Salamander reproduction courtship

My goals in this paper are to review the role of courtship pheromone delivery in salamander reproduction, and to consider this behavior in terms of sexual selection. I first summarize breeding patterns of aquatic and terrestrial salamanders [since the timing and mode of delivery of these pheromones can be very different in an aquatic versus a terrestrial medium],... 

Evidence from these three levels—courtship observations, morphology and experimental courtship manipulations—is summarized below. Most information is available for salamanders in three families (Ambystoma-tidae, Salamandridae, and Plethodontidae) which account for the majority of salamander species living today. The information below is not intended to duplicate detailed reviews of salamander reproduction and courtship behavior (e.g., Arnold, 1972, 1976, 1977 Houck, 1977, 1982 Joly, 1966 Organ, 1961 Salthe, 1967). Instead, I focus on specific examples that highlight the diversity of modes with which males deliver courtship pheromones to females. 

Major sensory stimuli important to salamander reproduction can include visual stimuli (e.g., Himstedt, 1979 Malacarne and Curtassa, 1983 Verrell, 1982b), tactile stimuli, and olfactory stimuli other than courtship pheromones (Margolis, 1980 Roth, 1976). Moreover, the effects of any sensory signals on any animal can depend strongly on daily and seasonal changes in motivational states (Halliday, 1977 Halliday and Sweatman,... 

Arnold, S.J. (1977) The courtship behavior of North American salamanders with some comments on Old World salamandrids. In D. Taylor and S. Guttman (Eds.), The Reproductive Biology of Amphibians. Plenum Press, New York, pp. 141-183. 

Arnold, S.J. 1977. The evolution of courtship behavior in New World salamanders with some comments on Old World salamanders. In The Reproductive Biology of Amphibians (Ed. by D.H. Taylor S.I. Guttman), pp. 141—183. New York Plenum Press. 

Salamander courtship pheromones produced by male P. jordani share the basic characteristics of substances known to affect female reproductive behavior. The R jordani extract was comprised primarily of glycoproteins, including highly stable and non-volatile... 

Critical investigations are just beginning, but analyses of salamander courtship pheromones potentially can offer compelling insights at the population level into sources of individual variation in reproductive success. At another level, these pheromones are candidates for examining predictions of sexual selection theory. At either level, the taxonomic variety and evolutionary persistence of courtship pheromone delivery in salamanders is a testimony to the reproductive significance of these chemical signals. 

Because females were tested at the end of their courtship season and may not have been in reproductive condition, additional tests were performed in order to allow females to choose between male odors and no salamander odor. In these tests, females who can discriminate between species should prefer no salamander odor over male odor in either the conspecific or heterospecific male choice tests. Females of both species from the nonhybridizing locality preferred no salamander odor over conspecific male odors, suggesting that they are avoiding male conspecifics, and can discriminate between species odors. However, females of both species from the hybridizing locality randomly chose between male odor and no salamander odor (Dawley, in prep.). This suggests that these females probably cannot discriminate between species odors. 

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