ИСТИНА

Species discrimination by odor cues is a key moment that determines choice of appropriate partner. It is well documented that animals prefer conspecific cues and such preference is formed as a result of early social experience. E.g., cross-fostering leads to an inversion of species-specific preference with pronounced interest to odors of foster species. However,some experimental data indicate that genetic relatedness may influence species preference. Thus, the question of the extent to which innate and acquired mechanisms can determine species preferences is still of interest. The use of interspecific hybrids and backcrosses as test subjects may provide an excellent opportunity to clarify the question, because we can manipulate by genotypes ratio and social experience as well. In this study Campbell’s hamsters (Phodopus campbelli, C) and Djungarian hamsters (Phodopus sungorus, S), interspecific hybrids obtained from direct (F1D) and reciprocal (F1R) crossing of parental species, four kinds of backcrosses (BC) and F2 were used as test subjects. Preference was scored in a set of two choice experiments where different combinations of urine odor of the same gender C, S and F1 donors were presented. In all experiments animals showed preference of urine odor from that category of subjects to that they were experienced with during postnatal ontogenesis. There was no any asymmetry in response to stimuli of not experienced category. The results indicate that early experience but not genetic relatedness of donors determines preference of social odors, and support an “odor image” hypothesis.