COS 105-1
Signal diversification, fly associations and the relative importance of visual and odour cues for spore dispersal in Splachnaceae mosses
Nearly half of the 73 species of Splachnaceae mosses possess two noteworthy ecological features: 1) their leafy gametophytes grown on feces and occasionally other animal matter, and 2) their sporophytes are highly modified and produce odours to attract flies to disperse their sticky spores. Signal diversification, fly associations and the relative importance of visual and odour cues for spore dispersal was examined in the field by trapping flies on pure and mixed populations of Splachnum ampullaceum and S. pensylvanicum. Fly trapping data were analyzed using both non-metric multi-dimensional scaling and Permanova to explore treatment differences.
Results/Conclusions
Approximately 1,000 flies were trapped; 60% on populations having both visual and odour cues and 40% on populations having odour cues only. In populations having both visual and odour cues, single species populations attract relatively distinct fly faunas whereas mixed species assemblages attract a fauna intermediate but not significantly different to those trapped on each species individually. In populations in which there were only odour cues, single species populations attract similar fly faunas whereas, in mixed species assemblages, each species alone attracts a distinct fly fauna from the mixed assemblage. Results demonstrate that fly associations are sensitive to signal diversification among moss species and that both visual and olfactory signals are important in attracting flies.