Presence of stable carbon centric free radicals and ferromagnetic elements in the antennae and the wings of nocturnal silk moth: A magnetic nanostructure for magneto sensing

Abstract

This work addresses an interesting, interdisciplinary problem of nature-"the mechanism by which animal senses the earth's magnetic field and navigate". Currently there are two existing theories trying to explain, "How the animal senses the magnetic field of earth". One theory is based on the presence of biogenic magnetic materials in the body of the animals. Such magnetic materials which are present inside the body, orients itself according to the earth's weak magnetic field and convey the information to the nervous system to develop the navigational map. The second theory is based on a light dependent photochemical reaction. A photochemical reaction leads to the generation of radical pairs, which helps in sensing the weak magnetic field of the earth. In this work, we are proposing a new model of magnetoreception. Unlike the existing radical pair system of magnetoreception, where a light-dependent reaction is essential to generate free radicals, here we show the presence of a large pool of stable carbon-centric free radicals in the nano-domains of the antennae and the wings of silk moth. This stable pool of carbon-centric free radicals is intrinsic in the nano-domains of these anatomical structures and responds to weak magnetic fields similar to that of Earth's (50 T) even in the absence of light. Hence we are proposing that nocturnal animals in their navigation could utilize such a light independent mechanism. We further observed the presence of ferromagnetic elements (Fe, Ni, Co, Mn) in these structures. In conclusion, we have discussed how carbon centric free radicals along with other ferromagnetic components present in the antennae and the wings of the nocturnal silk moth, might help them to avoid the bats.

Soft magnetic memory of silk cocoon membrane

“…Such type of carbon-centric free radicals are very stable in nature and extremely difficult to reduce or oxidize. Anthropogenic multi-walled carbon nanotubes trapped in spider web and antennae of the silk moth preserves such pool of carbon-centered free-radicals for a long period of time and exhibit soft magnetic behavior 13 14 . Thus EPR measurements indicate the presence of soft ferromagnetic elements and a pool of carbon-centered free radicals in the cocoon membrane ( Fig.…”

“…It is difficult to pinpoint the exact organic moiety in the silk fiber structure of cocoon, which possibly exhibits carbon centric free radical features. Since silk thread in cocoon is a super-coiled structure forming a rigid matrix, it may lead to ‘frustrated spin’ in several carbon moieties and such ‘frustrated spin on carbon’ leads to ‘carbon centric free radicals’ 13 14 .…”

The Radical Pair Mechanism and the Avian Chemical Compass: Quantum Coherence and Entanglement

“…Scientists found that many sources of directional information can contribute to birds' navigation, such as landmarks or topographic features [58,59], stars [60][61][62][63][64], the sun [65][66][67], and so on. Among these sources and hypotheses, magnetite as well as biochemical radical-pair reactions has been hypothesized to mediate sensitivity to Earthstrength magnetic fields through fundamentally different physical mechanisms [68,69].…”

“…the sun [65][66][67], and so on. Among these sources and hypotheses, magnetite as well as biochemical radical-pair reactions has been hypothesized to mediate sensitivity to Earthstrength magnetic fields through fundamentally different physical mechanisms [68,69].…”