Multisensory Logic of Infant-Directed Aggression by Males

Area of Science:

• Neuroscience
• Animal Behavior
• Chemical Ecology

Background:

• Newborn pups elicit parental care from adults but aggression in virgin males.
• Male aggression towards pups requires vomeronasal organ function.
• Specific infant cues triggering male aggression remain unidentified.

Purpose of the Study:

• To identify the specific infant cues that elicit aggressive responses in virgin male mice.
• To elucidate the vomeronasal receptors and pheromonal compounds involved in this aggressive behavior.

Main Methods:

• Developed a behavioral paradigm using reconstituted pup cues.
• Identified vomeronasal receptors activated by infant cues.
• Utilized genetic deletion to confirm receptor involvement in aggression.
• Employed biochemical fractionation to isolate pheromonal compounds.

Main Results:

• Discrete infant morphological features and salivary chemosignals robustly elicit male aggression.
• Seven vomeronasal receptors were identified, with Vmn2r65 and Vmn2r88 specifically implicated in aggression.
• Two pheromonal compounds, submandibular gland protein C and hemoglobins, were isolated.
• Identified cues and receptors were not exclusive to pups.

Conclusions:

• Infant-mediated aggression in virgin males involves recognition of physical traits and chemical cues.
• The sensory mechanisms underlying this aggression are not pup-specific.
• This study reveals complex chemosensory processing in male mouse aggression.