Salamander response

Table 1. Preferences of three species of Plethodon in trials with two substrate-home odor choices. In each trial, the female or male was given a choice of two substrates marked by another salamander. Response to substrate was measured every two minutes for two hours (for a total of 60 observations). T is the value of the Wilcoxon matched-pairs signed-ranks test, p is the two-sided probability with significance of a <= 0.05 and a<=0.01. C = conspecific, H = heterospecific. For P. teyahalee, HI = P. shennani, H2 = P. montanus for P. shermani, HI = P. montanus, Hl-P. teyahalee and for P. montanus, HI = P. shermani, H2 = P. teyahalee...

We examined the effects and possible interactions between snake diet treatment and salamander sex using a binomial regression with a log-log canonical link in Statistica s (StatSoft, Inc., 2001) Generalized Linear Model (GZLM). We tested the full factorial model, which examined the effects of treatment (TSpc, TSeb, distilled water) and sex of the test salamander on salamander responses. We tested for significant effects using the Wald statistic (analogous to least-squares estimates). 

Table 3. The results of the binomial regression of salamander sex and diet treatment on salamander response in early and late night field trials.

The first experiment was conducted on four consecutive evenings during the week of 21 May 2003, and the second experiment was conducted during the evenings of 1 and 2 July 2003. We used a previously established behavioral bioassay (Sullivan et al., 2002) to test salamander responses to the treatments. Each trial consisted of an array of 54 petri dishes lined with two semi-circular pieces of Whatman filter paper. One side of the dish was moistened with 1,5 ml of the treatment, while the opposite side of the dish was moistened with 1.5 ml of distilled water. Dishes were prepared in this way for each of the treatments (AE=36/treatment), All treatments were equally represented and randomly positioned in a 7 x 8 field of test dishes for each trial. 

Fig. 5.3(a) Post-synaptic responses of Salamander bulbar neurones to a single odour pulse (arrow), at nostril (from Kauer, 1991). 

The demonstration of this behavioural response to a male pheromone signal is significant because of the manner in which the pheromone was delivered. Most other vertebrate examples of reproductive pheromones involve reception via the olfactory system(s). In contrast, D. ocoee females received the pheromone via diffusion through the dorsal skin. We assume that the well developed superficial capillary system of these lungless salamanders is the route by which the male pheromone was transported to whatever target tissue(s) initiated responses that affected female reproductive behaviour. 

Chivers, D. P., Kiesecker, J. M., Anderson, M. T., and Wildy, B. A. R. (1996). Avoidance response of a terrestrial salamander Ambystoma macrodactylum) alarm cues. Journal of Chemical Ecology 22,1709-1716. 

Figure 2.3 Sensitivities of rods and cones of the mudpuppy (a large aquatic salamander) retina. The graph shows the intensity-response curves, which were measured intracellularly from the retina of a dissected eye. The response is shown as a fraction of the response at saturation. A fit to the data is also shown. Rods are approximately 25 times more sensitive than cones. (Reprinted with permission from Gordon L. Fain and John E. Dowling. Intracellular recordings from single rods and cones in the mudpuppy retina. Science, Vol. 180, pp. 1178-1181, June, Copyright 1973 AAAS).

Firestein S., Picco C. and Menini A. (1993) The relationship between stimulus and response in olfactory receptor cells of the tiger salamander. J. Physiol. (London) 468, 1-10. 

Chases LG (2008) The behavioral response of larval coastal giant salamanders, Dicamptodon tenebrosus, to chemical stimuli. MA Thesis. Humboldt State University, Biological Sciences... 

Monitoring the electrical activity of the nervous system does not appear to give results that accord with the behavior of conditioned animals. On the one hand, electrical responses are observed for volatile chemical stimuli that tiger salamanders apparently do not smell. On the other hand, no selective attenuation of their electrical responses takes place under conditions that reproducibly impair their behavioral responding to one odor but not to another. 

Arzt, A. H., Silver, W. L., Mason, J. R. Clark, L. 1986. "Olfactory Responses of Aquatic and Terrestrial Tiger Salamanders to Airborne and Waterborne Stimuli." Journal of Comparative Physiology A, 158 479-487. 

Dorries, K. M., White, J., Kauer, J. S. 1997. "Rapid Classical Conditioning of Odor Response in a Physiological Model for Olfactory Research, the Tiger Salamander." Chemical Senses, 22 277-286. 

Cinelli AR, Hamilton KA, Kauer JS. 1995. Salamander olfactory bulb neuronal activity observed by video rate, voltage-sensitive dye imaging. III. Spatial and temporal properties of responses evoked by odorant stimulation. J Neurophysiol 73 2053-2071. 

Responses of mitral cells to odors are typically complex during odor exposure, units may be initially excited then inhibited, inhibited then excited, or may exhibit more complex responses. The character of these responses may alter with odor concentration. Individual units may more reliably discriminate between odors if unit activity is recorded in relation to an artificial sniff cycle (Macrides and Chorover, 1972). Recent authors have emphasized the necessity of testing the response of each cell over a range of odor concentrations (Meredith, 1986 Harrison and Scott, 1986). Testing with several odors, each at several different concentrations, showed that a significant number of cells respond differently to at least two odors at all odor concentrations (Wellis et al. 1989). Similar results in the salamander led to the concept of concentration tuning of bulb units individual cells appeared to respond best to a particular concentration of each odorant (Kauer, 1974). 

Kauer, J.S. and Moulton, D.G. (1974) Responses of olfactory bulb neurons to odour stimulation of small nasal areas in the salamander. J. Physiol, 243, 717-737... 

Mackay-Sim, A., Shaman, P. and Moulton, D.G. (1982) Topographic coding of odor quality odorant-specific patterns of epithelial responsivity in the salamander, Ambystoma tigrinum. Anat. Embryo ., 170, 93-97. 

Johnson MS et al., Toxicological responses of red-backed salamanders Plethodon cinereus) to subchronic soil exposures of 2,4-dinitrotoluene. Environ. Pollut. 147, 604, 2007. 

Johnson MS et al., Toxicologic and histologic response of the terrestrial salamander Plethodon cinereus to soil exposures of l,3,5-trinitrohexahydro-l,3,5-triazine, Arch. Environ. Contam. Toxicol., 47, 496, 2004. 

Baylln, F. Temporal patterns and selectivity in the unitary responses of olfactory receptors in the tiger salamander to odor stimulation. J. Gen. Physiol., 1979, 74, 17-36. 

RESPONSES TO SEX- AND SPECIES-SPECIFIC CHEMICAL SIGNALS IN ALLOPATHIC AND SYMPATRIC SALAMANDER SPECIES... 

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