Submitted to: Mammali, International Journal of the Systematics, Biology, and Ecology of Mammals
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/30/2012
Publication Date: 5/8/2012
Publication URL: http://naldc.nal.usda.gov.d2.nal.usda.gov/download/54152/PDF
Citation: Morris, C.F., Mclean, D., Fuerst, E.P., Engleson, J.A., Burgos, F., Coburn, E. 2012. Some observations on the granivorous feeding behavior preferences of mice (Mus musculus L.). Mammali, International Journal of the Systematics, Biology, and Ecology of Mammals. 76:209-218. Interpretive Summary: The house mouse is one of the most successful and widespread mammals on earth. It is by nature an omnivore but has evolved and adapted to be a primary consumer of a wide range of seeds and cereal grains. The success of the house mouse is likely due to its adaptation to living in proximity and under some level of indirect protection by humans. As further intrigue, the commensal adaptation of the house mouse likely coincided with the establishment of sedentary agriculture in the Fertile Crescent and the cultivation and domestication of cereals some 10,000 years ago. Clearly, the evolutionary trajectories of mice, humans and the ‘fertile crescent’ cereal crops are inter-related. Our interest lies in the inter-generic through intra-specific differences among cereal grains, including the presence/absence, composition and adherence of hulls, grain color, texture, taste, and nutrition. In this report, we examine the feeding behaviour preferences of the house mouse in relation to various traits of wheat grains. Mice are by nature granivores, and in this study they readily consumed a variety of wheat grains that varied in kernel texture and color. In fact, mice preferred wheat grains over the laboratory feed pellets approximately four to one. Throughout the study there was a recurring theme that mice appeared to prefer a ‘mixed’ diet and never chose a single wheat type or food to the complete exclusion of another, regardless of degree of preference. Why the preference for wheat grains over pellets? Texture might play a role, but we were not able to test this. Similarly taste or olfactory cues could play a role.
Technical Abstract: The house mouse (Mus musculus L.) is a highly successful mammal worldwide, in part, due to its adaptive consumption of a wide range of seeds, especially those of the agricultural cereal crops. Preferences or avoidances of specific grain (kernel) attributes of wheat have not been fully characterized. The present study examined the granivorous feeding behaviour of mice in relationship to wheat kernel texture (hardness), bran color, and the presence/absence of hulls. Three wheat taxa were examined: Triticum aestivum ssp. aestivum L. (common bread wheat), T. aestivum ssp. spelta [L.] Thell.) (Spelt), and T. turgidum ssp. dicoccon [Schrank] Thell.) (Emmer). Wheat kernels were presented to individually-caged female mice solely or in paired contrasts (‘preference’ tests). There was a particularly strong (5 fold) preference for soft white wheat over hard red. Using Near Isogenic wheat lines, the preference was most highly associated with softer texture. This preference was also evidenced in Spelt (soft) vs. Emmer (very hard) comparisons, and non-vitreous (softer) vs. vitreous kernels drawn from the same hard red winter wheat grain lot. To develop a means of discriminating kernels of similar color and morphology, the use of a small dot of fluorescene, or red and blue ink to mark kernels was evaluated. An avoidance for fluorescene developed within a day, whereas red and blue ink showed no effect on consumption. For Spelt, hulls presented no deterrent to consumption, whereas in Emmer, the hulls significantly reduced consumption. In a number of trials, there was often observed a short lag in consumption patterns of new foods suggesting that learning was involved. Regardless of the factor evaluated, all grains were consumed at some level. Soft white wheat was preferred over pellets about 4 to 1. The results raise further questions about the ways mice evaluate grains and make consumption choices.