Male fire ant neurotransmitter precursors trigger reproductive development in females after mating

• Published in: Communications biology Vol. 4; no. 1; p. 1400
• Main Authors: Vander Meer, Robert K., Chinta, Satya P., Jones, Tappey H., O’Reilly, Erin E., Adams, Rachelle M. M.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 15-12-2021; Nature Publishing Group; Nature Portfolio
• Subjects: 631/45/607; 631/601/1466; 631/92/604; 82/58; Animal reproduction; Animals; Ants - physiology; Biology; Biomedical and Life Sciences; Female; Females; Hemolymph; Life Sciences; Male; Males; Mating; Neurotransmitter Agents - metabolism; Queen pheromone; Reproduction; Reproductive system; Sexual Behavior, Animal; Tyramine; Tyramine - analogs & derivatives; Tyramine - metabolism
• ISSN: 2399-3642; 2399-3642
• DOI: 10.1038/s42003-021-02921-5

Social insect queens have evolved mechanisms to prevent competition from their sexual daughters. For
Solenopsis invicta
, the fire ant, queens have evolved a primer pheromone that retards reproductive development in their winged reproductive daughters. If these daughters are removed from the influence of the queen, it takes about a week to start reproductive development; however, it starts almost immediately after mating. This dichotomy has been unsuccessfully investigated for several decades. Here we show that male fire ants produce tyramides, derivatives of the biogenic amine tyramine, in their reproductive system. Males transfer tyramides to winged females during mating, where the now newly mated queens enzymatically convert tyramides to tyramine. Tyramine floods the hemolymph, rapidly activating physiological processes associated with reproductive development. Tyramides have been found only in the large Myrmicinae ant sub-family (6,800 species), We suggest that the complex inhibition/disinhibition of reproductive development described here will be applicable to other members of this ant sub-family.
Vander Meer et al. investigate the mechanisms of male involvement in reproductive development in fire ant newly mated queens. The authors find that males produce tyramide compounds that, when transferred to females during mating, are converted to bioactive molecules that trigger wing loss, ovary development, and queen pheromone production.