Figure 8.21. Fruiting phenology of
Phytolacca rivinoides, Witheringia
meiantha, and W. coccoloboides at
Monteverde. Values given are for
the "average" individual of each
species, and error bars represent 1
standard error of the mean.
(Modified from Murray 1988)season (June-July), although some fruits can be found
in any month (Fig. 8.21). Fruiting of W. meiantha is
spread more evenly over the year. To determine the
extent to which fruiting phenology might be con-
strained by the timing of flowering, I examined the
temporal relationship between peak flowering and
fruit ripening within individual plants during the
first year. If the timing of fruit ripening is determined
wholly by the timing of flowering, then within-plant
ripening peaks should always follow flowering peaks
by the same amount of time. I determined the dates
of flowering and fruiting peaks in each census plant
and regressed dates of peak fruiting on dates of peak
flowering. Because W. meiantha and W. coccolo-
boides usually have two reproductive episodes per
year, I computed separate regressions for each of them.
In two cases (the early reproductive seasons of W.
meiantha and W. coccoloboides), fruiting phenology
followed flowering phenology closely. In P. rivinoides
and the late reproductive seasons of W. meiantha and
W. coccoloboides, plants that flowered later in the
season ripened their fruits faster than those that flow-
ered early. It is unlikely that fruiting phenology is
tightly constrained by flowering phenology.
To assess disperser abundance, I mist-netted in 14
plots including mature forest, building-phase treefall
gaps (sensu Whitmore 1975), and large artificial clear-
ings. Although at least 10 bird species are known to
take fruits of the three plant species (Wheelwright
et al. 1984), Black-faced Solitaires appeared to be the
primary dispersers of all three species in the MCFP.
They were the most commonly caught understory
frugivores and carried the most seeds (assessed from
analysis of fecal samples) of the three plant species.
However, solitaires migrate down the Caribbean slope
following the breeding season (Loiselle and Blake
1991), and are virtually absent from the Monteverde
area from late October through December (K. G.
Murray, pers. obs.; Fig. 8.22), when W. meiantha has
a minor fruiting peak.284 Plant-Animal Interactions