Conditioned response to a magnetic anomaly in the Pekin duck (Anas platyrhynchos domestica) involves the trigeminal nerve.
There have been recent calls to develop protocols that collect unambiguous measures of behaviour using automatic techniques in conditioning experiments on magnetic orientation. Here, we describe an automated technique for recording the behaviour of Pekin ducks in a conditioning test that allows them to express unrestricted searching behaviour. Pekin ducks were trained to find hidden food in one corner of a square arena below which was placed a magnetic coil that produced a local magnetic anomaly. The trigeminal nerve was anaesthetised by injection of lignocaine hydrochloride 2-3 mm caudal to the medial canthus of each eye, medial to the globe, prior to the presentation of unrewarded tests. Lignocaine-treated ducks showed no initial preference for the magnetic anomaly whereas saline-treated control ducks showed a significant preference at the same age. A second experiment was undertaken in which the trigeminal nerve was surgically severed and 2-3 mm removed, and this surgery abolished the previously observed preference for the corner with the magnetic coil in a small number of ducks. These data show that Pekin ducks are able to detect and use magnetic stimuli to guide unrestricted search behaviour and are consistent with a hypothesis of magnetoreception involving a putative cluster of magnetite in the upper beak.
School of Animal and Veterinary Sciences, Charles Sturt University, Locked Bag 588, Wagga Wagga, NSW 2650, Australia. rfreire@csu.edu.au
Rafael
R
Freire
Emma
E
Dunston
Emmalee M
EM
Fowler
Gary L
GL
McKenzie
Christopher T
CT
Quinn
Jacob
J
Michelsen
D000818:Animals; D003213:Conditioning, Psychological / Q000187:drug effects / Q000502:physiology*; D004372:Ducks / Q000502:physiology*; D008012:Lidocaine / Q000008:administration & dosage / Q000494:pharmacology; D060328:Magnetic Phenomena; D014276:Trigeminal Nerve / Q000187:drug effects / Q000502:physiology*
D008012:Lidocaine