Effect of light wavelength spectrum on magnetic compass orientation in Tenebrio molitor

Abstract

In many animal species, geomagnetic compass sensitivity has been demonstrated to depend on spectral composition of light to which moving animals are exposed. Besides a loss of magnetic orientation, cases of a shift in the compass direction by 90 degrees following a change in the colour of light have also been described. This hitherto unclear phenomenon can be explained either as a change in motivation or as a side effect of a light-dependent reception mechanism. Among the invertebrates, the 90 degrees shift has only been described in Drosophila. In this paper, another evidence of the phenomenon is reported. Learned compass orientation in the Tenebrio molitor was tested. If animals were trained to remember the magnetic position of a source of shortwave UV light and then tested in a circular arena in diffuse light of the same wavelength, they oriented according to the learned magnetic direction. If, however, they were tested in blue-green light after UV light training, their magnetic orientation shifted by 90 degrees CW. This result is being discussed as one of a few cases of 90 degrees shift reported to date, and as an argument corroborating the hypothesis of a close connection between photoreception and magnetoreception in insects.

Evaluation of some Accessions of Bambara Groundnut (Vigna Subterranean L. Verdc) for Resistance to Bruchid Infestation, Based on Grain Source and Seed Coat Colour

“…The effect of seed-coat colour in the present study is in line with the reports by many researchers like Orzolek and Murphy (1993), Vacha et al (2008), and Echezona and Offordile (2011), who state that insects have a preference for colours. However, reports specifically on the effect of seed coat on oviposition and survival of C. maculatus are contradictory.…”

A behavioral perspective on the biophysics of the light-dependent magnetic compass: a link between directional and spatial perception?

“…To better see the correspondence, rotate and/or invert firing fields so black geometric shape matches the corresponding shape in the center of B; see Sharp (Sharp, 2002;Sharp, 2006) for additional recordings from subicular place cells with similar spatial firing fields. (D)Inverse or complementary patterns to those shown in C, which are predicted to occur if subicular place cells receive input from a LDMC mechanism with antagonistic spectral properties similar to those found in amphibians and insects (Phillips and Borland, 1992a;Phillips and Sayeed, 1993;Phillips et al, 2001;Phillips et al, 2010;Freake and Phillips, 2005;Vacha et al, 2008b).…”

“…Evidence for a RPM-based magnetic compass in some animals includes: (1) sensitivity to the axis, but not polarity, of the magnetic field ( Fig.1) (Wiltschko and Wiltschko, 1972;Phillips, 1986); (2) involvement of a light-dependent magnetoreception mechanism (Phillips and Borland, 1992a;Phillips and Borland, 1992b;Phillips and Sayeed, 1993;Freake and Phillips, 2005;Wiltschko and Wiltschko, 2005;Vacha et al, 2008b); (3) disruption of magnetic compass orientation outside a narrow window of static field intensities ; (4) the absence of an effect of 'pulse remagnetization' (Beason and Semm, 1996;Munro et al, 1997a;Munro et al, 1997b); and (5) disruption by low-level alternating fields (~0.1% of the static field strength) in the low RF range (<100MHz) that should alter the magnetic field-dependent populations of singlet and triplet energy states in a RPM (Ritz et al, 2004;Ritz et al, 2009;Henbest et al, 2004;Thalau et al, 2005;Vacha et al, 2009). In migratory birds, the effects of low-level RF fields have been shown to depend on both the intensity and relative alignment of the static magnetic field (Ritz et al, 2004;Ritz et al, 2009) .…”

“…photoreceptors, the LDMC in insects (Phillips and Sayeed, 1993;Vacha et al, 2008b), amphibians (Phillips and Borland 1992a;Deutschlander et al, 1999a;Freake and Phillips, 2005) and, possibly, birds (Muheim et al, 2002;Wiltschko et al, 2010) share functional properties (i.e. light-dependent 90deg rotations in the direction of magnetic compass orientation) that appear to result, at least in part, from an antagonistic interaction of short-and longwavelength inputs (Phillips and Borland, 1992a;Deutschlander et al, 1999b;Phillips et al, 2010).…”

Spontaneous magnetic orientation in larval Drosophila shares properties with learned magnetic compass responses in adult flies and mice.

“…In contrast, studies of the effects of light on learned magnetic compass orientation by adult male D. melanogaster and mealworm beetles (Tenebrio molitor) have shown a wavelength-dependent 90deg shift in orientation that is consistent with a light-dependent (presumably radical pair-based) magnetic compass (Phillips and Sayeed, 1993;Vácha et al, 2008). A similar light-dependent 90deg shift in orientation in amphibians has been shown to result from a direct effect of light on the underlying magnetoreception mechanism, consistent with the involvement of a radical pair-based mechanism.…”