Current Research

Ants are a ubiquitous and dominant feature of the terrestrial landscape and often play vital roles in many ecological processes.  Specifically, ant-plant mutualisms are both common in nature and empirically well-studied.  Ants provide important services to plants (e.g. seed dispersal, protection from herbivores) and in return plants provide a wide array of resources to the ants (e.g. food, domatia).  The intensity of ant-plant mutualisms, including the number of participants and the benefits received, often vary across environmental gradients, such as elevation or fire frequency.  The wide-spread and amenable nature of ants and ant-plant mutualisms makes them an ideal model system to study mutualist interactions and community dynamics.

Myrmecochory (dispersal of seeds by ants) is an evolutionarily and ecologically common mutualism.  Most of the research on the costs and benefits of myrmecochory in North America assumes that ant-dispersed seeds are taken to, and left in, the ant nest.  Here, we show that seeds are often secondarily redispersed from the nest into the surrounding leaf litter.  Using a novel seed-tracking technique, we found that the keystone seed-dispersing ant, Aphaenogaster rudis, redispersed >90% of the seeds it took into its nest an average distance of 51.5 cm.  Redispersal increases the rate of population spread by 28% when incorporated into a model of population spread rate for a local myrmecochore, Hexastylis arifolia and nearly doubles expected dispersal distance away from the parent plant.  Our results suggest myrmecochory benefits plants in eastern North American forests by increasing the distance between the seed and parent plant and reducing competition among siblings.  Our study further supports the suggestion that myrmecochory evolved once plant populations spread into the forest and passive dispersal methods became ineffective, especially if dispersal distance is the primary benefit of myrmecochory.