Effect of congeneric chemical signals of different ages on foraging response and food choice in the field by golden spiny mice (Acomys russatus)

The common spiny mice Acomys dimidiatus and golden spiny mice Acomys russat us coexist in the extreme warm and dry, parts of the Rift Valley in Israel. However, they are temporally segregated in that the former is nocturnal, w hereas the latter is diurnal. Daily rhythms of physiological and behavioral variables in A. russatus responded to semiochemical signals released by A. dimidiatus (in the urine and feces). Both species feed upon the same food items but at different times of the 24-hr cycle. The main aim of the presen t study was to test under field conditions the foraging response of A. russ atus to odors of different ages released by A. dimidiatus. Various feeding and, behavioral variables were compared in three groups of A. russatus. The results show that fresh semiochemical signals released by A. dimidiatus de crease the feeding efficiency and increase the rate of smelling from a dist ance in A. russatus. These results support the idea that temporal segregati on between the two coexisting species is at least partly through semiochemi cals present in the urine and feces.