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Mouse aggression and the intruder-familiarity effect: evidence for multiple-factor determination c57bl
Abstract:
Male house mice attack their familiar cagemates less than novel intruders-an effect often attributed to habituation of aggression toward odors emanating from the cagemate. This interpretation is overly simplistic in that the effects of familiarizing preexposure depend additionally upon two factors. One factor is the aggression-inhibiting odors emanating from the test male that are deposited onto the cagemate by cohabitation. Supporting evidence is that attack inhibition to the cagemate failed to generalize to noncohabiting same-strain intruders and that eliminating physical contact between subject and cagemate during preexposure prevented the usual postexposure decline in aggression. The second factor is nonolfactory social stimuli emanating from the cagemate during aggressive encounters. The same intruder odors that elicited aggression when placed on a socially active mouse elicited only investigation when placed on models. When subjects were preexposed to an intruder's odor while prevented from socially interacting with the intruder, this investigation subsequently declined while aggression paradoxically increased.
Insights
Male house mice show reduced aggression towards familiar cagemates due to habituation to their odors. This effect is influenced by aggression-inhibiting odors from cohabitation and non-olfactory social cues during encounters.
Area of Science:
- Ethology
- Animal Behavior
- Neuroscience
Background:
- Male house mice exhibit reduced aggression towards familiar cagemates compared to novel intruders.
- This phenomenon is commonly attributed to habituation to odors associated with cagemates.
Purpose of the Study:
- To investigate the simplistic interpretation of habituation to odors as the sole cause of reduced aggression.
- To explore the additional factors influencing aggression inhibition in male house mice.
Main Methods:
- Experiments involved preexposure of male mice to cagemates and intruders under varying conditions.
- Manipulations included eliminating physical contact, altering social interaction, and using models with intruder odors.
- Aggression and investigation behaviors were quantified in response to familiar and novel stimuli.
Main Results:
- Attack inhibition to cagemates did not generalize to non-cohabiting intruders.
- Preventing physical contact during preexposure abolished the usual decline in aggression.
- Intruder odors elicited investigation on models but aggression towards socially active mice; preexposure without social interaction paradoxically increased aggression.
Conclusions:
- Aggression inhibition in male house mice is more complex than simple olfactory habituation.
- Aggression-inhibiting odors deposited by cohabitation and non-olfactory social stimuli play crucial roles.
- The context of social interaction significantly modulates responses to olfactory cues.