Female mouse tears contain an anti-aggression pheromone

Area of Science:

• Neuroethology
• Chemical Ecology
• Mammalian Behavior

Background:

• Tear pheromones in mice and rats influence various social and sexual behaviors, including aggression, mating, and pregnancy block.
• While male and pup tears have defined roles, the behavioral effects of female tears on male conspecifics remain largely unexplored.
• Lacrimal secretions act as crucial chemical signals in intraspecific and interspecific communication.

Purpose of the Study:

• To investigate the behavioral effects of female mouse tears on male social and sexual interactions.
• To identify the nature and regulation of any active components within female lacrimal fluid.
• To explore the neural mechanisms underlying the observed behavioral modulations.

Main Methods:

• Collection and analysis of female lacrimal fluid from different mouse strains.
• Behavioral assays to assess the impact of female tears on inter-male aggression and copulatory behavior.
• Hormonal manipulation (ovariectomy) and estrous cycle monitoring to study regulatory factors.
• Electrophysiological recordings in the lateral habenula to examine neural activity modulation.

Main Results:

• Female lacrimal fluid contains a small, involatile factor that significantly reduces inter-male aggression.
• This factor promotes a switch from aggressive to copulatory behavior in male mice.
• Production of the active molecule is hormone-dependent (sensitive to ovariectomy) but not directly linked to the estrous cycle.
• The pheromone modulates neuronal activity in the lateral habenula, a key area for evaluating interaction valence.

Conclusions:

• Female mouse tears possess an 'anti-aggression pheromone' that alters male social and sexual behavior.
• This pheromonal signaling is under hormonal control, suggesting a link to reproductive status.
• The lateral habenula is a critical neural substrate mediating the effects of this female-derived pheromone on aggression and mating.