Meeting Abstract

92.2  Friday, Jan. 7  Differential Responses of Two Species of Spiny Mouse to Glucosinolates in Sweet Mignonette Fruits SAMUNI, M*; IZHAKI, I; DEARING, D.M; ARAD, Z; Technion, Haifa, Israel; Univ. of Haifa, Haifa, Israel; Univ. of Utah, Salt Lake City, Utah; Technion, Haifa, Israel michal.samuni@gmail.com

Mammals have evolved physiological and behavioral adaptations for feeding on plants with toxic compounds. The common spiny mouse (Acomys cahirinus) and the golden spiny mouse (Acomys russatus) are sympatric rodent species that feed on the fruits of sweet mignonette (Ochradenus baccatus) in arid regions in Israel. The fruits of O. baccatus contain glucosinolates (GLSs) that are activated when the enzyme myrosinase is released from the seeds during crushing. In this study we examined ecophysiological-behavioral aspects of Acomys consuming O. baccatus fruit. Observations on captive A. russatus coupled with field observations revealed that A. russatus eat whole fruit, pulp and seeds of O. baccatus; no whole seeds were found in the feces. In contrast, A. cahirinus eat the pulp and expel the seeds from their mouth undamaged. In fact, 77% of expelled seeds germinated. Handling time taken to consume fruit by A. cahirinus was 13 times longer than by A. russatus. Physiologically, A. russatus maintained body mass feeding on a diet containing 80% O. baccatus fruit, mashed to activate the GSLs, while A. cahirinus lost ~10% of its initial body mass within two days. The results suggest that: (a) A. russatus exhibits physiological adaptations to whole fruit consumption that are lacking in A. russatus; (b) A. russatus is an O. baccatus seed predator while the A. cahirinus is a seed disperser.