Search

For organisms tracking a chemical cue to its source, the motion of their surrounding fluid provides crucial information for success. Swimming and flying animals engaged in olfaction-driven search often start by turning into the direction of an oncoming wind or water current. However, it is unclear how organisms adjust their strategies when directional cues are absent or unreliable, as is often the case in nature. Here, we use the genetic toolkit of Drosophila melanogaster to develop an optogenetic paradigm to deliver temporally precise "virtual" olfactory experiences for free-flying animals in either laminar wind or still air. We first confirm that in laminar wind flies turn upwind. Furthermore, we show that they achieve this using a rapid (∼ 100 ms) turn, implying that flies estimate the ambient wind direction prior to "surging" upwind. In still air, flies adopt a remarkably stereotyped "sink and circle" search state characterized by ∼ 60° turns at 3–4 Hz, biased in a consistent direction. Together, our results show that Drosophila melanogaster assesses the presence and direction of ambient wind prior to deploying a distinct search strategy. In both laminar wind and still air, immediately after odor onset, flies decelerate and often perform a rapid turn. Both maneuvers are consistent with predictions from recent control theoretic analyses for how insects may estimate properties of wind while in flight. We suggest that flies may use their deceleration and "anemometric" turn as active sensing maneuvers to rapidly gauge properties of their wind environment before initiating a proximal or upwind search routine. [Display omitted] • Activating Orco+ neurons in flying Drosophila elicits stereotyped plume tracking • In still air, flies use a novel search strategy: sink and circle • In wind, flies orient upwind with rapid ∼100-ms turns • We propose that flies use active sensing maneuvers to gauge wind properties Here, Stupski and van Breugel develop an optogenetic paradigm to precisely control the olfactory experiences of freely flying Drosophila melanogaster. They then investigate olfactory search in the absence of wind and describe "sink and circle." Finally, they describe an active sensing maneuver for how flies may measure the wind while flying. [ABSTRACT FROM AUTHOR]

Flying animals such as insects and birds use wing flapping for flight, occasionally pausing wing motion and transitioning into gliding to conserve energy for propulsion and achieve high flying efficiency. In this study, we have investigated the gliding performance of a gliding model based on a flapping-wing robot developed in a previous study, with the aim of developing a highly efficient flying robot that utilizes bio-inspired intermittent flight. Wind tunnel experiments with a gliding model have shown that the attitude of the wings has a strong influence on gliding performance and that a tail is effective in improving gliding performance. The results of this study provide important insights into the development of flying robots that can travel long distances with high efficiency. [ABSTRACT FROM AUTHOR]

The exodus of flying animals from their roosting locations is often visible as expanding ring‐shaped patterns in weather radar data. The NEXRAD network, for example, archives more than 25 years of data across 143 contiguous US radar stations, providing opportunities to study roosting locations and times and the ecosystems of birds and bats. However, access to this information is limited by the cost of manually annotating millions of radar scans. We develop and deploy an AI‐assisted system to annotate roosts in radar data. We build datasets with roost annotations to support the training and evaluation of automated detection models. Roosts are detected, tracked, and incorporated into our developed web‐based interface for human screening to produce research‐grade annotations. We deploy the system to collect swallow and martin roost information from 12 radar stations around the Great Lakes spanning 21 years. After verifying the practical value of the system, we propose to improve the detector by incorporating both spatial and temporal channels from volumetric radar scans. The deployment on Great Lakes radar scans allows accelerated annotation of 15 628 roost signatures in 612 786 radar scans with 183.6 human screening hours, or 1.08 s per radar scan. We estimate that the deployed system reduces human annotation time by ~7×. The temporal detector model improves the average precision at intersection‐over‐union threshold 0.5 (APIoU =.50) by 8% over the previous model (48%→56%), further reducing human screening time by 2.3× in its pilot deployment. These data contain critical information about phenology and population trends of swallows and martins, aerial insectivore species experiencing acute declines, and have enabled novel research. We present error analyses, lay the groundwork for continent‐scale historical investigation about these species, and provide a starting point for automating the detection of other family‐specific phenomena in radar data, such as bat roosts and mayfly hatches. [ABSTRACT FROM AUTHOR]

A new study exploits genetic approaches available in Drosophila to record the neural activity within the specialized mechanosensory fields of halteres, the unique equilibrium organs of flies. The results challenge the traditional explanation for how these rapidly oscillating structures encode angular velocity during flight. [ABSTRACT FROM AUTHOR]

Hummingbirds demonstrate remarkable robustness to wing defects by maintaining stable hovering during the molting process. However, mimicking these capabilities in flapping-wing robots presents significant challenges. To investigate the effectiveness of various controllers in maintaining the attitude of a hummingbird-mimetic flapping-wing robot against external disturbances under different wing defects, this study implemented a PD controller, a PID controller, and a three-loop feedback controller with a disturbance observer (3L-DOB controller). The flapping-wing robot features a pair of wings and controls its body's yaw, pitch, and roll rotations by modulating the tension of wing membranes and the neutral positions of wing torsion. The performance of these controllers was evaluated through semi-tethered experiments on a gimbal, employing three Wing Sets: intact wings, one wing was defective, and both wings were defective. The defective wing emulated hummingbird wing during molting, in which the wing area was cropped by 14.1%. As a result, the 3L-DOB controller showed the best performance in terms of responsiveness and accuracy across all Wing Sets, while the PID controller also achieved comparable performance. [ABSTRACT FROM AUTHOR]

Studies have investigated the potential of using farmed insects in animal feeds; however, little research has been done using wild-caught insects for this purpose. Concerns about inadequate quantities collected, environmental impacts, and the spread of pathogens contribute to the preferred utilization of farmed insects. Nevertheless, by harvesting certain pest species from intensified agricultural operations, producers could provide their animals with affordable and sustainable protein sources while also reducing pest populations. This study explores the possibility of collecting large quantities of pest flies from livestock operations and analyzes the flies' nutritional content, potential pathogen load, and various disinfection methods. Using a newly designed mass collection-trapping device, we collected 5 kg of biomass over 13 wk, primarily house flies, from a poultry facility. While a substantial number of pests were removed from the environment, there was no reduction in the fly population. Short-read sequencing was used to compare the bacterial communities carried by flies from differing source populations, and the bacterial species present in the fly samples varied based on farm type and collection time. Drying and milling the wild-caught flies as well as applying an additional heat treatment significantly reduced the number of culturable bacteria present in or on the flies, though their pathogenicity remains unknown. Importantly, these disinfection methods did not affect the nutritional value of the processed flies. Further research is necessary to fully assess the safety and viability of integrating wild-caught insects into livestock feed; however, these data show promising results in favor of such a system. [ABSTRACT FROM AUTHOR]

To understand the locomotory mechanisms of flying and swimming animals, it is often necessary to develop assays that enable us to measure their responses to external gust perturbations. Typically, such measurements have been carried out using a variety of gusts which are difficult to control or characterize owing to their inherently turbulent nature. Here, we present a method of generating discrete gusts under controlled laboratory conditions in the form of a vortex rings which are well-characterized and highly controllable. We also provide the theoretical guidelines underlying the design of gust generators for specific applications. As a case study, we tested the efficacy of this method to study the flight response of freely-flying soldier flies Hermetia illucens. The vortex ring based method can be used to generate controlled gusts to study diverse phenomena ranging from a natural flight in insects to the artificial flight of insect-sized drones and micro-aerial vehicles. [ABSTRACT FROM AUTHOR]

In flying animals, wing morphology is typically assumed to influence flight behaviours. Whether seasonal polymorphism in butterfly morphology is linked to adaptive flight behaviour remains unresolved. Here, we compare the flight behaviours and wing morphologies of the spring and summer forms of two closely related butterfly species, Pieris napi and P. rapae. We first quantify three‐dimensional flight behaviour by reconstructing individual flight trajectories using stereoscopic high‐speed videography in an experimental outdoor cage. We then measure wing size and shape, which are characteristics assumed to influence flight behaviours in butterflies. We show that seasonal, but not interspecific, differences in flight behaviour might be associated with divergent forewing shapes. During spring, Pieris individuals are small and have elongated forewings, and generally fly at low speed and acceleration, while having a high flight curvature. On the contrary, summer individuals are larger and exhibit rounded forewings. They fly at high speed and acceleration, while having high turning acceleration and advance ratio. Our study provides one of the first quantitative pieces of evidence of different flight behaviours between seasonal forms of two Pieris butterfly species. We discuss the possibility that this co‐divergence in flight behaviour and morphology is an adaptation to distinct seasonal environments. Properly identifying the mechanisms underpinning such divergence, nonetheless, requires further investigations to disentangle the interacting effects of microhabitats, predator community, parasitoid pressure and behavioural differences between sexes. [ABSTRACT FROM AUTHOR]

We derive an equation that applies for the wing-beat frequency of flying animals and to the fin-stroke frequency of diving animals like penguins and whales. The equation states that the wing/fin-beat frequency is proportional to the square root of the animal's mass divided by the wing area. Data for birds, insects, bats, and even a robotic bird—supplemented by data for whales and penguins that must swim to stay submerged—show that the constant of proportionality is to a good approximation the same across all species; thus the equation is universal. The wing/fin-beat frequency equation is derived by dimensional analysis, which is a standard method of reasoning in physics. We finally demonstrate that a mathematically even simpler expression without the animal mass does not apply. [ABSTRACT FROM AUTHOR]

Studying the detailed biomechanics of flying animals requires accurate three‐dimensional coordinates for key anatomical landmarks. Traditionally, this relies on manually digitizing animal videos, a labor‐intensive task that scales poorly with increasing framerates and numbers of cameras. Here, we present a workflow that combines deep learning–powered automatic digitization with filtering and correction of mislabeled points using quality metrics from deep learning and 3D reconstruction. We tested our workflow using a particularly challenging scenario: bat flight. First, we documented four bats flying steadily in a 2 m3 wind tunnel test section. Wing kinematic parameters resulting from manually digitizing bats with markers applied to anatomical landmarks were not significantly different from those resulting from applying our workflow to the same bats without markers for five out of six parameters. Second, we compared coordinates from manual digitization against those yielded via our workflow for bats flying freely in a 344 m3 enclosure. Average distance between coordinates from our workflow and those from manual digitization was less than a millimeter larger than the average human‐to‐human coordinate distance. The improved efficiency of our workflow has the potential to increase the scalability of studies on animal flight biomechanics. [ABSTRACT FROM AUTHOR]

In plants, the ubiquitin (Ub)-26S proteasome system (UPS) regulates numerous biological functions by selectively targeting proteins for ubiquitylation and degradation. However, the regulation of Ub itself on plant growth and development remains unclear. To demonstrate a possible impact of Ub supply, as seen in animals and flies, we carefully analyzed the growth and developmental phenotypes of two different poly-Ub (UBQ) gene overexpression plants of Arabidopsis thaliana. One is transformed with hexa-6His-UBQ (designated 6HU), driven by the cauliflower mosaic virus 35S promoter, while the other expresses hexa-6His-TEV-UBQ (designated 6HTU), driven by the endogenous promoter of UBQ10. We discovered that 6HU and 6HTU had contrasting seed yields. Compared to wildtype (WT), the former exhibited a reduced seed yield, while the latter showed an increased seed production that was attributed to enhanced growth vigor and an elevated silique number per plant. However, reduced seed sizes were common in both 6HU and 6HTU. Differences in the activity and size of the 26S proteasome assemblies in the two transgenic plants were also notable in comparison with WT, suggestive of a contributory role of UBQ expression in proteasome assembly and function. Collectively, our findings demonstrated that exogenous expression of recombinant Ub may optimize plant growth and development by influencing the UPS activities via structural variance, expression patterns, and abundance of free Ub supply. [ABSTRACT FROM AUTHOR]

In the 300-million-year evolutionary history of animal flight, fliers have universally evolved to exploit the physical principle of drag, whereby an animal uses wings to achieve lift. However, the treehopper Oeda – an Amazonian insect exhibiting a grotesquely large balloon-like thorax – has been described in what may be the only account of an animal engaging in buoyant flight, whereby an animal fills body cavities with low-density air to float, akin to a hot-air balloon. We use Oeda as a study system to conduct a theoretical analysis exploring the biomechanics of buoyant flight and the mechanisms preventing its widespread occurrence in animals. We show that not even an organism with the unique and disproportionate dimensions of Oeda can buoy more than 1% of its body weight. Instead, our results suggest Oeda's bloated thorax is a hindrance for flight that has selected for larger wings to compensate for the species' disproportionate dimensions. Our analysis illustrates that animals may only achieve buoyant flight by filling cavities thousands of times larger than the body with heated low-density biogases. Still, the evolution of such traits is likely restricted by a variety of developmental and ecological factors that have prevented animals from evolving buoyant flight. Whether any animal has evolved the means to conquer buoyant flight remains to be found in nature. [ABSTRACT FROM AUTHOR]

Dynamic preload assessment measures including pulse pressure variation (PPV), stroke volume variation (SVV), pleth variability index (PVI), and hypotension prediction index (HPI) have been utilized clinically to guide fluid management decisions in critically ill patients. These values aid in the balance of correcting hypotension while avoiding over-resuscitation leading to respiratory failure and increased mortality. However, these measures have not been previously validated at altitude or in those with temporary abdominal closure (TAC). Forty-eight female swine (39 ± 2 kg) were separated into eight groups (n = 6) including all combinations of flight versus ground, hemorrhage versus no hemorrhage, and TAC versus no TAC. Flight animals underwent simulated aeromedical evacuation via an altitude chamber at 8000 ft. Hemorrhagic shock was induced via stepwise hemorrhage removing 10% blood volume in 15-min increments to a total blood loss of 40% or a mean arterial pressure of 35 mmHg. Animals were then stepwise transfused with citrated shed blood with 10% volume every 15 min back to full blood volume. PPV, SVV, PVI, and HPI were monitored every 15 min throughout the simulated aeromedical evacuation or ground control. Blood samples were collected and analyzed for serum levels of serum IL-1β, IL-6, IL-8, and TNF-α. Hemorrhage groups demonstrated significant increases in PPV, SVV, PVI, and HPI at each step compared to nonhemorrhage groups. Flight increased PPV (P = 0.004) and SVV (P = 0.003) in hemorrhaged animals. TAC at ground level increased PPV (P < 0.0001), SVV (P = 0.0003), and PVI (P < 0.0001). When TAC was present during flight, PPV (P = 0.004), SVV (P = 0.003), and PVI (P < 0.0001) values were decreased suggesting a dependent effect between altitude and TAC. There were no significant differences in serum IL-1β, IL-6, IL-8, or TNF-α concentration between injury groups. Based on our study, PPV and SVV are increased during flight and in the presence of TAC. Pleth variability index is slightly increased with TAC at ground level. Hypotension prediction index demonstrated no significant changes regardless of altitude or TAC status, however this measure was less reliable once the resuscitation phase was initiated. Pleth variability index may be the most useful predictor of preload during aeromedical evacuation as it is a noninvasive modality. [ABSTRACT FROM AUTHOR]

Purpose: Myiases are infestations of human and animal tissues by fly larvae. These conditions are widespread in tropical countries and travelers in those areas are at risk of becoming infested. Although Cordylobia anthropophaga (Blanchard & Berenger-Feraud, 1872) is one of the most common myiasis-causing species, few high-quality images and molecular sequences are available for this fly. We present a case of C. anthropophaga infestation in an Italian patient returning from Senegal, with the aim of increasing both visual and molecular data for this species. Methods: After removal, the larva was determined following standardized morphological keys and photographed under a digital microscope. Molecular characterization of the Cytochrome c oxidase subunit I (COI) was performed using universal primers. Results: The general appearance, the structural organization of the cephalic region, of the cephaloskeleton, and of the posterior tracheal spiracles suggested that the causative agent of the myiasis was a third instar larva of C. anthropophaga. The morphological data are further supported by the molecular data: the COI sequence showed high levels of identity with the already published verified COI sequences of C. anthropophaga. Conclusion: We provide high-quality morphological and molecular data useful for the identification of larvae of C. anthropophaga. We highlight that myiasis might be common in Senegal and better data about its prevalence in travelers and in the endemic countries are needed to understand the burden of this condition. [ABSTRACT FROM AUTHOR]

Simple Summary: This study delves into the turning behavior of pigeons by examining the neural mechanisms of their midbrain motor nucleus. Correlating brain oscillations with turning behavior, we identified the distinct roles of oscillatory patterns in different frequency bands during active and passive turning behavior. Specifically, 80 Hz stimulation induced higher-frequency oscillation patterns. These findings unveil the intricate relationship between neural oscillations and pigeon turning, highlighting the significance of specific frequency bands. This study enhances our understanding of avian brain–behavior connections, offering valuable insights for further research on avian locomotion neural processes and serving as a reference for future studies on neuromodulation techniques in flying animal robots. Flexible turning behavior endows Homing Pigeons (Columba livia domestica) with high adaptability and intelligence in long-distance flight, foraging, hazard avoidance, and social interactions. The present study recorded the activity pattern of their local field potential (LFP) oscillations and explored the relationship between different bands of oscillations and turning behaviors in the formatio reticularis medialis mesencephali (FRM). The results showed that the C (13–60 Hz) and D (61–130 Hz) bands derived from FRM nuclei oscillated significantly in active turning, while the D and E (131–200 Hz) bands oscillated significantly in passive turning. Additionally, compared with lower-frequency stimulation (40 Hz and 60 Hz), 80 Hz stimulation can effectively activate the turning function of FRM nuclei. Electrical stimulation elicited stronger oscillations of neural activity, which strengthened the pigeons' turning locomotion willingness, showing an enhanced neural activation effect. These findings suggest that different band oscillations play different roles in the turning behavior; in particular, higher-frequency oscillations (D and E bands) enhance the turning behavior. These findings will help us decode the complex relationship between bird brains and behaviors and are expected to facilitate the development of neuromodulation techniques for animal robotics. [ABSTRACT FROM AUTHOR]

Squirrels and some corvids have successfully adapted to urban conditions. Their populations are often more abundant in city parks than in rural areas. These species may compete, especially in terms of food resources. We studied interactions between corvids (hooded crows and rooks) and red squirrels inhabiting urban park, mostly in relation to supplementary food utilisation in Poland. The study included the following: (a) feeding trials, when squirrels were offered hazelnuts and all stealing attempts by other animals were noted; (b) direct observations of groups of animals (at least one squirrel and one corvid species) with all behaviours being recorded. During the feeding trial, and with constant corvid presence, corvids tried to steal almost every third nut cached by squirrels. Regardless of the season, the share of nuts that corvids tried to steal was similar. When the feeding trial proceeded, more squirrels joined in order to obtain food. On the contrary, the presence of corvids seemed to refrain other corvids from joining the trial. The presence of a bird/squirrel audience did not result in more deceptive caches. During direct observations, squirrels interacted mostly with corvids, and less often with people or other squirrels. The most frequent interaction of squirrels with other animals was flight and chasing away; for corvids, it was chasing and following or attempting to steal food. Overall, we showed that corvids can be food competitors and kleptoparasites for red squirrels. Red squirrels, with whom people often have affinity relationships, benefited from direct supplementary feeding. Corvids, in turn, learnt to follow red squirrels to steal human-delivered nuts. [ABSTRACT FROM AUTHOR]

In 'Nature in the Active Voice', Val Plumwood called for a 'thorough rethink' of the logic of domination that has authorized both colonialism and the exploitation of animals (113). But this mandate creates a conundrum: that logic elevates mind over matter and cognition over emotion. If Audre Lorde was right that 'the master's tools will never dismantle the master's house' (110), then we are unlikely to succeed in undermining that logic by rethinking it. We need practices that will expose the tedious nonsensicality of human supremacy while simultaneously awakening our capacities for empathy, imagination, and full-bodied ecological reasoning. Plumwood noted the power of poetry, but nonverbal methods of cognition and communication such as music, dance, and visual art may be even more vital to the struggle to think truly differently. Underground currents of art and activism including Dada, Tropicália, Afrofuturism, and surrealisms from around the world may offer both instructive and cautionary lessons. Kiwi and other category-defying animals, whose minds are very different from our own but whose ideas may be legible through their ways of being in the world, may be especially important instructors in the praxis of eco-logic. [ABSTRACT FROM AUTHOR]

Tracking the flight patterns of birds and bats in three-dimensional space is central to key questions in evolutionary ecology but remains a difficult technical challenge. For example, complex aerial flight displays are common among birds breeding in open habitats, but information on flight performance is limited. Here, we demonstrate the feasibility of using a large ground-based 4-microphone planar array to track the aerial flight displays of the cryptic Jack Snipe Lymnocryptes minimus. The main element of male display flights resembles a galloping horse at a distance. Under conditions of sufficient signal-to-noise ratio and of vertical alignment with the microphone array, we successfully tracked male snipe in 3D space for up to 25 seconds with a total flight path of 280 m. The 'gallop' phase of male snipe dropped from ca. 141 to 64 m above ground at an average velocity of 77 km/h and up to 92 km/h. Our project is one of the first applications of bioacoustics to measure 3D flight paths of birds under field conditions, and our results were consistent with our visual observations. Our microphone array and post-processing workflow provides a standardised protocol that could be used to collect comparative data on birds with complex aerial flight displays. [ABSTRACT FROM AUTHOR]

The cellular mechanisms of neuroplastic changes in the structure of motoneurons and neuropils of the oculomotor (III) nuclei in mice after a 30-day space flight and 7 days after landing were studied. The results showed that microgravity caused degenerative phenomena in neurons: a decrease in the number of terminal dendritic branches was found both after flight and after readaptation to Earth's gravity. In mice after the flight, the number of axodendritic synapses was less than in the control, and their number was not restored after the readaptation. The number of mitochondria in the motoneurons of animals after the flight also decreased and after the readaptation reached only the control value. In addition, a significant number of dark motorneurons were found in mice after readaptation, which indicates that degeneration was caused not only by microgravity, but also by a reaction to the landing of the biosatellite. On the contrary, in the trochlear nucleus, as we showed earlier (Mikheeva et al. in Brain Res 15(1795):148077. https://doi.org/10.1016/j.brainres.2022.148077, 2022), after readaptation, the dendrites and synaptic contacts were restored, and mitogenesis is significantly enhanced. It has been suggested that morphological changes in the oculomotor nucleus may be the main cause of microgravity-induced nystagmus. [ABSTRACT FROM AUTHOR]

A recent study published in eLife has shed light on how animals navigate and stabilize themselves during flight. The study focused on the wiring of neurons in the visual system of fruit flies, specifically those that process motion. By mapping the connections of these neurons, researchers gained a better understanding of how flies process optic flow, which is crucial for maintaining altitude and navigating complex environments. The study also found similarities in the visual systems of fruit flies and blowflies, suggesting a common arrangement of neurons across fly species. This research serves as a foundation for further studies on how the brain utilizes optic flow signals to drive behavior. Additionally, this document provides a list of references to scientific articles that explore the visual system in fruit flies, covering topics such as brain wiring, direction selectivity in motion-sensitive neurons, and neurotransmitter classification. These articles offer valuable information for researchers studying the visual system and neural circuits in fruit flies. [Extracted from the article]

Background: Understanding and countering the well-established negative health consequences of spaceflight remains a primary challenge preventing safe deep space exploration. Targeted/personalized therapeutics are at the forefront of space medicine strategies, and cross-species molecular signatures now define the 'typical' spaceflight response. However, a lack of direct genotype–phenotype associations currently limits the robustness and, therefore, the therapeutic utility of putative mechanisms underpinning pathological changes in flight. Methods: We employed the worm Caenorhabditis elegans as a validated model of space biology, combined with 'NemaFlex-S' microfluidic devices for assessing animal strength production as one of the most reproducible physiological responses to spaceflight. Wild-type and dys-1 (BZ33) strains (a Duchenne muscular dystrophy (DMD) model for comparing predisposed muscle weak animals) were cultured on the International Space Station in chemically defined media before loading second-generation gravid adults into NemaFlex-S devices to assess individual animal strength. These same cultures were then frozen on orbit before returning to Earth for next-generation sequencing transcriptomic analysis. Results: Neuromuscular strength was lower in flight versus ground controls (16.6% decline, p < 0.05), with dys-1 significantly more (23% less strength, p < 0.01) affected than wild types. The transcriptional gene ontology signatures characterizing both strains of weaker animals in flight strongly corroborate previous results across species, enriched for upregulated stress response pathways and downregulated mitochondrial and cytoskeletal processes. Functional gene cluster analysis extended this to implicate decreased neuronal function, including abnormal calcium handling and acetylcholine signaling, in space-induced strength declines under the predicted control of UNC-89 and DAF-19 transcription factors. Finally, gene modules specifically altered in dys-1 animals in flight again cluster to neuronal/neuromuscular pathways, suggesting strength loss in DMD comprises a strong neuronal component that predisposes these animals to exacerbated strength loss in space. Conclusions: Highly reproducible gene signatures are strongly associated with space-induced neuromuscular strength loss across species and neuronal changes in calcium/acetylcholine signaling require further study. These results promote targeted medical efforts towards and provide an in vivo model for safely sending animals and people into deep space in the near future. [ABSTRACT FROM AUTHOR]

Summary: All plants are electrically excitable, but only few are known to fire a well‐defined, all‐or‐nothing action potential (AP). The Venus flytrap Dionaea muscipula displays APs with an extraordinarily high firing frequency and speed, enabling the capture organ of this carnivorous plant to catch small animals as fast as flies. The number of APs triggered by the prey is counted and serves as the basis for decisions within the flytrap's hunting cycle. The archetypical Dionaea AP lasts 1 s and consists of five phases: Starting from the resting state, an initial cytosolic Ca2+ transient is followed by depolarization, repolarization and a transient hyperpolarization (overshoot) before the original membrane potential is finally recovered. When the flytrap matures and becomes excitable, a distinct set of ion channels, pumps and carriers is expressed, each mastering a distinct AP phase. [ABSTRACT FROM AUTHOR]

The motions that make up animal behavior arise from the interplay between neural circuits and the mechanical parts of the body. Therefore, in order to comprehend the operational mechanisms governing behavior, it is essential to examine not only the underlying neural network but also the mechanical characteristics of the animal's body. The locomotor system of fly larvae serves as an ideal model for pursuing this integrative approach. By virtue of diverse investigation methods encompassing connectomics analysis and quantification of locomotion kinematics, research on larval locomotion has shed light on the underlying mechanisms of animal behavior. These studies have elucidated the roles of interneurons in coordinating muscle activities within and between segments, as well as the neural circuits responsible for exploration. This review aims to provide an overview of recent research on the neuromechanics of animal locomotion in fly larvae. We also briefly review interspecific diversity in fly larval locomotion and explore the latest advancements in soft robots inspired by larval locomotion. The integrative analysis of animal behavior using fly larvae could establish a practical framework for scrutinizing the behavior of other animal species. [ABSTRACT FROM AUTHOR]

Simple Summary: Bats play a crucial role as bioindicators of environmental changes, making their monitoring highly valuable. In particular, wind energy plants have been found to cause significant fatality rates among bats, as well as birds, mainly through direct collision with the rotor blades or through barotrauma effects. However, the manual identification and classification of bats through their echolocation sounds is an expensive and time-consuming process. To address this issue, we present an automated analysis pipeline applied to a large dataset recorded over a period of two years in a wind test field. This work proposes various statistical methods based on convolutional neural networks and clustering techniques to examine the relationship between background noise and bat echolocation sounds. In addition, the methodology performs classification at both the genus and species levels, with a high accuracy for most bat classes. Bats are widely distributed around the world, have adapted to many different environments and are highly sensitive to changes in their habitat, which makes them essential bioindicators of environmental changes. Passive acoustic monitoring over long durations, like months or years, accumulates large amounts of data, turning the manual identification process into a time-consuming task for human experts. Automated acoustic monitoring of bat activity is therefore an effective and necessary approach for bat conservation, especially in wind energy applications, where flying animals like bats and birds have high fatality rates. In this work, we provide a neural-network-based approach for bat echolocation pulse detection with subsequent genus classification and species classification under real-world conditions, including various types of noise. Our supervised model is supported by an unsupervised learning pipeline that uses autoencoders to compress linear spectrograms into latent feature vectors that are fed into a UMAP clustering algorithm. This pipeline offers additional insights into the data properties, aiding in model interpretation. We compare data collected from two locations over two consecutive years sampled at four heights (10 m, 35 m, 65 m and 95 m). With sufficient data for each labeled bat class, our model is able to comprehend the full echolocation soundscape of a species or genus while still being computationally efficient and simple by design. Measured classification F1 scores in a previously unknown test set range from 92.3% to 99.7% for species and from 94.6% to 99.4% for genera. [ABSTRACT FROM AUTHOR]

Worldwide, wildlife–aircraft strikes cost more than US$1.2 billion in aircraft damage and downtime and jeopardize the safety of aircrews, passengers, and animals. Radar has long been used to monitor flying animal movements and can be a useful tool for strike mitigation. In the USA, the Avian Hazard Advisory System (AHAS) is an early‐warning system that integrates data from next‐generation weather radar (NEXRAD) weather surveillance radars (WSRs) with historic bird occurrence data to quantify avian activity and forecast the relative bird risk within a ~9.3‐km radius of military and civilian airfields. Bird detection radars (BDRs) with both horizontal‐surveillance and vertical‐scanning components are also available for monitoring local avian activity at airports, but we have little information regarding the congruence of broad‐scale warnings and local avian activity where WSRs and BDRs overlap. We quantified trends in biological activity recorded at hourly intervals by a BDR at an airfield in Texas, USA, and in the most frequently assigned AHAS risk forecasts for that site during the same intervals. We then examined the strength of association between these datasets by season and time of day to determine when information from BDRs might best complement forecasts from the broad‐scale AHAS system. We found a strong overall association between the datasets but weak or moderate agreement during daylight periods, when most strikes occur. NEXRAD WSRs see only limited bird activity near the Earth's surface, where the majority of damaging strikes take place and, not surprisingly, AHAS warnings during our study were best predicted by the BDR at higher altitudes. Our results suggest BDRs might best complement early‐warning systems, like AHAS, as part of integrated strike mitigation plans at airfields with large numbers of hazardous birds flying at low altitudes during daylight hours, especially in late afternoon. [ABSTRACT FROM AUTHOR]

Spatial orientation is a prerequisite for most behaviors. In insects, the underlying neural computations take place in the central complex (CX), the brain's navigational center. In this region different streams of sensory information converge to enable context-dependent navigational decisions. Accordingly, a variety of CX input neurons deliver information about different navigation-relevant cues. In bees, direction encoding polarized light signals converge with translational optic flow signals that are suited to encode the flight speed of the animals. The continuous integration of speed and directions in the CX can be used to generate a vector memory of the bee's current position in space in relation to its nest, i.e., perform path integration. This process depends on specific, complex features of the optic flow encoding CX input neurons, but it is unknown how this information is derived from the visual periphery. Here, we thus aimed at gaining insight into how simple motion signals are reshaped upstream of the speed encoding CX input neurons to generate their complex features. Using electrophysiology and anatomical analyses of the halictic bees Megalopta genalis and Megalopta centralis, we identified a wide range of motion-sensitive neurons connecting the optic lobes with the central brain. While most neurons formed pathways with characteristics incompatible with CX speed neurons, we showed that one group of lobula projection neurons possess some physiological and anatomical features required to generate the visual responses of CX optic-flow encoding neurons. However, as these neurons cannot explain all features of CX speed cells, local interneurons of the central brain or alternative input cells from the optic lobe are additionally required to construct inputs with sufficient complexity to deliver speed signals suited for path integration in bees. [ABSTRACT FROM AUTHOR]

The present discussion critically explains two assumptions frequently represented in the general accounts of pain in horses. Firstly, the assumption that the purpose of expressing pain is to communicate it to conspecifics. Secondly, that the comparatively low expression of pain in horses results from its concealment in the wild, with the intention and/or the effect of hiding the reduced health and the pain from predators so that they do not become easy targets. By contrast, the facts considered here lead to the conclusion that the phenomena concerning the flight animal “horse” and the behaviour of the predators reveal the assumed deception of the predators to be improbable and a biologically futile measure. In view of the performance of fleeing animals, the wrong information provided to the predators about the health of the prey animals would be irrelevant, independent of the overrating of the mental ability of an equid. Furthermore, it remains hypothetical to what extent the predators, in view of the performance of the prey animals during flight, make an effort to find out about their state of pain, have the necessary ability for such recognition, and specifically smell or visually perceive injuries of the prey animals. Additionally, to what degree information of this kind has an effect on their behaviour during the hunt and when seizing the equids. Concerning the idea of the expression of pain as a communication to conspecifics, relevant facts suggest that, independent of the possibility, which is more or less largely accessible to humans, to infer the state of pain of a horse from its behaviour – which deviates from the norm – analogous to their own expressions and sensitivities, at least the repeatedly assumed purpose of the expressions, namely to inform conspecifics, remains equally hypothetical. In this respect, it is significant that neither the hippological nor the veterinary literature describes horses’ perception of the pain of their conspecifics or individual- and/or species-specific reactions to such perception in an empirically validated manner. In view of the uncertainty corresponding to these circumstances, it can at least be considered to see the purpose of the physical “accompanying” appearances of pain not in the communications to conspecifics, but rather to understand the physical symptoms primarily as genuine components of the psycho-physical phenomenon “pain”, namely as components which interact with the various other components of the complex event “pain”, i.e. which have an effect on them. In this respect, we should speak less of expressions of pain and more of its external aspect. In other words, the physical symptoms of pain presumably acquire their function primarily in the various components of the complex pain process of the affected organism, specifically as effects on the somatic stress existing in the experience of pain and as effects on the psychological process of experiencing and coping with pain. [ABSTRACT FROM AUTHOR]

Elucidating the adaptations that promote flight in animals can aid the understanding of evolution and species divergence, and/or provide inspiration for aerospace engineering and the design of better aerial vehicles. The famed long-distance migration of monarch butterflies in North America still holds many questions and opportunities for inspiration. For example, there is little research on whether the monarch's primary wing colors themselves (black, orange, or white) have any aerodynamic or migration function. Dark colors on wings of other animals have recently been shown to aid flight by enhancing solar absorption, which reduces drag forces. However, too much black surface could be problematic for monarchs, which are exposed to increasing amounts of solar energy along their flightpath. This paper describes the results of two related investigations that attempt to elucidate the importance of wing color to the monarch migration. By measuring the color proportions of nearly 400 monarch wings collected at different stages of their journey, we found, surprisingly, that successful migrants tended to have less black on their wings (about 3% less), but also more white pigment (about 3% more); monarchs have a band of light-colored marginal wing spots. Second, image analysis of museum specimens revealed migratory monarchs had significantly larger white spots, proportional to the wing area, than most non-migratory, New World Danaid butterflies, which argues spot size has evolved along with migratory behavior. Combined, these findings strongly suggest that the long-distance migration itself selects for larger white spots every fall, so that only those individuals with large spots will survive to pass on their genes. Further experimental work is needed to elucidate how the spots aid the migration, but it is possible that they enhance aerodynamic efficiency; other work by the authors demonstrates how alternating white and black pigment on wings can reduce drag. These results will serve as a useful starting point for such endeavors, which should improve understanding of one of the world's most fascinating animal migrations, and also provide practical knowledge for the field of aerospace engineering. [ABSTRACT FROM AUTHOR]

Flapping flight of animals has captured the interest of researchers due to their impressive flight capabilities across diverse environments including mountains, oceans, forests, and urban areas. Despite the significant progress made in understanding flapping flight, high-altitude flight as showcased by many migrating animals remains underexplored. At high-altitudes, air density is low, and it is challenging to produce lift. Here we demonstrate a first lift-off of a flapping wing robot in a low-density environment through wing size and motion scaling. Force measurements showed that the lift remained high at 0.14 N despite a 66% reduction of air density from the sea-level condition. The flapping amplitude increased from 148 to 233 degrees, while the pitch amplitude remained nearly constant at 38.2 degrees. The combined effect is that the flapping-wing robot benefited from the angle of attack that is characteristic of flying animals. Our results suggest that it is not a simple increase in the flapping frequency, but a coordinated increase in the wing size and reduction in flapping frequency enables the flight in lower density condition. The key mechanism is to preserve the passive rotations due to wing deformation, confirmed by a bioinspired scaling relationship. Our results highlight the feasibility of flight under a low-density, high-altitude environment due to leveraging unsteady aerodynamic mechanisms unique to flapping wings. We anticipate our experimental demonstration to be a starting point for more sophisticated flapping wing models and robots for autonomous multi-altitude sensing. Furthermore, it is a preliminary step towards flapping wing flight in the ultra-low density Martian atmosphere. [ABSTRACT FROM AUTHOR]

Wind energy is a major and rapidly expanding renewable energy source. Horizontal‐axis wind turbines, the main tool in this industry, induce mortality in flying animals and consequently bring about conservation concerns and regulatory restrictions. We utilized a unique combination of RADAR, LIDAR and ultrasonic acoustic recorders to test the utility of a novel technology meant to prevent wind turbine‐related mortality in bats. Our drone‐mounted deterrent device produces a pulsating combination of strong auditory and visual signals while moving through the air. LIDAR was used to assess the device's impact below its flight altitude and RADAR to assess its influence above its flight altitude. Continuous acoustic recordings from ground level to ~400 m above‐ground‐level were used to monitor bat activity in the research site. We recorded the nightly altitudinal distributions of multiple bat species throughout the experiment. Analysis revealed a significant change in activity while the deterrent was flying compared to baseline conditions. We also recorded a significant ~40% decrease below and a significant ~50% increase above the deterrent's flight altitude during its operation compared to the post‐flight control. The tested technology is independent of wind farm activities and does not require modifying wind turbine form or operation procedures. The device differs from previously proposed solutions by being dynamic – moving in the airspace and emitting constantly changing signals – thus decreasing the probability of animal habituation. Our findings suggest that the deterrent could dramatically decrease wind turbine‐related mortality by deterring bats from approaching rotor‐swept airspace. Focused implementation in conditions where bat activity and energy production are in conflict may provide a practical, cost‐effective mortality mitigation solution compared to current alternatives. Thus, our results should be considered by the wind‐turbine industry and environmental monitoring and animal conservation organizations, as well as by regulatory agencies, when pursuing alleviation of wind turbine‐related mortality. [ABSTRACT FROM AUTHOR]

This study focuses on the flapping mechanisms found in recently developed biometric flapping-wing air vehicles (FWAVs). FWAVs mimic the flight characteristics of flying animals, providing advantages such as maneuverability, inconspicuousness, and excellent flight efficiency in the low Reynolds number region. The flapping mechanism is a critical part of determining the aerodynamic performance of an FWAV since it is directly related to the wing motion. In this study, the flight characteristics of birds and bats are introduced, the incorporation of these flight characteristics into the development of FWAVs is elucidated, and the utilization of these flight characteristics in the development of FWAVs is explained. Next, the classification and analysis of flapping mechanisms are conducted based on wing motion and the strategy for improving aerodynamic performance. Lastly, the current research gap is elucidated, and potential future directions for further research are proposed. This review can serve as a guide during the early development stage of FWAVs. [ABSTRACT FROM AUTHOR]

Estimating animal populations is essential for conservation. Censusing large congregations is especially important since these are priorities for protection, but efficiently counting hundreds of thousands of moving animals remains a challenge. We developed a deep learning‐based system using consumer cameras that not only counts but also records behavioral information for large numbers of flying animals in a range of lighting conditions including near darkness. We built a robust training set without human labeling by leveraging data augmentation and background subtraction. We demonstrate this approach by estimating the size of a straw‐colored fruit bat (Eidolon helvum) colony in Kasanka National Park, Zambia with cameras encircling the colony to record evening emergence. Detection of bats was robust to deteriorating lighting conditions and changing backgrounds. Combined over five days, our population estimates ranged between 750,000 and 976,000 bats with a mean of 857,233. In addition to counts, we extracted wingbeat frequency, flight altitude, and local group polarity for 639,414 individuals. This open access method is an inexpensive but powerful approach that, in addition to radial emergences from central locations, can also be applied to unidirectional movements of flying groups, such as migratory streams of birds. [ABSTRACT FROM AUTHOR]

The efficiency with which flying animals convert metabolic power to mechanical power dictates an individual's flight behaviour and energy requirements. Despite the significance of this parameter, we lack empirical data on conversion efficiency for most species as in vivo measurements are notoriously difficult to obtain. Furthermore, conversion efficiency is often assumed to be constant across flight speeds, even though the components driving flight power are speed-dependent. We show, through direct measurements of metabolic and aerodynamic power, that conversion efficiency in the migratory bat (Pipistrellus nathusii) increases from 7.0 to 10.4% with flight speed. Our findings suggest that peak conversion efficiency in this species occurs near maximum range speed, where the cost of transport is minimized. A meta-analysis of 16 bird and 8 bat species revealed a positive scaling relationship between estimated conversion efficiency and body mass, with no discernible differences between bats and birds. This has profound consequences for modelling flight behaviour as estimates assuming 23% efficiency underestimate metabolic costs for P. nathusii by almost 50% on average (36–62%). Our findings suggest that conversion efficiency may vary around an ecologically relevant optimum speed and provide a crucial baseline for investigating whether this drives variation in conversion efficiency between species. [ABSTRACT FROM AUTHOR]

Flying Drosophila rely on their vision to detect visual objects and adjust their flight course. Despite their robust fixation on a dark, vertical bar, our understanding of the underlying visuomotor neural circuits remains limited, in part due to difficulties in analyzing detailed body kinematics in a sensitive behavioral assay. In this study, we observed the body kinematics of flying Drosophila using a magnetically tethered flight assay, in which flies are free to rotate around their yaw axis, enabling naturalistic visual and proprioceptive feedback. Additionally, we used deep learning-based video analyses to characterize the kinematics of multiple body parts in flying animals. By applying this pipeline of behavioral experiments and analyses, we characterized the detailed body kinematics during rapid flight turns (or saccades) in two different visual conditions: spontaneous flight saccades under static screen and bar-fixating saccades while tracking a rotating bar. We found that both types of saccades involved movements of multiple body parts and that the overall dynamics were comparable. Our study highlights the importance of sensitive behavioral assays and analysis tools for characterizing complex visual behaviors. [ABSTRACT FROM AUTHOR]

Mobility in flying animals can be assessed by variations in morpho–ecological traits such as body, thorax and wing sizes, wing shape and the proportion between body mass and wing area. Habitat loss and fragmentation can promote phenotypic plasticity and microevolutionary divergencies in natural populations. In this context, sexual differences in physiology and behaviour can impose different selection pressure on morphological aspects related to flight.We evaluated the relative impact of forest patch area and habitat amount in shaping flight‐related morpho–ecological traits of the tropical butterfly Hamadryas februa. We find a marked sexual dimorphism in the species, with females being larger, having larger thorax, higher wing loadings and larger wing total area than males. These trait values indicate females as the more dispersive sex. We show that habitat amount modulates body mass allocations in both sexes, leading to an increase in thorax mass with decreasing habitat amount. The effect of habitat amount was more pronounced in females, which increased total mass and wing loading while decreasing thorax allocation with decreasing habitat amount. This outcome suggests that females increase abdominal mass in response to a reduction in habitat amount. The focal forest patch increasing area was linked to increases in hindwing lengths in both females and males.We advocate that both landscape metrics (i.e., habitat amount and patch area) should be considered in studies evaluating landscapes' impacts on insect mobility. We discuss results in terms of the species' sexual differences in flight behaviour and the relative importance of both landscape metrics. [ABSTRACT FROM AUTHOR]

Automated 3D image‐based tracking systems are new and promising devices to investigate the foraging behavior of flying animals with great accuracy and precision. 3D analyses can provide accurate assessments of flight performance in regard to speed, curvature, and hovering. However, there have been few applications of this technology in ecology, particularly for insects. We used this technology to analyze the behavioral interactions between the Western honey bee Apis mellifera and its invasive predator the Asian hornet, Vespa velutina nigrithorax. We investigated whether predation success could be affected by flight speed, flight curvature, and hovering of the Asian hornet and honey bees in front of one beehive. We recorded a total of 603,259 flight trajectories and 5175 predator–prey flight interactions leading to 126 successful predation events, representing 2.4% predation success. Flight speeds of hornets in front of hive entrances were much lower than that of their bee prey; in contrast to hovering capacity, while curvature range overlapped between the two species. There were large differences in speed, curvature, and hovering between the exit and entrance flights of honey bees. Interestingly, we found hornet density affected flight performance of both honey bees and hornets. Higher hornet density led to a decrease in the speed of honey bees leaving the hive, and an increase in the speed of honey bees entering the hive, together with more curved flight trajectories. These effects suggest some predator avoidance behavior by the bees. Higher honey bee flight curvature resulted in lower hornet predation success. Results showed an increase in predation success when hornet number increased up to 8 individuals, above which predation success decreased, likely due to competition among predators. Although based on a single colony, this study reveals interesting outcomes derived from the use of automated 3D tracking to derive accurate measures of individual behavior and behavioral interactions among flying species. [ABSTRACT FROM AUTHOR]

The optomotor response (OMR) is central to the locomotory behavior in diverse animal species including insects, fish and mammals. Furthermore, the study of the OMR in larval zebrafish has become a key model system for investigating the neural basis of sensorimotor control. However, a comprehensive understanding of the underlying control algorithms is still outstanding. In fish it is often assumed that the OMR, by reducing average optic flow across the retina, serves to stabilize position with respect to the ground. Yet the degree to which this is achieved, and how it could emerge from the intermittent burst dynamics of larval zebrafish swimming, are unclear. Here, we combine detailed computational modeling with a new approach to free-swimming experiments in which we control the amount of visual feedback produced by a given motor effort by varying the height of the larva above a moving grid stimulus. We develop an account of underlying feedback control mechanisms that describes both the bout initiation process and the control of swim speed during bouts. We observe that the degree to which fish stabilize their position is only partial and height-dependent, raising questions about its function. We find the relative speed profile during bouts follows a fixed temporal pattern independent of absolute bout speed, suggesting that bout speed and bout termination are not separately controlled. We also find that the reverse optic flow, experienced when the fish is swimming faster than the stimulus, plays a minimal role in control of the OMR despite carrying most of the sensory information about self-movement. These results shed new light on the underlying dynamics of the OMR in larval zebrafish and will be crucial for future work aimed at identifying the neural basis of this behavior. Author summary: In many animals vision is central to the control of locomotory behaviors. In particular, innate motor responses to optic flow allow flying animals to react to gusts of air and fish to changes of current. As fish are washed downstream, for example, movement of the riverbed image across the retina evokes forward movement in bouts (short periods of swimming followed by rest periods). It is typically assumed that this translational optomotor response stabilizes the fish's position to prevent it drifting downstream. In larval zebrafish, this response has become a key model system for investigating the neural basis of sensorimotor behaviors in a vertebrate. Here, we combine behavioral experiments and computational modeling to elucidate the underlying control algorithms and explore the detailed relationship between visual stimuli and the initiation and speed of swim bouts. Surprisingly we find that the degree of stabilization is only partial and varies systematically with height above ground, raising questions of the function of this response. We also describe two separate processes underlying bout initiation and bout speed respectively which jointly prove sufficient to predict mean swim speed and degrees of regulation. These findings shed new light on the underlying dynamics which will be crucial for future work to identify the neural basis of this behavior. [ABSTRACT FROM AUTHOR]

Simple Summary: Theory predicts that flying animals maximizing their migratory distance should adjust their airspeeds for headwinds and tailwinds. This energy-conserving adjustment in airspeed is based on the theory that as an insect increases its airspeed, the power required to fly increases rapidly above a minimum power velocity. Here we sought to quantify the aerodynamic power required to fly at different speeds in a migratory butterfly Heliconius sara, and predict the adjustment in airspeed necessary to minimize energy consumption in headwinds or tailwinds. We filmed butterflies as they migrated naturally using two high-speed video cameras. Simultaneously we measured the butterflies' airspeeds while they flew across the Panama Canal, and we captured the same butterflies to measure weight distribution and the shape of the body and wings. We found that the power required to fly increased non-linearly from a minimum power velocity of 0.9 m/s. Faced with a headwind or tailwind, the butterflies increased or decreased their airspeed in accordance with that predicted. However, the null hypothesis of no compensation could not be rejected. This approach can be applied to predict insect movement between agricultural patches and the maximization of fuel efficiency when migrating overseas. Although theoretical work on optimal migration has been largely restricted to birds, relevant free-flight data are now becoming available for migratory insects. Here we report, for the first time in passion-vine butterflies, that Heliconius sara migrates directionally. To test optimal migration models for insects, we quantified the aerodynamic power curve for free-flying H. sara as they migrated across the Panama Canal. Using synchronized stereo-images from high-speed video cameras, we reconstructed three-dimensional flight kinematics of H. sara migrating naturally across the Panama Canal. We also reconstructed flight kinematics from a single-camera view of butterflies flying through a flight tunnel. We calculated the power requirements for flight for H. sara over a range of flight velocities. The relationship between aerodynamic power and velocity was "J"-shaped across the measured velocities with a minimum power velocity of 0.9 m/s and a maximum range velocity of 2.25 m/s. Migrating H. sara did not compensate for crosswind drift. Changes in airspeed with tailwind drift were consistent with the null hypothesis that H. sara did not compensate for tailwind drift, but they were also not significantly different from those predicted to maximize the migratory range of the insects. [ABSTRACT FROM AUTHOR]

To minimize the risk of colliding with the ground or other obstacles, flying animals need to control both their ground speed and ground height. This task is particularly challenging in wind, where head winds require an animal to increase its airspeed to maintain a constant ground speed and tail winds may generate negative airspeeds, rendering flight more difficult to control. In this study, we investigate how head and tail winds affect flight control in the honeybee Apis mellifera, which is known to rely on the pattern of visual motion generated across the eye—known as optic flow—to maintain constant ground speeds and heights. We find that, when provided with both longitudinal and transverse optic flow cues (in or perpendicular to the direction of flight, respectively), honeybees maintain a constant ground speed but fly lower in head winds and higher in tail winds, a response that is also observed when longitudinal optic flow cues are minimized. When the transverse component of optic flow is minimized, or when all optic flow cues are minimized, the effect of wind on ground height is abolished. We propose that the regular sidewards oscillations that the bees make as they fly may be used to extract information about the distance to the ground, independently of the longitudinal optic flow that they use for ground speed control. This computationally simple strategy could have potential uses in the development of lightweight and robust systems for guiding autonomous flying vehicles in natural environments. [ABSTRACT FROM AUTHOR]

The aerodynamic characteristics of the foil undergoing the coexisting of fast and slow pitching have been studied via Immersed Boundary (IB) method. With an adjustable parameter k , the foil kinematics is defined by making the period corresponding to the positive amplitude faster than that corresponding to the negative amplitude, and vice versa. An opposite scenario is observed at k < 0. 5 and k > 0. 5 , where the positive lift is improved via decreasing k at k < 0. 5 but the negative lift enlarges with increasing k at k > 0. 5 , which is of benefit to generate up-burst and dive of the pitching foil, respectively. The lift generation is investigated with the time history of the lift coefficient and the time-mean streamwise velocity, which renders a physical basis for understanding the behavior of flying animals. [ABSTRACT FROM AUTHOR]

Background: With the largest cattle population in Africa and vast swathes of fertile lands infested by tsetse flies, trypanosomosis is a major challenge for Ethiopian farmers. Managing the problem strategically and rationally requires comprehensive and detailed information on disease and vector distribution at the national level. To this end, the National Institute for Control and Eradication of Tsetse and Trypanosomosis (NICETT) developed a national atlas of tsetse and African animal trypanosomosis (AAT) for Ethiopia. Methods: This first edition of the atlas focused on the tsetse-infested areas in western Ethiopia. Data were collected between 2010 and 2019 in the framework of national surveillance and control activities. Over 88,000 animals, mostly cattle, were tested with the buffy-coat technique (BCT). Odour-enhanced traps were deployed in approximately 14,500 locations for the entomological surveys. Animal- and trap-level data were geo-referenced, harmonized and centralized in a single database. Results: AAT occurrence was confirmed in 86% of the districts surveyed (107/124). An overall prevalence of 4.8% was detected by BCT in cattle. The mean packed cell volume (PCV) of positive animals was 22.4, compared to 26.1 of the negative. Trypanosoma congolense was responsible for 61.9% of infections, T. vivax for 35.9% and T. brucei for 1.7%. Four tsetse species were found to have a wide geographic distribution. The highest apparent density (AD) was reported for Glossina pallidipes in the Southern Nations, Nationalities and People's Region (SNNPR) (3.57 flies/trap/day). Glossina tachinoides was the most abundant in Amhara (AD 2.39), Benishangul-Gumuz (2.38), Gambela (1.16) and Oromia (0.94) regions. Glossina fuscipes fuscipes and G. morsitans submorsitans were detected at lower densities (0.19 and 0.42 respectively). Only one specimen of G. longipennis was captured. Conclusions: The atlas establishes a reference for the distribution of tsetse and AAT in Ethiopia. It also provides crucial evidence to plan surveillance and monitor control activities at the national level. Future work on the atlas will focus on the inclusion of data collected by other stakeholders, the broadening of the coverage to tsetse-free areas and continuous updates. The extension of the atlas to data on control activities is also envisaged. [ABSTRACT FROM AUTHOR]

Background: Documentation on water mites in Spain is scarce, as is information on the parasite-host relationship between certain water mite species and representatives of the dipteran family Simuliidae. The discomfort caused to humans and animals by black flies seems to be increasing in recent years. In this context, an investigation of parasitic water mites is of great importance, not only from the point of view of biodiversity, but also in terms of their potential to control black fly populations. Methods: Rivers across a wide region of eastern Spain were sampled to determine the specific richness of simuliid dipterans and to investigate their possible parasites, such as water mites, mermithid nematodes and microsporidia (fungal microbes). Data on environmental variables, abundance, prevalence and intensity of parasitism on the collected specimens were analyzed. Results: In 10 streams, 15,396 simuliid pupae were collected and checked for the presence of water mite larvae; 426 pupae in seven streams were found to be associated with water mite larvae. Of the 21 simuliid species identified based on morphological characters, eight were found to be associated with water mite larvae. Water mite infection was not equally distributed among black fly species. Also, the prevalence of parasitism was low and differed among simuliid species, ranging from one to 13 water mites per black fly pupa. Variation at the intra- and interspecific levels was detected in terms of the number of water mites inside the black fly cocoons. Free-living deutonymphal and adult water mites representing 15 different species of six genera and five families were morphologically identified. The taxonomic identity of the parasitic mite larvae is unclear at present. Morphologically, they fit descriptions of larval Sperchon (Hispidosperchon) algeriensis Lundblad, 1942, but the possibility cannot be excluded that they represent Sperchon algeriensis, the most abundant species at the adult stage in this study and unknown at the larval stage, or even another species of the genus. A molecular analysis produced for the first time cytochrome oxidase I gene sequences for S. algeriensis. Conclusions: Our results contribute to current knowledge on Spanish Hydrachnidia and their relationships with simuliids as hosts. However, further research is needed to evaluate the diversity, distribution, bioecology and prevalence of this parasitism. [ABSTRACT FROM AUTHOR]