Chemical cues associated with ant]mediated seed dispersal

Ant‐mediated seed dispersal has evolved multiple times in many regions around the world, affecting plant distributions through both primary and secondary dispersal. Most research investigating the chemical cues associated with ant‐mediated seed dispersal has focused on dispersal of myrmecochourous plants. Myrmecochorous plants have food bodies called elaiosomes attached to their seeds. Elaiosomes contain chemicals that ants cue in on and these signals may be more important than any nutritional benefits for eliciting seed removal. Seeds without elaiosomes can also be attractive to ants and this may be a form of chemically mediated manipulation by the plant to get ants to disperse seeds without providing a reward. To examine the chemical cues that play a role in seed dispersal, we field‐tested hexane and methanol extracts from seeds of neotropical pioneer tree species on Barro Colorado Island, Panama and seeds from herbaceous understory plant species in central Illinois. All four neotropical species studied lack elaiosomes, but three elicited a seed carrying response from ants. Illinois species with and without elaiosomes were used for comparison. We measured both removal and attempted removal rates of each seed and beads treated with their chemical extract by a common generalist ant species, Ectatomma ruidum in Panama, and common generalist seed dispersing ants in Illinois. By comparing the chemical profiles of the extracts deemed attractive based on ant behavior, we have begun to determine candidate chemicals cues involved in eliciting seed removal in both tropical and temperate climates.