Scatter-hoarding by rodents is expected to benefit palm recruitment by allowing cached seeds to escape predation and to colonize new areas, but evidence that seedlings emerge from cached seeds is scarce. We aimed to assess to what extent seedling establishment of two palm species (Astrocaryum aculeatissimum and Attalea humilis) is favoured by seed caching by rodents in a large Atlantic Forest remnant. We mapped the location of conspecific seedlings within circular plots of 15-m radius around five adult individuals of each palm species, checking if seedlings established from dispersed (>2 m from parent palms) or non-dispersed seeds (0–2 m from parent palms), and from buried or unburied seeds. We found a total of 42 A. aculeatissimum seedlings and 16 A. humilis seedlings. Nearly all (98%) seedlings established from seeds dispersed away from parents (mainly located 10–15 m from parents), and 83% and 75% of seedlings of A. aculeatissimum and A. humilis, respectively, established from seeds buried in the soil. Results show that both palm species depend almost entirely on caching of seeds by rodents to establish seedlings. Our study suggests that checking for endocarps associated with established seedlings can accurately estimate the process behind seedling establishment, improving our understanding about the net outcome of seed caching for large-seeded palms.

Infestation rates by palm bruchid beetles (Bruchidae: Pachymerini) on Attalea palm seeds are so high that most endocarps remaining near parent trees contain larvae rather than endosperm a few months after the peak fruiting season. Vertebrates feeding on palm endocarp contents may therefore be feeding on animal rather than plant matter, and the timing of use of endocarps may be influenced by the presence of larvae rather than by background fruit availability. On Maracá Island Ecological Reserve, Roraima State, Brazil, white-lipped peccaries (Tayassu pecari), agoutis (Dasyprocta leporina) and squirrels (Sciurus igniventris) all fed on bruchid beetle larvae from Attalea maripa palm endocarps. Squirrels fed on both larvae and endosperm year-round in all habitat types; agoutis fed on both larvae and seeds only at times and at sites where alternate foods were not available; and white-lipped peccaries fed almost exclusively on bruchid larvae in high-palm-density habitats. Differences in timing and location of endocarp use by these species may provide an index of mammal community dynamics in neotropical forests.

The reproductive ecology of piassava palm (Attalea funifera Mart.) was investigated for 19 months in the Atlantic forests of eastern Brazil. Its breeding biology is characterized by the production of functionally female, male and bisexual inflorescences. Staminate sterility is positively correlated with number of pistillate flowers. Staminate and pistillate flowers are receptive at anthesis. Bagging tests for apomixis were negative. Although geitonogamy can occasionally occur, outcrossing predominates. Pollen is relatively dry, but wind pollination is not a significant factor in cross pollination. Although inflorescences are visited by large numbers of insects, pollination is effected mainly by small sap beetles (Mystrops sp.) and weevils (Phyllotrox tatianae), which feed and breed in fertile staminate flowers. Pistillate flowers, which offer no reward to pollinators, appear to attract insect visitors by olfactory and visual imitation of staminate flowers, that is, via Bakerian mimicry. Flower production, fruit maturation, leaf production and leaf abscission occur continuously throughout the year. Flowering exhibits a distinct peak during the warmest months (Dec–Apr). Given its ubiquity throughout the region, A. funifera may well serve as a flowering and fruiting keystone species.