Animal-fed plants: an investigation into the uptake of ant-derived nutrients by the far-eastern epiphytic fern Lecanopteris Reinw. (Polypodiaceae)

The epiphytic fern genus Lecanopteris (Polypodiaceae) is regularly inhabited by five species of Iridomyrmex and Crematogaster, which nest and deposit debris in the hollow rhizomes. These epiphytes gain nutrients from ants in two ways: by root absorption from carton runways which surround plants, and by uptake of solutes from ant faeces and debris through the inner rhizome walls. The rhizome cavity surface is black, minutely pitted and bears no specialized absorptive structures. Nutrients containing 14-glucose, 86-rubidium and 32-phosphorus injected into the rhizome cavity were translocated through the plant. Ants inhabiting Lecanopteris were fed glycine and urea containing 15-nitrogen, and this label was incorporated into the fern tissues. Thus ant-derived nutrients can be incorporated into Lecanopteris tissues. The ferns may gain other benefits from the ants such as defence against herbivores, nurture of juveniles or spore dispersal.