Use of Marasmius neocrinis-equi rhizomorphs in the construction of towiri (Psarocolius decumanus) nests in the Brazilian Amazon rainforest

The birds called towiri by the Baniwa people include three species: Psarocolius decumanus Pallas, P. bifasciatus Spix, and P. viridis Statius Muller. These are known respectively as japu, japuguaçu and japu-verde in Portuguese, and as Crested Oropendola, Olive Oropendola and Green Oropendola in English. This study investigated the use of rhizomorphs in nests constructed by the P. decumanus. Females of this species build large, pocket-shaped nests that form colonies of 7–12 nests in tall trees. We examined P. decumanus nests collected from two localities in Manaus, and Psarocolius sp. from São Gabriel da Cachoeira in the Brazilian Amazon rainforest, and conducted phylogenetic analyses based on internal transcribed spacer sequences to identify the incorporated rhizomorphs, which belonged to Marasmius neocrinis-equi R.A Koch & Aime. This is the first report of this fungal species in Brazil. In addition, we discuss the role of Psarocolius spp. in the traditions of the indigenous Baniwa people and the observation of kite string in P. decumanus nests in an urban area of Manaus, Brazil.

Key words
Birds-fungi interaction; Japu; Horsehair fungus; Icteridae; Marasmiaceae; Oropendola