Long-distance Navigation Research Articles

The Neural Basis of Long-Distance Navigation in Birds.

Migratory birds can navigate over tens of thousands of kilometers with an accuracy unobtainable for human navigators. To do so, they use their brains. In this review, we address how birds sense navigation- and orientation-relevant cues and where in their brains each individual cue is processed. When little is currently known, we make educated predictions as to which brain regions could be involved. We ask where and how multisensory navigational information is integrated and suggest that the hippocampus could interact with structures that represent maps and compass information to compute and constantly control navigational goals and directions. We also suggest that the caudolateral nidopallium could be involved in weighing conflicting pieces of information against each other, making decisions, and helping the animal respond to unexpected situations. Considering the gaps in current knowledge, some of our suggestions may be wrong. However, our main aim is to stimulate further research in this fascinating field.

Sensory mechanisms of long-distance navigation in birds: a recent advance in the context of previous studies

Displacement studies have clearly shown that experienced avian migrants are able to perform true navigation, i.e., they can find the correct direction leading to a target destination from unfamiliar sites. The sensory mechanisms of true navigation remain poorly understood, though some remarkable progress has been made in the last 10–15 years. There are two primary hypotheses explaining the sensory nature of navigation: (1) a magnetic map hypothesis proposes that birds use parameters of the geomagnetic field that are predictably distributed on the globe. As for the sensory nature of this hypothesis, it has been assumed by some researchers that the magnetic receptor cells reside in the upper beak (the so-called “beak organ”), and transmit information via the trigeminal nerve to the brain; (2) an olfactory map hypothesis assumes that birds can smell their position by taking advantage of odours distributed in the atmosphere. There are a growing number of studies supporting both of the hypotheses mentioned though in different avian model species. In this review, an attempt is made to provide an overview of the evidence for different navigational cues proposed thus far, with the main focus on the recent studies addressing the magnetic and olfactory navigation hypotheses. Also, a list of key open questions, together with possible experimental approaches, is proposed.

Long-Distance Geomagnetic Navigation: Imitations of Animal Migration Based on a New Assumption

Plenty of evidence has implied that animals like pigeons and sea turtles utilize geomagnetic information for long-distance migration and homing. In this paper, we conduct an ab initio investigation to imitate a migratory animal's geomagnetic homing across a long distance over the surface of the Earth. Based on a simple assumption that such animals have a natural ability to sense and compare the included angle between the vector geomagnetic field (GF) and a specific geographic direction such as the due north, we show that a long-distance geomagnetic navigation (GN) can be accomplished without any assistance of prestored geomagnetic and geographic information, as long as the navigation is inside a vast area where such a spatial angle can uniquely determine a geographic location. Without any requirement of measuring the strength of the GF, this GN will not be visibly affected by the recurrent fluctuation of the GF that severely hampers traditional GN. By introducing the extended-Kalman-filter algorithm, it is able to find a shortcut in the geomagnetic space, overcoming interferences of strong Gaussian and local-area geomagnetic anomaly. We believe that the proposed approach will find a wide range of potential applications in global, local, and indoor navigations based on magnetic field in the future.

Receptive Fields of Locust Brain Neurons Are Matched to Polarization Patterns of the Sky

Many animals, including insects, are able to use celestial cues as a reference for spatial orientation and long-distance navigation [1]. In addition to direct sunlight, the chromatic gradient of the sky and its polarization pattern are suited to serve as orientation cues [2-5]. Atmospheric scattering of sunlight causes a regular pattern of E vectors in the sky, which are arranged along concentric circles around the sun [5, 6]. Although certain insects rely predominantly on sky polarization for spatial orientation [7], it has been argued that detection of celestial E vector orientation may not suffice to differentiate between solar and antisolar directions [8, 9]. We show here that polarization-sensitive (POL) neurons in the brain of the desert locust Schistocerca gregaria can overcome this ambiguity. Extracellular recordings from POL units in the central complex and lateral accessory lobes revealed E vector tunings arranged in concentric circles within large receptive fields, matching the sky polarization pattern at certain solar positions. Modeling of neuronal responses under an idealized sky polarization pattern (Rayleigh sky) suggests that these "matched filter" properties allow locusts to unambiguously determine the solar azimuth by relying solely on the sky polarization pattern for compass navigation.

A Two-Mode INS/CNS Navigation Method for Lunar Rovers

A secure and autonomous navigation system is needed for the lunar rover in future lunar missions. The inertial navigation system (INS) and celestial navigation system (CNS) are two usually used autonomous navigation systems for rovers. Because INS and CNS are complementary to each other, INS/CNS integrated navigation becomes a very attractive solution for long-time and long-distance navigation. Traditional INS/CNS methods for aircrafts or ballistic missiles are not optimal for rovers because these methods only work in one motion state, but the rover operates in two motion states. For solving this problem, a two-mode INS/CNS navigation method for lunar rovers is presented in this paper. When the rover is stationary, a tightly coupled mode is used to correct the position and attitude of the rover. When the rover is in motion, a loosely coupled mode is used to correct the attitude of the rover. Two modes use different system models and different measurements to fulfill different targets and keep the error of position and attitude from accumulation. The validity and feasibility of the two-mode method is tested and examined by ground test system. The longitude and latitude errors within 50 m in distance can be achieved by this two-mode method during an 80-min traverse. These results demonstrate that it is a good choice of autonomous and high-accuracy navigation for lunar rovers.

Losing professional identity? Deck officers in the Spanish merchant marine, 1868–1914

As transatlantic trade between Spain and her American colonies developed from the sixteenth century onwards, a new class of ocean-going vessel commander emerged. Gradually, pilotos, who were trained in nautical schools, replaced the former coastal trade patrones as masters and mates in long-distance navigation. During the eighteenth and nineteenth centuries, accession to this professional class entailed the completion of a challenging programme of study, which was assessed through a range of examinations and tests to yield a mate’s qualification for those who successfully negotiated the course. Only then would ship-owners have sufficient confidence to consider mates for promotion to the rank of master and manager of a shipping venture. The transition from sail to steam greatly affected the work and life of seafarers in the world shipping industry, especially those who belonged to the class of professional masters and mates. This was particularly so in the Spanish merchant marine, which had some peculiarities that must be borne in mind if this particular process of change is to be fully understood. The aim of this article is to analyse from various perspectives the complex roles of the master, who functioned as both employer and employee, in Spanish shipping enterprises. By so doing, it is intended that a platform for further research, and broader, comparative analyses, will be constructed.

Polarized Light Sensitivity and Orientation in Coral Reef Fish Post-Larvae

Recent studies of the larvae of coral-reef fishes reveal that these tiny vertebrates possess remarkable swimming capabilities, as well as the ability to orient to olfactory, auditory, and visual cues. While navigation according to reef-generated chemicals and sounds can significantly affect dispersal, the effect is limited to the vicinity of the reef. Effective long-distance navigation requires at least one other capacity–the ability to maintain a bearing using, for example, a sun compass. Directional information in the sun’s position can take the form of polarized-light related cues (i.e., e-vector orientation and percent polarization) and/or non-polarized-light related cues (i.e., the direct image of the sun, and the brightness and spectral gradients). We examined the response to both types of cues using commercially-reared post-larvae of the spine-cheeked anemonefish Premnas biaculeatus. Initial optomotor trials indicated that the post-larval stages are sensitive to linearly polarized light. Swimming directionality was then tested using a Drifting In-Situ Chamber (DISC), which allowed us to examine the response of the post-larvae to natural variation in light conditions and to manipulated levels of light polarization. Under natural light conditions, 28 of 29 post-larvae showed significant directional swimming (Rayleigh’s test p<0.05, R = 0.74±0.23), but to no particular direction. Swimming directionality was positively affected by sky clarity (absence of clouds and haze), which explained 38% of the observed variation. Moreover, post-larvae swimming under fully polarized light exhibited a distinct behavior of tracking the polarization axis, as it rotated along with the DISC. This behavior was not observed under partially-polarized illumination. We view these findings as an indication for the use of sun-related cues, and polarized light signal in specific, by orienting coral-reef fish larvae.

Orientation from open water to settlement habitats by coral reef fish: behavioral flexibility in the use of multiple reliable cues

Most coastal marine organisms have a dispersive oceanic larval stage, during which they must be able to distinguish and respond to relevant environmental cues when settling into their first benthic habitat. Chemical stimuli emanating from settlement habitats and being dis- persed by water plumes could enable long-distance navigation by larval reef fish, but we know lit- tle about the cues responsible and their interactive effects. In the present study, we tested this by conducting several ex situ choice experiments in which the response of the coral reef fish Lutjanus fulviflamma towards different chemical cues from coastal habitats was tested close to their settle- ment stage. Fish preferred seagrass habitat water over that from coral reef and mangrove habitats. Furthermore, fish were attracted to chemical cues from their own species (conspecifics) and other fish species, as well as vegetation of 4 different seagrass species, when offered in isolation (i.e. soaked in neutral water), but a strong response remained only towards cues from conspecifics and seagrass leaves when these cues were mixed with seagrass habitat water that naturally contains other cues. Hierarchical effects were observed as fish preferred chemical cues from seagrass leaves over those from conspecifics when both were offered at the same time. The importance of visual habitat cues only overruled that of chemical cues when it concerned preferred cues (i.e. seagrass as opposed to mangrove cues). Our findings indicate that pelagic fish and settlers possess the ability to use multiple reliable chemical cues to locate suitable early life stage habitats, although the importance of these cues is context-dependent. Nevertheless, this flexibility in choice behavior is probably an adaptive strategy to enhance fitness by increasing successful ori- entation towards preferred settlement habitats.

Implementation of a Long-Distance Navigation Method of Low Cost Structure That Combines a Localization Using Magnetic Information and a Lateral Position Compensation

We have proposed a navigation method using magnetic information that occurs in the environment. This paper proposes a improve navigation method that combines a localization using magnetic information and a lateral error compensation based on external geometric information. In our previous method, it is required to adjust parameters used for the robot navigation. This adjustment is needed excluding unreliable magnetic information. On the other hand, our proposed method enables a robot to travel long distance without adjustment parameters even if the unreliable magnetic information is included. The robot is able to identify its position with the particle filter on a topological map using magnetic information. Furthermore, the robot uses external geometric information for only compensate the lateral error. As a result, the localization accuracy is increased and is not depend on geometric information. In addition, these methods are applicable to the robot using simple algorithm, computational and memory costs are low. Through the navigation experiments, we show that the robot achieved over 2 km navigation in real world. Moreover, the proposed method is compared to other two methods. Finally, the usefulness and advantage of the proposed method are presented.

Path Integration Controls Nest-Plume Following in Desert Ants

The desert ant Cataglyphis fortis is equipped with sophisticated navigational skills for returning to its nest after foraging. The ant's primary means for long-distance navigation is path integration, which provides a continuous readout of the ant's approximate distance and direction from the nest. The nest is pinpointed with the aid of visual and olfactory landmarks. Similar landmark cues help ants locate familiar food sites. Ants on their outward trip will position themselves so that they can move upwind using odor cues to find food. Here we show that homing ants also move upwind along nest-derived odor plumes to approach their nest. The ants only respond to odor plumes if the state of their path integrator tells them that they are near the nest. This influence of path integration is important because we could experimentally provoke ants to follow odor plumes from a foreign, conspecific nest and enter that nest. We identified CO(2) as one nest-plume component that can by itself induce plume following in homing ants. Taken together, the results suggest that path-integration information enables ants to avoid entering the wrong nest, where they would inevitably be killed by resident ants.

Path integration controls nest-plume following in desert ants

Event Abstract Back to Event Path integration controls nest-plume following in desert ants Cornelia Buehlmann1*, Bill S. Hansson1 and Markus Knaden1 1 Max Planck Institute for Chemical Ecology, Evolutionary Neuroethology, Germany The desert ant Cataglyphis fortis is equipped with sophisticated navigational skills for returning to its nest after foraging. The ant’s primary means for long-distance navigation is path integration, which provides a continuous readout of the ant’s approximate distance and direction from the nest. The nest is pinpointed additionally with the aid of landmarks. Here we show that homing ants move upwind along nest-derived odor plumes to approach their nest. The ants only respond to odor plumes if the state of their path integrator tells them that they are near the nest. This influence of path integration is important because we could experimentally provoke ants to follow odor plumes from a foreign, conspecific nest and enter that nest. We identified CO2 as one nest-plume component that can by itself induce plume following in homing ants. Taken together, the results suggest that path-integration information enables ants to avoid entering the wrong nest, where they would inevitably be killed by resident ants. This project was supported by the Max Planck Society. Keywords: Cataglyphis, Desert ants, Landmark guidance, navigation, Olfaction, path integration, Plume following Conference: Tenth International Congress of Neuroethology, College Park. Maryland USA, United States, 5 Aug - 10 Aug, 2012. Presentation Type: Poster (but consider for participant symposium and student poster award) Topic: Orientation and Navigation Citation: Buehlmann C, Hansson BS and Knaden M (2012). Path integration controls nest-plume following in desert ants. Conference Abstract: Tenth International Congress of Neuroethology. doi: 10.3389/conf.fnbeh.2012.27.00080 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 30 Mar 2012; Published Online: 07 Jul 2012. * Correspondence: Miss. Cornelia Buehlmann, Max Planck Institute for Chemical Ecology, Evolutionary Neuroethology, Jena, 07745, Germany, cbuehlmann@ice.mpg.de Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Cornelia Buehlmann Bill S Hansson Markus Knaden Google Cornelia Buehlmann Bill S Hansson Markus Knaden Google Scholar Cornelia Buehlmann Bill S Hansson Markus Knaden PubMed Cornelia Buehlmann Bill S Hansson Markus Knaden Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

1A2-I09 環境磁場を用いたトポロジカルマップによる長距離ナビゲーション手法(車輪型/クローラ型移動ロボット(2))

1A2-I09 環境磁場を用いたトポロジカルマップによる長距離ナビゲーション手法(車輪型/クローラ型移動ロボット(2))

Flying Drosophila Orient to Sky Polarization

Insects maintain a constant bearing across a wide range of spatial scales. Monarch butterflies and locusts traverse continents [1, 2], and foraging bees and ants travel hundreds of meters to return to their nests [1, 3, 4], whereas many other insects fly straight for only a few centimeters before changing direction. Despite this variation in spatial scale, the brain region thought to underlie long-distance navigation is remarkably conserved [5, 6], suggesting that the use of a celestial compass is a general and perhaps ancient capability of insects. Laboratory studies of Drosophila have identified a local search mode in which short, straight segments are interspersed with rapid turns [7, 8]. However, this flight mode is inconsistent with measured gene flow between geographically separated populations [9-11], and individual Drosophila can travel 10 km across desert terrain in a single night [9, 12, 13]-a feat that would be impossible without prolonged periods of straight flight. To directly examine orientation behavior under outdoor conditions, we built a portable flight arena in which a fly viewed the natural sky through a liquid crystal device that could experimentally rotate the polarization angle. Our findings indicate that Drosophila actively orient using the sky's natural polarization pattern.

A bat's perspective on navigation

Much has been learned during the past decades about how animals navigate in their local environment. We know that most taxonomic groups, from arthropods to mammals, use multiple mechanisms to find their way (1). Animals may reach goals by following trails or approaching salient beacons or by computationally more sophisticated strategies, such as path integration (1, 2) and the use of geometric “cognitive maps” of the external environment (3, 4). The mammalian brain has specialized systems for many of these functions. Key components include, in the hippocampus, place cells, which are cells that fire only when the animal is in specific positions (4, 5), and, in the entorhinal cortex, grid cells, which provide the animal with a universally applicable metric of local space (5, 6). Together with direction-coding cells (7), place and grid cells are known to form a map-like neural representation of the animal's external environment (4–6). Despite these emerging insights, the growing knowledge of how space is computed in the mammalian brain is based almost exclusively on small-scale laboratory studies in which rodents forage in a test box or on a track. Whether similar mechanisms are used during large-scale navigation in the animal's natural habitat remains to be determined. Most of our knowledge about long-distance navigation comes from studies of nonmammalian species, such as birds, insects, fish, and sea turtles. Those studies have identified sources of information used by animals to determine compass direction as well as spatial location, for example the geomagnetic field, olfactory gradients, and celestial cues such as the sun and the stars (1, 8–11). The physiological mechanisms used to extract the information are not well understood, however, and the relationship to local spatial representation mechanisms described in mammals has almost not been examined at all.

Desert ants benefit from combining visual and olfactory landmarks

The desert ant, Cataglyphis fortis, uses both visual and olfactory cues to guide its return to the nest. The ants use vision-based path integration for long-distance navigation and memorize the visual and olfactory surrounding of the nest to finally locate the entrance. In the present study we investigated how the visual and the olfactory navigation systems interact. In field experiments ants were trained to associate the nest with a visual cue, an olfactory cue or a combination of both cues. We tested ants after one, five and 15 training runs, to investigate whether the ants would make use of the training cues to pinpoint the nest. We found that they were slow to learn the location of the nest when it was specified by just an olfactory or a visual cue. However, the ants focused their nest search after the first training run with the combined cue. Equally experienced ants responded to the individually presented visual or olfactory cues with the same high accuracy as they did to the combined cue. After 15 training runs, the combined cue still evoked an accurate response in the test, whereas the individually presented cues no longer did. Apparently, C. fortis benefit from combining their visual and olfactory navigational tools, because the bimodal sensory input accelerates the acquisition of landmark information.

Do desert ants smell the scenery in stereo?

Desert ants, Cataglyphis fortis, navigate individually in the inhospitable saltpans of Tunisia using path integration for long-distance navigation, and visual and olfactory landmarks for fine-scale orientation in the vicinity of the nest entrance. Here, we show in a field experiment that the ants are able to locate the nest entrance within a two-dimensional olfactory array. Ants were trained to forage in an open channel and to memorize the nest entrance relative to four odours that were applied at the corners of an invisible quadratic array. In a test situation, the ants pinpointed the fictive nest only when the odours were present at their learned positions. Our results suggest that the ants had learned the olfactory scenery around their nest. Furthermore, unilaterally antennectomized ants could not pinpoint the nest within a two-dimensional array. Hence, this kind of orientation depends on the simultaneous input of both antennae, that is, on a stereo sense of smell. Until now, insects and mammals, including humans, have only been known to use bilateral sensory input to follow a concentration gradient of an odour. Our evidence suggests that desert ants require a stereo sense of smell to make use of the olfactory scenery around their nest for homing.

Antennal regulation of migratory flight in the neotropical mothUrania fulgens

Migrating insects use their sensory systems to acquire local and global cues about their surroundings. Previous research on tethered insects suggests that, in addition to vision and cephalic bristles, insects use antennal mechanosensory feedback to maintain their airspeeds. Owing to the large displacements of migratory insects and difficulties inherent in tracking single individuals, the roles of these sensory inputs have never been tested in freely migrating insects. We tracked individual uraniid moths (Urania fulgens) as they migrated diurnally over the Panama Canal, and measured airspeeds and orientation for individuals with either intact or amputated flagella. Consistent with prior observations that antennal input is necessary for flight control, 59 per cent of the experimental moths could not fly after flagella amputation. The remaining fraction (41%) was flight-capable and maintained its prior airspeeds despite severe reduction in antennal input. Thus, maintenance of airspeeds may not involve antennal input alone, and is probably mediated by other modalities. Moths with amputated flagella could not recover their proper migratory orientations, suggesting that antennal integrity is necessary for long-distance navigation.

Behavior of Scandinavian Bats during Migration and Foraging at Sea

We studied bats migrating and foraging over the sea by direct observations and automatic acoustic recording. We recorded 11 species (of a community of 18 species) flying over the ocean up to 14 km from the shore. All bats used sonar during migration flights at sea, often with slightly lower frequencies and longer pulse intervals compared to those used over land. The altitude used for migration flight was most often <10 m above sea level. Bats must use other sensory systems for long-distance navigation, but they probably use echoes from the water surface to orient to the immediate surroundings. Both migrant and resident bats foraged over the sea in areas with an abundance of insects in the air and crustaceans in the surface waters. When hunting insects near vertical objects such as lighthouses and wind turbines, bats rapidly changed altitude, for example, to forage around turbine blades. The findings illustrate why and how bats might be exposed to additional mortality by offshore wind power.

The bird GPS – long-range navigation in migrants

Nowadays few people consider finding their way in unfamiliar areas a problem as a GPS (Global Positioning System) combined with some simple map software can easily tell you how to get from A to B. Although this opportunity has only become available during the last decade, recent experiments show that long-distance migrating animals had already solved this problem. Even after displacement over thousands of kilometres to previously unknown areas, experienced but not first time migrant birds quickly adjust their course toward their destination, proving the existence of an experience-based GPS in these birds. Determining latitude is a relatively simple task, even for humans, whereas longitude poses much larger problems. Birds and other animals however have found a way to achieve this, although we do not yet know how. Possible ways of determining longitude includes using celestial cues in combination with an internal clock, geomagnetic cues such as magnetic intensity or perhaps even olfactory cues. Presently, there is not enough evidence to rule out any of these, and years of studying birds in a laboratory setting have yielded partly contradictory results. We suggest that a concerted effort, where the study of animals in a natural setting goes hand-in-hand with lab-based study, may be necessary to fully understand the mechanism underlying the long-distance navigation system of birds. As such, researchers must remain receptive to alternative interpretations and bear in mind that animal navigation may not necessarily be similar to the human system, and that we know from many years of investigation of long-distance navigation in birds that at least some birds do have a GPS - but we are uncertain how it works.

Experiments with Cooperative Control of Underwater Robots

In this paper we describe cooperative control algorithms for robots and sensor nodes in an underwater environment. Cooperative navigation is defined as the ability of a coupled system of autonomous robots to pool their resources to achieve long-distance navigation and a larger controllability space. Other types of useful cooperation in underwater environments include: exchange of information such as data download and retasking; cooperative localization and tracking; and physical connection (docking) for tasks such as deployment of underwater sensor networks, collection of nodes and rescue of damaged robots. We present experimental results obtained with an underwater system that consists of two very different robots and a number of sensor network modules. We present the hardware and software architecture of this underwater system. We then describe various interactions between the robots and sensor nodes and between the two robots, including cooperative navigation. Finally, we describe our experiments with this underwater system and present data.