Crayfish avoid noxious high, but not low, temperatures
The University of Texas-Pan American, Department of Biology, USA
Nociceptors (sensory neurons that respond to tissue damage) have not yet been characterized in any crustacean, due in part to a lack of an effective noxious stimulus that causes nociceptive behaviour. Previous research with decapod crustaceans typically showed no behavioural response to extremes of pH (acids and bases), and algogenic chemicals (capsaicin and isothiocyanate). Some studies yielded conflicting results with these stimuli. Nociceptors are often responsive to temperature extremes, even in temperature aquatic animals (e.g., trout). To test responses to noxious high temperature, we touched the inside of the claws of Louisiana red swamp crayfish with the top of a soldering iron that was either heated (temperature higher than 45°C) or at room temperature. Similarly, to test responses to noxious low temperatures, we touched the claws with a piece of dry ice (temperature lower than -70°C) held within plastic forceps, or the room temperature plastic forceps alone. Crayfish showed significantly greater responses to the high temperatures than the control, often with rapid avoidance responses, up to and including tailflips. In contrast, crayfish showed no differences in behaviour to low temperatures. Some individuals would pinch and hold on to dry ice for several seconds. These behaviours are broadly consistent with crayfish responses to more moderate changes in temperature (i.e., crayfish more likely to respond to increase in temperature rather than a decrease). Future research is needed to determine if these responses are mediated by nociceptors or thermoreceptors.
SP was supported by a Howard Hughes Medical Institute (HHMI) undergraduate research grant (award #52006321) and an Undergraduate Research Initiative award from The University of Texas-Pan American.
Tenth International Congress of Neuroethology, College Park. Maryland USA, USA, 5 Aug - 10 Aug, 2012.
Poster Presentation (see alternatives below as well)
(2012). Crayfish avoid noxious high, but not low, temperatures.
Front. Behav. Neurosci.
Tenth International Congress of Neuroethology.
02 May 2012;
07 Jul 2012.
Dr. Zen Faulkes, The University of Texas-Pan American, Department of Biology, Edinburg, TX, 78539, USA, firstname.lastname@example.org