Factors affecting selection of native seeds in two species of Australian desert rodents

The preferences for different species of native seeds by two species of Australian desert rodents, the sandy inland mouse,Pseudomys hermannsburgensis, and the spinifex hopping-mouseNotomys alexis, were investigated. In two sets of cafeteria trials providing low and high numbers of different seed species, both rodent species showed discrimination, preferentially consuming certain seed species, while avoiding others. In one of the two trials,P. hermannsburgensisselected seeds with the highest free water content, whileN. alexisshowed no clear mechanism of seed choice in either trial. It is suggested that although both species of rodents are omnivorous,P. hermannsburgensisrelies more on seeds than doesN. alexis, and is thus the more efficient seed harvester.