Results
We gathered information on 1,614 interactions between 34 primate
species, in six subfamilies and three families, and 960 plant species in
311 genera and 98 families across Neotropical rainforests. Primates were
the exclusive seed dispersers of 627 (65%) species (in 233 genera)
(Fig. 1). Birds overlapped 147 plant species with primates (in 80
genera), bats 48 (in 32 genera), ungulates 17 (in 16 genera), and small
mammals 9 (in nine genera). Finally, 112 plant species (in 68 genera)
were found to be dispersed by more than one vertebrate group plus
primates. The most exclusively primate-dispersed family was Sapotaceae
(70 species, or 5.5% of the total 1,273 species), followed by
Menispermaceae (22 species, or 5% of the 440 species), and Moraceae (44
species, or 3.7% of the 1,180 species) (Figure S6).
We detected a strong evidence of a coupled evolutionary history among
primates and plants based on seed dispersal interactions (R= 0.99,
p<0.001). The residual contribution to the overall magnitude
of the signal varied among interacting species.
Specialization or generalization of each plant and primate species
(quantified by the number of interaction partners) predicted the CS of
their interactions: the most interacting primates (those presenting
highest degrees) had the shortest residual distances, thus contributing
more to the CS (t = -8.76, p < 0.001). In turn, the most
interacting plants were those with the largest residual distances,
contributing less to the CS (t = 2.5, p = 0.01, Figure S7). Primate
functional traits (degree of frugivory: F = 4.65, p = 0.03; feeding
guild: F = 7405.30, p < 0.001), but not plant traits (fruit
length: F = 0.21, p = 0.65; seed diameter: F = 0.13, p = 0.72),
determined the magnitude of the influence of the interaction on the
overall CS.
At the continental scale, major frugivore primates (Ateles ,Lagothrix and Brachyteles ) and the frugivore-folivores
(Alouatta ) contributed more to the strength of the CS, followed
by the omnivores (Cebus andS a p ajus )
and frugivore-insectivores (Leontopithecus and Saguinus ).
On the other hand, mostly seed predators (Cacajao ,Chiropotes and Callicebus species) showed the largest
Procrustean residual values, with the smallest contribution to the
signal as expected (Fig. 2, Table S8.a and Figure S8.a, Tables S9).
The continental pattern was consistent when broken-down at the
regional/biome scale. We found a strong CS on primate-fruit interactions
in the Atlantic forest (R= 0.98, p< 0.001), the Amazon forest
(R= 0.99, p= 0.014), and in Mesoamerican forests (R= 0.98, p= 0.008).
The contribution by each primate feeding guild in Amazon followed the
continental pattern, while in the Atlantic Forest folivores contributed
slightly more than frugivores, and in the Mesoamerica omnivores had the
greatest contribution to CS (Fig. 3, Tables S8.b and Figure S8.b).