Plethodontid receptivity factor

Fig. 3.2 Amphibian protein-chemosignalling PRF (plethodontid receptivity factor interleukin-6), broadcast from male salamander mental gland in the forward current produced by tail-fanning (after Arnold, 1997 Rollman, 1999).

The chemoreceptive mechanisms in amphibia are undoubtedly worthy of further analysis, not only for their own sake, but to provide clues as to the origination of advanced chemosignal systems. As noted above, a pheromonal signal from the mental gland acts as a courtship/ receptivity inducer. The plethodontid receptivity factor (PRF) (Chap. 3) despite its size (22 kD), seems to have been converted from its internal role as an inter-cellular cytokine, to an inter-individual coordinator of reproductive activity (Rollmann et al., 1999). Endocrine or... 

Courtship pheromones are not necessarily species specific. Pairs of the woodland salamander, Plethodon shermani, courted for an equally long time (about 35 to 50 minutes) whether male pheromone from the mental gland of conspecifics or the allopatric species P. montanus or P. yonahlosscc was present, even though the composition of the proteinacous pheromones (plethodontid receptivity factor of these three species differ considerably (Rollmann et al, 2003). 

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