Passage of spores of the dung moss Tayloria callophylla (Splachnaceae) through an avian digestive tract—a novel mode of dispersal?

Abstract

The dispersal of reproductive material plays a key role in the ecology of plants. Dung mosses (Splachnaceae), have evolved to utilise insects to disperse spores to habitat sites consisting of dung or dead animals—a marked departure from the wind based spore dispersal seen in other mosses. However, adapting to insect dispersal likely precludes long distance airborne dispersal, and limits dispersal events to the movements of the spore bearing insect. However, there are several disjunct populations of these mosses, incompatible with insect dispersal, raising questions over the manner of their origin. Hypotheses put forward include the dispersal of the mosses to these sites by birds. Here, the possibility that insectivorous birds could internally transport spores is explored by feeding insects bearing spores to captive myna birds. We tested if the spores of the New Zealand dung moss, Tayloria callophylla, can survive gut passage. Ultimately 9 of 10 dung samples produced viable moss colonies after a period of 30 days, demonstrating the survival of the spores through an avian digestive tract. Our results provide evidence for a unique model of dispersal in dung mosses, where a spore bearing insect is eaten by a bird that eats insects transports the spores in its gut over a much greater distance than otherwise likely with the insect alone.