This research was funded in part by a grant from the Ford Foundation to Earlham College, and from additional funds provided by the College
Insect-plant relationships, Ants -- Ecology, Seeds -- Dispersal
Two co—occurring deciduous forest myrmecochores, Asarum canadense and Jeffersonia diphylla, release their seeds at approximately the same time, and therefore potentially compete for ants as dispersers. Within a single woodlot, we placed seeds of both species inside a dense Jeffersonia population away from Asarum plants, inside a dense Asarum population away from Jeffersonia plants, and in a site where plants of neither species occurred. No preference was exhibited by ants where natural populations were absent. Preference at the other two sites was frequency dependent: ants preferred seeds of the introduced species. Species preferred by ants have higher seed and seedling survival because by being carried into ant nests they escape predation and avoid nutrient deficiency. Implications of frequency—dependent dispersal are discussed.
Brent H. Smith, Catherine E. deRivera, Cara Lin Bridgman, and John J. Woida 1989. Frequency-Dependent Seed Dispersal by Ants of Two Deciduous Forest Herbs. Ecology 70:1645–1648.