Pheromone female receptivity

The production of a female-influencing secretion from the chin gland of male Plethodontid salamander (P. jordani) points to a similar extension of function by the acquisition of female olfactory sensitivity to an intercellular signal protein. Female receptivity is enhanced by a male cytokine-like compound of the interleukin-6 family, in its released form. Rollman et al. (1999) note that pheromonal activity is a previously unrecognised function for cytokines. 

Rollmann S., Houck L. and Feldhoff R. (1999). Proteinaceous pheromone affecting female receptivity in a terrestrial salamander. Science 285, 1907-1909. 

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

Male D. ocoee Pheromone Increased Female Receptivity... 

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. 

Houck, L.D. and Reagan, N.L. (1990) male courtship pheromones increase female receptivity in a plethodontid salamander. Anim. Behav. 39, 729-734. 

Conspecific and heterospecific pheromone effects on female receptivity. Animal Behaviour 66,857-861. 

Fig. 3.5 When sponges are treated with ceramides and pheromones from receptive females, males of Erimacrus isenbeckii, Telmessus cheiragonus, and other species guard and attempt to copulate with the sponges. Drawing by Jorge A. Varela Ramos...

Delivery styles vary greatly among species of salamanders, yet the only function demonstrated for salamander courtship pheromones has been to increase female receptivity. The change in receptivity is inferred on the basis of reduced courtship time as a result of pheromone delivery. Reduced courtship time has been demonstrated quantitatively for two species of terrestrial plethodontid salamanders. In D. ocoee (the species using an injection mode of delivery), courtship time was shorter when a female was treated with a pheromone extract versus an inactive (saline) control solution (Houck Reagan, 1990). In the plethodontid R jordani, pairs in which the female was pre-treated with courtship pheromones escalated to advanced stages of courtship more quickly on average than did pairs in which the... 

Extracts from P. jordani courtship glands also contain a second prominent protein. This protein, Pj-10, is much smaller than Pj-22, and occurs in gland extracts in a consistent 2 1 stoichiometric ratio with Pj-22. Also, SDS-PAGE gels showed that Pj-22 and Pj-10 were not linked by disulfide bonds, and therefore might act independently. The consistent 2 1 ratio suggests a role for Pj-10, possibly at some stage in the production, if not the function, of courtship pheromones. Behavioral tests are planned that will examine the effects of a purified solution of Pj-10 on female receptivity. 

When delivery of glandular secretions was diminshed (expts. i and ii), a female tended not to respond to the male. These results support the contention that male courtship pheromones influence female receptivity in N. viridescens. Rogoff published only a brief abstract of his work, however, and the experimental investigation of courtship pheromones in N. viridescens has been continued only recently. Paul Watson (pers. comm.) has devised a new technique to occlude genial glands in N, viridescens. Using a two-step... 

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