Seed dispersal of the hemiparasitic plant Thesium chinense by Tetramorium tsushimae and Pristomyrmex punctatus

摘要

Heterotrophic plants normally produce a vast number of dust-like seeds containing minimal energy reserves, which are usually wind dispersed. However, some heterotrophic species have evolved adaptive strategies to use zoochorous seed dispersal. Seed dispersal by ants, known as myrmecochory, is one of the most widespread animal dispersal systems and has been reported in a diverse range of plant taxa. However, the combination of myrmecochory and heterotrophy seems to be very rare. Here I report the discovery of myrmecochory in the hemiparasitic plant Thesium chinense by Tetramorium tsushimae and Pristomyrmex punctatus. Myrmecochory would be an advantageous dispersal system for T.chinense because its fruits are quickly transferred to the ants' nests, which provide a refuge from the seed predator Canthophorus niveimarginatus. Myrmecochory is also potentially beneficial for T.chinense, as the nests of these ants are frequently located close to poaceous plants, which are the preferred hosts.