A Candidate Vertebrate Pheromone, SPF, Increases Female Receptivity in a Salamander

Evolutionary shifts in courtship pheromone composition revealed by EST analysis of plethodontid salamander mental glands

“…Analysis using NH 2 -terminal protein sequencing, SDS-PAGE and HPLC revealed three structurally unrelated proteins that constitute the major components of the male courtship pheromones in these two species Houck et al, 2008b;Rollmann et al, 1999). The first pheromone that was isolated, Plethodontid Receptivity Factor (PRF), is related to the interleukin-6 family of cytokines and reduces the duration of courtship in P. shermani .…”

Mechanisms of action and co-optive evolution for hypervariable courtship pheromones in plethodontid salamanders.

“…represented ~33% of the total pheromone, and experimental application of SPF on female D. ocoee salamanders reduced courtship time [81]. In contrast to this relatively complex blend, analysis of the P. shermani pheromone extract revealed that >98% of the total pheromone included only three major protein components of 22 kDa, 19 kDa, and 7 kDa [69].…”

“…Desmognathes ocoee using scratching delivery) have been used to chemically characterize the three major pheromone components [69,81]. In P. shermani, ~85% of the total pheromone is comprised of two proteins: Plethodontid Receptivity Factor (PRF), a 22-kDa protein related to IL-6 cytokines, and Plethodontid Modulating Factor (PMF), a 7-kDa protein related to three-finger protein superfamily which includes snake neuroand cytotoxins, complement system regulators, and receptors in the plasminogen activation system [Chapter II].…”

“…inhibitors [81,97] [81,83,93] Molecular surveys of the expression of mRNAs for these three pheromone components across the plethodontid phylogeny demonstrate that while PMF and SPF are ubiquitously found in all plethodontid species, PRF is restricted to the four eastern Plethodon groups [95]. Relative stasis has been observed in many elements of the functional complex, such as mating behavior (tail straddling walk), morphology (mental gland), and delivery mode (scratching vs. olfactory); yet models of molecular evolution revealed that all three pheromone families display signatures of positive selection [96].…”

“…In the majority of species, males deliver non-volatile proteinaceous courtship pheromones using enlarged premaxillary teeth to "scratch" the female's dorsum [44]. A small gland on the male's chin (mental gland) secretes pheromones that are applied to the abraded area and presumably diffuse into the female's bloodstream, where they may freely diffuse and affect any number of target tissues [81]. Assuming a successful persuasion, the male and female salamander will enter into TSW, where a female straddles a male's undulating tail, and the two walk in unison for an extended period of minutes to hours ( Figure 1).…”