Skip to main content

Certain seed dispersers may benefit plants by depositing seeds in specific microsites favorable for survival or growth. This has been called "directed dispersal." We examine the effects of seed dispersal by ants on the demography of two seed cohorts of Corydalis aurea: one relocated to ant nests by undisturbed ant foragers, and a control cohort of equal numbers planted by hand in the vicinity of each nest. The ant-treated cohort produced 90% more offspring than the control cohort and had a higher finite rate of increase: a finite rate of increase of 2.83 per year versus a rate of 2.05 per year for the control. The higher rate for the ant-treated cohort was the result not of an increase in the fecundity of reproductive plants, which did not differ significantly from that of the control, but of a significant increase in survival to reproduction. The benefit to the ant-handled plants was determined by the specific end point of dispersal, not by the removal of seeds from the parent plant per se or the distance moved.