Temperature dependent attraction by goldfish to a chemical feeding cue presented alone and in combination with heated...

An eight cell multiple-choice experiment was used to investigate the influence of temperature on the locomotor response of goldfish (Carassius auratus) to a chemical feeding cue. When a food extract was infused into a single cell at ambient temperatures of 26, 28, 30, 32, and 34 degrees C (ambient temperature=acclimation temperature) the goldfish spent more time in the extract cell than three similarly outfitted dummy cells at all temperatures, but the intensity of their attraction varied over the thermal interval. Attraction was highest at 28 degrees C and gradually declined to its lowest level by 34 degrees C. Goldfish acclimated and tested at 26 degrees C spent more time visiting a combination of food extract and heated water (H+E) than either food extract (E) or heated water (H) alone. The preference for H+E over H and E increased with the temperature differential between heated and ambient waters. Successive increased in acclimation/ambient temperature (30, 32, and 34 degrees C) extinguished the differences between H+E and H and E but did not eliminate the attraction for the thermal and chemical stimuli, per se. The importance of temperature in the variability of chemoreceptive behavior and the interaction between chemical and thermal stimuli are discussed.