Effect of a magnetic pulse on orientation behavior in rainbow trout (Oncorhynchus mykiss)

Biological Effects of Electric, Magnetic, and Electromagnetic Fields from 0 to 100 MHz on Fauna and Flora: Workshop Report

This report summarizes effects of anthropogenic electric, magnetic, and electromagnetic fields in the frequency range from 0 to 100 MHz on flora and fauna, as presented at an international workshop held on 5-7 November in 2019 in Munich, Germany. Such fields may originate from overhead powerlines, earth or sea cables, and from wireless charging systems. Animals and plants react differentially to anthropogenic fields; the mechanisms underlying these responses are still researched actively. Radical pairs and magnetite are discussed mechanisms of magnetoreception in insects, birds, and mammals. Moreover, several insects as well as marine species possess specialized electroreceptors, and behavioral reactions to anthropogenic fields have been reported. Plants react to experimental modifications of their magnetic environment by growth changes. Strong adverse effects of anthropogenic fields have not been described, but knowledge gaps were identified; further studies, aiming at the identification of the interaction mechanisms and the ecological consequences, are recommended.

Magnetic alignment in free-ranging Indian Leopard (Panthera pardus fusca)

The earth’s geomagnetic field (GMF) is known to influence the behaviour of a wide range of species, but remains one of the most enigmatic of animal senses. Animals are known to utilize the GMF for a wide range of survival capabilities such as navigation and orienteering, migration, territoriality, homing, etc. Despite a lot of study in this regard on vertebrates, little is known about the effects of GMF on felids. Hence, we analyzed the body alignment of the Indian Leopard during defecation, and walking along the trails in the Jhalana Reserve Forest in India. Using circular statistics, we found that the leopards aligned their bodies on the north-south axis during defecation (mean azimuth -176.4°), while no such preference was found when walking (mean azimuth 52.9°). Thus we prove that leopards are sensitive to the GMF during basic physiological activities and in this context show similar behaviour to other vertebrates studied to date.

Magnetoreception and magnetic navigation in fishes: a half century of discovery

As the largest and most diverse vertebrate group on the planet, fishes have evolved an impressive array of sensory abilities to overcome the challenges associated with navigating the aquatic realm. Among these, the ability to detect Earth's magnetic field, or magnetoreception, is phylogenetically widespread and used by fish to guide movements over a wide range of spatial scales ranging from local movements to transoceanic migrations. A proliferation of recent studies, particularly in salmonids, has revealed that fish can exploit Earth's magnetic field not only as a source of directional information for maintaining consistent headings, but also as a kind of map for determining location at sea and for returning to natal areas. Despite significant advances, much about magnetoreception in fishes remains enigmatic. How fish detect magnetic fields remains unknown and our understanding of the evolutionary origins of vertebrate magnetoreception would benefit greatly from studies that include a wider array of fish taxa. The rich diversity of life-history characteristics that fishes exhibit, the wide variety of environments they inhabit, and their suitability for manipulative studies, make fishes promising subjects for magnetoreception studies.