Seed fate in a population of Carex pilulifera L. : I. Seed dispersal and ant-seed mutualism.

Seed dispersal of the myrmecochorous Carex pilulifera (Cyperaceae) was studied in a wood land area in NE Zealand, Denmark. Nearly all seeds fell within a distance of 40 cm from the center of the parental plants. Ant dispersal of seeds was predominantly by Myrmica ruginodis. Data on foraging activity and seed transport into and out of the ant nest is presented. The resulting dispersal distances were between 0 and 1.4 m from Carex plants. It is suggested that the secondary relocation of seeds from the ant nest is of primary importance to the recruitment of seedlings. Formicarium experiments confirmed the myrmecochorous status of C. pilulifera, and demonstrated the function of the elaiosome and the attraction of fresh diaspores. Data on removal rates and ant activity is also presented and discussed. The study indicated that for a period the ant colony was nourished almost exclusively by C. pilulifera diaspores in the field. Information concerning M. ruginodis is presented, and the ant-seed mutualism is discussed.