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Abstract Flapping Wing Micro Air Vehicles (FWMAVs) are susceptible to destabilization following in-flight wing collisions. Recent efforts to enhance FWMAV collision robustness have introduced bio-inspired buckling mechanisms into the wings to passively mitigate destabilizing effects. However, the physical mechanisms by which these joints influence vehicle stability remain poorly understood. To better understand the role of buckling joints in stability, we designed a test beam comprised of two flexible segments interconnected by a buckling joint. The test beam was subjected to a series of quasi-static torque-displacement and dynamic disturbance tests. Results of the test beam were compared against a homogeneous control beam. In quasi-static torque–displacement tests, the test beam dissipated 3 times more energy compared to the control beam as indicated by hysteresis loops. In dynamic disturbance tests, the test beam exhibited reduced path disturbance as described by the Integral of Squared Error (ISE), which quantifies the cumulative deviation of a signal from a reference trajectory over time. Specifically, the test beam reduced average ISE by over 90% from the control averages for 6 out of 9 input conditions tested. The improved trajectory recovery in the test beam results from lower angular impulse and work imparted by the disturbance. Overall, angular work done by the disturbance was 3 times higher for the control beam than the test beam and the maximal average impulse imparted by the disturbance was approximately 5 times higher for the control beam than the test beam at the same input setting. This study advances the understanding of how bio-inspired buckling joints can improve FWMAV stability following collisions. 

AbstractAbstract The annual westward migration of army cutworm moths, Euxoa auxiliaris (Grote), to the Rocky Mountains plays a crucial role in the diet of grizzly bears, Ursus arctos horribilis (L.), which face considerable variability in food availability throughout the year. During the bears’ hyperphagia period, when they must consume an excess of calories to prepare for hibernation, these migrating moths provide a vital and reliable energy source. Seasonal dispersal of E. auxiliaris has been primarily documented through ground observations. However, advancements in radar technology now offer new opportunities to track high-altitude migrations including direction, speed, and wingbeat frequency (WBF) of flying insects. Atmospheric conditions such as temperature and pressure can influence insect flight dynamics, yet their effects on E. auxiliaris remain poorly understood. Therefore, we characterized the WBF of lab-reared E. auxiliaris under 9 combinations of air temperature (7, 13, 24 °C) and pressure (550, 700, 850 hPa). Using a pressure-controlled altitude chamber, individual moths were systematically subjected to combinations of these conditions, and their WBFs were recorded. Our results show that temperature significantly affected WBF, but barometric pressure did not. These findings provide critical baseline data for understanding the flight dynamics of E. auxiliaris and highlight the importance of integrating biological data into radar-based studies of migration. These results enhance the interpretation and utility of radar-derived datasets and contribute to the development of more accurate monitoring tools, particularly for the study of insect migration. 

Flapping wing insects leverage the dynamics of their compliant flight systems to reduce the energetic costs of flying. However, the extent to which the wing hinge dynamics contribute to the overall system dynamics remains unknown. Therefore, we developed an approach to (i) quantify the passive dynamic properties of the wing hinge and (ii) identify the resonant frequency of the isolated wing/wing hinge system. First, we measured the frequency response relating thorax deformation to wing stroke angle in sacrificed honeybees and army cutworm moths. Using these data, we developed a linear model of the flight system, which we then extended to incorporate nonlinear effects associated with large wing stroke angles. Our findings revealed that both species flap below the linear resonance of the wing hinge. At larger angles, nonlinear aerodynamic damping reduces the resonant frequency, causing both species to flap above wing hinge resonance. We discuss how wing–thorax coupling and muscle dynamics may cause the resonant frequency of the entire flight system to deviate from that of the wing/wing hinge system. Our estimates of wing hinge stiffness and damping provide quantitative parameters that can be incorporated into models of the insect flight system to enable more accurate predictions of resonance behaviour. 

Abstract Flying insects have a robust flight system that allows them to fly even when their forewings are damaged. The insect must adjust wingbeat kinematics to aerodynamically compensate for the loss of wing area. However, the mechanisms that allow insects with asynchronous flight muscle to adapt to wing damage are not well understood. Here, we investigated the phase and amplitude relationships between thorax deformation and flapping angle in tethered flying bumblebees subject to wing clipping and weighting. We used synchronized laser vibrometry and high-speed videography to measure thorax deformation and flapping angle, respectively. We found that changes in wing inertia did not affect thorax deformation amplitude but did influence wingbeat frequency. Increasing wing inertia increased flapping amplitude and caused a phase lag between thorax deformation and flapping angle, whereas decreasing wing inertia did not affect flapping amplitude and caused the flapping angle to lead thorax deformation. Our findings indicate that bumblebees adapt to wing damage by adjusting their wingbeat frequency rather than altering their wing stroke amplitude. Additionally, our results suggest that bumblebees operate near a wing-hinge-dominated resonant frequency, and that moments generated by steering muscles within the wing hinge influence the phase between thorax deformation and wing stroke nontrivially. These insights can inform the design of resilient, insect-inspired flapping-wing micro air vehicles. 

Buzz pollination involves the release of pollen from, primarily, poricidal anthers through vibrations generated by certain bee species. Despite previous experimental and numerical studies, the intricacies of pollen dynamics within vibrating anthers remain elusive due to the challenges in observing these small-scale, opaque systems. This research employs the discrete element method to simulate the pollen expulsion process in vibrating anthers. By exploring various frequencies and displacement amplitudes, a correlation between how aggressively the anther shakes and the initial rate of pollen expulsion is observed under translating oscillations. This study highlights that while increasing both the frequency and displacement of vibration enhances pollen release, the rate of release does not grow linearly with their increase. Our findings also reveal the significant role of pollen–pollen interactions, which account for upwards of one-third of the total collisions. Comparisons between two types of anther exits suggest that pore size and shape also influence expulsion rates. This research provides a foundation for more comprehensive models that can incorporate additional factors such as cohesion, adhesion and Coulomb forces, paving the way for deeper insights into the mechanics of buzz pollination and its variability across different anther types and vibration parameters. 

Honey bee colony deaths are associated with viruses, which frequently do not cause morphological symptoms in adult bees. To assess the impact of these inapparent infections, we measured flight performance as a proxy for honey bee health. We hypothesized that deformed wing virus (DWV) and/or sacbrood virus (SBV) would reduce flight performance and that co-infections would have compounding, negative impacts. We identified virus-specific effects; bees with DWV flew shorter distances at slower speeds, whereas bees with SBV flew greater distances at higher speeds. Bees with high virus loads expressed more heat shock protein 90, and SBV-infected bees expressed more octopamine ß-2 receptor (Oß-2R). Oß-2R binds octopamine, a ‘fight or flight’ molecule, stimulating metabolic activity, neuromuscular transmission, and movement. To examine relationships between virus infection, octopamine, and flight, we compared the flight performance of DWV-infected bees with octopamine treatment and demonstrated that octopamine negated DWV associated flight impairment. These findings have organismal, colony-, and ecosystem-level implications. 

Abstract Several agriculturally valuable plants store their pollen in tube-like poricidal anthers, which release pollen through buzz pollination. In this process, bees rapidly vibrate the anther using their indirect flight muscles. The stiffness and resonant frequency of the anther are crucial for effective pollen release, yet the impact of turgor pressure on these properties is not well understood. Here, we performed three-point flexure tests and experimental modal analysis to determine anther transverse stiffness and resonant frequency, respectively. Dynamic nanoindentation was used to identify the anther storage modulus as a function of excitation frequency. We subsequently developed mathematical models to estimate how turgor pressure changes after the anther is removed from a flower, thereby emulating zero water availability. We found that anther stiffness decreased by 60% at 30 min post-ablation and anther resonant frequency decreased by 20% at 60 min post-ablation. Models indicated that turgor pressure in the fresh anther was ~0.2–0.3 MPa. Our findings suggest that natural fluctuations in turgor pressure due to environmental factors such as temperature and light intensity may require bees to adjust their foraging behaviors. Interestingly, the anther storage modulus increased with excitation frequency, underscoring the need for more sophisticated mechanical models that consider viscous fluid transport through plant tissue. 

Synopsis Animal-mediated pollination is one of the most ecologically and economically important mutualisms and serves as a remarkable example of cross-kingdom communication and coevolution. Unfortunately, pollinators, plants, and the interactions between them are threatened in the Anthropocene. While pollination emerges from interactions across biological scales, existing research and expertise have developed in distinct silos reflecting traditional fields of study such as ecology, plant physiology, neuroethology, etc. This forward-looking review and perspective is a culmination of the “Plant-pollinator interactions in the Anthropocene” symposium at the 2025 Society for Integrative and Comparative Biology meeting, which collected expertise across these disciplinary silos to identify pressing questions our community needs to tackle in the next decade. In this perspective piece, we argue that an integrative, organismally informed systems approach is critical to unraveling the complexity of how plant-pollinator relationships are impacted by dynamic anthropogenic stressors. Specifically, this calls for an intentional and iterative integration of holistic modeling studies with empirical studies. Modeling the emergent properties driven by organismal interactions in pollination systems can identify impactful variables; this in turn should drive design of empirical studies that elucidate how organisms respond to changing environments in the context of those impactful variables, feeding back into improved models. Repetition of this process will allow better predictive power over pollination stability in changing landscapes. Finally, we consider both existing barriers to this integration, as well as emerging opportunities (such as new technologies) that can help bridge across traditional fields.