place individual proteins (or capsomers) at the maxima of interference patterns generated by these waves. By examining the structures presented in the protein data bank (PDB), we identify 22 structural types of shells well rationalized within the theory and discuss the principles controlling protein order. In particular, we explain why these assemblies often possess local quasicrystalline order and predict the structures of yet unknown shells with cubic symmetries. The results obtained offer valuable insights into the rational design of stable, functional protein nanocages.</p>","PeriodicalId":17488,"journal":{"name":"Journal of The Royal Society Interface","volume":"23 240","pages":""},"PeriodicalIF":3.4,"publicationDate":"2026-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148549630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"IC2: interventional dynamical causality under latent confounders.","authors":"Jinling Yan, Shao-Wu Zhang, Jifan Shi, Chihao Zhang, Luonan Chen","doi":"10.1098/rsif.2025.1289","DOIUrl":"10.1098/rsif.2025.1289","url":null,"abstract":"<p><p>Understanding causality is central to scientific discovery, importantly enabling the elucidation of mechanisms within complex systems. However, current methods of causal inference face significant challenges in uncovering interventional causal interactions within non-interventional systems, in particular under latent confounders, as they either focus solely on associations or require additional interventional manipulation. To overcome these limitations, here we introduce a novel method of Interventional Dynamical Causality under Invisible/Latent confounders (named ICIC or IC2) to decipher interventional dynamical causality based solely on non-interventional data even under latent confounders. IC2 is theoretically grounded in the dual orthogonal decomposition theorem in the delay embedding space and is computationally implemented with the constructed interventional data from observed non-interventional data by deep neural networks. Comprehensive benchmarking demonstrates that IC2 outperforms alternative methods in recovering causal structures in various biological applications. In particular, IC2 was not only validated by true interventional effects with knockout experiments, but also reconstructed biological networks from real-world data, and predicted the perturbation effects of single-cell CRISPR perturbation experiments. These results show the power of IC2 in estimating interventional effects where experimental intervention is not feasible.</p>","PeriodicalId":17488,"journal":{"name":"Journal of The Royal Society Interface","volume":"23 240","pages":""},"PeriodicalIF":3.4,"publicationDate":"2026-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148549678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Folgert Karsdorp, Anne Kandler, Mike Kestemont, Iza Romanowska, Rombert Stapel
{"title":"Correcting collection bias in comparative studies of diversity.","authors":"Folgert Karsdorp, Anne Kandler, Mike Kestemont, Iza Romanowska, Rombert Stapel","doi":"10.1098/rsif.2026.0163","DOIUrl":"10.1098/rsif.2026.0163","url":null,"abstract":"<p><p>Comparative analyses of diversity in human populations often rely on historical, archival and observational data, which are systematically shaped by uneven documentation, preservation and research attention. Such collection bias can distort comparisons across populations, regions or time periods, obscuring genuine patterns of variation or generating spurious ones. Standard approaches that equalize sample size or sampling effort implicitly assume comparable sampling completeness, which is an assumption rarely satisfied in human and historical datasets. Here, we evaluate coverage-based standardization, adapted from ecological diversity estimation, as a general framework for comparative diversity analysis under biased and incomplete observation. Using population-level simulations, we show that coverage-based approaches reliably recover true diversity relationships across multiple, qualitatively distinct mechanisms of collection bias, whereas sample-size-based methods yield systematically distorted inferences. We illustrate the utility of this framework with an application to a large historical cultural dataset, where correcting for uneven documentation substantially refines inferred diversity patterns. By conditioning comparisons on sampling completeness rather than raw sample size, coverage-based standardization offers a principled and broadly applicable solution for comparative research in any domain where observation is biased, incomplete or historically contingent.</p>","PeriodicalId":17488,"journal":{"name":"Journal of The Royal Society Interface","volume":"23 240","pages":""},"PeriodicalIF":3.4,"publicationDate":"2026-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148447628","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kyu Min Huh, Marco Klein Heerenbrink, Steven J Portugal, Graham Keith Taylor
{"title":"Natural take-off flight performance is repeatable and scalable in mixed flock tit species.","authors":"Kyu Min Huh, Marco Klein Heerenbrink, Steven J Portugal, Graham Keith Taylor","doi":"10.1098/rsif.2025.0827","DOIUrl":"10.1098/rsif.2025.0827","url":null,"abstract":"<p><p>Modelling small bird flights is challenging, as small birds (<20 g) rarely engage in steady-state flights assumed by traditional flight models. Additionally, their flights are difficult to measure in the field owing to the mass of high-resolution GPS loggers and the low resolution in lightweight geolocators. This study aimed to measure and model spontaneous, non-steady-state take-off flights of wild tit species that forage in mixed flocks during winter, despite differences in body sizes and ecological niches. We recorded 1434 spontaneous flights from 49 individuals of great tits (Parus major), blue tits (Cyanistes caeruleus) and marsh tits (Poecile palustris) in the Paridae family using two automated radio frequency identification infrared tunnels. We developed a power margin model to predict in-flight acceleration based on initial velocity, scaled by species-specific wing loading. Lastly, we tested the repeatability of flight metrics to assess whether flight may be interpreted as an individual behavioural trait. We found significant differences in initial velocity and in-flight acceleration between species. The observed difference in the in-flight acceleration aligned with the power margin model prediction. Finally, we found significant individual repeatability in both initial velocity and in-flight acceleration. Our findings suggest that the flight performance of small birds can be consistently measured in the field, modelled beyond steady-state assumptions and interpreted as an individual behavioural trait.</p>","PeriodicalId":17488,"journal":{"name":"Journal of The Royal Society Interface","volume":"23 240","pages":""},"PeriodicalIF":3.4,"publicationDate":"2026-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148447634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Eleonora Gatti, Andreagiovanni Reina, Hannah Williams
{"title":"Energetic benefits of social information for movement in patchy landscapes.","authors":"Eleonora Gatti, Andreagiovanni Reina, Hannah Williams","doi":"10.1098/rsif.2025.1322","DOIUrl":"10.1098/rsif.2025.1322","url":null,"abstract":"<p><p>Movement is costly, and animals are under strong selective pressure to move efficiently; however, in patchy, dynamic landscapes, decision-making is inherently uncertain. We quantify the energy savings achieved by using up-to-date information presented within social cues to reduce movement costs. We use an agent-based model, which is founded on realistic aeronautical rules and is parametrized on the Andean condor (Vultur gryphus), to study movement in patchy landscapes. By explicitly considering altitude, flight results in a sequence of soaring and gliding in three-dimensional space. We investigate how the cost of movement to an overall goal varies when birds use social information from others that are either fixed in space or moving collectively to the common goal, and under different risk-taking speed strategies, from slow and cautious to fast and risky. The value of social information is operationalized as energy savings in units of the basal metabolic rate (BMR). Under low predictability, agents with intermediate risk and high social-information use exhibit lowest movement costs, with up to 41% energy savings over asocial movement. By extending classical aeronautical theory to social and variable environments, we demonstrate the adaptive value of social information for efficient movement in patchy, unpredictable landscapes.</p>","PeriodicalId":17488,"journal":{"name":"Journal of The Royal Society Interface","volume":"23 240","pages":""},"PeriodicalIF":3.4,"publicationDate":"2026-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148447674","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}