In Japan, myrmecochory has been observed in at least 41 genera across 28 angiosperm families. However, ants have never been reported to transport seeds away directly from fruits located more than 1 m above the ground. In 2024, during an observation of vespicochory in Aristolochia kaempferi var. kaempferi, we documented a seed-dispersal behavior by a Formica ant that climbed the vine and transported a seed directly from a dehiscent capsule at a height of approximately 5 m. Although this was only observed once, it suggests that the seeds of A. kaempferi and its relatives might be actively dispersed by ants as well as vespid wasps. In this study, we observed dehisced capsules of A. kaempferi var. laevipes hanging approximately 1.5 m above the ground, along with the surrounding forest floor. Arboreal ants, Crematogaster matsumurai and semi-ground-dwelling ants, Camponotus obscuripes, removed seeds from the capsule and transported them. Seeds that fell to the ground were transported to the nest by other ant species, such as Aphaenogaster japonica and Formica japonica. These findings suggest that ant-mediated seed dispersal in A. kaempferi involves both primary myrmecochory, in which ants transport seeds directly from elevated capsules, and diplochory, where ants act as secondary dispersers for seeds that fall by gravity or are occasionally dropped by vespid wasps and other ants.
