[Orienting-exploratory behavior: a comparative analysis of the synanthropic and wild-living forms of house mice of the superspecies complex Mus musculus s. lato]

Abstract

Studies of protein polymorphism, restriction of mitochondrial DNA and karyology revealed two large, divergent groups in Mus musculus s. lato. The first group includes the commensal forms M. m. musculus, M. m. domesticus, M. m. bactrianus and some others; the second group comprises the wild species M. spretus, M. abbotti, and M. spicilegus. M. domesticus and M. musculus are very flexible in terms of ecology and consist of obligatory commensal and outdoor populations. This study was aimed at comparative analysis of exploratory behavior in commensal and wild forms of Mus musculus s. lato in terms of phylogeny in Mus musculus s. l. and evolution of commensalism. Experiments in an enclosure measuring 4 x 4 x 1.5 m ("living room") showed nine patterns of exploratory behavior in eight forms of different commensal level (3 populations of musculus, 1 domesticus, 1 musculus x domesticus, 1 praetextus, 1 spretus, and 1 spicilegus). The searching behavior of the commensal and wild living forms differed both qualitatively and quantitatively. The commensal forms investigated the entire new territory, including high objects, while the wild forms investigated mostly the floor area of the enclosure. Significant species-specific and ecological differences were found by analysis of variance (ANOVA). Three functions were obtained by discriminant analysis. This demonstrated that the vertical activity and method of making contact with new objects are different in commensal and wild forms. Exploratory behavior is very similar in wild species and wild forms of musculus. Commensal forms are more active and have a high motor activity. The "commensal" phenotype of exploratory behavior is more expressed in M. m. domesticus. Three hypotheses of the evolutionary development of the "commensal" exploratory phenotype are discussed.