Out of the Nest: Effects of Seed Treatment and Redispersal by Ants on Seed Predation

Science Center A154

Seed dispersal is one of the most well studied mutualisms between animals and plants. Myrmecochory, or seed dispersal by ants, is documented in over 11,000 plants and has been shown to confer numerous fitness advantages to plants. However, a recent study showed that for a keystone genus of seed-dispersing ants in eastern North America, Aphaenogaster, redispersal of the seeds nearby but outside of the ant nest is the dominant mode of dispersal. This calls into question some of the putative benefits of myrmecochory, namely the role of myrmecochory as an escape from seed predation. I evaluate the hypothesis that myrmecochory in eastern forests does provide an escape from predation through two modes of action: 1) elaiosome removal and 2) short-distance redispersal. I conducted a field experiment that simulated myrmecochory to evaluate whether ant-mediated escape from conspecifics and ant handling provide an escape from seed predation for the spring ephemerals Jeffersonia diphylla and Asarum canadense. I present evidence that myrmecochory provides different advantages to different plants: for J. diphylla seeds, elaiosome removal reduced seed predation, whereas for A. canadense, relocation away from conspecifics reduced seed predation.