Magnetic anisotropy and organization of nanoparticles in heads and antennae of neotropical leaf-cutter ants, Atta colombica

Odivaldo C. Alves, Robert B. Srygley, Andre J. Riveros, Marcia A. Barbosa, Darci M. S. Esquivel, Eliane Wajnberg

Resultado de la investigación: Contribución a RevistaArtículo

3 Citas (Scopus)

Resumen

Oriented magnetic nanoparticles have been suggested as a good candidate for a magnetic sensor in ants. Behavioural evidence for a magnetic compass in neotropical leaf-cutter ants, Atta colombica (Formicidae: Attini), motivated a study of the arrangement of magnetic particles in the ants' four major body parts by measuring the angular dependence of the ferromagnetic resonance spectra at room temperature. Spectra of the thoraces and those of the abdomens showed no significant angular dependence, while those of the antennae and those of the heads exhibited a periodic dependence relative to the magnetic field. Fitting of the angular dependence of the resonant field resulted in an unexpected magnetic anisotropy with uniaxial symmetry. High values of the first order anisotropy constant were observed for the magnetic material in antennae (−2.9  ×  105 erg cm−3) and heads (−1  ×  106 erg cm−3) as compared to body parts of other social insects. In addition, the magnitude of the anisotropy in the heads was comparable to that observed in magnetite nanoparticles of 4–5 nm diameter. For the antennae, the mean angle of the particles' easy magnetization axis (EA) was estimated to be 41° relative to the straightened antenna's long axis. For the heads, EA was approximately 60° relative to the head's axis running from midway between the spines to the clypeus. These physical characteristics indicate organized magnetic nanoparticles with a potential for directional sensitivity, which is an important feature of magnetic compasses.
Idioma originalEnglish
PublicaciónJournal Physics D: Applied Physics
Volumen47
N.º43
DOI
EstadoPublished - oct 29 2014

Citar esto

Alves, Odivaldo C. ; Srygley, Robert B. ; Riveros, Andre J. ; Barbosa, Marcia A. ; Esquivel, Darci M. S. ; Wajnberg, Eliane. / Magnetic anisotropy and organization of nanoparticles in heads and antennae of neotropical leaf-cutter ants, Atta colombica. En: Journal Physics D: Applied Physics. 2014 ; Vol. 47, N.º 43.
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title = "Magnetic anisotropy and organization of nanoparticles in heads and antennae of neotropical leaf-cutter ants, Atta colombica",
abstract = "Oriented magnetic nanoparticles have been suggested as a good candidate for a magnetic sensor in ants. Behavioural evidence for a magnetic compass in neotropical leaf-cutter ants, Atta colombica (Formicidae: Attini), motivated a study of the arrangement of magnetic particles in the ants' four major body parts by measuring the angular dependence of the ferromagnetic resonance spectra at room temperature. Spectra of the thoraces and those of the abdomens showed no significant angular dependence, while those of the antennae and those of the heads exhibited a periodic dependence relative to the magnetic field. Fitting of the angular dependence of the resonant field resulted in an unexpected magnetic anisotropy with uniaxial symmetry. High values of the first order anisotropy constant were observed for the magnetic material in antennae (−2.9  ×  105 erg cm−3) and heads (−1  ×  106 erg cm−3) as compared to body parts of other social insects. In addition, the magnitude of the anisotropy in the heads was comparable to that observed in magnetite nanoparticles of 4–5 nm diameter. For the antennae, the mean angle of the particles' easy magnetization axis (EA) was estimated to be 41° relative to the straightened antenna's long axis. For the heads, EA was approximately 60° relative to the head's axis running from midway between the spines to the clypeus. These physical characteristics indicate organized magnetic nanoparticles with a potential for directional sensitivity, which is an important feature of magnetic compasses.",
author = "Alves, {Odivaldo C.} and Srygley, {Robert B.} and Riveros, {Andre J.} and Barbosa, {Marcia A.} and Esquivel, {Darci M. S.} and Eliane Wajnberg",
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Magnetic anisotropy and organization of nanoparticles in heads and antennae of neotropical leaf-cutter ants, Atta colombica. / Alves, Odivaldo C.; Srygley, Robert B.; Riveros, Andre J.; Barbosa, Marcia A.; Esquivel, Darci M. S.; Wajnberg, Eliane.

En: Journal Physics D: Applied Physics, Vol. 47, N.º 43, 29.10.2014.

Resultado de la investigación: Contribución a RevistaArtículo

TY - JOUR

T1 - Magnetic anisotropy and organization of nanoparticles in heads and antennae of neotropical leaf-cutter ants, Atta colombica

AU - Alves, Odivaldo C.

AU - Srygley, Robert B.

AU - Riveros, Andre J.

AU - Barbosa, Marcia A.

AU - Esquivel, Darci M. S.

AU - Wajnberg, Eliane

PY - 2014/10/29

Y1 - 2014/10/29

N2 - Oriented magnetic nanoparticles have been suggested as a good candidate for a magnetic sensor in ants. Behavioural evidence for a magnetic compass in neotropical leaf-cutter ants, Atta colombica (Formicidae: Attini), motivated a study of the arrangement of magnetic particles in the ants' four major body parts by measuring the angular dependence of the ferromagnetic resonance spectra at room temperature. Spectra of the thoraces and those of the abdomens showed no significant angular dependence, while those of the antennae and those of the heads exhibited a periodic dependence relative to the magnetic field. Fitting of the angular dependence of the resonant field resulted in an unexpected magnetic anisotropy with uniaxial symmetry. High values of the first order anisotropy constant were observed for the magnetic material in antennae (−2.9  ×  105 erg cm−3) and heads (−1  ×  106 erg cm−3) as compared to body parts of other social insects. In addition, the magnitude of the anisotropy in the heads was comparable to that observed in magnetite nanoparticles of 4–5 nm diameter. For the antennae, the mean angle of the particles' easy magnetization axis (EA) was estimated to be 41° relative to the straightened antenna's long axis. For the heads, EA was approximately 60° relative to the head's axis running from midway between the spines to the clypeus. These physical characteristics indicate organized magnetic nanoparticles with a potential for directional sensitivity, which is an important feature of magnetic compasses.

AB - Oriented magnetic nanoparticles have been suggested as a good candidate for a magnetic sensor in ants. Behavioural evidence for a magnetic compass in neotropical leaf-cutter ants, Atta colombica (Formicidae: Attini), motivated a study of the arrangement of magnetic particles in the ants' four major body parts by measuring the angular dependence of the ferromagnetic resonance spectra at room temperature. Spectra of the thoraces and those of the abdomens showed no significant angular dependence, while those of the antennae and those of the heads exhibited a periodic dependence relative to the magnetic field. Fitting of the angular dependence of the resonant field resulted in an unexpected magnetic anisotropy with uniaxial symmetry. High values of the first order anisotropy constant were observed for the magnetic material in antennae (−2.9  ×  105 erg cm−3) and heads (−1  ×  106 erg cm−3) as compared to body parts of other social insects. In addition, the magnitude of the anisotropy in the heads was comparable to that observed in magnetite nanoparticles of 4–5 nm diameter. For the antennae, the mean angle of the particles' easy magnetization axis (EA) was estimated to be 41° relative to the straightened antenna's long axis. For the heads, EA was approximately 60° relative to the head's axis running from midway between the spines to the clypeus. These physical characteristics indicate organized magnetic nanoparticles with a potential for directional sensitivity, which is an important feature of magnetic compasses.

U2 - 10.1088/0022-3727/47/43/435401

DO - 10.1088/0022-3727/47/43/435401

M3 - Artículo

VL - 47

JO - Journal Physics D: Applied Physics

JF - Journal Physics D: Applied Physics

SN - 0022-3727

IS - 43

ER -