flower holds four long, whitish catkins, hanging in
fingerlike clusters. Research in Mexico showed that 48
animal species, including leaf- cutter ants, iguanas, birds,
and mammals, made direct use of Cecropia obtusifolia.
More than 30 bird species from 10 families,
including some North American migrants, have been
documented feeding on cecropia flowers or fruit
(plate 7- 21). Mammals from bats to monkeys eat the
fruit, and sloths gorge (in slow motion) on the leaves.
One North American migrant bird, the Worm- eating
Warbler (Helmitheros vermivorum), specializes in
searching for arthropod prey in dried leaf clusters,
often those of cecropias, which abound in Neotropical
forest and forest edge. Cecropia leaves are huge,
and curl when they drop, forming ideal habitat for
arthropods. This wood warbler is specialized to reach
deeply into the cave- like curled leaves (plates 7- 22–
23). On its breeding grounds it spends about 75% of its
time gleaning insects from live leaves.
The natural history of cecropia, as with all species, is a
series of evolutionary life history trade- offs. Cecropias
make a heavy investment in seeds— exhibiting high
fecundity— that are generally well dispersed. But the
seeds do not persist long in the soil and germinate only
in a gap with abundant sunlight. Should a gap occur,
the seeds germinate and the tree grows at a rapid rate.
It may attain canopy stature, though its persistence in
the canopy is usually of shorter duration than that of
many other species. Cecropias have obviously profited
from human activities, as cutting the forest provides
exactly the conditions it requires.
Ants (Azteca spp.) reside inside stems of some
cecropias. These ants feed on glycogen- rich structures
called Müllerian bodies (a form of extrafloral nectary)
produced at the leaf axils. More will be said of these
resident ants in chapter 11.
Kapok, Ceiba, or Silk- cotton Tree
One of the commonest, most widespread, and most
impressive Neotropical trees is the Kapok, Ceiba, or
Silk- cotton Tree (Ceiba pentandra, family Malvaceae,
formerly in Bombacaceae). Kapoks are sometimes left
standing when surrounding forest is felled (plate 7- 24).
The look of today’s tropics throughout much of Central
America is a cattle pasture watched over by a lone Kapok.
The Kapok is striking in appearance. From its
buttressed roots rises a smooth gray trunk often
ascending 50 m (165 ft) before spreading into a wide
flattened crown. Trees may surpass 60 m (about 200
ft) though such giants are rare. Leaves are compound,
with five to eight leaflets dangling like fingers from a
long stalk. The major branches radiate horizontally
from the trunk and are usually covered with epiphytes.
Many lianas typically adorn the tree.
Kapoks originated in the American tropics but
dispersed naturally to West Africa. They are grown
commercially (for the fiber accompanying the seeds)
in Southeast Asia as well, so today they are distributed
throughout the world’s tropics.
Ceibas require high light intensity to grow and are
most common along forest edges, riverbanks, and
disturbed areas. Like most successional trees, they exhibit
rapid growth, up to 3 m (nearly 10 ft) annually. They are
deciduous, dropping their leaves during the dry season.
When the trees are leafless, masses of epiphytes and vines
stand out dramatically, silhouetted against the sky.
Leaf drop precedes flowering, and thus the flowers are
well exposed to bats, their major pollinators. The five-
petaled flowers are white or pink, opening during early
evening. Their high visibility and sour odor probably
help attract the flying mammals. Cross- pollination is
facilitated by the opening of only a few flowers each
night, which means it takes two to three weeks for the
entire tree to complete its flowering. Flowers close in
the morning, but many insects, hummingbirds, and
mammals seeking nectar visit the remnant flowers. A
single Kapok may flower only every five to ten years,
but each tree is capable of producing 500 to 4,000 fruits,
each with approximately 200 or more seeds. A single
tree can therefore produce up to 800,000 seeds during
one year of flowering. Seeds are contained in oval fruits,Plate 7- 24. A single distant Kapok Tree is all that remains of a
once- forested landscape in Belize. Photo by John Kricher.110 chapter 7 if a tree falls . . . rain forest disturbance dynamics