The Evolution of Tyramides in Male Fungus-Growing Ants (Formicidae: Myrmicinae: Attini: Attina)

Branched tyramides from males of the harvester ant, Pogonomyrmex badius

Tyramides are produced in microgram quantities by males of species in the large Myrmicine ant sub-family (> 7000 species). Tyramides are transferred to female sexuals during mating where a specific female sexual evolved enzyme hydrolyzes the tyramides to the biogenic amine, tyramine. Tyramine is a ligand for receptors that rapidly activate reproductive development in the newly mated queen-previously reproductively inhibited by the mother queen. Without this elaborate biogenic amine precursor and co-evolved female sexual derived tyramide hydrolase, the defenseless newly mated queen's worker production would be delayed by up to 6 days, which could be lethal to the new queen. This is one of possibly several ant species separation mechanisms evolved to maintain species integrity. Here we report two methyl-branched tyramides from harvester ant, Pogonomyrmex badius, males, including one highly branched tyramide not previously reported.