The Brazilian Atlantic rainforest harbours at least 129 non-volant mammal s
pecies. There is also a diverse and numerous epiphytic flora associated wit
h this Neotropical rainforest, including several species of Araceae. Nevert
heless, knowledge of the ecology of this group of plants and its interactio
n with animals is poor. In this study we investigated the interactions betw
een epiphytic aroids and arboreal mammals in the Atlantic forest. We carrie
d out the field work between November 1995 and June 1997 in the Parque Esta
dual Intervales, southeastern Brazil, a still well preserved forest area of
approximately 490 km(2). We analysed faecal samples from primates (Cebus a
pella and Brachyteles arachnoides), collected during observations in the fi
eld, and marsupials (Didelphis aurita, Micoureus demerarae, Gracilinanus mi
crotarsus), collected from animals captured monthly or bi-monthly in live-t
raps. We recorded 17 species of Araceae in the study area. The seeds of eig
ht species occurred in the faecal samples: Anthurium harrissi, Monstera ada
nsonii, Philodendron corcovadense, P. appendiculatum, P. exymium, P. crassi
nervium, P. obliquifolium, and Heteropsis oblongifolia. Aroids were present
in faecal samples of the primates during most of the year, with a mean mon
thly percentage of occurrence of about 56.2%. For marsupials, aroids also w
ere a seasonally important food source, as between November and June the me
an monthly percentage of occurrence in faecal samples was about 26.5%. Our
data indicate that aroids are an important food source for arboreal and sem
i-arboreal mammals and that these animals may play an important role as see
d dispersers of this group. Aroids and arboreal mammals appear to interact
more strongly in Atlantic forest than in other Neotropical forests.