Large bees Flowers adapted for pollination by
large bees (principally Anthophorinae, Apinae, Xylo-
copinae, Colletidae, and Megachilidae) produce sweet
odors but are otherwise very diverse. Some are highly
specialized (including bilateral symmetry), corre-
sponding to the traits of particular bees. Nine percent
(196 species) of Monteverde's flora is pollinated prin-
cipally by large bees (Table 8.1). The majority of these
plants are vines, lianas, and herbs; some are trees
or shrubs (Frankie et al. 1983). Five plant families
(Fabaceae, Melastomataceae, Asteraceae, Malpighia-
ceae, and Convolvulaceae) include most species; 22
families are represented in all.
Small bees Flowers pollinated by small bees
(Apidae, especially Apinae and Halictidae) also tend
to produce sweet odors and to be diverse in other
traits. The flowers are small and not brightly colored
and may be visited by other small insects (Bawa 1994).
This pollination system is common in Monteverde
(Table 8.1); the 258 Monteverde plant species polli-
nated by small bees are in 31 families, with the ma-
jority in the Melastomataceae, Myrtaceae, Fabaceae,
Arecaceae, and Asteraceae. In contrast to "large bee
plants," the majority of species are trees and shrubs.
Other bees Bee pollination is documented for 295
plant Monteverde species (in 39 families), more than
14% of the flora (Table 8.1). It refers to bee-adapted
flowers that have not yet been observed sufficiently
to be designated more specifically. The majority of
these species are in the Rubiaceae, Solanaceae, or
Passifloraceae. Most are shrubs, herbs, and trees.
Small Diverse Insects Many Monteverde plant
species have "generalized" flowers; they are visited
by a wide variety of small insects, including small
bees and wasps, beetles, flies, and butterflies that are
able to reach pollen and nectar (Bawa et al. 1985). The
small, open, pale-colored flowers are sometimes ar-
ranged together to form a flat "landing platform." In-
teractions among the small visitors may affect their
movement patterns and how they function as polli-
nators (Janzen 1983). This pollination category ac-
counts for over one-third (687) of Monteverde's plant
species, including nearly half of the large trees (Table
8.1); Ocotea tenera and other Lauraceae are examples
(Wheelwright 1985a). The majority of species with
such a pollination syndrome are trees, epiphytes, and
lianas.
Pollination by small diverse insects is important
in tropical montane forests (Bawa 1990), although
with further study, many plant species now included
in this pollination system may be found to be polli-
nated by a subset of the animals that visit their flow-
ers. Plants with diverse floral visitors should not be
assumed to be buffered from the human-caused deple-
tion of insect populations in tropical forests. The
pollination ecology of such plant species demands
attention (Bawa 1994).Specialized insect-pollination systems. Extremely spe-
cialized plant-pollinator mutualisms are rare but fa-
mous (Feinsinger 1983, Bawa 1990, Thompson 1994),
and Monteverde offers good opportunities for their
study. Euglossine bees (Janzen 1983) and their spe-
cialized orchid flowers have been studied elsewhere
(Schatz 1990, Proctor et al. 1996), but not in Monte-
verde, where many of the 450 orchid species are euglos-
sine pollinated (W. Haber, pers. comm.). Buzz polli-
nation, in which pollen is expelled by bees vibrating
the anthers, is also associated with highly specialized
flowers (Buchmann 1983). In Monteverde, it has been
noted in species of Solanaceae (Haber 1983b), Melasto-
mataceae, and Myrsinaceae, among others (W. Haber,
pers. comm.). Figs (Moraceae: Ficus spp.) and their
tiny host-specific pollinating wasps have been the
focus of a series of investigations in Monteverde (see
Bronstein, "Fig Pollination," pp. 271-273).Abiotic, rare, and absent pollination systems. Certain
pollination systems are either uncommon or unknown
in the neotropics or in Monteverde.
Wind Wind pollination is common in temperate
forest trees but uncommon in most tropical wet for-
ests (especially lowland rain forests) because condi-
tions are unsuitable to pollen delivery by wind: low-
density plant populations, year-round dense foliage,
and high humidity (Whitehead 1983). For Monte-
verde dicots, wind-pollination is characteristic of
only 83 wind pollinated species (in 15 families, half
in Urticaceae and Moraceae), which represent less
than 5% (103 species) of the dicot flora. Twenty-
three of the species are medium-large canopy trees,
and 15 are small trees (see sec. 8.1.2). Oak (Quercus
spp., Fagaceae) is a wind-pollinated genus familiar
to temperate biologists, and occurs high in the cloud
forest on wind-swept ridges. Another wind-pollinated
tree is the single Monteverde representative of the
Podocarpaceae. In contrast to the low incidence of
wind pollination in the dicot flora, 12% (101 species)
of Monteverde's monocot species are wind pollinated.
The species richness of two classically wind-polli-
nated monocot families (Poaceae and Cyperaceae;
Faegri and van der Pijl 1979) and some Juncaceae
drives this pattern. Most of these species occur in
more open habitats.
Nonflying mammals Pollination by mammals,
including marsupials, rodents, and primates (Janson
et al. 1981, Cunningham 1991, Kress et al. 1994, Proc-
tor et al. 1996), is known from many places in the
world. The one apparent Monteverde case occurs
when pollen is transferred by mice near the Continen-249 Plant-Animal Interactions