Courtship Pheromone Use in a Model Urodele, the Mexican Axolotl (Ambystoma mexicanum)

Abstract

Sex pheromones have been shown to constitute a crucial aspect of salamander reproduction. Until now, courtship pheromones of Salamandridae and Plethodontidae have been intensively studied, but information on chemical communication in other urodelan families is essentially lacking. The axolotl (Ambystoma mexicanum, Ambystomatidae) has a courtship display that suggests a key role for chemical communication in the orchestration of its sexual behavior, but no sex pheromones have yet been characterized from this species. Here we combined whole transcriptome analyses of the male cloaca with proteomic analyses of water in which axolotls were allowed to court to show that male axolotls secrete multiple ca. 20 kDa glycosylated sodefrin precursor-like factor (SPF) proteins during courtship. In combination with phylogenetic analyses, our data show that the male cloaca essentially secretes a courtship-specific clade of SPF proteins that is orthologous to salamandrid courtship pheromones. In addition, we identified an SPF protein for which no orthologs have been described from other salamanders so far. Overall, our study advocates a central role for SPF proteins during the courtship display of axolotls and adds knowledge on pheromone use in a previously unexplored deep evolutionary branch of salamander evolution.

Exaptation as a Mechanism for Functional Reinforcement of an Animal Pheromone System

“…The oldest known vertebrate sex pheromone system is the ''sodefrin precursor-like factor'' (SPF) pheromone system, a series of proteins involved in the courtship process of many salamander families (Plethodontidae, Ambystomatidae and Salamandridae) [9,[12][13][14][15][16][17]. In aquatically reproducing newts (Salamandridae), males display an underwater courtship dance in which they direct a stream of these water-soluble protein pheromones from their cloaca toward the female [18,19].…”

Interface Effects on Epilayer Surface Density of States by Scanning Tunneling Spectroscopy and Density Functional Theory

“…Silicides and silicon‐based materials have been at the heart of numerous studies; traditionally considered as metallic contacts, they have been considered more recently as plasmonic, photovoltaic, and thermoelectric materials, as well as for energy harvesting and magnetic applications . Though mostly employed as a contact material in electronic devices, recent studies of mesoscopic and nanometric nickel silicide structures have shed light on their other less known properties.…”

Imorin: a sexual attractiveness pheromone in female red-bellied newts (Cynops pyrrhogaster)

“…This peptide was named sodefrin and was both the first pheromone to be identified in an amphibian and the first peptide pheromone to be identified in a vertebrate. Since then, peptide and protein sex pheromones have been identified in several species of urodeles34567, including geographical variants8. However, these pheromones have only been found in males.…”