Individual recognition mating preferences

The urine of the mouse is the source of estrus synchronization, pregnancy block, group and individual recognition, sexual attraction, aggregation, histocompatibility-related mating preference, fear and stress (293). 

Successful reproductive behavior relies on the ability to identify and approach appropriate mating partners within the environment. Critically, mate recognition requires identifying species and sex characteristics of possible mates. As in many mammalian species, rodents use odor cues as the primary mechanism for mate recognition (Johnston 1983). Thus, sexually mature rodents typically display strong behavioral preferences for conspecific odors from opposite-sex individuals compared to odors from the same-sex or heterospecific individuals (Johnston 1983). 

Species-specificity of chemicals and their role in reproductive isolation While there are general patterns in the chemical communication systems, there also seem to be species-specific differences. Some amphipod species appear unable to distinguish between mates and individuals of closely related species (Kolding 1986). Also in some isopod species, males pair with females from closely related species (e.g., Hargeby and Erlandsson 2006), which suggests that mate recognition via chemical cues is not (yet) fully developed. Possibly, selection on contact pheromones has been weak, because other life-history traits ensure reproductive isolation under natural conditions (e.g., size, habitat preference). 

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