Fig. 1. Wavelength-dependence of shoreward compass orientation (A,B) and homing orientation (C,D) by newts housed in outdoor tanks under full-spectrum light prior to testing (data from Phillips and Borland, 1994). In shoreward orientation tests, (A) newts tested under 400 nm and 450 nm light oriented in the correct shoreward direction and were indistinguishable from controls tested under full-spectrum light (not shown), while (B) newts tested under 550 nm and 600 nm light exhibited significant magnetic orientation that was rotated approximately 90° counterclockwise of the shore direction. In homing tests, (C) newts tested under 400 nm and 450 nm light exhibited homeward orientation, while (D) newts tested under 550 nm and 600 nm light failed to show a consistent direction of orientation relative to home (NS, not significant). In the homing tests, newts tested under 550 nm and 600 nm light were also randomly distributed with respect to the direction of shore in the outdoor training tanks and with respect to magnetic north (not shown). Data points are magnetic bearings of individual newts tested in one of four symmetrical magnetic field alignments (see Materials and methods) plotted relative to the magnetic bearing of the artificial shore in the outdoor training tank (A,B) or relative to the magnetic direction of the newts' home ponds (C,D). In both the shoreward and homing tests, data are pooled from newts collected from ponds that differed in home direction by approximately 90°, and held prior to testing in tanks with three different shore directions; see Phillips and Borland (1994).

Return to article