The Palatability of Freshly Fallen Forest Tree Leaves to Millipeds

Abstract

M\Iillipeds are quite widely distributed throughout the forests and cultivated lands of the Northeast, and they are of some importance in the decomposition of the forest floor and in the incorporation of organic matter into the upper soil layers. Romell ('35) has noted the importance of a large species, Fontaria trimaculata (Wood), in the formation of one type of mull and Heiberg and Chandler ('41) have indicated that millipeds are rather common in fine mull. The fact that mulls permit rapid infiltration of water thereby minimizing soil erosion is well known and the action of millipeds is, therefore, of importance not only from the standpoint of favorable forest growth but also from the standpoint of the conservation of the soil. This present study was conducted by the use of the common brown milliped, Dipioiulus londonensis caeruleocinctus (Wood),2 an European form, long established in the Eastern United States and Canada, and the aim of the study was to discover: (a) The time of year when millipeds are most active. (b) Which tree leaves are most desirable as food to millipeds. (c) How palatability of the leaves varies with soil type. (d) How palatability of the leaves varies with the amount of ash and calcium present. The importance of millipeds in the decomposition of the forest floor should not be over estimated. Millipeds, in general, probably do not devour more than one to five per cent of the forest floor except in isolated areas, and, no doubt, they are of less importance in this respect than are earthworms and minute insects. Nevertheless, the results of this study may be of value because it suggests a rather rapid laboratory method for studying the relative palatabilities of tree leaves to one species of forest floor inhabitant and shows how the palatability of several tree species of economic importance varies with the soil type. These data have practical application providing the hypothesis is made that the leaves which are most palatable to millipeds are also most palatable to the more numerous forest floor invertebrates. The close connection between the presence of mulls and certain forest trees, (Chandler, '39, '41), the prevalence of fauna in certain types of forest floor, and the likes and dislikes of earthworms, (Gast, '37), (Johnston, '36), would seem to furnish grounds for believing that this hypothesis is tenable.