scholarly journals Changes in the geomagnetic field has little effect on the overwintering range of Eastern North American fall migratory monarch butterflies (Danaus plexippus), indicating a lack of an innate magnetic map sense for navigation

2020 ◽  
Author(s):  
Patrick Anthony Guerra ◽  
Stephen Matter
Keyword(s):  
Magnetic Field ◽  
North American ◽  
Geomagnetic Field ◽  
Danaus Plexippus ◽  
Monarch Butterfly ◽  
Central Mexico ◽  
Earth’S Magnetic Field ◽  
Long Distance ◽  
Monarch Butterflies ◽  
Earth's Magnetic Field

Abstract BackgroundIndividuals of many species that perform annual long-distance migrations are capable of stopping at specific overwintering destinations, despite having not been there before. The iconic monarch butterfly (Danaus plexippus) and its annual long-distance fall migration is a famous example of this phenomenon. During the fall, Eastern North American monarch butterflies use various compass mechanisms to properly orient their flight southwards, in order to leave their summer breeding grounds in Southern Canada and the Northern United States, and reach their overwintering sites in Central Mexico. It remains a mystery, however, how monarchs locate and stop at these specific, consistent overwintering sites, especially since these individuals are on their maiden voyage. MethodsWe test the hypothesis that fall migrant monarchs locate these overwintering sites by using an innate, inherited map sense based on sensing and responding to specific geomagnetic signatures that are correlated with the overwintering sites. Using a natural displacement approach, we examined if the locations of overwintering sites and the abundance of monarchs at them, changes with the natural shift of the Earth’s magnetic field over time (2004-2018).ResultsWe found that despite the natural displacement of the geomagnetic field over the years, the locations of the overwintering sites and monarch abundance were unaffected. For example, fall monarchs continued to overwinter at the most southern sites in Mexico, even when the geomagnetic coordinates associated with these sites would have shifted north due to the natural shift of the Earth’s magnetic field, placing these sites significantly outside the range of the overwintering area.ConclusionsOur results suggest that monarchs do not employ a map sense based on geomagnetic cues for finding their overwintering sites, and might instead use other mechanisms or strategies for locating them (potentially using localized sensory cues) once they are near or have arrived in Central Mexico. We suggest that future work should now focus on understanding what these cue parameters are, in order to inform conservation efforts that are aimed at protecting the threatened monarch butterfly and preserving its annual long-distance migration.

scholarly journals Magnetic maps in animal navigation

2022 ◽  
Author(s):  
Kenneth J. Lohmann ◽  
Kayla M. Goforth ◽  
Alayna G. Mackiewicz ◽  
Dana S. Lim ◽  
Catherine M. F. Lohmann
Keyword(s):  
Magnetic Field ◽  
Positional Information ◽  
Natal Philopatry ◽  
Earth’S Magnetic Field ◽  
Long Distance ◽  
Natal Homing ◽  
Potential Source ◽  
Animal Navigation ◽  
Earth's Magnetic Field ◽  
The Magnetic Field

AbstractIn addition to providing animals with a source of directional or ‘compass’ information, Earth’s magnetic field also provides a potential source of positional or ‘map’ information that animals might exploit to assess location. In less than a generation, the idea that animals use Earth’s magnetic field as a kind of map has gone from a contentious hypothesis to a well-established tenet of animal navigation. Diverse animals ranging from lobsters to birds are now known to use magnetic positional information for a variety of purposes, including staying on track along migratory pathways, adjusting food intake at appropriate points in a migration, remaining within a suitable oceanic region, and navigating toward specific goals. Recent findings also indicate that sea turtles, salmon, and at least some birds imprint on the magnetic field of their natal area when young and use this information to facilitate return as adults, a process that may underlie long-distance natal homing (a.k.a. natal philopatry) in many species. Despite recent progress, much remains to be learned about the organization of magnetic maps, how they develop, and how animals use them in navigation.

scholarly journals Evidence that pigeons orient to geomagnetic intensity during homing

2007 ◽  
Vol 274 (1614) ◽  
pp. 1153-1158 ◽  
Author(s):  
Todd E Dennis ◽  
Matt J Rayner ◽  
Michael M Walker
Keyword(s):  
Magnetic Field ◽  
Geomagnetic Field ◽  
Columba Livia ◽  
Earth’S Magnetic Field ◽  
Naturally Occurring ◽  
Intensity Field ◽  
Earth's Magnetic Field ◽  
Field Information ◽  
Local Intensity ◽  
Tracking Devices

The influence of the Earth's magnetic field on locomotory orientation has been studied in many taxa but is best understood for homing pigeons ( Columba livia ). Effects of experimentally induced and naturally occurring perturbations in the geomagnetic field suggest that pigeons are sensitive to changes in geomagnetic parameters. However, whether pigeons use the Earth's magnetic field for position determination remains unknown. Here we report an apparent orientation to the intensity gradient of the geomagnetic field observed in pigeons homing from sites in and around a magnetic anomaly. From flight trajectories recorded by GPS-based tracking devices, we noted that many pigeons released at unfamiliar sites initially flew, in some cases up to several kilometres, in directions parallel and/or perpendicular to the bearing of the local intensity field. This behaviour occurred irrespective of the homeward direction and significantly more often than what was expected by random chance. Our study describes a novel behaviour which provides strong evidence that pigeons when homing detect and respond to spatial variation in the Earth's magnetic field—information of potential use for navigation.

scholarly journals Contemporary loss of migration in monarch butterflies

2019 ◽  
Vol 116 (29) ◽  
pp. 14671-14676 ◽  
Author(s):  
Ayşe Tenger-Trolander ◽  
Wei Lu ◽  
Michelle Noyes ◽  
Marcus R. Kronforst
Keyword(s):  
North American ◽  
Indoor Environment ◽  
Captive Breeding ◽  
Danaus Plexippus ◽  
Monarch Butterfly ◽  
Population Recovery ◽  
Monarch Butterflies ◽  
Commercial Population ◽  
Open Question ◽  
The Impact

The annual migration of the monarch butterfly Danaus plexippus is in peril. In an effort to aid population recovery, monarch enthusiasts across North America participate in a variety of conservation efforts, including captive rearing and release of monarch butterflies throughout the summer and autumn. However, the impact of captive breeding on monarchs remains an open question. Here, we show that captive breeding, both commercially and by summertime hobbyists, causes migratory behavior to be lost. Monarchs acquired commercially failed to orient south when reared outdoors in the autumn, unlike wild-caught North American monarchs, yet they did enter reproductive diapause. The commercial population was genetically highly divergent from wild-caught North American monarchs and had rounder forewings, similar to monarchs from nonmigratory populations. Furthermore, rearing wild-caught monarchs in an indoor environment mimicking natural migration-inducing conditions failed to elicit southward flight orientation. In fact, merely eclosing indoors after an otherwise complete lifecycle outdoors was enough to disrupt southern orientation. Our results provide a window into the complexity—and remarkable fragility—of migration.

scholarly journals The Use of Magnetic Field and Magnetometers in Supporting the Air Navigation

2015 ◽  
Vol 22 (1) ◽  
pp. 21-29 ◽  
Author(s):  
Ireneusz Ogórek ◽  
Marek Grzegorzewski ◽  
Maciej Maciejowski
Keyword(s):  
Magnetic Field ◽  
Geomagnetic Field ◽  
Magnetic Intensity ◽  
Earth’S Magnetic Field ◽  
Aircraft Navigation ◽  
Earth's Magnetic Field ◽  
Additional Support ◽  
Magnetic Field Variations

Abstract At present, the Earth’s magnetic field (geomagnetic field) undergoes considerable variations. The use of towers measuring areal variations in magnetic intensity may provide additional support for aircraft navigation. This paper presents the idea of using magnetometers for supporting GNSS as well as for creating a landing system based on magnetic field variations.

scholarly journals Short Communications Relationship Between Es and the Earth's Magnetic Field at Middle Latitudes

1972 ◽  
Vol 25 (1) ◽  
pp. 97
Author(s):  
GL Goodwin
Keyword(s):  
Magnetic Field ◽  
Geomagnetic Field ◽  
Time Data ◽  
Earth’S Magnetic Field ◽  
Night Time ◽  
Middle Latitudes ◽  
Consistent Relationship ◽  
Different Seasons ◽  
Earth's Magnetic Field

Attempts have been made, with some success, to find an association between changes in the intensity of Es ionization and in the intensity of the Earth's magnetic field (Wilkie and McNicol 1962; Fatkullin 1965; Goodwin 1965; Ovezgel'dyyev 1965). Nevertheless, the overall results of these investigations have not revealed a consistent relationship between Es and the Earth's field. This is partly due to the fact that daytime and night-time data, or data for the different seasons, were generally not treated separately. In the present paper an analysis of new observations is presented and the results of some previous analyses are also reappraised. A consistent relationship is found between night-time Es observations and the geomagnetic field.

scholarly journals Effects of early-life exposure to sublethal levels of a common neonicotinoid insecticide on the orientation and migration of monarch butterflies (Danaus plexippus)

2020 ◽  
Vol 224 (4) ◽  
pp. jeb230870
Author(s):  
Alana A. E. Wilcox ◽  
Amy E. M. Newman ◽  
Nigel E. Raine ◽  
Greg W. Mitchell ◽  
D. Ryan Norris
Keyword(s):  
Danaus Plexippus ◽  
Monarch Butterfly ◽  
Flight Simulator ◽  
Testing Time ◽  
Long Distance ◽  
Monarch Butterflies ◽  
Early Life Exposure ◽  
Neonicotinoid Insecticide ◽  
In The Wild ◽  
And Migration

ABSTRACTMigratory insects use a variety of innate mechanisms to determine their orientation and maintain correct bearing. For long-distance migrants, such as the monarch butterfly (Danaus plexippus), these journeys could be affected by exposure to environmental contaminants. Neonicotinoids are synthetic insecticides that work by affecting the nervous system of insects, resulting in impairment of their mobility, cognitive performance, and other physiological and behavioural functions. To examine how neonicotinoids might affect the ability of monarch butterflies to maintain a proper directional orientation on their ∼4000 km migration, we grew swamp milkweed (Asclepias incarnata) in soil that was either untreated (0 ng g−1: control) or mixed with low (15 ng g−1 of soil) or high (25 ng g−1 of soil) levels of the neonicotinoid clothianidin. Monarch caterpillars were raised on control or clothianidin-treated milkweed and, after pupation, either tested for orientation in a static flight simulator or radio-tracked in the wild during the autumn migration period. Despite clothianidin being detectable in milkweed tissue consumed by caterpillars, there was no evidence that clothianidin influenced the orientation, vector strength (i.e. concentration of direction data around the mean) or rate of travel of adult butterflies, nor was there evidence that morphological traits (i.e. mass and forewing length), testing time, wind speed or temperature impacted directionality. Although sample sizes for both flight simulator and radio-tracking tests were limited, our preliminary results suggest that clothianidin exposure during early caterpillar development does not affect the directed flight of adult migratory monarch butterflies or influence their orientation at the beginning of migration.

scholarly journals Alexander von Humboldt's charts of the Earth's magnetic field: an assessment based on modern models

2010 ◽  
Vol 1 (2) ◽  
pp. 63-76 ◽  
Author(s):  
M. Mandea ◽  
M. Korte ◽  
A. Soloviev ◽  
A. Gvishiani
Keyword(s):  
Magnetic Field ◽  
19Th Century ◽  
Geomagnetic Field ◽  
Earth’S Magnetic Field ◽  
Broad Area ◽  
150Th Anniversary ◽  
Alexander Von Humboldt ◽  
Earth's Magnetic Field ◽  
Long Life ◽  
The 19Th Century

Abstract. The 19th century witnessed a resurgence of interest in Earth's magnetic field. Both observational and theoretical aspects were involved, and one of the emblematic figures of this period was Alexander von Humboldt. Throughout a long life he maintained a strong interest in a broad area of subjects, however, here we are interested in his role in geomagnetism, and particularly in his pioneering contributions to charting the geomagnetic field. Alexander von Humboldt efforts in measuring and charting the Earth's magnetic field are recounted and the maps of declination, inclination and total intensity he had prepared are compared, favorably, with maps for the same epoch based on a modern model of the geomagnetic field, gufm1. This modern assessment of the accuracy of von Humboldt's geomagnetic charts illustrates the importance of his work, being also our homage to the 150th anniversary of the death of Alexander von Humboldt.

7. The Earth’s magnetic field

2018 ◽  
pp. 106-126
Author(s):  
William Lowrie
Keyword(s):  
Magnetic Field ◽  
Geomagnetic Field ◽  
Plate Tectonics ◽  
Magnetic Anomalies ◽  
Earth’S Magnetic Field ◽  
The Earth ◽  
Earth's Magnetic Field ◽  
Reversed Polarity ◽  
Harmful Radiation ◽  
The Magnetic Field

The Earth is surrounded by a magnetic field, which originates inside its molten core, and which for centuries has helped travellers to navigate safely across uncharted regions. The magnetic field protects life on the Earth by acting as a shield against harmful radiation from space, especially from the Sun. ‘The Earth’s magnetic field’ explains that the magnetic field at the Earth’s surface is dominantly that of an inclined dipole. The Sun’s deforming effect on the magnetic field outside the Earth is described, as are the magnetic fields of other planets. The magnetism of rocks forms the basis of palaeomagnetism, which explains how plate tectonics displaced the continents and produced oceanic magnetic anomalies whenever the geomagnetic field reversed polarity.

scholarly journals 14C Dating and Magnetostratigraphy

Radiocarbon ◽  
1983 ◽  
Vol 25 (2) ◽  
pp. 229-238 ◽  
Author(s):  
Roy Thompson
Keyword(s):  
Magnetic Field ◽  
Geomagnetic Field ◽  
Cosmic Ray ◽  
Lava Flows ◽  
Earth’S Magnetic Field ◽  
14C Dating ◽  
Fine Grained ◽  
Magnetic Remanence ◽  
Earth's Magnetic Field ◽  
History Of

The history of the earth's magnetic field is preserved in the fossil magnetism of archaeologic specimens, natural rocks and sediments. Samples such as lava flows and baked sherds that acquired a thermoremanent magnetization on cooling can be used to estimate ancient geomagnetic field intensities and directions. Paleofield directions can also be obtained from fine-grained sediments that acquired detrital magnetic remanence when deposited. Study of the earth's magnetic field over the last few tens of thousands of years yields information on geomagnetic dynamo theories, causes of fluctuations in cosmic-ray activity, and the formulation of a new regional chronologic tool.

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